© Semiconductor Components Industries, LLC, 2016
June, 2016 − Rev. 8 1Publication Order Number:
NCP1615/D
NCP1615
High Voltage High
Efficiency Power Factor
Correction Controller
The NCP1615 is a high voltage PFC controller designed to drive
PFC boost stages based on an innovative Current Controlled
Frequency Foldback (CCFF) method. In this mode, the circuit
operates in critical conduction mode (CrM) when the inductor current
exceeds a programmable value. When the current is below this preset
level, the NCP1615 linearly decays the frequency down to a minimum
of about 26 kHz at the sinusoidal zero−crossing. CCFF maximizes the
efficiency at both nominal and light load. In particular, the standby
losses are reduced to a minimum. Innovative circuitry allows near−
unity power factor even when the switching frequency is reduced.
The integrated high voltage start−up circuit eliminates the need for
external start−up components and consumes negligible power during
normal operation. Housed in a SOIC−14 or SOIC−16 package, the
NCP1615 incorporates the features necessary for robust and compact
PFC stages, with few external components.
General Features
•High Voltage Start−Up Circuit with Integrated Brownout Detection
•Input to Force Controller into Standby Mode
•Restart Pin Allows Adjustment of Bulk Voltage Hysteresis in
Standby Mode
•Skip Mode Near the Line Zero Crossing
•Fast Line / Load Transient Compensation
•Valley Switching for Improved Efficiency
•High Drive Capability: −500 mA/+800 mA
•Wide VCC Range: from 9.5 V to 28 V
•Input Voltage Range Detection
•Input X2 Capacitor Discharge Circuitry
•Power Saving Mode (PSM) Enables < 30 mW No−load
Power Consumption
•This is a Pb and Halogen Free Device
Safety Features
•Adjustable Bulk Undervoltage Detection (BUV)
•Soft Overvoltage Protection
•Line Overvoltage Protection
•Overcurrent Protection
•Open Pin Protection for FB and FOVP/BUV Pins
•Internal Thermal Shutdown
•Bi−Level Latch Input for OVP and OTP
•Bypass/Boost Diode Short Circuit Protection
•Open Ground Pin Protection
Typical Applications
•PC Power Supplies
•Off Line Appliances Requiring Power Factor Correction
•LED Drivers
•Flat TVs
PIN CONNECTIONS
HVFB
FB
Restart
FOVP/BUV
VControl
FFControl
Fault
STDBY
HV
VCC
DRV
GND
CS/ZCD
PFCOK
PSTimer
NCP1615 16 Pins (Top View) NCP1615 14 Pins (Top View)
FB
Restart
FOVP/BUV
VControl
FFControl
Fault
STDBY
HV
VCC
DRV
GND
CS/ZCD
PFCOK
SOIC−14 NB
CASE 751AN
MARKING DIAGRAMS
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See detailed ordering and shipping information in the package
dimensions section on page 6 of this data sheet.
ORDERING INFORMATION
1
14
NCP1615xxG
AWLYWW
1
14
NCP1615xx = Specific Device Code
xx = A, A1, B, C, C2, C3, C4, C5, D or D2
A = Assembly Location
WL = Wafer Lot
Y = Year
WW = Work Week
G = Pb−Free Package
SOIC−16 NB
CASE 752AC
1
16
1
16
NCP1615xxG
AWLYWW
NCP1615
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Figure 1. NCP1615C/D Typical Application Circuit
Figure 2. NCP1615A/B Typical Application Circuit
N1
L
N
Dhv2
Rhv2
L1
Dhv1
Rhv1
DRV
Rrestart2
Rrestart1
Cvcc
Ccomp2
Cbulk
BD1
BD2 BD3
BD4
Daux
Dbypass
Dboost
Rfb2
Lcm
Lboost
Mboost
Lin
F1
Rfb1
CX1
Rfovp/buv2
Rfovp/buv1
Rff
Rcomp1
Rzcd Rcs
Rgs
Rsense
Raux
Rdrv
Ccomp1
Cin1
Cin2
DRV
Standby
PFCok
L1
N1
RV1
Rfault
U1
NCP1615A/B
Control
FFcontrol
CS/ZCD STDBY
VCC
Restart
HV FB
FOVP/BUV
DRV
PFCok
GND
Fault
RX1
RX2
Vaux
Ext. Vcc
Vaux
Rpsm
N1
Cpsm
L
N
Dhv2
Rhv2
L1
Dhv1
Rhv1
DRV
PSM_Control
Rrestart2
Rrestart1
Cvcc
Ccomp2
Cbulk
BD1
BD2 BD3
BD4
Daux
Dbypass
Dboost
Rfb2
Lcm
Lboost
Mboost
Lin
F1
Rfb1
CX1
Rfovp/buv2
Rfovp/buv1
Rff
Rcomp1
Rzcd
Rcs
Rgs
Rsense
Raux
Rdrv
Ccomp1
Cin1
Cin2
DRV
Standby
PFCok
L1
N1
RV1
U1
NCP1615C/D
Control
FFcontrol
PStimer
CS/ZCD STDBY
VCC
Restart
HV FB
FOVP/BUV
DRV
PFCok
GND
HVFB
Fault
Rfault
Vaux
Ext. Vcc
Vaux
NCP1615
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Figure 3. NCP1615 Functional Block Diagram
Error
Amplifier
PFC_OK
Control
FB
StaticOVP
R
SQ
CLK GND
Clamp
DRV
Regulator
VREF
IREF
VDD
CS/ZCD
Current Limit
Comparator
ZCD
Comparator
Detection
of excessive
current
DRV
OCP
OverStress
ZCD
Current Information
Generator and
dead−time control
FFcontrol DT
CLK
OverStress
DRV ZCDLLline
PFCok
DRV
DRV
−
+STDBY
Standby
LEB
LEB
CENTRAL
LOGIC
Thermal
Shutdown
Restart
Line Removal
Detector
Brownout
Detector
Line Sense
Detector
LLine
Line Removal
BO_NOK
HV
FB Logic SoftOVP
UVP1
DRE
In_Regulation
DRE
Level
Shift
Vton
Processing
Circuitry
DT
SKIP
softOVP
Internal
Timing
Ramp
LLine
DRV
PWM
Comparator
Restart_OK
Standby
Lower
Clamp
Upper
Clamp
OFF
BO
OFF
BO
STOP
PWM
R
S
QIn_Regulation
PFC_OK Clear
PFCok
Driver
SKIP
OCP
staticOVP
STOP
OverStress
Line_OVP
PWM
Standby
Vton OFF
Vton OFF
PFC_OK Clear
PFC_OK
STDWN
UVP1
Enable PFC
Line OVP
Blank Delay Line_OVP
FOVP/
Restart_OK
+
−
Blanking
Delay
OVP
Comparator
−
+
+
−
OTP Comparator
−
+
Fault
Blanking
Delay
Delay Auto−Recovery
Control Auto−Recovery
Enable PFC
Auto−Recovery
Latch
Latch
Version C/DV ersion A/B Version B/DV ersion A/C
Enable PFC
HVFB
Power
Saving
Mode (PSM)
Detector
In PSM
In PSM
PStimer
In PSM
In PSM
Istart1
Istart2
BUV
VCC
VREGUL
VDD
IFault
VREGUL
ISENSE
ICC(discharge)
VCC(reset)
VCC(on)/VCC(off)
VFOVP
VBUV
ISENSE
VUVP2
VUVP3
Vrestart
IFOVP/UVP(bias)
IRestart(bias) VCC
Vstandby
VDD
VDD
VOCP
VZCD(rising)/
VZCD(falling)
tOVS(LEB)
tOCP(LEB)
toff1
VDD VDD
VPS_in/
VPS_out
VPSTimer2
ICS/ZCD2
ICS/ZCD1
IPSTimer2
IPSTimer1
VDD VDD
RFault(clamp)
VFault(clamp)
VFault(OTP)
tdelay(OVP)
VFault(OVP)
tdelay(OTP)
tblank(OTP)
IControl(BO)
IFB(bias)
VREF
Iboost(DRE)
Iboost(startup)
VDD
NCP1615
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Table 1. PIN FUNCTION DESCRIPTION
Pin Number
Name Function
NCP1615C/D NCP1615A/B
1 N/A HVFB High voltage PFC feedback input. An external resistor divider is used to sense the
PFC bulk voltage. The divider high side resistor chain from the PFC bulk voltage
connects to this pin. An internal high−voltage switch disconnects the high side
resistor chain from the low side resistor when the PFC is latched or in PSM in
order to reduce input power.
2 1 FB This pin receives a portion of the PFC output voltage for the regulation and the
dynamic response enhancer (DRE) that speeds up the loop response when the
output voltage drops below 95.5% of the regulation level. VFB is also the input
signal for the Soft−Overvoltage Comparators as well as the Undervoltage (UVP)
Comparator. The UVP Comparator prevents operation as long as VFB is lower
than 12% of the reference voltage (VREF). The Soft−Overvoltage Comparator
(Soft−OVP) gradually reduces the duty ratio to zero when VFB exceeds 105% of
VREF. A 250 nA sink current is built−in to trigger the UVP protection and disable
the part if the feedback pin is accidentally open. A dedicated comparator monitors
the bulk voltage and disables the controller if a line overvoltage fault is detected.
3 2 Restart This pin receives a portion of the PFC output voltage for determining the restart
level after entering standby mode.
4 3 FOVP/BUV Input terminal for the Fast Overvoltage (Fast−OVP) and Bulk Undervoltage (BUV)
Comparators. The circuit disables the driver if the VFOVP/BUV exceeds the VFOVP
threshold which is set 2% higher than the reference for the Soft−OVP comparator
monitoring the FB pin. This allows the both pins to receive the same portion of the
output voltage. The BUV Comparator trips when VFOVP/BUV falls below 76% of the
reference voltage. A BUV fault disables the driver and grounds the PFCOK pin.
The BUV function has no action whenever the PFCOK pin is in low state. Once
the downstream converter is enabled the BUV Comparator monitors the output
voltage to ensure it is high enough for proper operation of the downstream con-
verter. A 250 nA current pulls down the pin and disable the controller if the pin is
accidentally open.
5 4 Control The error amplifier output is available on this pin. The network connected between
this pin and ground sets the regulation loop bandwidth. It is typically set below 20
Hz to achieve high power factor ratios. This pin is grounded when the controller is
disabled. The voltage on this pin gradually increases during power up to achieve a
soft−start.
6 5 FFcontrol This pin sources a current representative to the line current. Connect a resistor
between this pin and GND to generate a voltage representative of the line current.
When this voltage exceeds the internal 2.5 V reference, the circuit operates in
critical conduction mode. If the pin voltage is below 2.5 V, a dead−time is gen-
erated that approximately equates [83 ms • (1 − (VFFcontrol/VREF))]. By this means,
the circuit increases the deadtime when the current is smaller and decreases the
deadtime as the current increases.
The circuit skips cycles whenever VFFcontrol is below 0.65 V to prevent the PFC
stage from operating near the line zero crossing where the power transfer is par-
ticularly inefficient. This does result in a slightly increased distortion of the current.
If superior power factor is required, offset the voltage on this pin by more than
0.75 V to inhibit skip operation.
7 6 Fault The controller enters fault mode if the voltage of this pin is pulled above or below
the fault thresholds. A precise pull up current source allows direct interface with an
NTC thermistor. Fault detection triggers a latch or auto−recovery depending on
device version.
8 7 STDBY This pin is used to force the controller into standby mode.
9 N/A PSTimer Power saving mode (PSM) timer adjust. A capacitor between this pin and GND,
CPSTimer, sets the delay time before the controller enters power saving mode.
Once the controller enters power saving mode the IC is disabled and the current
consumption is reduced to a maximum of 100 mA. The input filter capacitor dis-
charge function is available while in power saving mode. The device enters PSM if
the voltage on this pin exceeds the PSM threshold, VPS_in. A secondary side con-
troller optocoupler pulls down on the pin to prevent the controller from entering
PSM when the load is connected to the power supply. The controller is enabled
once VPSTimer drops below VPS_out.
10 8 PFCOK This pin is grounded until the PFC output has reached its nominal level. It is also
grounded if the controller detects a fault. The voltage on this pin is 5 V once the
controller reaches regulation.
NCP1615
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Table 1. PIN FUNCTION DESCRIPTION
Pin Number
FunctionName
NCP1615C/D FunctionName
NCP1615A/B
11 9 CS/ZCD This pin monitors the MOSFET current to limit its maximum current. This pin is
also connected to an internal comparator for zero current detection (ZCD). This
comparator is designed to monitor a signal from an auxiliary winding and to detect
the core reset when this voltage drops to zero. The auxiliary winding voltage is to
be applied through a diode to avoid altering the current sense information for the
on time (see application schematic).
12 10 GND Ground reference.
13 11 DRV MOSFET driver. The high current capability of the totem pole gate drive (−0.5/
+0.8 A) makes it suitable to effectively drive high gate charge power MOSFETs.
14 12 VCC Supply input. This pin is the positive supply of the IC. The circuit starts to operate
when VCC exceeds VCC(on). After start−up, the operating range is 9.5 V up to 28 V.
15 13 Removed for creepage distance.
16 14 HV This pin is the input for the line removal detection, line level detection, and
brownout detection circuits. For versions C and D, this pin is also the input for the
high voltage start−up circuit.
NCP1615
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Table 2. ORDERABLE PART OPTIONS
Part Number VCC
HV
Start−Up OTP Fault PSM VCC
Discharge Start−Up
Iboost Brownout Max
Dead−Time High Line
Threshold
NCP1615ADR2G 10.5 V No Latch No No No 100 Vdc 13 ms250 Vdc
NCP1615A1DR2G
(Notes 2, 3 & 4) 10.5 V No Latch No No No 100 Vdc 13 ms236 Vdc
NCP1615BDR2G 10.5 V No Auto−Recovery No No No 100 Vdc 13 ms250 Vdc
NCP1615CDR2G 17 V Yes Latch Yes Yes Yes 100 Vdc 13 ms250 Vdc
NCP1615C2DR2G 17 V Yes Latch Yes Yes Yes 87 Vdc 13 ms250 Vdc
NCP1615C3DR2G 17 V Yes Latch Yes Yes Yes 104 Vdc 38 ms257 Vdc
NCP1615C4DR2G
(Notes 1 & 4) 17 V Yes Latch Yes Yes Yes 100 Vdc 13 ms250 Vdc
NCP1615C5DR2G
(Notes 1, 2 & 4) 17 V Yes Latch Yes Yes Yes 100 Vdc 13 ms236 Vdc
NCP1615DDR2G 17 V Yes Auto−Recovery Yes Yes Yes 100 Vdc 13 ms250 Vdc
NCP1615D2DR2G 17 V Yes Auto−Recovery Yes Yes Yes 87 Vdc 13 ms250 Vdc
Table 3. ORDERING INFORMATION
Part Number Device Marking Package Shipping†
NCP1615ADR2G NCP1615A SOIC−14 NB, LESS PIN 13
(Pb−Free) 2500 / Tape & Reel
NCP1615A1DR2G (Notes 2, 3 & 4) NCP1615A1
NCP1615BDR2G NCP1615B
NCP1615CDR2G NCP1615C
SOIC−16 NB, LESS PIN 15
(Pb−Free) 2500 / Tape & Reel
NCP1615C2DR2G NCP1615C2
NCP1615C3DR2G NCP1615C3
NCP1615C4DR2G (Notes 1 & 4) NCP1615C4
NCP1615C5DR2G (Notes 1, 2 & 4) NCP1615C5
NCP1615DDR2G NCP1615D
NCP1615D2DR2G NCP1615D2
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
1. Versions C4 and C5 have increased values for ton(HL) and IDT2. Please refer to the electrical characteristics table for details.
2. For Versions A1 and C5, the line valley counter is replaced with a lockout timer .
3. For Version A1, X2 Discharge is disabled.
4. For Versions A1, C4 and C5, Line OVP is disabled.
NCP1615
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Table 4. MAXIMUM RATINGS (Notes 8 and 9)
Rating Pin Symbol Value Unit
High Voltage Start−Up Circuit Input V oltage HV VHV −0.3 to 700 V
High Voltage Feedback Input Voltage HVFB VHVFB −0.3 to 700 V
High Voltage Feedback Input Current HVFB IHVFB 0.5 mA
Zero Current Detection and Current Sense Input Voltage (Note 10) CS/ZCD VCS/ZCD −0.3 to VCS/ZCD(MAX) V
Zero Current Detection and Current Sense Input Current CS/ZCD ICS/ZCD +5 mA
Control Input Voltage (Note 11) Control VControl −0.3 to VControl(MAX) V
Supply Input Voltage VCC VCC(MAX) −0.3 to 28 V
Fault Input Voltage Fault VFault −0.3 to (VCC + 0.6) V
PSTimer Input Voltage PSTimer VPSTimer −0.3 to (VCC + 0.6) V
Driver Maximum Voltage (Note 12) DRV VDRV −0.3 to VDRV V
Driver Maximum Current DRV IDRV(SRC)
IDRV(SNK) 500
800 mA
Maximum Input Voltage (Note 13) Other Pins VMAX −0.3 to 7 V
Maximum Operating Junction Temperature TJ−40 to 150 °C
Storage Temperature Range TSTG –60 to 150 °C
Lead Temperature (Soldering, 10 s) TL(MAX) 300 °C
Moisture Sensitivity Level MSL 1 −
Power Dissipation (TA = 70°C, 1 Oz Cu, 0.155 Sq Inch Printed Circuit
Copper Clad)
Plastic Package SOIC−14NB/SOIC−16NB
PD
465
mW
Thermal Resistance, (Junction to Ambient 1 Oz Cu Printed Circuit
Copper Clad)
Plastic Package SOIC−14NB/SOIC−16NB RqJA
RqJC 172
68
°C/W
ESD Capability (Note 14)
Human Body Model per JEDEC Standard JESD22−A114E.
Machine Model per JEDEC Standard JESD22−A114E.
Charge Device Model per JEDEC Standard JESD22−C101E.
> 2000
> 200
> 500
V
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be af fected.
5. All references to Version A include V ersions A/A1, unless otherwise noted.
6. All references to Version C include Versions C/C2/C3, unless otherwise noted.
7. All references to Version D include Versions D/D2, unless otherwise noted.
8. This device contains Latch−Up protection and exceeds ± 100 mA per JEDEC Standard JESD78.
9. Low Conductivity Board. As mounted on 80 x 100 x 1.5 mm FR4 substrate with a single layer of 50 mm2 of 2 oz copper traces and heat
spreading area. As specified for a JEDEC51−1 conductivity test PCB. Test conditions were under natural convection of zero air flow.
10.VCS/ZCD(MAX) is the CS/ZCD pin positive clamp voltage.
11. VControl(MAX) is the Control pin positive clamp voltage.
12.When VCC exceeds the driver clamp voltage (VDRV(high)), VDRV is equal to VDRV(high). Otherwise, VDRV is equal to VCC.
13.When the voltage applied to these pins exceeds 5.5 V, they sink a current about equal to (Vpin − 5.5 V) / (4 kW). An applied voltage of 7 V
generates a sink current of approximately 0.375 mA.
14.Pins HV, HVFB are rated to the maximum voltage of the part, or 700 V.
NCP1615
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Table 5. ELECTRICAL CHARACTERISTICS (VCC = 15 V, VHV = 120 V, VFB = 2.4 V, RHVFB = 200 kW, VHVFB = 20 V, CVControl =
10 nF, VFFcontrol = 2.6 V, VZCD/CS = 0 V, RZCD/CS = 3 kW, VFOVPBUV = 2.4 V, VSTDBY = 1 V, VRestart = 1 V, VPSTimer = 0 V, VFault = open,
VPFCOK = open, CDRV = 1 nF, for typical values TJ = 25°C, for min/max values, TJ is −40°C to 125°C, unless otherwise noted)
Characteristics Conditions Symbol Min Typ Max Unit
START−UP AND SUPPLY CIRCUITS
Start−Up Threshold
A/B Version
C/D Version
VCC increasing VCC(on) 9.75
16.0 10.5
17.0 11.25
18.0
V
Minimum Operating Voltage VCC decreasing VCC(off) 8.5 9.0 9.5 V
VCC Hysteresis
A/B Version
C/D Version
VCC(on) − VCC(off) VCC(HYS) 1.0
7.0 1.5
8.0 –
–
V
Internal Latch / Logic Reset Level VCC decreasing VCC(reset) 7.3 7.8 8.3 V
Difference Between VCC(off) and VCC(reset) VCC(off) − VCC(reset) DVCC(reset) 0.5 – – V
Regulation Level in Power Saving Mode Version C/D VCC(PS_on) –11 – V
Transition from Istart1 to Istart2 (C/D Version) VCC increasing, IHV = 650 mAVCC(inhibit) – 0.8 – V
Start−Up Time (C/D Version) CVCC = 0.47 mF,
VCC = 0 V to VCC(on) tstart−up – – 2.5 ms
Inhibit Current Sourced from VCC Pin
(C/D Version) VCC = 0 V, VHV = 100 V Istart1 0.375 0.5 0.87 mA
Start−Up Current Sourced from VCC Pin
(C/D Version) VCC = VCC(on) – 0.5 V,
VHV = 100 V Istart2 6.5 12 16.5 mA
Start−Up Circuit Off−State Leakage Current VHV = 400 V
VHV = 700 V IHV(off1)
IHV(off2)
–
––
–30
50 mA
Minimum Voltage for Start−Up Circuit
Start−Up (C/D Version)
During PSM (C/D Version)
Istart2 = 6.5 mA,
VCC = VCC(on) – 0.5 V
Istart2 = 6.5 mA, VCC =
VCC(PS_on) – 0.5 V
VHV(MIN)
VHV(MIN_PSM)
–
–
–
–
38
30
V
Supply Current
In Power Saving Mode (C/D Version)
Latch
Before Start−Up (A/B Version)
Standby Mode
No Switching
Operating Current
VCC = VCC(PS_on)
VFault = 4 V
VCC = VCC(on) – 0.5 V
Vstandby = 0 V, VRestart = 3 V
VFB = 2.55 V
f = 50 kHz, CDRV = open,
VControl = 2.5 V, VFB = 2.45 V
ICC1
ICC2
ICC2b
ICC3
ICC4
ICC5
−
–
–
–
–
−
−
0.6
0.6
–
–
2.0
0.1
1.0
1.0
1.0
2.8
3.5
mA
LINE REMOVAL (ALL VERSIONS EXCEPT A1)
Line Voltage Removal Detection Timer tline(removal) 60 100 165 ms
Discharge Timer Duration tline(discharge) 21 32 60 ms
Discharge Current (C/D Version) VCC = VCC(off) + 200 mV
VCC = VCC(discharge) + 200 mV ICC(discharge) 20
10 25
16.5 30
30 mA
HV Discharge Level VHV(discharge) – – 40 V
VCC Discharge Level (C/D Version) VCC(discharge) 3.8 4.5 5.4 V
LINE DETECTION
High Line Level Detection Threshold
A/B/C/C2/C4/D/D2 Version
C3 Version
A1/C5 Version
VHV increasing Vlineselect(HL) 232
239
220
250
257
236
267
274
252
V
Low Line Level Detection Threshold
A/B/C/C2/C4/D/D2 Version
C3 Version
A1/C5 Version
VHV decreasing Vlineselect(LL) 220
227
207
236
243
222
252
259
237
V
NCP1615
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Table 5. ELECTRICAL CHARACTERISTICS (VCC = 15 V, VHV = 120 V, VFB = 2.4 V, RHVFB = 200 kW, VHVFB = 20 V, CVControl =
10 nF, VFFcontrol = 2.6 V, VZCD/CS = 0 V, RZCD/CS = 3 kW, VFOVPBUV = 2.4 V, VSTDBY = 1 V, VRestart = 1 V, VPSTimer = 0 V, VFault = open,
VPFCOK = open, CDRV = 1 nF, for typical values TJ = 25°C, for min/max values, TJ is −40°C to 125°C, unless otherwise noted)
Characteristics UnitMaxTypMinSymbolConditions
LINE DETECTION
Line Select Hysteresis VHV increasing Vlineselect(HYS) 10 – – V
High to Low Line Mode Selector Timer
A1/C5 Version
All Other Versions
VHV decreasing tline 20
43 25
54 30
65
ms
Low to High Line Mode Selector Timer VHV increasing tdelay(line) 200 300 400 ms
Line Valley Lockout Counter
(All versions except A1/C5) After tline expires nLL – 8 –
Line Level Lockout Timer
(A1/C5 Version Only) After tline expires tline(lockout) 120 150 180 ms
POWER SAVING MODE (C/D VERSION)
PSM Enable Threshold VPSTimer increasing VPS_in 3.325 3.500 3.675 V
PSM Disable Threshold VPSTimer decreasing VPS_out 0.45 0.50 0.55 V
PSTimer Pull Up Current Source VPSTimer = 0.9 V IPSTimer1 4.5 5.9 7.3 mA
PSTimer Fast Pull Up Current Source VPSTimer = 3.4 V IPSTimer2 800 1000 1200 mA
PSTimer Leakage Current VPSTimer = 4 V IPSTimer(bias) – – 100 nA
IPSTimer2 Enable Threshold VPSTimer2 0.95 1.00 1.05 V
Filter Delay Before Entering PSM VPSTimer > VPS_in tdelay(PS_in) – 40 − ms
Detection Delay Before Exiting PSM and
Turning On Start−Up Circuit VPSTimer < VPS_out tdelay(PS_out) – – 100 ms
PSTimer Discharge Current VPSTimer = VPSTimer(off) + 10 mV IPSTimer(DIS) 160 – – mA
PSTimer Discharge Turn Off Threshold VPSTimer decreasing VPSTimer(off) 0.05 0.10 0.15 V
PFC FB SWITCH (C/D VERSION)
PFC Off−State Leakage Current VPSTimer = 4 V, VHVFB = 500 V IHVFB(off) – 0.1 3 mA
PFC Feedback Switch On Resistance VHVFB = 2.75 V, IHVFB = 100 mARFBswitch(on) – – 10 kW
ON−TIME CONTROL
Maximum On T ime − Low Line VHV = 162.5 V,
VControl = VControl(MAX)
VHV = 162.5 V, VControl = 2.5 V ton(LL)
ton(LL)2 22
10.5 25
12.5 29
14.0
ms
Maximum On T ime − High Line
Versions C4 and C5
All Other Versions
VHV = 325 V,
VControl = VControl(MAX) ton(HL) 6.8
5.2 8.1
6.0 9.2
7.0
ms
Minimum On−Time VHV = 162 V
VHV = 325 V tonLL(MIN)
tonHL(MIN)
–
––
–200
100 ns
CURRENT SENSE
Current Limit Threshold VILIM 0.46 0.50 0.54 V
Leading Edge Blanking Duration tOCP(LEB) 100 200 350 ns
Current Limit Propagation Delay Step VCS/ZCD > VILIM to DRV
falling edge tOCP(delay) – 40 200 ns
Overstress Leading Edge Blanking Duration tOVS(LEB) 50 100 170 ns
Over Stress Detection Propagation Delay VCS/ZCD > VZCD(rising) to DRV
falling edge tOVS(delay) – 40 200 ns
REGULATION BLOCK
Reference Voltage TJ = 25°C
TJ = −40 to 125°CVREF
VREF 2.475
2.460 2.500
2.500 2.525
2.540 V
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Table 5. ELECTRICAL CHARACTERISTICS (VCC = 15 V, VHV = 120 V, VFB = 2.4 V, RHVFB = 200 kW, VHVFB = 20 V, CVControl =
10 nF, VFFcontrol = 2.6 V, VZCD/CS = 0 V, RZCD/CS = 3 kW, VFOVPBUV = 2.4 V, VSTDBY = 1 V, VRestart = 1 V, VPSTimer = 0 V, VFault = open,
VPFCOK = open, CDRV = 1 nF, for typical values TJ = 25°C, for min/max values, TJ is −40°C to 125°C, unless otherwise noted)
Characteristics UnitMaxTypMinSymbolConditions
REGULATION BLOCK
Error Amplifier Current Source
Sink VFB = 2.4 V, VVControl = 2 V
VFB = 2.6 V, VVControl = 2 V IEA(SRC)
IEA(SNK) 16
16 20
20 24
24 mA
Open Loop Error Amplifier Transconduc-
tance VFB = VREF +/− 100 mV gm180 210 245 mS
Maximum Control Voltage VFB = 2 V VControl(MAX) – 4.5 – V
Minimum Control Voltage VFB = 2.6 V VControl(MIN) – 0.5 – V
EA Output Control Voltage Range VControl(MAX) − VControl(MIN) DVControl 3.9 4.0 4.1 V
DRE Detect Threshold VFB decreasing VDRE – 2.388 – V
DRE Threshold Hysteresis VFB increasing VDRE(HYS) – – 25 mV
Ratio between the DRE Detect Threshold
and the Regulation Level VFB decreasing, VDRE / VREF KDRE 95.0 95.5 96.0 %
Control Pin Source Current During Start−Up
(C/D Version) PFCOK = Low, VVControl = 2 V IControl(start−up) 80 100 113 mA
EA Boost Current During Start−Up
(C/D Version) Iboost(start−up) – 80 – mA
Control Pin Source Current During DRE VVControl = 2 V IControl(DRE) 180 220 250 mA
EA Boost Current During DRE Iboost(DRE) – 200 – mA
PFC GATE DRIVE
Rise T ime (10−90%) VDRV from 10 to 90% of VDRV tDRV(rise) – 40 80 ns
Fall T ime (90−10%) 90 to 10% of VDRV tDRV(fall) – 20 60 ns
Source Current Capability VDRV = 0 V IDRV(SRC) − 500 − mA
Sink Current Capability VDRV = 12 V IDRV(SNK) − 800 − mA
High State Voltage VCC = VCC(off) + 0.2 V,
RDRV = 10 kW
VCC = 28 V, RDRV = 10 kW
VDRV(high1)
VDRV(high2)
8
10
–
12
–
14
V
Low Stage Voltage VSTDBY = 0 V VDRV(low) – – 0.25 V
ZERO CURRENT DETECTION
Zero Current Detection Threshold VCS/ZCD rising
VCS/ZCD falling VZCD(rising)
VZCD(falling)
675
200 750
250 825
300 mV
ZCD and Current Sense Ratio VZCD(rising)/VILIM KZCD/ILIM 1.4 1.5 1.6 –
Positive Clamp Voltage ICS/ZCD = 0.75 mA
ICS/ZCD = 5 mA VCS/ZCD(MAX1)
VCS/ZCD(MAX2) 7.1
15.4 7.4
15.8 7.8
16.1 V
CS/ZCD Input Bias Current VCS/ZCD = VZCD(rising)
VCS/ZCD = VZCD(falling)
ICS/ZCD(bias1)
ICS/ZCD(bias2)
0.5
0.5 –
–2.0
2.0 mA
ZCD Propagation Delay Measured from VCS/ZCD =
VZCD(falling) to DRV rising tZCD – 60 200 ns
Minimum detectable ZCD Pulse Width Measured from VZCD(rising) to
VZCD(falling) tSYNC –110 200 ns
Maximum Off −Time (Watchdog Timer) VCS/ZCD > VZCD(rising)
toff1
toff2
80
700 200
1000 320
1300 ms
Missing Valley Timeout Timer Measured after last ZCD transition ttout 20 30 50 ms
Pull−Up Current Source Detects open pin fault. ICS/ZCD1 – 1 – mA
Source Current for CS/ZCD Impedance
Testing Pulls up at the end of toff1 ICS/ZCD2 – 250 – mA
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Table 5. ELECTRICAL CHARACTERISTICS (VCC = 15 V, VHV = 120 V, VFB = 2.4 V, RHVFB = 200 kW, VHVFB = 20 V, CVControl =
10 nF, VFFcontrol = 2.6 V, VZCD/CS = 0 V, RZCD/CS = 3 kW, VFOVPBUV = 2.4 V, VSTDBY = 1 V, VRestart = 1 V, VPSTimer = 0 V, VFault = open,
VPFCOK = open, CDRV = 1 nF, for typical values TJ = 25°C, for min/max values, TJ is −40°C to 125°C, unless otherwise noted)
Characteristics UnitMaxTypMinSymbolConditions
CURRENT CONTROLLED FREQUENCY FOLDBACK
Minimum Dead Time VFFCntrol = 2.6 V tDT1 – – 0 ms
Median Dead Time
C3 Version
All Other Versions
VFFCntrol = 1.75 V tDT2 14
4.5 18
6.5 22
7.5
ms
Maximum Dead Time
C3 Version
All Other Versions
VFFCntrol = 1.0 V tDT3 32
11 38
13 44
15
ms
FFcontrol Pin Current − Low Line VHV = 162.5V, VControl = VControl(MAX) IDT1 180 200 220 mA
FFcontrol Pin Current − High Line
C4/C5 Version
All Other Versions
VHV = 325 V, VControl = VControl(MAX) IDT2 120
92 135
103 148
114
mA
FFcontrol Skip Level VFFCntrol = increasing
VFFCntrol = decreasing Vskip(out)
Vskip(in)
–
0.55 0.75
0.65 0.85
–V
FFcontrol Skip Hysteresis VSKIP(HYS) 50 – – mV
Minimum Operating Frequency fMIN – 26 – kHz
FEEDBACK OVER AND UNDERVOLTAGE PROTECTION
Soft−OVP to VREF Ratio VFB = increasing, VSOVP/VREF KSOVP/VREF 104 105 106 %
Soft−OVP Threshold VFB = increasing VSOVP – 2.625 – V
Soft−OVP Hysteresis VFB = decreasing VSOVP(HYS) 35 50 65 mV
Static OVP Minimum Duty Ratio VFB = 2.55 V, VControl = open DMIN – – 0 %
Undervoltage to VREF Ratio VFB = increasing, VUVP1/VREF KUVP1/VREF 8 12 16 %
Undervoltage Threshold VFB = decreasing VUVP1 – 300 – mV
Undervoltage to VREF Hysteresis Ratio VFB = increasing VUVP1(HYS) – – 25 mV
Feedback Input Sink Current VFB = VSOVP, HVFB = open
VFB = VUVP1, HVFB = open IFB(SNK1)
IFB(SNK2)
50
50 200
200 450
450 nA
FAST OVERVOLTAGE AND BULK UNDERVOLTAGE PROTECTION (FOVP and BUV)
Fast OVP Threshold VFOVP/BUV increasing VFOVP – 2.675 – V
Fast OVP Hysteresis VFOVP/BUV decreasing VFOVP(HYS) 15 30 60 mV
Ratio Between Fast and Soft OVP Levels KFOVP/SOVP = VFOVP/ VSOVP KFOVP/SOVP 101.5 102.0 102.5 %
Ratio Between Fast OVP and VREF KFOVP/VREF = VFOVP/ VREF KFOVP/VREF 106 107 108 %
Bulk Undervoltage Threshold VFOVP/BUV decreasing VBUV – 1.9 – V
Undervoltage Protection Threshold to VREF
Ratio VFOVP/BUV decreasing, VBUV/VREF KBUV/VREF 74 76 78 %
Open Pin Detection Threshold VFOVP/BUV decreasing VUVP2 0.2 0.3 0.4 V
Open Pin Detection Hysteresis VFOVP/BUV increasing VUVP2(HYS) − 10 − mV
Pull−Down Current Source VFOVP/BUV = VBUV
VFOVP/ BUV = VUVP2
IFOVP/BUV(bias1)
IFOVP/BUV(bias2)
50
50 200
200 450
450 nA
LINE OVP (ALL VERSIONS EXCEPT A1/C4/C5)
Ratio Between Line OVP and VREF VFB increasing KLOVP 111 112.5 114 %
Line Overvoltage Threshold VLOVP – 2.813 – V
Line Overvoltage Filter VFB increasing tLOVP(blank) 45 55 65 ms
STANDBY INPUT
Standby Input Threshold VSTDBY decreasing Vstandby 285 300 315 mV
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Table 5. ELECTRICAL CHARACTERISTICS (VCC = 15 V, VHV = 120 V, VFB = 2.4 V, RHVFB = 200 kW, VHVFB = 20 V, CVControl =
10 nF, VFFcontrol = 2.6 V, VZCD/CS = 0 V, RZCD/CS = 3 kW, VFOVPBUV = 2.4 V, VSTDBY = 1 V, VRestart = 1 V, VPSTimer = 0 V, VFault = open,
VPFCOK = open, CDRV = 1 nF, for typical values TJ = 25°C, for min/max values, TJ is −40°C to 125°C, unless otherwise noted)
Characteristics UnitMaxTypMinSymbolConditions
STANDBY INPUT
Standby Input Blanking Duration tblank(STDBY) 0.8 1 1.2 ms
RESTART
Restart Threshold Ratio VRestart/VREF Krestart 97.5 98.0 98.5 %
Restart Threshold Vrestart – 2.45 – V
Restart Input Pull Down Current VRestart = VUVP3 Irestart(bias) 50 200 450 nA
Open Pin Detection Threshold VUVP3 0.2 0.3 0.4 V
Open Pin Detection Hysteresis VUVP3(HYS) − 10 − mV
BROWNOUT DETECTION
System Start−Up Threshold
A/A1/B/C/C4/C5/D Version
C2/D2 Version
C3 Version (Note 15)
VHV increasing VBO(start) 102
86
106/110
111
95
115
118
102
121
V
System Shutdown Threshold
A/A1/B/C/C4/C5/D Version
C2/D2 Version
C3 Version (Note 16)
VHV decreasing VBO(stop) 92
78
95/99
100
87
104
108
94
110
V
Hysteresis
A/A1/B/C/C4/C5/D Version
C2/D2 Version
VHV increasing VBO(HYS) 7
511
8–
−
V
Brownout Detection Blanking Time VHV decreasing, delay from
VBO(stop) to drive disable tBO(stop) 43 54 65 ms
Control Pin Sink Current in Brownout tBO(stop) expires IControl(BO) 40 50 60 mA
FAULT INPUT
Overvoltage Protection (OVP) Threshold VFault increasing VFault(OVP) 2.79 3.00 3.21 V
Delay Before Fault Confirmation
Used for OVP Detection
Used for OTP Detection VFault increasing
VFault decreasing tdelay(OVP)
tdelay(OTP)
22.5
22.5 30.0
30.0 37.5
37.5
ms
Overtemperature Protection (OTP) Thresh-
old VFault decreasing VFault(OTP_in) 0.38 0.40 0.42 V
OTP Exiting Threshold (B/D Versions) VFault increasing VFault(OTP_out) 0.874 0.920 0.966 V
OTP Blanking Delay During Start−Up tblank(OTP) 4 5 6 ms
OTP Pull−Up Current Source VFault = VFault(OTP_in) + 0.2 V IFault(OTP) 43 46 49 mA
Fault Input Clamp Voltage VFault = open VFault(clamp) 1.15 1.7 2.25 V
Fault Input Clamp Series Resistor RFault(clamp) 1.32 1.55 1.78 kW
PFCOK SIGNAL
PFCOK Output Voltage IPFCOK = −5 mA VPFCOK 4.75 5.00 5.25 V
PFCOK Low State Output Voltage IPFCOK = 5 mA VPFCOK(low) – – 250 mV
THERMAL SHUTDOWN
Thermal Shutdown Temperature increasing TSHDN – 150 – °C
Thermal Shutdown Hysteresis Temperature decreasing TSHDN(HYS) – 50 – °C
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
15.Min value of 110 V corresponds to TJ = 0°C to 125°C, whereas Min value of 106 V corresponds to TJ = −40°C to 125°C.
16.Min value of 99 V corresponds to TJ = 0°C to 125°C, whereas Min value of 95 V corresponds to TJ = −40°C to 125°C.
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DETAILED OPERATING DESCRIPTION
INTRODUCTION
The NCP1615 is designed to optimize the efficiency of your
PFC stage throughout the load range. In addition, it
incorporates protection features for rugged operation. More
generally, the NCP1615 is ideal in systems where cost
effectiveness, reliability, low standby power and high
efficiency are the key requirements:
•Current Controlled Frequency Foldback: the NCP1615
operates in Current Controlled Frequency Foldback
(CCFF). In this mode, the circuit operates in classical
Critical conduction Mode (CrM) when the inductor
current exceeds a programmable value. When the
current falls below this preset level, the NCP1615
linearly reduces the operating frequency down to a
minimum of about 26 kHz when the input current
reaches zero. CCFF maximizes the efficiency at both
nominal and light load. In particular, standby losses are
reduced to a minimum. Similar to frequency clamped
CrM controllers, internal circuitry allows near−unity
power factor at lower output power.
•Skip Mode: to further optimize the efficiency, the
circuit skips cycles near the line zero crossing when the
current is very low. This is to avoid circuit operation
when the power transfer is particularly inefficient at the
cost of input current distortion. When superior power
factor is required, this function can be inhibited by
offsetting the FFcontrol pin by 0.75 V.
•Integrated High Voltage Start−Up Circuit (Versions C
and D): Eliminates the need of external start−up
components. It is also used to discharge the input filter
capacitors when the line is removed.
•Integrated X2 Capacitor Discharge: reduces input
power by eliminating external resistors for discharging
the input filter capacitor.
•PFCOK signal: the PFCOK pin is used to
disable/enable the downstream converter. This pin is
internally grounded when a fault is detected or when
the PFC output voltage is below its regulation level.
•Fast Line / Load Transient Compensation (Dynamic
Response Enhancer): since PFC stages exhibit low loop
bandwidth, abrupt changes in the load or input voltage
(e.g. at start−up) may cause an excessive over or
undervoltage condition. This circuit limits possible
deviations from the regulation level as follows:
♦The soft and fast Overvoltage Protections accurately
limit the PFC stage maximum output voltage.
♦The NCP1615 dramatically speeds up the regulation
loop when the output voltage falls below 95.5% of
its regulation level. This function is disabled during
power up to achieve a soft−start.
•Power Saving Mode: disables the controller and
reduces the input power consumption of the system
enabling very low input power applications.
•Standby Mode Input: allows the downstream converter
to inhibit the PFC drive pulses when the load is reduced.
•Safety Protections: the NCP1615 permanently monitors
the input and output voltages, the MOSFET current and
the die temperature to protect the system during fault
conditions making the PFC stage extremely robust and
reliable. In addition to the bulk overvoltage protection,
the NCP1615 include:
♦Maximum Current Limit: the circuit senses the
MOSFET current and turns off the power switch if
the maximum current limit is exceeded. In addition,
the circuit enters a low duty−ratio operation mode
when the current reaches 150% of the current limit
as a result of inductor saturation or a short of the
bypass/boost diode.
♦Undervoltage Protection (UVP): this circuit turns off
when it detects that the output voltage is below 12%
of the voltage reference (typically). This feature
protects the PFC stage if the ac line is too low or if
there is a failure in the feedback network (e.g., bad
connection).
♦Bulk Undervoltage Detection (BUV): the circuit
monitors the output voltage to detect when the PFC
stage cannot regulate the bulk voltage (BUV fault).
When the BUV fault is detected, the control pin is
gradually discharged followed by the grounding of
the PFCOK pin, to disable the downstream
converter.
♦Brownout Detection: the circuit detects low ac line
conditions and stops operation thus protecting the
PFC stage from excessive stress.
♦Thermal Shutdown: an internal thermal circuitry
disables the gate drive when the junction
temperature exceeds the thermal shutdown
threshold.
♦A latch fault input can be used to disable the
controller if a fault is detected (i.e. supply
overvoltage, overtemperature)
♦A line overvoltage circuit monitors the bulk voltage
and disables the controller if voltage exceeds the
overvoltage level.
•Output Stage Totem Pole Driver: the NCP1615
incorporates a 0.5 A source / 0.8 A sink gate driver to
efficiently drive most medium to high power
MOSFETs.
HIGH VOLTAGE START−UP CIRCUIT
Versions C and D of the NCP1615 integrate a high voltage
start−up circuit accessible by the HV pin. The start−up
circuit is rated at a maximum voltage of 700 V.
A start−up regulator consists of a constant current source
that supplies current from a high voltage rail to the supply
capacitor on the VCC pin (CVCC). The start−up circuit
current (Istart2) is typically 12 mA. Istart2 is disabled if the
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VCC pin is below VCC(inhibit). In this condition the start−up
current is reduced to Istart1, typically 0.5 mA. The internal
high voltage start−up circuit eliminates the need for external
start−up components. In addition, this regulator reduces no
load power and increase the system efficiency as it uses
negligible power in the normal operation mode
Once CVCC is charged to the start−up threshold, VCC(on),
typically 17 V (10.5 V for versions A and B), the start−up
regulator is disabled and the controller is enabled. The
start−up regulator remains disabled until VCC falls below the
lower supply threshold, VCC(off), typically 9.0 V, is reached.
Once reached, the PFC controller is disabled reducing the
bias current consumption of the IC.
The controller is disabled once a fault is detected. The
controller will restart next time VCC reaches VCC(on) or after
all non−latching faults are removed.
The supply capacitor provides power to the controller
during power up. The capacitor must be sized such that a
VCC voltage greater than VCC(off) is maintained while the
auxiliary supply voltage is building up. Otherwise, VCC will
collapse and the controller will turn off. The operating IC
bias current, ICC5, and gate charge load at the drive outputs
must be considered to correctly size CVCC. The increase in
current consumption due to external gate charge is
calculated using Equation 1.
ICC(gatecharge) +f@QG(eq. 1)
where f i s the operating frequency and QG is the gate char ge
of the external MOSFETs.
OPERATING MODE
The NCP1615 PFC controller achieves power factor
correction using the novel Current Controlled Frequency
Foldback (CCFF) topology. In CCFF the circuit operates in
the classical critical conduction mode (CrM) when the
inductor current exceeds a programmable value. Once the
current falls below this preset level, the frequency is linearly
reduced, reaching about 26 kHz when the current is zero.
Figure 4. CCFF Operation
As illustrated in the top waveform in Figure 4, at high
load, the boost stage operates in CrM. As the load decreases,
the controller operates in a controlled frequency
discontinuous mode.
Figure 5 details CCFF operation. A voltage representative
of the input current (“current information”) is generated. If
this signal is higher than a 2.5 V internal reference (named
“Dead−T ime Ramp Threshold”), there is no deadtime and
the circuit operates in CrM. If the current information signal
is lower than the 2.5 V threshold, deadtime is added. The
deadtime is the time necessary for the internal ramp to reach
2.5 V from the current information floor. Hence, the lower
the current information is, the longer the deadtime. When
the current information is 0.75 V, the deadtime is 15 ms.
To further reduce the losses, the MOSFET turn on is
further delayed until its drain−source voltage is at its valley.
As illustrated in Figure 5, the ramp is synchronized to the
drain−source ringing. If the ramp exceeds the 2.5 V
threshold while the drain−source voltage is below Vin, the
ramp is extended until it oscillates above Vin so that the drive
will turn on at the next valley.
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Figure 5. Dead−Time Generation
CURRENT INFORMATION GENERATION
The FFcontrol pin sources a current that is representative
of the input current. In practice, IFFcontrol is built by
multiplying the internal control signal (VREGUL, i.e., the
internal signal that controls the on time) by the internal sense
voltage (VSENSE) that is proportional to the input voltage
seen on the HV pin (see Figure 6).
The multiplier gain (Km of Figure 6) is four times less in
high line conditions (that is when the “LLine” signal from
the brownout block is in low state) so that IFFcontrol provides
a voltage representative of the input current across resistor
RFF placed between the FFcontrol pin and ground. The
FFcontrol vo l tage, VFFcontrol, is representative of the current
information. Figure 6. Generation of the Current Information in
the NCP1615
+
Multiplier
PFC_OK
Control
FFcontrol
SKIP
ISENSE IREGUL LLline
V to I
Converter IREGUL = K*V REGUL
Km*IREGUL*ISENSE
RAMP
SUM
Brown−out
and Line Range
Detection ISENSE
Vskip(in)/
Vskip(out)
HV
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SKIP MODE
As illustrated in Figure 6 the circuit also skips cycles near
the line zero crossing where the current is very low and
subsequently the voltage across RFF is low. A comparator
monitors VFFcontrol and inhibits the switching operation
when V FFcontrol falls below the skip level, Vskip(in), typically
0.65 V. Switching resumes when VFFcontrol exceeds the skip
exit threshold, Vskip(out), typically 0.75 V (100 mV
hysteresis). This function disables the driver to reduce
power dissipation when the power transfer is particularly
inefficient at the expense of slightly increased input current
distortion. When superior power factor is needed, this
function can be inhibited offsetting the FFcontrol pin by
0.75 V. The skip mode capability is disabled whenever the
PFC stage is not in nominal operation represented by the
PFCOK signal.
The circuit does not abruptly interrupt the switching when
VFFcontrol falls below Vskip(in). Instead, the signal VTON that
controls the on time is gradually decreased by grounding the
VREGUL signal applied to the VTON processing block shown
in Figure 11. Doing so, the on time smoothly decays to zero
in 3 to 4 switching periods typically. Figure 7 shows the
practical implementation of the FFcontrol circuitry.
Figure 7. CCFF Practical Implementation
200 us delay
(watchdog) S
R
Q
Vzcd(th)
DRV
DRV
S
R
Q
DRV
S
R
Q
DRV
TimeOut
delay
CLK
2.5 V
Zero Current Detection Dead−time (DT)
Detection
Ramp For DT Control
CS / ZCD
FFcontrol
Clock Generation
DT SUM
CCFF maximizes the efficiency at both nominal and light
load. In particular, the standby losses are reduced to a
minimum. Also, this method avoids that the system stalls or
jumps be tween drain voltage valleys. Instead, the circuit acts
so that the PFC stage transitions from the n valley to (n + 1)
valley or vice versa from the n valley to (n − 1) cleanly as
illustrated by Figure 8.
Figure 8. Valley Transitions Without Valley Jumping
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ON TIME MODULATION
Let’s analyze the ac line current absorbed by the PFC
boost stage. The initial inductor current at the beginning of
each switching cycle is always zero. The coil current ramps
up when the MOSFET is on. The slope is (Vin/L) where L
is the coil inductance. At the end of the on time period (t1),
the inductor starts to demagnetize. The inductor current
ramps down until it reaches zero. The duration of this phase
is (t2). In some cases, the system enters then the dead−time
(t3) that lasts until the next clock is generated.
One can show that the ac line current is given by:
Iin +Vinƪt1ǒt1)t2Ǔ
2TL ƫ(eq. 2)
Where T = ( t 1 + t2 + t3) is the switching period and Vin is the
ac line rectified voltage.
In light of this equation, we immediately note that Iin is
proportional to Vin if [t1*(t1 + t2)/T] is a constant.
Figure 9. PFC Boost Converter (left) and Inductor Current in DCM (right)
The NCP1615 operates in voltage mode. As portrayed by
Figure 10, t1 is controlled by the signal VTON generated by
the regulation block and an internal ramp as follows:
t1+Cramp @VTON
Ich (eq. 3)
The charge current is constant at a given input voltage (as
mentioned, it is four times higher at high line compared to
its value at low line). Cramp is an internal timing capacitor.
The output of the regulation block, VControl, is linearly
transformed into the signal VREGUL varying between 0 and
1.5 V. VREGUL is the voltage that is injected into the PWM
section t o modulate the MOSFET duty ratio. The NCP1615
includes circuitry that processes VREGUL to generate the
VTON signal that is used in the PWM section (see Figure 11).
It is modulated in response to the deadtime sensed during the
precedent current cycles, that is, for a proper shaping of the
ac line current. This modulation leads to:
VTON +T@VREGUL
t1)t2(eq. 4)
or
VTON @ǒt1)t2Ǔ
T+VREGUL
Given the low regulation bandwidth of the PFC systems,
VControl and thus VREGUL are slow varying signals. Hence,
the (Vton*(t1 + t2)/T) term is substantially constant.
Provided that during t1 it is proportional to VTON,
Equation 2 leads to:
Iin +k@Vin,
where k is a constant.
k+constant +ƪ1
2L @VREGUL
VREGUL(MAX) @ton(MAX)ƫ
Where ton(MAX) is the maximum on time obtained when
VREGUL is at its maximum level, VREGUL(MAX). The
parametric table shows that ton(MAX) is equal to 25 ms
(tON(LL)) at low line and to 6.3 ms (ton(HL)) at high line.
Hence, we can rewrite the above equation as follows:
Iin +
Vin @ton(LL)
2@L@VREGUL
VREGUL(MAX)
at low line.
Iin +
Vin @ton(HL)
2@L@VREGUL
VREGUL(MAX)
From these equations, we can deduce the expression of the
average input power at low line as shown below:
Pin(ave) +
Vin,rms 2@ton(LL) @VREGUL
2@L@VREGUL(MAX)
The input power at high line is shown below:
Pin(ave) +
Vin,rms 2@ton(HL) @VREGUL
2@L@VREGUL(MAX)
Hence, the maximum power that can be delivered by the
PFC stage at low line is given by equation below:
Pin(MAX) +
Vin,rms2@ton(LL)
2@L
The maximum power at high line is given by the equation
below:
Pin(MAX) +
Vin,rms2@ton(HL)
2@L
The input current is then proportional to the input voltage
resulting in a properly shaped ac line current.
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One can note that this analysis is also valid in CrM
operation. This condition is just a particular case of this
functioning where (t3 = 0), which leads to (t1 + t2 = T) and
(VTON = VREGUL). That is why the NCP1615 automatically
adapts to the conditions and transitions from DCM to CrM
(and vice versa) without power factor degradation and
without discontinuity in the power delivery.
Figure 10. PWM Circuit and Timing Diagram
PWM
Comparator
Turns off MOSFET
Vton
ramp voltage
PWM output
closed when
output low VTON
Cramp
Ich
Figure 11. VTON Processing Circuit
PWM
Comparator
to PWM latch
C1 S3
S1
S2
R1
OA1
STOP
OCP
DT
(high during
dead−time)
IN1
Internal timing
saw−tooth
VTON
VREGUL
−>VTON during (t1+t2)
−>0 V During t3 (dead−time)
−>VTON*(t1+t2)/T in average
The integrator OA1 amplifies the error be-
tween VREGUL and IN1 so that on average,
VTON*t1+t2)/T) equates VREGUL.
It is important to note that the “VTON processing circuit”
compensates for long interruption of the driver activity by
grounding the VTON signal as shown in Figure 11. Long
driver interruptions are represented by the STOP signal.
Such faults (excluding OCP) are BUV_fault, OVP,
BONOK, OverStress, SKIP, staticOVP, Fast−OVP,
RestartNOK and OFF mode. Otherwise, a long off time will
be interpreted as normal deadtime and the circuit would over
dimension VTON to compensate it. Grounding the VTON
signal leads to a short soft−start period due to ramp up of
VTON. This helps reduce the risk of acoustic noise.
VOLTAGE REFERENCE
A transconductance error amplifier regulates the PFC
output voltage, Vbulk, by comparing the PFC feedback
signal to an internal reference voltage, VREF. The feedback
signal is applied to the inverting input and the reference is
connected to the non−inverting input of the error amplifier.
A resistor divider scales down Vbulk to generate the PFC
feedback signal. VREF is trimmed during manufacturing to
achieve an accuracy of ± 2.4%.
REGULATION BLOCK AND LOW OUTPUT VOLTAGE
DETECTION
A transconductance error amplifier (OTA) with access to
the inverting input and output is provided. Access to the
inverting input is provided by the FB pin and the output is
accessible through the Control pin. The OTA features a
typical transconductance gain, gm, of 210 mS. The amplifier
source and sink currents, IEA(SRC) and IEA(SNK), are
typically 20 mA.
The output voltage of the PFC stage is typically scaled
down by a resistors divider and fed into the FB pin. The pin
input bias current is minimized (less than 500 nA) to allow
the use of a high impedance feedback network. At the same
time, the bias current is enough t o e ffectively ground the FB
if the pin is open or floating.
The output of the error amplifier is brought to the Control
pin for external loop compensation. The compensation
network on the Control pin is selected to filter the bulk
voltage ripple such that a constant control voltage is
maintained across the ac line cycle and provide adequate
phase boost. Typically a type 2 network is used, to set the
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regulation bandwidth below about 20 Hz and to provide a
decent phase boost.
The minimum control voltage, VControl(MIN) is typically
0.5 V and it is set by an internal diode drop or VF. maximum
control voltage, VControl(MAX) is typically 4.5 V. Therefore,
the V Control swing is 4 V. VControl is of fset down by a VF and
scaled down by a resistor divider before it connects to the
“VTON processing block” and the PWM section as shown in
Figure 12. The output of the regulation block is a signal
(“VREGUL” of the block diagram) that varies between 0 and
a maximum value corresponding to the maximum on−time.
Figure 12. Regulation Block Diagram (left) Correspondence Between Vcontrol and VREGUL (right)
VREGUL
VREGUL(MAX)
VControl
In_Regulation
VDD
VfVf+ 4 V
VUVP1
VSOVP
VDRE
0.5 V
StaticOVP
(0.5V bottom
clamp
is activated)
0.5V Bottom
Clamp
0.5 V
IFB(bias)
UVP2
SoftOVP
Error
Amplifier
+
−VREF
VDD
PFC_OK
Control
OFF
FB
+
−
VREGUL
4 V
DRE
Comparator
Soft−OVP
Comparator
UVP Comparator
Iboost(DRE)
ICONTROL(BO)
3R
R
Regulation
Detector
VFOVP fastOVP
Fast−OVP Comparator
VDD
Iboost(startup)
STOP
PFC_OK
BO_NOK
UVP
Given the low bandwidth of the regulation loop, abrupt
variations of the load, may result in excessive over or
undershoots.
The NCP1615 embeds a “dynamic response enhancer”
circuitry (DRE) that limits output voltage undershoots. An
internal comparator monitors the FB pin and if its voltage
falls below 95.5% of its nominal value, it enables a pull−up
current source, Iboost(DRE), to increase the Control voltage
by charging the compensation network and bring the system
into regulation. The total current sourced from the Control
Pin during DRE, IControl(DRE), is typically 220 mA. This
effectively appears as a 10x increase in the loop gain.
For versions A and B, Iboost(DRE) is disabled until the
PFCOK signal goes high. The slow and gradual charge of the
Control capacitor during power up softens the start−up
sequence effectively achieving a soft−start. For versions C
and D, a reduced current source, Iboost(start−up) (typically
80 mA), is enabled to speed up the start−up sequence and
achieve a faster start−up time. Iboost(start−up) is disabled when
faults (i.e. Brownout) are detected.
Voltage overshoots are limited by the Soft Overvoltage
Protection (SOVP) connected to the FB pin. The circuit
reduces the power delivery when the output voltage exceeds
105% of its desired level. The NCP1615 does not abruptly
interrupt the switching. Instead, the VTON signal that
controls the on time is gradually decreased by grounding the
VREGUL signal applied to the VTON processing block as
shown in Figure 11. Doing so, the on time smoothly decays
to zero in 3 to 4 cycles. If the output voltage keeps
increasing, the Fast Overvoltage Protection (FOVP)
comparator immediately disables the driver when the output
voltage exceeds 107% of its desired level.
The Undervoltage (UVP) Comparator monitors the FB
voltage and disables the PFC stage if the bulk voltage falls
below 1 2% of its r egulation level. Once a n undervoltage fault
is detected, the PFCOK signal goes low to disable the
downstream converter and the c ontrol c apacitor is g rounded.
The Bulk Undervoltage Comparator (BUV) monitors the
bulk voltage and disables the controller if the BUV voltage
falls below the BUV threshold. The BUV threshold is a ratio
of VREF and it is given by KBUV/VREF, typically 76% of
VREF. Once a BUV fault is detected the controller is disabled
and the PFCOK signal goes low. The Control capacitor is
slowly discharged until it falls below the skip level. The
discharge delay forces a minimum off time for the
downstream converter. Once the discharge phase is
complete the circuit may attempt to restart if VCC is above
VCC(on). Otherwise, it will restart at the next VCC(on). The
BUV fault is blanked while the PFCOK signal is low (i.e.
during start−up) to allow a correct start−up sequence.
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A dedicated comparator monitors the FB voltage to detect
the presence of a line overvoltage (LOVP) fault. The line
overvoltage threshold, VFB(LOVP), is typically 112.5%. A
timer , tLOVP(blank), t ypically 5 0 ms, b lanks t he l ine detect s ignal
to prevent false detection during line transients and surge.
Once a line OVP fault is detected the converter is latched.
Line OVP is disabled in Versions A1, C4 and C5.
The input to the Error Amplifier, the soft-OVP, line OVP,
UVP and DRE Comparators is the FB pin. The table below
shows the relationship between the nominal output voltage,
Vout(NOM), and the DRE, soft-OVP, Fast-OVP, line OVP and
UVP levels.
Parameter Symbol/Value
Nominal Output Voltage Vout(NOM)
DRE Threshold Vout(NOM)*95.5%
Soft−OVP Vout(NOM)*105%
UVP Vout(NOM)*12%
Fast−OVP Vout(NOM)*107%
Line−OVP Vout(NOM)*112.5%
CURRENT SENSE AND ZERO CURRENT DETECTION
The NCP1615 combines the PFC current sense and zero
current detectors (ZCD) in a single input terminal, CS/ZCD.
Figure 13 shows the circuit schematic of the current sense
and ZCD detectors.
Figure 13. PFC Current Sense and ZCD Detectors
Schematic
CS/ZCD
Current Limit
Comparator
VOCP
ZCD
Comparator
VZCD(rising)/
VZCD(falling)
VDD
LEB
tOVS(LEB)
Detection
of excessive
current
DRV
OCP
OverStress
ZCD
DRV
LEB
tOCP(LEB)
DRV
+
−
+
−
VDD
toff1
ICS/ZCD1
ICS/ZCD2
Current Sense
The PFC Switch current is sensed across a sense resistor,
Rsense, and the resulting voltage ramp is applied to the
CS/ZCD pin. The current signal is blanked by a leading edge
blanking (LEB) circuit. The blanking period eliminates the
leading edge spike and high frequency noise during the
switch turn−on event. The LEB period, tOCP(LEB), is
typically 200 ns. The Current Limit Comparator disables the
driver once the current sense signal exceeds the overcurrent
threshold, VOCP, typically 0.5 V.
PFC Zero Current Detection
The CS pin is also designed to receive a signal from an
auxiliary winding to detect the inductor demagnetization or
for zero current detection (ZCD). This winding is commonly
known as a zero crossing detector (ZCD) winding. This
winding provides a scaled version of the inductor voltage.
Figure 14 shows the ZCD winding arrangement.
Figure 14. ZCD Winding Implementation
CS/ZCD
+
PFC
Output
Voltage
−
+
Recitied
ac line
voltage
−
+
VZCD
−
RZCD1
RZCD2
RCS
PFC Inductor
Rsense
PFC Switch
DRV
DZCD
The ZCD winding voltage, VZCD, is positive while the
PFC Switch is off and the inductor current decays to zero.
VZCD drops to and rings around zero volts once the inductor
is demagnetized. The ZCD winding voltage is applied
through a diode, DZCD, to prevent this signal from distorting
the current sense information during the on time. Therefore,
the overcurrent protection is not impacted by the ZCD
sensing circuitry.
As illustrated in Figure 13, an internal ZCD Comparator
monitors the CS/ZCD voltage, VCS/ZCD. The start of the
demagnetization phase is detected (signal ZCD is high) once
VCS/ZCD exceeds the ZCD arming threshold, VZCD(rising),
typically 750 mV. This comparator is able to detect ZCD
pulses with a duration longer than 200 ns. When VCS/ZCD
drops below the lower or trigger ZCD threshold,
VZCD(falling), the end of the demagnetization phase is
detected and the driver goes high within 200 ns.
When a ZCD signal is not detected during start−up or
during the off time, an internal watchdog timer, toff1,
initiates the next drive pulse. The watchdog timer duration
is typically 200 ms. Once the watchdog timer expires the
circuit senses the impedance at the CS/ZCD pin to detect if
the pin is shorted and disable the controller. The CS/ZCD
external components must be selected to avoid false fault
detection. The recommended minimum impedance
connected to the CS/ZCD pin is 3.9 kW. Practically, RCS in
Figure 14 must be higher than 3.9 kW.
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POWER SAVING MODE
Versions C and D of the NCP1615 has a low current
consumption mode known as power saving mode (PSM).
The supply current consumption in this mode is below
100 mA. PSM operation is controlled by an external control
signal. This signal is typically generated on the secondary
side of the power supply and fed via an optocoupler.
The NCP1615 enters PSM in the absence of the control
signal. The control signal is applied to the PSTimer pin. The
block diagram is shown in Figure 15. Power saving mode
operating waveforms are shown in Figure 16.
The NCP1615 controller starts once VCC reaches VCC(on)
and no faults are present. The PST imer pin is held at ground
until the PFCOK signal goes high. This ensures the time to
enter PSM is always constant.
Once the PFCOK signal goes high, the current source on
the PSTimer pin, IPSTimer1, is enabled. IPSTimer1 is typically
5.9 mA. The current source charges the capacitor connected
from this pin to ground. Once VPSTimer reaches VPSTimer2 a
2nd current source, IPSTimer2, is enabled to speed up the
charge of CPSM. VPSTimer2 and IPSTimer2 are typically 1 V
and 1 mA, respectively. The controller enters PSM if the
voltage on this exceeds, VPS_in, typically 3.5 V. An external
optocoupler or switch needs to pull down on this pin before
its voltage reaches VPS_in to prevent entering PSM. IPSTimer
is disabled once the controller enters PSM. A resistor
between this pin and ground discharges the PSTimer
capacitor. The controller exits PSM once VPSTimer drops
below VPS_out, typically 0.5 V. At this time the start−up
circuit is enabled to charge VCC up to VCC(on). Once VCC
charges to VCC(on) the capacitor on the PSTimer pin is
discharged with an internal pull down transistor. The
transistor is disabled once the PFCOK signal goes high. Th e
time to enter PSM mode is calculated using Equations 3
through 7. The time to exit PSM mode is calculated using
Equation 8.
tPSM(in) +tPSM(in1) )tPSM(in2) (eq. 5)
tPSM(in1) [−RPSMCPSM @lnǒ1*VPSTimer2
IPSTimer1 *RPSMǓ
(eq. 6)
tPSM(in2) [−RPSMCPSM @lnǒ1*VPS_in *VPSTimer2
IPSTimer2 *RPSM Ǔ
(eq. 7)
tPSM(out) +−RPSMCPSM @lnǒVPS_out
VPS_in Ǔ(eq. 8)
During PSM, the start−up circuit on the HV pin maintains
VCC above VCC(off). The input filter capacitor discharge
circuitry continues operation in PSM. The supply voltage is
maintained in PSM by enabling the HV pin start−up circuit
once VCC falls below VCC(PS_on) (typically 11 V) and VHV
is at its minimum value as detected by the valley detection
circuitry. The start−up circuit current in PSM is increased t o
Istart2, typically 12 mA, to reduce the time the start−up circuit
is on and thus a lower voltage on the HV pin.
The start−up circuit is disabled once VCC exceeds
VCC(PS_on). A voltage offset is observed on VCC while the
start−up circuit is enabled due to the capacitor ESR. This
will cause the start−up circuit to turn off because VCC
exceeds V CC(PS_on). Internal circuitry prevents the start−up
circuit from turning on multiple times on the same ac line
half−cycle. The start−up circuit will turn on the next
half−cycle. Eventually, VCC will be regulated several
millivolts below VCC(PS_on). The offset is dependent on the
capacitor ESR.
This architecture enables the start−up circuit for the exact
amount of time needed to regulate VCC. This results in a
significant reduction in power dissipation because the
average input voltage during which the start−up circuit is on
is greatly reduced. Figure 16 shows operating waveforms
while in PSM.
Figure 15. NCP1615 Power Saving Mode Control Block Diagram
PSTimer
+
−
VPSTimer2
VDD
VDD
VPS_in/
VPS_out
+
−
Initial
Discharge
PSM
Control
CPSM
RPSM
In PSM Mode
Detector
IPSTimer1
IPSTimer2
In PSM
In PSM
PFCok
Power
Saving
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Figure 16. Power Saving Mode Operating Waveforms
Since the NCP1615 maintains the VCC pin at VCC(PS_on)
during PSM, the current consumption of the downstream
converter can have an undesirable impact to power
consumption. A simple mechanism to disconnect the supply
voltage to the downstream converter during PSM is shown
in Figure 17.
Figure 17. Downstream Converter Supply Removal
Circuit
PFCok
VCC VCC
Enable
PFC
Converter
Downstream
Converter
BYPASS/BOOST DIODE SHORT CIRCUIT AND
INRUSH CURRENT PROTECTION
It may be possible to turn on the MOSFET while a high
current flows through the inductor. Examples of this
condition include start−up when large inrush current is
present to charge the bulk capacitor. T raditionally, a bypass
diode is generally placed between the input and output
high−voltage rails to divert this inrush current. If this diode
is accidentally shorted or damaged, the MOSFET will
operate at a minimum on time but the current can be very
high causing a significant temperature increase.
The NCP1615 operates in a very low duty ratio to reduce
the MOSFET temperature and protect the system in this
“Over Stress” condition. This is achieved by disabling the
drive signal if the VZCD(rising) threshold is reached during
the MOSFET conduction time. In this condition, a latch is
set and the “OverStress” signal goes high. The driver is then
disabled for a period determined by the overstress watchdog
timer , t off2, typically 1 ms. This longer delay leads to a very
low duty−ratio operation to reduce the risk of overheating.
This operation also protects the system in the event of a boost
diode short.
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Figure 18. Current Sense and Zero Current Detection Blocks
VOCP
S
R
Q
DRV
OCP
OverStress
ZCD signal for valley
detection and CCFF
CS/ZCD
Rsense
DRV
Q1
D1
CBULK
CIN
Current Limit
Comparator
LEB
tOVS(LEB)
RCS
RZCD1
RZCD2
DZCD
Vin Vout
ACin ZCD
Comparator
VZCD(rising)/
VZCD(falling) Overstress
watchdog
timer (toff2)
LEB
tOCP(LEB)
PFCOK SIGNAL
The PFCOK pin provides a dedicated 5 V reference when
the PFC stage is in regulation. The pin is internally grounded
during the following conditions:
•During Start−Up: It remains low until the output
voltage achieves regulation and the voltage stabilizes at
the right level.
•Low Output Voltage: If the PFC stage output voltage is
below the bulk undervoltage (BUV_Fault) level, this is
indicative of a fault. The PFCOK signal then provides a
means to disable and protect the downstream converter.
•Brownout fault is detected (after discharge of control
capacitor).
•Low supply voltage: VCC falls below VCC(off).
•Feedback undervoltage fault.
•Fault condition: A fault detected through the Fault pin.
•Open FB pin.
•Thermal Shutdown.
•Line voltage removal.
The circuit schematic of the PFCOK block is shown
Figure 19.
Figure 19. PFCOK Circuit Schematic
PFC_OK
R
SQ
Dominant
Reset
Latch Q
PFCOK
OVLflag
OFF
BUV_fault
Line_OVP
In_Regulation
The PFCOK circuit monitors the current sourced by the
OT A. The OTA current reaches zero when the output voltage
has reached its nominal level. This is represented in the
block diagram by the “In_Regulation” Signal. The PFCOK
signal goes high when the current reaches zero or falls below
zero. The start−up phase is then complete and the PFCOK
signal goes high until a fault is detected.
Another signal considered before setting the PFCOK
signal is the BUV. The PFCOK signal will remain low until
the bulk voltage is above the undervoltage threshold. The
PFCOK signal will go low if the bulk voltage drops below
its undervoltage threshold.
BROWNOUT DETECTION
The HV pin provides access to the brownout and line
voltage detectors. It also provides access to the input filter
capacitor discharge circuit. The brownout detector detects
main interruptions and the line voltage detector determines
the presence of either 1 10 V or 220 V ac mains. Depending
on the detected input voltage range device parameters are
internally adjusted to optimize the system performance.
Line and neutral are diode “ORed” before connecting to
the HV pin as shown in Figure 20. The diodes prevent the
pin voltage from going below ground. A low value resistor
in series with the diodes can be used for protection. A low
value resistor is needed to reduce the voltage offset while
sensing the line voltage.
Figure 20. High−Voltage Input Connection
EMI
AC
IN
HV
Controller
FILTER
The controller is enabled once VHV is above the brownout
threshold, VBO(start), typically 111 V, and VCC reaches
VCC(on). Figure 21 shows typical power up waveforms.
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Figure 21. Start−Up Timing Diagram
A timer is enabled once VHV drops below its disable
threshold, VBO(stop), typically 100 V. The controller is
disabled if VHV doesn’t exceed VBO(stop) before the
brownout timer expires, tBO, typically 54 ms. The timer is
set long enough to ignore a single cycle dropout. The timer
ramp starts charging once VHV drops below VBO(stop).
Figure 22 shows brownout detector waveforms during line
dropout.
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Figure 22. Brownout Operation During Line Dropout
LINE RANGE DETECTOR
The input voltage range is detected based on the peak
voltage measured at the HV pin. The line range detection
circuit allows more optimal loop gain control for universal
(wide input mains) applications. Discrete values are selected
for the PFC stage gain (feedforward) depending on the input
voltage range.
The controller compares VHV to the high line select
threshold, Vlineselect(HL), typically 250 V. Once VHV
exceeds V lineselect(HL), the PFC stage operates in “high line”
(Europe/Asia) or “220 Vac” mode. In high line mode the
loop gain is divided by four, thus the internal PWM ramp
slope is four times steeper. For Versions C4 and C5, the gain
is divided by three, thus the ramp is three times steeper.
The default power−up mode of the controller is low line.
The controller switches to “high line” mode if VHV exceeds
the high line select threshold for longer than the low to high
line timer, tdelay(line), typically 300 ms as long as it was not
previously in high line mode. If the controller has switched
to “low line” mode, it is prevented from switching back to
“high line” mode until the valley detection circuit detects 8
valleys, even if tdelay(line) has expired. In Versions A1 and
C5, a lockout timer is started upon transitioning to “low line”
mode. Instead of counting valleys, transition to “high line”
mode is prevented until the lockout timer, tline(lockout)
(typically 150 ms), expires. The timer and logic is included
to prevent unwanted noise from toggling the operating line
level.
In “high line” mode the high to low line timer, tline,
(typically 25 m s for Versions A1/C5 and 54 ms for all other
versions) is enabled once VHV falls below Vlineselect(LL),
typically 236 V. It is reset if VHV exceeds Vlineselect(LL). The
controller switches back to “low line” mode if the high to
low line timer expires. Figures 23 and 24 show operating
waveforms of the line detector circuit. For Versions A1/C5,
Figure 25 shows the operation of the lockout timer.
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time
time
VHV
Low Line
Select
Timer
Operating
Mode
time
Transition to
High Line
Allowed?
Vlineselect(HL)
High Line
No Yes
Vlineselect(LL)
Low Line High Line
Low Line
Entered
Line Timer
Running
HL Transitions
Blanked by Lockout Timer
time
High Line
Lockout
Timer Lockout Timer
Running
Figure 25. Lockout Timer Operation (Versions A1/C5 Only)
OUTPUT DRIVE SECTION
The NCP1615 incorporates a large MOSFET driver. It is
a totem pole optimized to minimize the cross conduction
current during high frequency operation. It has a high drive
current capability (−500/+800 mA) allowing the controller
to effectively drive high gate charge power MOSFET.
The device maximum supply voltage, VCC(MAX), is 30 V.
Typical high voltage MOSFETs have a maximum gate
voltage rating of 20 V. The driver incorporates an active
voltage clamp to limit the gate voltage on the external
MOSFETs. The voltage clamp, VDRV(high), is typically 12 V
with a maximum limit of 14 V.
The gate driver is kept in a sinking mode whenever the
controller is disabled. This occurs when the Undervoltage
Lockout i s active or more generally whenever the controller
detects a fault and enters of f mode (i.e., when the “STDWN”
signal of the block diagram is high).
OFF MODE
The controller is disabled and in a low current mode if any
of the following faults are detected:
•Low supply input voltage. An undervoltage (or UVLO)
fault is detected if VCC falls below VCC(off).
•Thermal shutdown is activated due to high die
temperature.
•A brownout fault is detected.
•The controller enters skip mode (see block diagram)
•A bulk undervoltage fault is detected.
•The controller enters latch mode.
Generally speaking, the circuit turns off when the
conditions are not proper for desired operation. In this mode,
the controller stops operation and most of the internal
circuitry is disabled to reduce power consumption. Below is
description of the IC operation in off mode:
•The driver is disabled.
•The controller maintains VCC between VCC(on) and
VCC(off).
•The following blocks or features remain active:
♦Brownout detector.
♦Thermal shutdown.
♦The undervoltage protection (“UVP”) detector.
♦The overvoltage latch input remains active
•VControl is grounded to ensure a controlled start−up
sequence once the fault is removed.
•The PFCOK pin is internally grounded.
•The output of the “VTON processing block” is grounded.
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SYSTEM FAILURE DETECTION
When manufacturing a power supply, elements can be
accidentally shorted or improperly soldered. Such failures
can also occur as the system ages due to component fatigue,
excessive stress, soldering faults, or external interactions. In
particular, a pin can be grounded, left open, or shorted to an
adjacent pin. Such open/short situations require a safe
failure without smoke, fire, or loud noises. The NCP1615
integrates functions that ease meeting this requirement.
Among them are:
•GND connection fault. If the GND pin is properly
connected, the supply current drawn from the positive
terminal of the VCC capacitor, flows out of the GND
pin and returns to the negative terminal of the VCC
capacitor. If the GND pin is disconnected, the internal
ESD protection diodes provides a return path. An open
or floating GND pin is detected if current flows in the
CS/ZCD ESD diode. If current flow is detected for
200 ms, a fault is acknowledged and the controller stops
operating.
•Open CS/ZCD Pin: A pull-up current source,
ICS/ZCD(bias1), on the CS/ZCD pin allows detection of
an open CS/ZCD pin. ICS/ZCD1, is typically 1 mA. If the
pin is open, the voltage on the pin will increase to the
supply rail. This condition is detected and the controller
is disabled.
•Grounded CS/ZCD Pin: If the CS/ZCD pin is
grounded, the circuit cannot detect a ZCD transition,
activating the watchdog timer (typically 200 ms). Once
the watchdog timer expires, a pull-up current source,
ICS/ZCD2, sources 250 mA to pull-up the CS/ZCD pin.
The driver is inhibited until the CS/ZCD pin voltage
exceeds the ZCD arming threshold, VZCD(rising),
typically 0.75 V. Therefore, if the pin is grounded, the
voltage on the pin will not exceed VZCD(rising) and
drive pulses will be inhibited. The external impedance
should be above 3.9 kW to ensure correct operation.
•Boost or bypass diode short. The NCP1615 addresses
the short situations of the boost and bypass diodes (a
bypass diode is generally placed between the input and
output high-voltage rails to divert this inrush current).
Practically, the overstress protection is implemented to
detect such conditions and forces a low duty ratio
operation until the fault is removed.
FAULT INPUT
The NCP1615 includes a dedicated fault input accessible
via the Fault pin. The controller can be latched by pulling up
the pin above the upper fault threshold, VFault(OVP),
typically 3.0 V. The controller is disabled if the Fault pin
voltage, VFault, is pulled below the lower fault threshold,
VFault(OTP_in), typically 0.4 V. The lower threshold is
normally used for detecting an overtemperature fault. The
controller operates normally while the Fault pin voltage is
maintained within the upper and lower fault thresholds.
Figure 26 shows the architecture of the Fault input.
The lower fault threshold is intended to be used to detect
an overtemperature fault using an NTC thermistor . A pull up
current source IFault(OTP), (typically 45.5 mA) generates a
voltage drop across the thermistor. The resistance of the
NTC thermistor decreases at higher temperatures resulting
in a lower voltage across the thermistor. The controller
detects a fault once the thermistor voltage drops below
VFault(OTP_in). Versions A and C latch-off the controller after
an overtemperature fault is detected. In versions B and D the
controller is re-enabled once the fault is removed such that
VFault increases above VFault(OTP_out) and VCC reaches
VCC(on). Figure 27 shows typical waveforms related to the
latch version where−as Figure 28 shows waveforms of the
auto-recovery version.
An active clamp prevents the Fault pin voltage from
reaching the upper latch threshold if the pin is open. To reach
the upper threshold, the external pull-up current has to be
higher than the pull-down capability of the clamp (set by
RFault(clamp) at VFault(clamp)). The upper fault threshold is
intended to be used for an overvoltage fault using a Zener
diode and a resistor in series from the auxiliary winding
voltage, VAUX. The controller is latched once VFault.exceeds
VFault(OVP).
The Fault input signal is filtered to prevent noise from
triggering the fault detectors. Upper and lower fault detector
blanking delays, tdelay(OVP) and tdelay(OTP) are both typically
30 ms. A fault is detected if the fault condition is asserted for
a period longer than the blanking delay.
The controller bias current is reduced during power up by
disabling most of the circuit blocks including IFault(OTP).
This current source is enabled once VCC reaches VCC(on). A
bypass capacitor is usually connected between the Fault and
GND pins and it will take some time for VFault to reach its
steady state value once IFault(OTP) is enabled. To prevent
false detection of an OTP fault during power up, a dedicated
timer, tblank(OTP), blanks the OTP signal during power up.
The t blank(OTP), duration is typically 5 ms. In versions B and
D, IFault(OTP) remains enabled while the lower fault is
present independent of VCC in order to provide temperature
hysteresis. IFault(OTP) is disabled once the fault is removed.
The controller can detect an upper fault (i.e. overvoltage)
once VCC exceeds VCC(reset).
Once the controller is latched, it is reset if a brownout
condition is detected or if VCC is cycled down to its reset
level, VCC(reset). In the typical application these conditions
occur only if the ac voltage is removed from the system. The
internal latch also resets once the controller enters power
saving mode. Prior to reaching VCC(reset) Vfault(clamp) is set
at 0 V.
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Figure 28. OTP Auto−Recovery Timing Diagram
STANDBY OPERATION
A signal proportional to the downstream converter output
power is applied to the STDBY pin to enable standby mode
operation. A STDBY voltage below the standby threshold,
Vstandby, typically 300 mV, forces the controller into a
controlled burst mode, or standby mode.
In standby mode, the driver is disabled until the bulk
voltage falls below the bulk restart level. At which point, the
driver is re−enabled. The bulk restart level determines the
minimum bulk voltage in standby mode. As long as the
STBY pin voltage is below the standby threshold, the
controller will operate in controlled burst mode.
The controller is not allowed to enter standby mode while
the PFCOK signal is low. A dedicated timer, tblank(STDBY),
blanks the standby signal for 1 ms (typically) right after the
PFCOK signal transitions high. This ensures the signal
proportional to the downstream converter output power has
enough time to build up and prevent disabling the PFC while
powering up the downstream converter. The standby circuit
block is shown in Figure 29.
Figure 29. Standby Circuit Block
tblank(STDBY)
In_Regulation
Vstandby
STDBY
QDRV Disable
S
R
PFC_OK
0.98*VREF
Restart
IRestart
VUVP3
UVP3
ADJUSTABLE BULK VOLTAGE HYSTERESIS
The bulk restart threshold allows the user to enable the
bulk level at which the controller exits standby mode. The
restart threshold is set at 2% below the internal reference,
VREF. The ratio between VREF and the restart level is given
by KRestart. The user can set a restart level of 2% below the
regulation level without using additional components as
shown in Figure 30. If a different restart level is desired, a
resistor network can be used as shown in Figure 31.
Figure 30. Minimum Restart Level Configuration
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Figure 31. Restart Level Adjustment
IFB(SNK)
Irestart(bias)
A pull-down current source, Irestart(bias), pulls the Restart
pin down to ground if it is left open. This triggers the open
pin protection and disables the controller.
LINE REMOVAL (ALL VERSIONS EXCEPT A1)
Safety agency standards require the input filter capacitors
to be discharged once the ac line voltage is removed. A
resistor network is the most common method to meet this
requirement. Unfortunately, the resistor network consumes
power across all operating modes and it is a major
contributor of input power losses during light−load and
no−load conditions.
The NCP1615 eliminates the need of external discharge
resistors by integrating active input filter capacitor
discharge circuitry. A novel approach is used to reconfigure
the high voltage start−up circuit to discharge the input filter
capacitors upon removal of the ac line voltage. The line
removal detection circuitry is always active to ensure safety
compliance.
The line removal is detected by digitally sampling the
voltage present at the HV pin, and monitoring the slope.
A timer, tline(removal) (typically 100 ms), is used to detect
when the slope of the input signal is negative or below the
resolution level. The timer is reset any time a positive slope
is detected. Once the timer expires, a line removal condition
is acknowledged initiating an X2 capacitor discharge.
Once the controller detects the absence of the ac line
voltage, the controller is disabled and the PFCOK signal
transitions low.
A second timer , t line(discharge) (typically 32 ms), is used for
the time limiting of the discharge phase to protect the device
against overheating. Once the discharge phase is complete,
tline(discharge) is reused while the device checks to see if the
line voltage is reapplied. The discharging process is cyclic
and continues until the ac line is detected again or the voltage
across the X2 capacitor is lower than VHV(discharge) (30 V
maximum). This feature allows the device to dischar ge large
X2 capacitors in the input line filter to a safe level. It is
important to note that the HV pin cannot be connected
to any dc voltage due to this feature, i.e. directly to bulk
capacitor.
The diodes connecting the AC line to the HV pin should
be placed after the system fuse. A resistor in series with the
diodes is recommended to limit the current during transient
events. A low value resistor (< 1 kW) should be used to
reduce the voltage drop and thus allow more accurate
measurement of the input voltage when the start−up circuit
is enabled.
Larger resistor values may be used to improve surge
immunity, however, care must be taken to avoid falsely
triggering brownout during start−up. A maximum VCC
capacitor of 22 mF ± 20% ensures that brownout will never
be triggered during start−up.
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VCC DISCHARGE (VERSIONS C AND D ONLY)
If the downstream converter is latched due to a fault, it will
require the supply voltage to be removed to reset the
controller. Depending on the supply capacitor and current
consumption, this may take a significant amount of time
after the line voltage is removed. The NCP1615 uses the
voltage at the HV pin to detect a line removal and discharge
the VCC capacitor, effectively resetting the downstream
converter.
Immediately following the X2 discharge phase, VCC is
discharged b y a current sink, ICC(discharge), typically 23 mA.
The current sink is disabled and the device is allowed to
restart once VCC to falls down to VCC(discharge) (5 V
maximum). This operation is shown in Figure 32.
If the ac line is reapplied during the X2 discharge phase,
the device will immediately enter the VCC discharge phase
as shown in Figure 33. The device will not restart until the
VCC discharge phase is completed and VCC charges to
VCC(on).
FEEDBACK DISCONNECT
The PFC output voltage is typically sensed using a resistor
divider comprised of R3 and R4 as shown in Figure 34. The
resistor divider consumes power when the PFC stage is
disabled. Versions C and D of the NCP1615 integrate a
700 V switch, PFC FB Switch, between the HVFB and FB
pins. The PFC FB Switch connects in series between R3 and
R4 to disconnect the resistors and reduce input power when
the PFC stage is in PSM or latched mode.
Figure 34. PFC FB Switch
HVFB
The maximum on resistance of the PFC FB Switch,
RPFBswitch(on), is 10 kW. Because the PFC FB Switch is in
series with R3 and R3’s value is several orders of
magnitudes larger, the switch introduces minimal error on
the regulation level. The off state leakage current of the PFC
FB Switch, IPFBSwitch(off), is less than 3 mA.
TEMPERATURE SHUTDOWN
An internal thermal shutdown circuit monitors the
junction temperature of the IC. The controller is disabled if
the junction temperature exceeds the thermal shutdown
threshold, TSHDN, typically 150°C. A continuous VCC
hiccup is initiated after a thermal shutdown fault is detected.
The controller restarts at the next VCC(on) once the IC
temperature drops below below TSHDN by the thermal
shutdown hysteresis, TSHDN(HYS), typically 50°C.
The thermal shutdown fault is also cleared if VCC drops
below VCC(reset), or if a brownout/line removal fault is
detected. A new power up sequences commences at the next
VCC(on) once all the faults are removed.
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TYPICAL CHARACTERISTICS
Figure 35. VCC(on) (Version A/B) vs.
Temperature Figure 36. VCC(on) (Version C/D) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
10.395
10.400
10.405
10.410
10.415
10.420
10.425
10.430
100806040200−20−40
16.79
16.80
16.81
16.82
16.83
16.84
16.85
16.86
VCC(on) (V)
VCC(on) (V)
120 120
Figure 37. VCC(off) vs. Temperature Figure 38. VCC(HYS) (Version A/B) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
8.945
8.950
8.955
8.960
8.965
8.970
8.975
100806040200−20−40
1.4755
1.4760
1.4765
1.4770
1.4775
1.4780
1.4785
1.4790
Figure 39. VCC(HYS) (Version C/D) vs.
Temperature Figure 40. VCC(reset) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
7.845
7.850
7.855
7.860
7.865
7.875
7.880
7.885
100806040200−20−40
7.66
7.68
7.70
7.72
7.74
7.76
7.78
7.80
VCC(off) (V)
VCC(HYS) (V)
VCC(HYS) (V)
VCC(reset) (V)
120 120
120120
7.870
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TYPICAL CHARACTERISTICS
Figure 41. VCC(inhibit) vs. Temperature Figure 42. tstartup vs. Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
0.1
0.3
0.4
0.6
0.7
0.9
1.0
100806040200−20−40
0
0.2
0.4
0.8
1.0
1.4
1.6
1.8
VCC(inhibit) (V)
tstartup (ms)
120 120
0.2
0.5
0.8
0.6
1.2
Figure 43. Istart1 (Version C/D) vs. Temperature Figure 44. Istart2 (Version C/D) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0.510
0.515
0.520
0.525
0.530
0.535
100806040200−20−40
11.6
11.7
11.8
11.9
12.0
12.1
12.2
12.3
Figure 45. IHV(off1) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
20.35
20.40
20.50
20.55
20.65
20.70
20.80
20.85
Istart1 (mA)
Istart2 (mA)
IHV(off1) (mA)
120 120
120
20.45
20.60
20.75
Figure 46. ICC1 vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0.042
0.043
0.044
0.045
0.047
0.048
0.050
0.051
ICC1 (mA)
120
0.046
0.049
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TYPICAL CHARACTERISTICS
Figure 47. ICC2 vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0.61
0.62
0.63
0.64
0.65
0.66
0.67
0.68
Figure 48. ICC2b (Version A/B) vs. Temperature
Figure 49. ICC3 vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0.58
0.59
0.60
0.61
0.62
0.63
0.64
0.65
100806040200−20−40
0.82
0.83
0.85
0.86
0.88
0.89
0.91
0.92
Figure 50. ICC4 vs. Temperature
Figure 51. ICC5 vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
2.45
2.46
2.48
2.50
2.51
2.53
2.54
2.56
100806040200−20−40
2.85
2.90
2.95
3.00
3.05
3.10
ICC2 (mA)
ICC2b (mA)
ICC3 (mA)
ICC4 (mA)
ICC5 (mA)
120
120
120
120
120
0.84
0.87
0.90
2.47
2.49
2.52
2.55
Figure 52. tline(removal) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
20
40
60
80
100
120
140
tline(removal) (ms)
120
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TYPICAL CHARACTERISTICS
Figure 53. tline(discharge) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
5
15
20
25
30
40
45
tline(discharge) (ms)
120
10
35
Figure 54. VBO(start) (Version A/B/C/D) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
109.0
109.5
110.0
110.5
111.0
111.5
112.0
VBO(start) (V)
120
Figure 55. VBO(start) (Version C2/D2) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
93.2
93.4
93.8
94.0
94.2
94.6
95.0
95.2
Figure 56. VBO(start) (Version C3) vs.
Temperature
Figure 57. VBO(stop) (Version A/B/C/D) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
98.6
98.8
99.2
99.4
99.8
100.2
100.4
100.8
100806040200−20−40
85.2
85.4
85.6
86.0
86.2
86.4
86.8
87.0
Figure 58. VBO(stop) (Version C2/D2) vs.
Temperature
VBO(start) (V)
VBO(stop) (V)
VBO(stop) (V)
120
120120
93.6
94.4
94.8
99.0
99.6
100.0
100.6
85.8
86.6
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
113.5
114.0
114.5
115.0
115.5
116.0
VBO(start) (V)
120
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TYPICAL CHARACTERISTICS
Figure 59. VBO(stop) (Version C3) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
7.94
7.96
7.98
8.00
8.04
8.06
8.08
8.10
VBO(HYS) (V)
120
8.02
Figure 60. VBO(HYS) (Version A/B/C/C3/D) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
245.0
246.0
245.5
246.5
247.0
249.0
249.5
250.5
Vlineselect(HL) (V)
120
247.5
248.0
248.5
250.0
Figure 61. VBO(HYS) (Version C2/D2) vs.
Temperature Figure 62. Vlineselect(HL) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
10.65
10.70
10.75
10.80
10.85
10.90
VBO(HYS) (V)
120
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
102.6
102.8
103.2
103.4
103.8
104.2
104.4
104.8
VBO(stop) (V)
120
103.0
103.6
104.0
104.6
Figure 63. Vlineselect(HL) (Version C3) vs.
Temperature Figure 64. Vlineselect(LL) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
232.0
232.5
233.0
234.0
234.5
235.5
236.5
237.0
Vlineselect(LL) (V)
120
233.5
235.0
236.0
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
253.0
257.0
258.0
260.0
Vlineselect(HL) (V)
120
254.0
255.0
256.0
259.0
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TYPICAL CHARACTERISTICS
Figure 65. Vlineselect(LL) (Version C3) vs.
Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
2.488
2.490
2.492
2.496
2.498
2.500
2.504
2.506
VREF (V)
120
2.494
2.502
Figure 66. Vlineselect(HYS) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
214.4
214.6
214.8
215.0
215.2
215.4
215.6
gm (mS)
120
Figure 67. IHVFB(off) vs. Temperature Figure 68. RFBswitch(on) vs. Temperature
Figure 69. VREF vs. Temperature Figure 70. gm vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
0.05
0.10
0.15
0.20
0.25
0.30
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
0.5
1.0
1.5
2.0
2.5
IHVFB(off) (mA)
RFBswitch(on) (kW)
120 120
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
12.8
12.9
13.1
13.2
13.3
13.4
13.6
13.7
Vlineselect(HYS) (V)
120
13.0
13.5
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
240.0
240.5
241.0
242.0
242.5
243.5
244.5
245.0
Vlineselect(LL) (V)
120
241.5
243.0
244.0
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TYPICAL CHARACTERISTICS
Figure 71. VDRE vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0.5045
0.5050
0.5055
0.5060
0.5065
0.5070
0.5075
0.5080
Figure 72. VDRE(HYS) vs. Temperature
Figure 73. ton(LL) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
160
162
164
168
170
174
176
178
VILIM (V)
tOCP(LEB) (ns)
120 120
166
172
Figure 74. ton(HL) vs. Temperature
Figure 75. VILIM vs. Temperature Figure 76. tOCP(LEB) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
2.378
2.380
2.382
2.384
2.386
2.388
2.390
2.394
100806040200−20−40
0
1
2
3
4
5
6
VDRE (V)
VDRE(HYS) (mV)
120 120
2.392
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
23.5
23.6
23.7
23.8
23.9
24.0
24.1
24.2
ton(LL) (ms)
120
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
5.90
5.92
5.94
5.96
5.98
6.00
6.02
6.04
ton(HL) (ms)
120
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TYPICAL CHARACTERISTICS
Figure 77. tOCP(delay) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
20
40
60
80
100
120
tOCP(delay) (ns)
120
Figure 78. tOVS(LEB) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
71
72
74
75
77
78
79
81
tOVS(LEB) (ns)
120
73
76
80
Figure 79. tOVS(delay) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
10
20
30
40
60
70
80
tOVS(delay) (ns)
120
50
Figure 80. tZCD vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
20
40
60
100
120
140
160
tZCD (ns)
120
80
Figure 81. tDT2 vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
6.18
6.19
6.21
6.22
6.24
6.26
6.27
6.29
Figure 82. tDT2 (Version C3) vs. Temperature
tDT2 (ms)
120
6.20
6.23
6.25
6.28
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
18.58
18.60
18.64
18.66
18.70
18.74
18.76
tDT2 (ms)
120
18.62
18.68
18.72
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TYPICAL CHARACTERISTICS
Figure 83. tDT3 vs. Temperature Figure 84. tDT3 (Version C3) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
12.52
12.54
12.56
12.58
12.60
12.62
12.64
tDT3 (ms)
120
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
38.00
38.02
38.04
38.06
38.08
38.10
38.12
tDT3 (ms)
120
38.14
38.16
38.18
38.20
Figure 85. tDRV(rise) vs. Temperature Figure 86. tDRV(fall) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
0
5
10
15
20
25
35
40
100806040200−20−40
0
5
10
15
20
30
35
40
Figure 87. VDRV(high2) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
11.4
11.6
11.8
12.0
12.2
12.4
12.6
tDRV(rise) (ns)
tDRV(fall) (ns)
VDRV(high2) (V)
120120
120
25
30
Figure 88. IFB(SNK1) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
240
245
255
260
265
275
285
290
IFB(SNK1) (nA)
120
250
270
280
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44
TYPICAL CHARACTERISTICS
Figure 89. IFB(SNK2) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
230
235
245
255
260
270
275
285
I
FB(SNK2)
(nA)
120
240
250
265
280
Figure 90. IFOVP/UVP(bias1) vs. Temperature
Figure 91. IFOVP/UVP(bias2) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
232
234
236
238
240
242
244
246
100806040200−20−40
222
224
226
228
232
234
238
240
IFOVP/UVP(bias1) (nA)
IFOVP/UVP(bias2) (nA)
120
120
230
236
Figure 92. Irestart(bias) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
234
236
238
240
244
246
250
252
Irestart(bias) (nA)
120
242
248
Figure 93. IFault(OTP) vs. Temperature
TJ, JUNCTION TEMPERATURE (°C)
100806040200−20−40
45.5
45.6
45.7
45.8
45.9
46.0
46.1
IFault(OTP) (mA)
120
NCP1615
www.onsemi.com
45
PACKAGE DIMENSIONS
SOIC−14 NB, LESS PIN 13
CASE 751AN
ISSUE A
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE PROTRUSION
SHALL BE 0.13 TOTAL IN EXCESS OF AT
MAXIMUM MATERIAL CONDITION.
4. DIMENSIONS D AND E DO NOT INCLUDE
MOLD PROTRUSIONS.
5. MAXIMUM MOLD PROTRUSION 0.15 PER
SIDE.
H
14 8
71
M
0.25 B M
C
h
X 45
SEATING
PLANE
A1
A
M
_
DIM MIN MAX
MILLIMETERS
D8.55 8.75
E3.80 4.00
A1.35 1.75
b0.35 0.49
L0.40 1.25
e1.27 BSC
A3 0.19 0.25
A1 0.10 0.25
M0 7
H5.80 6.20
h0.25 0.50
__
6.50
13X
0.58
13X
1.18
1.27
DIMENSIONS: MILLIMETERS
1
PITCH
SOLDERING FOOTPRINT*
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
S
A
M
0.25 B S
C
b
13X
B
A
E
D
e
DET AIL A
L
A3
DET AIL A
NCP1615
www.onsemi.com
46
PACKAGE DIMENSIONS
SOIC−16 NB, LESS PIN 15
CASE 752AC
ISSUE O
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE PROTRUSION SHALL BE
0.13 TOTAL IN EXCESS OF THE b DIMENSION AT
MAXIMUM MATERIAL CONDITION.
4. DIMENSIONS D AND E DO NOT INCLUDE MOLD
PROTRUSIONS.
5. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.
18
16 9
SEATING
PLANE
L
M
hx 45_
e
15X
HE
D
M
0.25 B M
A1
A
DIM MIN MAX
MILLIMETERS
D9.80 10.00
E3.80 4.00
A1.35 1.75
b0.35 0.49
L0.40 1.25
e1.27 BSC
C0.19 0.25
A1 0.10 0.25
M0 7
H5.80 6.20
h0.25 0.50
__
6.40
15X
0.58
15X 1.12
1.27
DIMENSIONS: MILLIMETERS
1
PITCH
SOLDERING FOOTPRINT*
16
89
M
0.25 A S
b15X
TBS
A B
C
C
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
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