NCP1239JD65R2G - ON SEMICONDUCTOR

May, 2020 − Rev. 24

1Publication Order Number

NCP1239/D

Fixed Frequency

Current‐Mode Controller for

Flyback Converter

NCP1239

The NCP1239 is a fixed-frequency current-mode controller

featuring a high-voltage start-up current source to provide a quick and

lossless power-on sequence. This function greatly simplifies the

design of the auxiliary supply and the VCC capacitor by activating the

internal start-up current source to supply the controller during start-up,

transients, latch, stand-by etc.

With a supply range up to 35 V, the controller hosts a jittered 65 or

100-kHz switching circuitry operated in peak current mode control.

When the power on the secondary side starts to decrease, the controller

automatically folds back its switching frequency down to minimum

level of 26 kHz. As the power further goes down, the part enters skip

cycle while limiting the peak current that insures excellent efficiency

in light load condition.

NCP1239 features a timer-based fault detection circuitry that

ensures a quasi-flat overload detection, independent of the input

voltage.

Features

•Fixed-Frequency 65-kHz or 100-kHz Current-Mode Control

Operation

•Frequency Foldback Down to 26 kHz and Skip Mode to Maximize

Performance in Light Load Conditions

•Adjustable Over Power Protection (OPP) Circuit

•High-Voltage Current Source with Brown-Out (BO) Detection

•Internal Slope Compensation

•Internal Fixed Soft-Start

•Frequency Jittering in Normal and Frequency Foldback Modes

•64-ms Timer-Based Short-Circuit Protection with Auto-Recovery or

Latched Operation

•Pre-Short Ready for Latched OCP Versions

•Latched OVP on VCC – Autorecovery for C and E Versions

•Latched OVP/OTP Input for Improved Robustness

•35-V VCC Operation

•±500 mA Peak Source/Sink Drive Capability

•Internal Thermal Shutdown

•Extremely Low No-Load Standby Power

•Pin-to-Pin Compatible with the Existing NCP1236/1247 Series

•These Devices are Pb-Free and are RoHS Compliant

Typical Applications

•AC-DC Converters for TVs, Set-Top Boxes and Printers

•Offline Adapters for Notebooks and Netbooks

MARKING DIAGRAM

SOIC−7

CASE 751U

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PIN CONNECTIONS

1239xfff = Specific Device Code

x = A, B, C, D, E, F, G, H, I,

J, K, L, M, N, P, Q or R

fff = 065 or 100

A = Assembly Location

L = Wafer Lot

Y = Year

W = Work Week

G= Pb−Free Package

1239xfff

ALYWX

VCC

DRV

Fault

GND

ORDERING INFORMATION

See detailed ordering and shipping information on page 26 of

this data sheet.

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Figure 1. Application Schematic (OPP Adjustment)

NCP1239

Vbulk

OPP

adjsut.

Vout

OVP

NTC

Table 1. PIN FUNCTION DESCRIPTION

Pin No. Pin Name Description

1 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.

2 FB Hooking an optocoupler collector to this pin will allow regulation.

3 CS This pin monitors the primary peak current but also offers an overpower compensation adjustment. When the

CS pin is brought above 1.2 V, the part is permanently latched off.

4 GND The controller ground.

5 DRV The driver’s output to an external MOSFET gate.

6 VCC This pin is connected to an external auxiliary voltage. An OVP comparator monitors this pin and offers a

means to latch the converter in fault conditions.

7 NC Non-connected for improved creepage distance.

8 HV Connected to the bulk capacitor or rectified ac line, this pin powers the internal current source to deliver a start-

up current. It is also used to provide the brown-out detection and the HV sensing for the Overpower protection.

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Table 2. DEVICE OPTION AND DESIGNATIONS

Device

Fre-

quency

OCP

Protection

OCP

Timer

Vcc OVP

Threshold

Vcc OVP

Protection

Fault pin

Protection

Levels

Timer

Soft−

start

Timer

DSS

Func-

tion

NCP1239AD65R2G 65 kHz Latch 64 ms 25.5 V Latch Latch 110 / 101 68 ms 8 ms Disable

NCP1239BD65R2G 65 kHz Auto−

Recovery

64 ms 25.5 V Latch Latch 110 / 101 68 ms 8 ms Disable

NCP1239CD65R2G 65 kHz Auto−

Recovery

64 ms 25.5 V Auto−

Recovery

Latch 110 / 101 68 ms 8 ms Disable

NCP1239DD65R2G 65 kHz Auto−

Recovery

64 ms 25.5 V Latch Latch 101 / 95 68 ms 8 ms Disable

NCP1239ED65R2G 65 kHz Auto−

Recovery

64 ms 25.5 V Auto−

Recovery

Auto−

Recovery

110 / 101 68 ms 8 ms Disable

NCP1239FD65R2G 65 kHz Latch 64 ms 32 V Latch Latch 229 / 176 68 ms 4 ms Disable

NCP1239HD65R2G 65 kHz Latch 64 ms 25.5 V Latch Latch 229 / 224 68 ms 8 ms Disable

NCP1239ID65R2G 65 kHz Latch 128 ms 25.5 V Latch Latch 101 / 95 68 ms 4 ms Disable

NCP1239JD65R2G 65 kHz Latch 128 ms 32 V Latch Latch 101 / 95 68 ms 8 ms Enable

NCP1239KD65R2G 65 kHz Auto−

Recovery

128 ms 25.5 V Auto−

Recovery

Auto−

Recovery

110 / 101 68 ms 8 ms Disable

NCP1239LD65R2G 65 kHz Auto−

Recovery

128 ms 25.5 V Latch Latch 82 / 77 68 ms 4 ms Disable

NCP1239MD65R2G 65 kHz Auto−

Recovery

128 ms 32 V Auto−

Recovery

Auto−

Recovery

229 / 224 68 ms 4 ms Enable

NCP1239ND65R2G 65 kHz Auto−

Recovery

128 ms 32 V Auto−

Recovery

Latch 229 / 224 68 ms 4 ms Enable

NCP1239PD65R2G 65 kHz Auto−

Recovery

64 ms 25.5 V Auto−

Recovery

Auto−

Recovery

82 / 79 68 ms 8 ms Disable

NCP1239QD65R2G 65 kHz Auto−

Recovery

128 ms 25.5 V Auto−

Recovery

Auto−

Recovery

82 / 79 68 ms 8 ms Disable

NCP1239RD65R2G 65 kHz Auto−

Recovery

128 ms 25.5 V Latch Latch 101 / 95 272 ms 4 ms Disable

NCP1239AD100R2G 100 kHz Latch 64 ms 25.5 V Latch Latch 110 / 101 68 ms 8 ms Disable

NCP1239BD100R2G 100 kHz Auto−

Recovery

64 ms 25.5 V Latch Latch 110 / 101 68 ms 8 ms Disable

NCP1239DD100R2G 100 kHz Auto−

Recovery

64 ms 25.5 V Latch Latch 101 / 95 68 ms 8 ms Disable

NCP1239ED100R2G 100 kHz Auto−

Recovery

64 ms 25.5 V Auto−

Recovery

Auto−

Recovery

110 / 101 68 ms 8 ms Disable

NCP1239GD100R2G 100 kHz Latch 64 ms 25.5 V Latch Latch 95 / 86 136 ms 8 ms Disable

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Figure 2. Simplified Block Diagram

Vcc

Drv

LEB

GND

Dual HV startup

current source

HV sample

600−ns time

constant

Up counter

RST

OVP/OTP

gone?

Fault

Vfault(clamp)

VFault(OTP)

VFault(OVP)

IOTP

Option for

OVP_VCC

Up counter

RST

VLimit2

LEB

120 ns

300 ns

VLimit1

Soft−start

Ramp

8 ms

SS end

Vdd

/ 4

Rup Vskip

Overcurrent

Soft−start

PWM

Oscillator

65 kHz / 100 kHz

Compensation

Slope

Stop

Foldback

Jitter

OCP_flag

PWM

OCP

Timer

64 ms

OCP_flag

Skip

HV detection

& sampling

Vcc logic

management

20us time

constant

TSD

VCC(OVP)

OVP_VCC

(option)

Vdd

Vcc(reset)

UVLO

Vcc(reset)

Latch

Protection

Mode

Reset

Vcc(reset)

Timer

1 s

Auto−recovery

Clamp

Clock

Latch

TSD

Skip

Clock

BO end

UVLO

Vdd

Ibias

OCP Fault

gone?

TSD

TSD end

Iopp

HV sample

Dmax

OPP Current

Generation

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Table 3. MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply Voltage, VCC Pin, Continuous Voltage VCC −0.3 to 35 V

Maximum Voltage on Low Power Pins CS, FB and Fault −0.3 to 5.5 V

Maximum Voltage on DRV Pin VDRV −0.3 to 20 V

High Voltage Pin HV −0.3 to 650 V

Thermal Resistance Junction-to-Air

Single Layer PCB 25 mm@, 2 Oz Cu Printed Circuit Copper Clad

RθJ−A250 °C/W

Maximum Junction Temperature TJ(max) 150 °C

Storage Temperature Range TSTG −60 to 150 °C

ESD Capability (Note 2) Human Body Model – All Pins Except HV

Machine Model

ESDHBM

ESDMM

200

Charged-Device Model ESD Capability per JEDEC JESD22−C101E 1 kV

Moisture Sensitivity Level MSL 1

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 affected.

1. Refer to ELECTRICAL CHARACTERISTICS, RECOMMENDED OPERATING RANGES and/or APPLICATION INFORMATION for Safe

Operating parameters.

2. This device series incorporates ESD protection and is tested by the following methods:

ESD Human Body Model tested per JEDEC JESD22−A114F

ESD Machine Model tested per JEDEC JESD22−A115C

Charged-Device Model ESD Capability tested per JEDEC JESD22−C101E

Latch-up Current Maximum Rating: ≤150 mA per JEDEC standard: JESD78

Table 4. ELECTRICAL CHARACTERISTICS

(For typical values TJ = 25°C, for min/max Values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

Parameter Test Conditions Symbol Min Typ Max Unit

START-UP SECTION

Minimum Voltage for Current Source Operation IHV = 90% ISTART2,

VCC = VCC(on) − 0.5 V

VHV(min) −25 60 V

Current Flowing Out of VCC Pin VCC = 0 V ISTART1 0.2 0.5 0.8 mA

Current Flowing Out of VCC Pin VCC = VCC(on) – 0.5 V ISTART2 1.5 3 4.5 mA

HV Pin Leakage Current VHV = 325 V ILEAK1 −8 20 mA

SUPPLY SECTION

Start-Up Threshold

HV Current Source Stop Threshold

VCC Increasing VCC(on) 11.0 12.0 13.0 V

HV Current Source Restart Threshold VCC Decreasing VCC(min) 9.0 10.0 11.0 V

Minimum Operating Voltage VCC Decreasing VCC(off) 8.0 8.8 9.4 V

Operating Hysteresis VCC(on) = VCC(off) VCC(hys) 3.0 − − V

VCC Level for ISTART1 to ISTART2 Transition VCC(inhibit) 0.7 1.2 1.7 V

VCC Level where Logic Functions are Reset VCC Decreasing VCC(reset) 6.5 7 7.5 V

Internal IC Consumption VFB = 3.2 V, FSW = 65 kHz

and CL=0

ICC1 −1.4 2.2 mA

Internal IC Consumption VFB = 3.2 V, FSW = 65 kHz

and CL=1nF

ICC2 −2.1 3.0 mA

Internal IC Consumption VFB = 3.2 V, FSW = 100 kHz

and CL=0

ICC1 −1.7 2.5 mA

Internal IC Consumption VFB = 3.2 V, FSW = 100 kHz

and CL= 1 nF

ICC2 −3.1 4.0 mA

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product per-

formance may not be indicated by the Electrical Characteristics if operated under different conditions.

1. Guaranteed by design

2. CS pin source current is a sum of IBIAS and IOPP

, thus at VHV = 125 V is observed the IBIAS only, because IOPC is switched off.

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Table 4. ELECTRICAL CHARACTERISTICS (continued)

(For typical values TJ = 25°C, for min/max Values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

Parameter UnitMaxTypMinSymbolTest Conditions

SUPPLY SECTION

Internal IC Consumption in Skip Cycle VCC = 12 V, VFB = 0.775 V

Driving 8 A/600 V MOSFET

ICC(stb) −500 −mA

Internal IC Consumption in Skip Cycle

L, P and Q versions

VCC = 12 V, VFB = 0.775 V

Driving 8 A/600 V MOSFET

ICC(stb) −565 −mA

Internal IC Consumption in Fault Mode Fault or Latch ICC3 −400 −mA

Internal IC Consumption in Fault Mode

L, P and Q versions

Fault or Latch ICC3 −480 −mA

Internal IC Consumption before Start-Up VCC(min) < VCC < VCC(on) ICC4 −310 −mA

Internal IC Consumption before Start-Up VCC < VCC(min) ICC5 −20 −mA

DRIVE OUTPUT

Rise Time (10−90%) VDRV from 10 to 90%

VCC = VCC(off) + 0.2 V,

CL = 1 nF

tR−40 −ns

Fall Time (90−10%) VDRV from 90 to 10%

VCC = VCC(off) + 0.2 V,

CL = 1 nF

tF−30 −ns

Source Resistance ROH −6−W

Sink Resistance ROL −6−W

Peak Source Current DRV High State,

VDRV = 0 V (Note 1)

VCC = VCC(off) + 0.2 V,

CL = 1 nF

ISOURCE −500 −mA

Peak Sink Current DRV Low State,

VDRV = VCC (Note 1)

VCC = VCC(off) + 0.2 V,

CL = 1 nF

ISINK −500 −mA

High State Voltage

(Low VCC Level)

VCC = 9 V, RDRV = 33 kW

DRV High State

VDRV(low) 8.8 − − V

High State Voltage

(High VCC Level)

VCC = VCC(OVP) – 0.2 V,

DRV High State and Unloaded

VDRV(clamp) 11.0 13.5 16.0 V

CURRENT COMPARATOR

Input Pull-Up Current VCS = 0.7 V IBIAS −1−mA

Maximum Internal Current Setpoint TJ from −40°C to +125°C

(No OPP)

VLIMIT1 0.752 0.800 0.848 V

Abnormal Over-Current Fault Threshold TJ = +25°C (No OPP) VLIMIT2 1.10 1.20 1.30 V

Default Internal Voltage Set Point for

Frequency Foldback Trip Point

~59% of VLIMIT VFOLD(CS) −475 −mV

Internal Peak Current Setpoint Freeze ~31% of VLIMIT VFREEZE(CS) −250 −mV

Propagation Delay from VLIMIT Detection to

Gate Off-State

DRV Output Unloaded tDEL −50 100 ns

Leading Edge Blanking Duration tLEB1 −300 −ns

Abnormal Over-Current Fault Blanking

Duration for VLIMIT3

tLEB2 −120 −ns

Number of Clock Cycles before Fault

Confirmation

tCOUNT −4−

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product per-

formance may not be indicated by the Electrical Characteristics if operated under different conditions.

1. Guaranteed by design

2. CS pin source current is a sum of IBIAS and IOPP

, thus at VHV = 125 V is observed the IBIAS only, because IOPC is switched off.

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Table 4. ELECTRICAL CHARACTERISTICS (continued)

(For typical values TJ = 25°C, for min/max Values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

Parameter UnitMaxTypMinSymbolTest Conditions

CURRENT COMPARATOR

Internal Soft-Start Duration Activated upon startup or

auto−recovery

A, B, C, D, E, G, H, J, K, P or Q

versions

F, I, L, M, N or R versions

tSS

−

INTERNAL OSCILLATOR

Oscillation Frequency (65-kHz Version) fOSC 60 65 70 kHz

Oscillation Frequency (100-kHz Version) fOSC 92 100 108 kHz

Maximum Duty-Cycle DMAX 76 80 84 %

Frequency Jittering In Percentage of fOSC – Jitter is

Kept even in Foldback Mode

fJITTER −±5−%

Swing Frequency fSWING −240 −Hz

FEEDBACK SECTION

Equivalent AC Resistor from FB to GND (Note 1) REQ −25 −kW

Internal Pull-Up Voltage on FB Pin FB open VFB(ref) 4.1 4.3 −V

VFB to Current Setpoint Division Ratio KFB −4−

Feedback Voltage below which the Peak

Current is Frozen

VFREEZE −1.0 −V

FREQUENCY FOLDBACK

Frequency Foldback Level on FB Pin ≈59% of Maximum Peak

Current

VFOLD −1.90 −V

Transition Frequency below which Skip-Cycle

Occurs

VFB =V

SKIP + 0.5 V fTRANS 22 26 30 kHz

End of Frequency Foldback Feedback Level fSW = fMIN VFOLD(end) −1.50 −V

Skip-Cycle Level Voltage on FB Pin VSKIP −0.80 −V

Hysteresis on the Skip Comparator (Note 1) VSKIP(hyst) −30 −mV

INTERNAL RAMP COMPENSATION

Compensation Ramp Slope FSW = 65 kHz, RUP = 30 kW

FSW = 100 kHz, RUP = 30 kW

S65

S100

−

−29

−45

−

mV/ms

OVERPOWER COMPENSATION (OPP)

VHV to IOPP Conversion Ratio KOPP −0.54 −mA/V

Current Flowing Out of CS Pin

(Note 2)

VHV = 125 V

VHV = 162 V

VHV = 328 V

VHV = 365 V

IOPP(125)

IOPP(162)

IOPP(328)

IOPP(365)

−

105

110

130

−

150

Current Flowing Out of CS Pin for L version

(Note 2)

VHV = 108 V

VHV = 145 V

VHV = 294 V

VHV = 327 V

IOPP(108)

IOPP(145)

IOPP(294)

IOPP(327)

−

105

110

130

−

150

Percentage of Applied OPP Current VFB < VFOLD IOPP1 −0−%

Percentage of Applied OPP Current VFB > VFOLD + 0.7 V (VOPP) IOPP2 −100 −%

Clamped OPP Current VHV > 365 V IOPP3 105 130 150 mA

Watchdog Timer for DC Operation tWD(OPP) −32 −ms

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product per-

formance may not be indicated by the Electrical Characteristics if operated under different conditions.

1. Guaranteed by design

2. CS pin source current is a sum of IBIAS and IOPP

, thus at VHV = 125 V is observed the IBIAS only, because IOPC is switched off.

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Table 4. ELECTRICAL CHARACTERISTICS (continued)

(For typical values TJ = 25°C, for min/max Values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

Parameter UnitMaxTypMinSymbolTest Conditions

BROWN-OUT (BO)

Brown-Out Thresholds (A,B,C,E & K versions) VHV Increasing VBO(on) 100 110 120 V

Brown-Out Thresholds (A,B,C,E & K versions) VHV Decreasing VBO(off) 93 101 109 V

Brown-Out Thresholds (D, I, J and R versions) VHV Increasing VBO(on) 92 101 110 V

Brown-Out Thresholds (D, I, J and R versions) VHV Decreasing VBO(off) 87 95 103 V

Brown-Out Thresholds (F version only) VHV Increasing VBO(on) 211 229 247 V

Brown-Out Thresholds (F version only) VHV Decreasing VBO(off) 164 176 188 V

Brown-Out Thresholds (G version only) VHV Increasing VBO(on) 86 95 104 V

Brown-Out Thresholds (G version only) VHV Decreasing VBO(off) 79 86 93 V

Brown-Out Thresholds (H, M and N versions) VHV Increasing VBO(on) 211 229 247 V

Brown-Out Thresholds (H, M and N versions) VHV Decreasing VBO(off) 208 224 240 V

Brown-Out Thresholds (L version only) VHV Increasing VBO(on) 74 82 90 V

Brown-Out Thresholds (L version only) VHV Decreasing VBO(off) 70 77 84 V

Brown−out thresholds (P and Q versions) VHV increasing VBO(on) 74 82 90 V

Brown−out thresholds (P and Q versions) VHV decreasing VBO(off) 72 79 86 V

Brown-Out Timer Duration (A, B, C, D, E, F, H,

I, J, K, L, M, N, P and Q versions)

VHV Decreasing tBO 54 68 82 ms

Brown-Out Timer Duration (G version only) VHV Decreasing tBO 110 136 162 ms

Brown-Out Timer Duration (R version only) VHV Decreasing tBO 216 272 324 ms

FAULT INPUT (OTP/OVP)

Over-Voltage Protection Threshold VFAULT Increasing VFAULT(OVP) 2.8 3.0 3.2 V

Over-Temperature Protection Threshold VFAULT Decreasing VFAULT(OTP) 0.37 0.40 0.43 V

NTC Biasing Current VFAULT = 0 V IOTP 39 45 51 mA

Additional NTC Biasing Current during

Soft-Start Only

VFAULT = 0 V − During Soft-Start

Only

IOTP_boost 38 44 50 mA

Latch Clamping Voltage IFAULT = 0 mA VFAULT(clamp)0 1.1 1.35 1.6 V

Latch Clamping Voltage IFAULT = 1 mA VFAULT(clamp)1 2.2 2.7 3.2 V

Blanking Time after Drive Turn Off tLATCH(blank) −1−ms

Number of Clock Cycles before Latch

Confirmation

tLATCH(count) −4−

OVER-CURRENT PROTECTION (OCP)

Internal OCP Timer Duration A, B, C, D, E, F, G, H and P

versions

tOCP 51 64 77 ms

Internal OCP Timer Duration I, J, K, L, M, N, Q and R

versions

tOCP 102 128 154 ms

Auto-Recovery Timer tAUTOREC 0.85 1 1.35 s

VCC OVER-VOLTAGE (VCC OVP)

Latched Over Voltage Protection on VCC Pin A, B, C, D, E, G, H, I, K, L, P, Q

or R versions

VCC(OVP) 24.0 25.5 27.0 V

Latched Over Voltage Protection on VCC Pin F, J, M and N versions VCC(OVP) 30.0 32.0 34.0 V

Delay before OVP on VCC Confirmation tOVP(delay) −20 −ms

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product per-

formance may not be indicated by the Electrical Characteristics if operated under different conditions.

1. Guaranteed by design

2. CS pin source current is a sum of IBIAS and IOPP

, thus at VHV = 125 V is observed the IBIAS only, because IOPC is switched off.

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Table 4. ELECTRICAL CHARACTERISTICS (continued)

(For typical values TJ = 25°C, for min/max Values TJ = −40°C to +125°C, VHV = 125 V, VCC = 11 V unless otherwise noted)

Parameter UnitMaxTypMinSymbolTest Conditions

THERMAL SHUTDOWN (TSD)

Temperature Shutdown TJ Increasing (Note 1) TSHDN 135 150 165 °C

Temperature Shutdown Hysteresis TJ Decreasing (Note 1) TSHDN(hys) −20 −°C

Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product per-

formance may not be indicated by the Electrical Characteristics if operated under different conditions.

1. Guaranteed by design

2. CS pin source current is a sum of IBIAS and IOPP

, thus at VHV = 125 V is observed the IBIAS only, because IOPC is switched off.

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Figure 3. VCC(on) vs. Junction Temperature Figure 4. VCC(min) vs. Junction Temperature

Temperature (5C)

806040200

VCC(on) (V)

−40

12.5

12.0

11.5

11.0

13.0

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 5. VCC(off) vs. Junction Temperature Figure 6. VCC(inhibit) vs. Junction Temperature

Figure 7. ICC2 (65-kHz Version) vs. Junction

Temperature

Figure 8. ICC2 (100-kHz Version) vs. Junction

Temperature

−20 100 120

Temperature (5C)

806040200

VCC(min) (V)

−40

10.5

10.0

9.5

9.0

11.0

−20 100 120

Temperature (5C)

806040200

VCC(off) (V)

−40

9.2

8.8

8.4

8.0

−20 100 120

Temperature (5C)

806040200

VCC(inhibit) (V)

−40

1.3

1.1

0.9

0.7

−20 100 120

1.7

1.5

Temperature (5C)

806040200

ICC2 (mA)

−40

2.6

2.2

1.8

1.4

−20 100 120

3.0

Temperature (5C)

806040200

ICC2 (mA)

−40

2.8

2.4

2.0

1.6

−20 100 120

3.2

3.6

4.0

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Figure 9. ISTART1 vs. Junction Temperature Figure 10. ISTART2 vs. Junction Temperature

Temperature (5C)

806040200

ISTART1 (mA)

−40

0.5

0.4

0.3

0.2

0.6

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 11. ILEAK1 vs. Junction Temperature Figure 12. VLIMIT1 vs. Junction Temperature

Figure 13. VLIMIT2 vs. Junction Temperature Figure 14. tDEL vs. Junction Temperature

−20 100 120

Temperature (5C)

806040200

ISTART2 (mA)

−40

3.0

2.5

2.0

1.5

3.5

−20 100 120

Temperature (5C)

806040200

ILEAK1 (mA)

−40

−20 100 120

Temperature (5C)

806040200

VLIMIT1 (V)

−40

0.82

0.80

0.78

0.76

−20 100 120

0.84

Temperature (5C)

806040200

VLIMIT2 (V)

−40

1.25

1.20

1.15

1.10

−20 100 120

1.30

Temperature (5C)

806040200

tDEL (ns)

−40

−20 100 120

0.7

0.8

4.0

4.5

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Figure 15. tLEB1 vs. Junction Temperature Figure 16. tLEB2 vs. Junction Temperature

Temperature (5C)

806040200

tLEB1 (ns)

−40

260

220

180

140

300

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 17. tSS vs. Junction Temperature Figure 18. fOSC (65-kHz Version) vs. Junction

Temperature

Figure 19. fOSC (100-kHz Version) vs. Junction

Temperature

Figure 20. DMAX vs. Junction Temperature

−20 100 120

Temperature (5C)

806040200

tLEB2 (ns)

−40

100

120

−20 100 120

Temperature (5C)

806040200

tSS (ms)

−40

−20 100 120

Temperature (5C)

806040200

fOSC (kHz)

−40

−20 100 120

Temperature (5C)

806040200

fOSC (kHz)

−40

104

100

−20 100 120

108

Temperature (5C)

806040200

DMAX (%)

−40

−20 100 120

340

380

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Figure 21. REQ vs. Junction Temperature Figure 22. IOOP3 vs. Junction Temperature

Temperature (5C)

806040200

REQ (kW)

−40

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 23. VBO(on) vs. Junction Temperature Figure 24. VBO(off) vs. Junction Temperature

Figure 25. tBO vs. Junction Temperature Figure 26. VFAULT

(

OVP

)

vs. Junction Temperature

−20 100 120

Temperature (5C)

806040200

IOOP3 (mA)

−40

140

130

120

110

150

−20 100 120

Temperature (5C)

806040200

VBO(on) (V)

−40

104

100

−20 100 120

Temperature (5C)

806040200

VBO(off) (V)

−40

105

101

−20 100 120

Temperature (5C)

806040200

tBO (ms)

−40

−20 100 120

Temperature (5C)

806040200

VFAULT(OVP) (V)

−40

3.1

3.0

2.9

2.8

−20 100 120

3.2

120

112

108

109

116

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Figure 27. VFAULT(OTP) vs. Junction Temperature Figure 28. IOTP vs. Junction Temperature

Temperature (5C)

806040200

VFAULT(OTP) (V)

−40

0.40

0.39

0.38

0.37

0.41

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 29. tOCP vs. Junction Temperature Figure 30. tAUTOREC vs. Junction Temperature

Figure 31. VCC

(

OVP

)

vs. Junction Temperature

−20 100 120

Temperature (5C)

806040200

IOTP (mA)

−40

−20 100 120

Temperature (5C)

806040200

tOCP (ms)

−40

−20 100 120

Temperature (5C)

806040200

tAUTOREC (s)

−40

1.1

1.0

0.9

0.8

−20 100 120

Temperature (5C)

806040200

VCC(OVP) (V)

−40

26.0

25.0

24.0

−20 100 120

27.0

0.43

1.3

26.5

25.5

24.5

0.42 49

1.2

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DEFINITION

General

The NCP1239 implements a standard current mode

architecture where the switch-off event is dictated by the

peak current setpoint. This component represents the ideal

candidate where low part-count and cost effectiveness are

the key parameters, particularly in low-cost ac-dc adapters,

open-frame power supplies etc. The NCP1239 packs all the

necessary components normally needed in today modern

power supply designs, bringing several enhancements such

as a non-dissipative over power protection (OPP),

a brown-out protection or HV start-up current source.

Current-Mode Operation with Internal Ramp

Compensation

Implementing peak current mode control operating at a 65

or 100-kHz switching frequency, the NCP1239 offers

a fixed internal compensation ramp that can easily by

summed up to the sensed current. The controller can be used

in CCM applications with wide input voltage range thanks

to its fixed ramp compensation that prevents the appearance

of sub-harmonic oscillations

Internal Brown-Out Protection

A portion of the bulk voltage is internally sensed via the

high-voltage pin monitoring (pin 8). When the voltage on

this pin is too low, the part stops pulsing. No re-start attempt

is made until the controller senses that the voltage is back

within its normal range. When the brown-out comparator

senses the voltage is acceptable, de-latch occurs and the

controller authorizes a re-start synchronized with VCC(on).

Adjustable Overpower Compensation

The high input voltage sensed on the HV pin is converted

into a current. This current builds an offset superimposed on

the current sense voltage which is proportional to the input

voltage. By choosing the resistance value in series with the

CS pin, the amount of compensation can be adjusted to the

application.

High-Voltage Start-Up

Low standby power results cannot be obtained with the

classical resistive start-up network. In this part,

a high-voltage current-source provides the necessary

current at start-up and turns off afterwards. An option is

available to activate the Dynamic Self−Supply (DSS). The

start−up current source is turned on to supply the controller

if the Vcc voltage drops below a certain level in light load.

EMI Jittering

An internal low-frequency modulation signal varies the

pace at which the oscillator frequency is modulated. This

helps spreading out energy in conducted noise analysis. To

improve the EMI signature at low power levels, the jittering

will not be disabled in frequency foldback mode (light load

conditions).

Frequency Foldback Capability

A continuous flow of pulses is not compatible with

no-load/light-load standby power requirements. To excel in

this domain, the controller observes the feedback pin and

when it reaches a level of 1.9 V, the oscillator starts to reduce

its switching frequency as the feedback level continues to

decrease. When the feedback level reaches 1.5 V, the

frequency hits its lower stop at 26 kHz. When the feedback

pin goes further down and reaches 1.0 V, the peak current

setpoint is internally frozen. Below this point, if the power

continues to drop, the controller enters classical skip-cycle

mode at a 31% frozen peak current.

Internal Soft-Start

A soft-start precludes the main power switch from being

stressed upon start-up. In this controller, the soft-start is

internally fixed to 8 ms. Soft-start is activated when a new

start-up sequence occurs or during an auto-recovery hiccup.

Fault Input

The NCP1239 includes a dedicated fault input accessible

via its fault pin (pin 1). It can be used to sense an

over-voltage condition on the adapter. The circuit can be

latched off by pulling the pin above the upper fault threshold,

VFAULT(OVP), typically 3.0 V. The controller is also disabled

if the fault pin voltage, VFAULT, is pulled below the lower

fault threshold, VFAULT(OTP), typically 0.4 V. The lower

threshold is normally used for detecting an over-temperature

fault (by the means of an NTC).

OVP Protection on VCC

It is sometimes interesting to implement a circuit

protection by sensing the VCC level. This is what this

controller does by monitoring its VCC pin. When the voltage

on this pin exceeds Vcc(ovp) threshold, the pulses are

immediately stopped and the part enters in an endless hiccup

or auto-recovery mode depending on controller options.

Short-Circuit/Overload Protection

Short-circuit and especially overload protections are

difficult to implement when a strong leakage inductance

between auxiliary and power windings affects the

transformer (the aux winding level does not properly

collapse in presence of an output short). Here, every time the

internal 0.8-V maximum peak current limit is activated, an

error flag is asserted and a time period starts, thanks to the

64-ms timer. When the fault is validated, all pulses are

stopped and the controller enters an auto-recovery burst

mode, with a soft-start sequence at the beginning of each

cycle. An internal timer keeps the pulses off for 1 s typically

which, associated to the 64-ms pulsing re-try period, ensures

a duty-cycle in fault mode less than 10%, independent from

the line level. As soon as the fault disappears, the SMPS

resumes operation. Please note that some version offers an

auto-recovery mode as we just described, some do not and

latch off in case of a short-circuit.

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HV CURRENT SOURCE PIN

The NCP1239 HV circuitry provides three features:

•Start-Up Current Source to Charge the VCC Capacitor

at Power On

•Brown-Out Protection: when the HV Pin Voltage is

below VBO(off) for the 68-ms Blanking Time (136 ms

for G version), the NCP1239 Stops Operating and

Recovers whenthe HV Pin Voltage Exceeds VBO(on)

•Over Power Protection: HV Pin Voltage is Sensed to

Determine the Amount of OPP Current Flowing Out

the CS Pin

The HV pin can be connected either to the bulk capacitor

or to the input line terminals through a diode. It is further

recommended to implement one or two resistors (in the

range of 2.2 kW) to reduce the noise that can be picked-up

by the HV pin.

START-UP SEQUENCE

The start-up time of a power supply largely depends on the

time necessary to charge the VCC capacitor to the controller

start-up threshold (VCC(on) which is 12 V typically). The

NCP1239 high-voltage current-source provides the

necessary current for a prompt start-up and turns off

afterwards. The delivered current (ISTART1) is reduced to

less than 0.5 mA when the VCC voltage is below VCC(inhibit)

(1.2 V typically). This feature reduces the die stress if the

VCC pin happens to be accidentally grounded. When VCC

exceeds VCC(inhibit), a 3-mA current (ISTART2) is provided

and charges the VCC capacitor. Please note that the internal

IC consumption is increased from few mA to 310 mA (ICC4)

when VCC crosses VCC(min) in order to have internal logic

wake-up when VCC reaches VCC(on).

The VCC charging time is then the total of the three

following durations:

•Charge from 0 V to VCC(inhibit):

tSTART1 +

VCC(inhibit) @CVCC

ISTART1 *ICC5

(eq. 1)

•Charge from VCC(inhibit) to VCC(min):

tSTART2 +

ǒVCC(min) *VCC(inhibit)Ǔ@CVCC

ISTART2 *ICC5

(eq. 2)

•Charge from VCC(min) to VCC(on):

tSTART3 +

ǒVCC(on) *VCC(min)Ǔ@CVCC

ISTART2 *ICC4

(eq. 3)

Assuming a 22-mF VCC capacitor is selected and replacing

ISTART1, ISTART2, ICC4, ICC5, VCC(inhibit) and VCC(on) by

their typical values, it comes:

tSTART1 +12 @22 u

500 u *20 u +55 ms (eq. 4)

tSTART2 +(10 *1.2)@22 u

3m*20 u +65 ms (eq. 5)

tSTART3 +(12 *10) @22 u

3m*310 u +16 ms (eq. 6)

tSTART +tSTART1 )tSTART2 )tSTART3 +136 ms (eq. 7)

Figure 32. The VCC at Start-Up is Made of Two Segments Given the Short-Circuit Protection

Implemented on the HV Source

tstart1 tstart2 tstart3

vcc(t)

Vcc(on)

Vcc(inhibit)

Vcc(min)

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If the VCC capacitor is first dimensioned to supply the

controller for the traditional 5 to 50 ms until the auxiliary

winding takes over, no-load standby requirements usually

cause it to be larger. The HV start-up current source is then

a key feature since it allows keeping short start-up times with

large VCC capacitors (the total start-up sequence duration is

often required to be less than 1 s).

When the DSS mode is enable (NCP1239JD65), the VCC

voltage is maintained between VCC(on) and VCC(min) by

turning the HV start−up current source on and off. This

function can be used only during transient load or in light

load condition. The HV current source cannot supply the

controller in Fixed−frequency operation otherwise the die

will overheat. As a result, an auxiliary voltage source is

needed to supply VCC during normal operation.

BROWN-OUT CIRCUITRY

For the vast majority of controllers, input line sensing is

performed via a resistive network monitoring the bulk

voltage or the incoming ac signal. When in the quest of low

standby power, the external network adds a consumption

burden and deteriorates the power supply standby power

performance. Owing to its proprietary high-voltage

technology, ON Semiconductor now offers onboard line

sensing without using an external network. The system

includes a 90-MW resistive network that brings a minimum

start-up threshold and an auto-recovery brown-out

protection. Both levels are independent from the input

voltage ripple. The brown-out thresholds are fixed (see

levels in the electrical characteristics table), but they are

designed to fit most of standard ac-dc converter

applications. The simplified internal schematic appears in

Figure 33 while typical operating waveforms are drawn in

Figure 34 and Figure 35.

Figure 33. A Simplified View of the Brown-Out Circuitry

NEMI

Filter

Vbulk

Rbo_H

Rbo_L

GND

BO_OK

VBO

When the HV pin voltage drops below the VBO(off)

threshold, the brown-out protection trips: the controller

stops generating DRV pulses once the BO timer elapses.

VCC is discharged to VCC(min) by the controller

consumption itself. When this level is reached, the HV

current source is activated to lifts VCC up again. At new

VCC(on), BO signal is again sensed. If VHV >V

BO(on), the

parts restarts. If the condition is not met, no drive pulse is

delivered and internal IC consumption brings VCC down

again. As a result, VCC operates in hiccup mode during a BO

event.

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Figure 34. BO Event during Normal Operation

BO_OK = "0"

èDrive pulse stops

Vcc(on)

Vcc(off)

Vcc(min)

vcc(t)

BO(t)

BO_OK = "0"

BO_OK = "1"

vDRV(t)

No pulse area

BO_OK = "1"

Vcc hiccup waiting

BO signal

Figure 35. BO Event before Start-Up

BO no OK

èNo drive pulse

BO_OK = "1"

èWait the next Vcc(on) for

fresh start-up sequence

Vcc(on)

Vcc(off)

Vcc(min)

First drive pulse

vcc(t)

Vcc hiccup waiting

BO signal

Vcc(inhibit)

BO(t)

BO_OK = "0"

BO_OK = "1"

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OVER POWER PROTECTION

Over Power Protection (OPP) is a known means to limit

the output power runaway at high mains. Several elements

such as propagation delays and operating mode explain why

a converter operated at high line delivers more power than

at low line. NCP1239 senses the input voltage via HV pin.

This line voltage is transformed into a current information

further applied to the current sense pin (CS). A resistor

placed in series from the sense resistor to the CS pin will

create an offset voltage proportional to the input voltage

variation. An added current sink will ensure a zero OPP

current at low line (125 V dc), leaving the converter power

capability intact in the lowest operating voltage. Figure 36

presents the internal simplified architecture of this OPP

circuitry.

Figure 36. Over Power Protection is Provided via the Bulk Voltage Present on HV Pin

HV sample

& sampling

HV detection

ROPP

Rsense

offset

To CS

comparator

EMI

Filter

Vbulk

Iopp

OPP current

generation

Vfb

The HV voltage will be transformed into a current equal

to 67.5 mA when the HV pin is biased to 125 V. However,

there is an internal fixed sink of 67.5 mA. Therefore, the net

current flowing into ROPP is 0 at this low-voltage input

(≤125 V dc), ensuring an almost non-compensated

converter at low line: at a 115-V rms input (162 V dc), the

current from the OTA block will induce a 87.5-mA current,

turning into a 20-mA offset current flowing into ROPP

. Now,

assume a 260-V rms input voltage (365 V dc), the controller

will generate an offset current of:

365 @0.54 u *67.5 u +130 mA(eq. 8)

Assume we need to reduce the maximum peak current

setpoint by 250 mV to limit the maximum power at the

considered 260-V rms input. In that case, we will need to

generate a 250-mV offset across ROPP

. With a 130-mA

current, ROPP should be equal to:

250 m

130 u +192 kW(eq. 9)

A small 100−220-pF capacitor closely connected between

the CS and GND pins will form an effective noise filter and

nicely improves the converter immunity. Now, with this

1.92-kW resistance, the low-line 20-mA offset current will

incur a 38-mV drop, which, in relationship to a 800-mV

maximum peak, generates a small 5% reduction. Assuming

a full DCM operation, the power would be reduced by 0.952

or 9.75% only. Please note that the OPP current is clamped

for a HV pin voltage greater than 365 V dc. Should you lift

the pin above this voltage, there will be no increase of the

OPP current.

The offset voltage can affect the standby power

performance by reducing the peak current setpoint in

light-load conditions. For this reason, it is desirable to cancel

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its action as soon as frequency folback occurs. A typical

curve variation is shown in Figure 37. At low power, below

the frequency folback starting point, 100% of the OPP

current is internally absorbed and no offset is created

through the CS pin. When feedback increases again and

reaches the frequency foldback point, as the frequency goes

up, OPP starts to build up and reaches its full value at

VFOLD + 0.7 V.

Figure 37. The OPP Current is Applied when the Feedback Voltage Exceeds the Folback Point. It is 0 below it

+ 0.7 V

Vfold

vFB(t)

IOPP(%)

100

max

Fsw

decreases

Fsw

increases

FAULT INPUT

The NCP1239 includes a dedicated fault input accessible

via the fault pin. Figure 38 shows the architecture of the fault

input. The controller can be latched by pulling up the pin

above the upper fault threshold, VFAULT(OVP), typically

3.0 V. An active clamp prevents the Fault pin voltage from

reaching the VFAULT(OVP) 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.

VFAULT(OVP) *VFAULT(clamp)

RFAULT(clamp)

+3V*1.35 V

1.35 kW,(eq. 10)

i.e. approximately 1.2 mA

This function is typically used to detect a VCC or auxiliary

winding over-voltage by means of a Zener diode generally

in series with a small resistor (see Figure 38).

Neglecting the resistor voltage drop, the OVP threshold is

then:

VAUX(OVP) +VZ)VFAULT(OVP) (eq. 11)

where VZ is the Zener diode Voltage.

The controller can also be latched off if the fault pin

voltage, VFAULT, is pulled below the lower fault threshold,

VFAULT(OTP), typically 0.4 V. This capability is normally

used for detecting an over-temperature fault by means of an

NTC thermistor. A pull up current source IOTP

, (typically

45 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).

The circuit detects an over-temperature situation when:

RNTC @IOTP +VFAULT(OTP) (eq. 12)

Hence, the OTP protection trips when

RNTC +

VFAULT(OTP)

IOTP

+8.9 kW(Typically) (eq. 13)

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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(min).

A bypass capacitor is usually connected between the Fault

and GND pins. It will take some time for VFAULT to reach

its steady state value once IOTP is enabled. Therefore, the

lower fault comparator (i.e. over-temperature detection) is

ignored during soft-start. In addition, in order to speed up

this fault pin capacitor, OTP current is doubled during the

soft-start period.

Figure 38. Fault Detection Schematic

Fault

NTC

Vaux

Latch

Up counter

Power on

reset

OVP/OTP gone

RST

Vfault(clamp) VFault(OTP)

VFault(OVP)

IOTP

Vdd

DRV

Rfault(clamp)

600 ns

Time constant

Blanking Time

Falling edge

As a matter of fact, the controller operates normally while

the fault pin voltage is maintained within the upper and

lower fault thresholds. Upper and lower fault detectors have

blanking delays to prevent noise from triggering them. Both

OVP and OTP comparator output are validated only if its

high-state duration lasts a minimum of 600 ns. Below this

value, the event is ignored. Then, a counter ensures that

OVP/OTP events occurred for 4 successive drive clock

pulses before actually latching the part.

When the part is latched-off, the drive is immediately

turned off and VCC goes in endless hiccup mode. The power

supply needs to be un-plugged to reset the part (VCC(reset) or

BO event). Please note that this protection on the Fault pin

is autorecovery for the E, K, M, P and Q versions.

AUTO-RECOVERY SHORT-CIRCUIT PROTECTION

In case of output short-circuit or if the power supply

experiences a severe overloading situation, an internal error

flag is raised and starts a countdown timer. If the flag is

asserted longer than the timer’s programmed value, the

driving pulses are stopped and a 1-s auto-recovery timer

starts. If VCC voltage is below VCC(min), HV current source

is activated to build up the voltage to VCC(on). On the

contrary, if VCC voltage is above VCC(min), HV current

source is not activated, VCC falls down as the auxiliary

pulses are missing and the controller waits that VCC(min) is

crossed to enable the stat-up current source. During the timer

count down, the controller purposely ignores the re-start

when VCC crosses VCC(on) and waits for another VCC cycle.

By lowering the duty cycle in fault condition, it naturally

reduces the average input power and the rms current in the

output cable. Illustration of such principle appears in

Figure 39. Please note that soft-start is activated upon

re-start attempt.

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Figure 39. An Auto-Recovery Hiccup Mode is Entered in Case a Faulty Event Longer than 64 ms

is Acknowledged by the Controller

Autorecovery timer

Vcc(on)

Vcc(off)

Vcc(min)

Overload on the

output voltage

OCP timer

vcc(t)

vDRV(t)

No pulse area

Autorecovery timer

OCP timer

The hiccup is operating regardless of the brown-out level.

However, when the internal comparator toggles indicating

that the controller recovers from a brown-out situation (the

input line was ok, then too low and back again to normal),

the hiccup is interrupted and the controller re-starts to the

next available VCC(on). Figure 40 displays the resulting

waveform: the controller is protecting the converter against

an overload. The mains suddenly went down, and then back

again at a normal level. Right at this moment, the hiccup

logic receives a reset signal and ignores the next hiccup to

immediately initiate a re-start signal.

Figure 40. BO Event in Auto-Recovery or Latch Mode

Autorecovery timer

Vcc(on)

Vcc(off)

Vcc(min)

Overload on the

output voltage

OCP timer

vcc(t)

vDRV(t)

No pulse area

BO(t)

BO_OK = "0"

BO_OK = "1" BO_OK = "1"

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LATCHED SHORT CIRCUIT PROTECTION WITH PRE-SHORT

In some applications, the controller must be fully latched

in case of an output short circuit presence. When the error

flag is asserted, meaning the controller is asked to deliver its

full peak current, upon timer completion, the controller

latches off: all pulses are immediately stopped and VCC

hiccups between the two levels, VCC(on) and VCC(min).

However, in presence of a small VCC capacitor, it can very

well be the case where the stored energy does not give

enough time to let the timer elapse before VCC touches the

VCC(off). When this happens, the latch is not acknowledged

since the timer countdown has been prematurely aborted. To

avoid this problem, NCP1239 combines the error flag

assertion together with the UVLO flag: upon start up, as

maximum power is asked to increase VOUT, the error flag is

temporarily raised until regulation is met. If during the time

the flag is raised an UVLO event is detected, the part latches

off immediately. When latched, VCC hiccups between the

two levels, VCC(on) and VCC(min) until a reset occurs

(Brown-out event or VCC cycled down below VCC(reset)). In

normal operation, if a UVLO event is detected for any

reason while the error flag is not asserted, the controller will

naturally resume operations. Please also note that this

pre-short protection is activated only during start-up

sequence. In normal operation, even if an UVLO event

occurs while the error flag is asserted, the controller will

enters in auto-recovery mode. Details of this behavior are

given in Figure 41.

Figure 41. UVLO Event during Start-Up Sequence and in Normal Operation

New sequence

UVLO

AND

OCP flag

at start−up

latched resumed

Glitch or

overloa

OCP flag

reset Fb

Vcc(on)

Vcc(off)

Vcc(min)

vcc(t)

vDRV(t)

LATCHING OR AUTO-RECOVERY MODE

The B, C, D, E, K, L, M, N, P, Q and R versions are

auto-recovery. When an overload fault is detected, they stop

generating drive pulses and VCC hiccups between VCC(min)

and VCC(on) during the auto-recovery timer before initiate a

fresh start-up sequence with soft-start.

The A, F, G, H, I and J versions latch off when they detect

an overload situation. In this condition, the circuit stops

generating drive pulses and let VCC drop down. When VCC

has reached 10-VCC(min) level, the circuit charged up VCC

to VCC(on). The controller enters in an endless hiccup mode.

The device cannot recover operation until VCC drops below

VCC(reset) or brownout recovery signal is applied.

Practically, the power supply must be unplugged to be reset

(VCC <V

CC(reset)). Please note that the controller always

enters in auto-recovery mode when the UVLO event occurs

without internal error flag signal (ie: without overload).

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FREQUENCY FOLDBACK

The reduction of no-load standby power associated with

the need for improving the efficiency, requires to change the

traditional fixed-frequency type of operation. This

controller implements a switching frequency folback when

the feedback voltage passes below a certain level, VFOLD,

set at 1.9 V. At this point, the oscillator turns into

a Voltage-Controlled Oscillator (VCO) and reduces

switching frequency down to a feedback voltage of 1.5 V

where switching frequency is 26 kHz typically. Below

1.5 V, the frequency is fixed and cannot go further down.

The peak current setpoint is free to follow the feedback

voltage from 3.2 V (full power) down to 1 V. At 1 V, as both

frequency and peak current are frozen (250 mV or ≈31% of

the maximum 0.8-V setpoint) the only way to further reduce

the transmitted power is to enter skip cycle. This is what

happens when the feedback voltage drops below 0.8 V

typically. Figure 42 depicts the adopted scheme for the part.

Figure 42. By Observing the Voltage on the Feedback Pin, the Controller Reduces its Switching Frequency for an

Improved Performance at Light Load

FSW

VFB

VCS

VFB

65 kHz

26 kHz

0.8 V 3.2 V

Vfold

3.2 V

0.8 V

0.47 V

Vfreeze

[0.25 V

1.0 V 1.9 V

1.9 V

max

min

Frequency Peak current setpoint

Vfold

[

min

Vskip Vskip

0.8 V

1.5 V

Vfold(end)

skip

SLOPE COMPENSATION

Slope compensation is a known means to fight

sub-harmonic oscillations in peak-current mode controlled

power converters (flyback in our case). By adding an

artificial ramp to the current sense information or

subtracting it from the feedback voltage, you implement

slope compensation. How much compensation do you need?

The simplest way is to consider the primary-side inductor

downslope and apply 50% of its value for slope

compensation. For instance, assume a 65-kHz/19-V output

flyback converter whose transformer turns ratio 1:N is

1:0.25. The primary inductor is 600 mH. As such, assuming

a 1-V forward drop of the output rectifier, the downslope is

evaluated to:

SOFF +

VOUT )Vf

NLp+19 )1

0.25 @600 u +(eq. 14)

+133 kAńsor133mAńms

If we have a 0.33-W sense resistor, then the current

downslope turns into a voltage downslope whose value is

simply:

SȀ

OFF +SOFF @RSENSE +(eq. 15)

+133 m @0.33 [44 mVńms

50% of this value is 22 mV/ms. The internal slope

compensation level is typically 29 mV/ms (for the 65-kHz

version) so it will nicely compensate this design example.

What if my converter is under compensated? You can still

add compensation ramp via a simple RC arrangement

showed in Figure 43. Please look at AND8029 available

from www.onsemi.com regarding calculation details of this

configuration.

NCP1239

www.onsemi.com

Figure 43. An Easy Means to Add Slope Compensation is by Using an Extra RC Network Building a Ramp

from the Drive Signal

1N4148

Rsense

DRV

A 2ND OVER-CURRENT COMPARATOR FOR ABNORMAL OVER-CURRENT FAULT DETECTION

A severe fault like a winding short-circuit can cause the

switch current to increase very rapidly during the on-time.

The current sense signal significantly exceeds VILIM1. But,

because the current sense signal is blanked by the LEB

circuit during the switch turn on, the power switch current

can become huge causing system damage.

The NCP1239 protects against this fault by adding an

additional comparator for abnormal over-current fault

detection. The current sense signal is blanked with a shorter

LEB duration, tLEB2, typically 120 ns, before applying it to

the abnormal over-current fault comparator. The voltage

threshold of the comparator, VILIM2, typically 1.2 V, is set

50 % higher than VLIMIT1, to avoid interference with normal

operation. Four consecutive abnormal over-current faults

cause the controller to enter latch mode. The count to 4

provides noise immunity during surge testing. The counter

is reset each time a DRV pulse occurs without activating the

Fault Over-Current Comparator.

Please note that abnormal over−current fault is following

the timer−based short−circuit protection behavior (auto−

recovery or latching off).

OVER-VOLTAGE PROTECTION ON VCC PIN

The NCP1239 hosts a dedicated comparator on the VCC

pin. When the voltage on this pin exceeds 25.5 V typically

(32.0 V for F, J, M and N versions) for more than 20 ms, a

signal is sent to the internal latch and the controller

immediately stops the driving pulses while remaining in a

lockout state. Depending controller options, this OVP on

VCC pin can be auto-recovery or latched. For latching-off

versions, the part can be reset by cycling down its VCC, for

instance by pulling off the power plug but also if a brown-out

recovery is sensed by the controller. This technique offers a

simple and cheap means to protect the converter against

optocoupler.

PROTECTING FROM A FAILURE OF THE CURRENT SENSING

A 1-mA (typically) pull-up current source, ICS, pulls up the

CS pin to disable the controller if the pin is left open.

In addition the maximum duty ratio limit (80% typically)

avoids that the MOSFET stays permanently on if the switch

current cannot reach the setpoint when for instance, the input

voltage is low or if the CS pin is grounded. In this case, the

OCP timer is activated. If the timer elapses, the controller

enters in auto-recovery or endless hiccup mode depending

on the controller option. This unexpected operation can lead

to deep CCM with destructive consequences.

NCP1239

www.onsemi.com

SOFT-START

Soft-start is achieved by ramping up an internal reference,

VSSTART, and comparing it to current sense signal. VSSTART

ramps up from 0 V once the controller powers up. The

setpoint rise is then limited by the VSSTART ramp so that a

gradual increase of the power switch current during start-up.

The soft-start duration (that is, the time necessary for the

ramp to reach the VILIM1 steady state current limit), tSSTART,

is typically 8 ms.

DRIVER

The NCP1239 maximum supply voltage, VCC(max), is

25.5 V (32.0 V for F and J versions). Typical high-voltage

MOSFETs have a maximum gate-source voltage rating of

20 V. The DRV pin incorporates an active voltage clamp to

limit the gate voltage on the external MOSFETs. The DRV

voltage clamp, VDRV(high) is typically 13.5 V with a

maximum limit of 16 V.

THERMAL 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 20_C.

The thermal shutdown is also cleared if VCC drops below

VCC(reset) or a brown-out fault is detected. A new power up

sequences commences at the next VCC(on) once all the faults

are removed.

Table 5. ORDERING INFORMATION

Device Marking Freq.

OCP

Protection

VCC OVP

Protection

Fault Pin

Protection

Levels Package Shipping

†

NCP1239AD65R2G 1239A065 65 kHz Latch Latch Latch 110/101

SOIC−7

(Pb-Free)

2500 /

Tape &

Reel

NCP1239BD65R2G 1239B065 65 kHz Auto-Recovery Latch Latch 110/101

NCP1239CD65R2G 1239C065 65 kHz Auto-Recovery Auto-Recovery Latch 110/101

NCP1239DD65R2G 1239D065 65 kHz Auto-Recovery Latch Latch 101/95

NCP1239ED65R2G 1239E065 65 kHz Auto-Recovery Auto-Recovery Auto-Recovery 110/101

NCP1239FD65R2G 1239F065 65 kHz Latch Latch Latch 229/176

NCP1239HD65R2G 1239H065 65 kHz Latch Latch Latch 229/224

NCP1239ID65R2G 1239I065 65 kHz Latch Latch Latch 101/95

NCP1239JD65R2G 1239J065 65 kHz Latch Latch Latch 101/95

NCP1239KD65R2G 1239K065 65 kHz Auto-Recovery Auto-Recovery Auto-Recovery 110/101

NCP1239LD65R2G 1239L065 65 kHz Auto-Recovery Latch Latch 82/77

NCP1239MD65R2G 1239M065 65 kHz Auto-Recovery Auto-Recovery Auto-Recovery 229/224

NCP1239ND65R2G 1239N065 65 kHz Auto-Recovery Auto-Recovery Latch 229/224

NCP1239PD65R2G 1239P065 65 kHz Auto-Recovery Auto-Recovery Auto-Recovery 82/79

NCP1239QD65R2G 1239Q065 65 kHz Auto-Recovery Auto-Recovery Auto-Recovery 82/79

NCP1239RD65R2G 1239R065 65 kHz Auto-Recovery Latch Latch 101/95

NCP1239AD100R2G 1239A100 100 kHz Latch Latch Latch 110/101

NCP1239BD100R2G 1239B100 100 kHz Auto-Recovery Latch Latch 110/101

NCP1239DD100R2G 1239D100 100 kHz Auto-Recovery Latch Latch 110/95

NCP1239ED100R2G 1239E100 100 kHz Auto-Recovery Auto-Recovery Auto-Recovery 110/101

NCP1239GD100R2G 1239G100 100 kHz Latch Latch Latch 95/86

†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging

Specification Brochure, BRD8011/D.

SOIC−7

CASE 751U−01

ISSUE E

DATE 20 OCT 2009

SEATING

PLANE

X 45 _

NOTES:

1. DIMENSIONING AND TOLERANCING PER

ANSI Y14.5M, 1982.

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSION A AND B ARE DATUMS AND T

IS A DATUM SURFACE.

4. DIMENSION A AND B DO NOT INCLUDE

MOLD PROTRUSION.

5. MAXIMUM MOLD PROTRUSION 0.15 (0.006)

PER SIDE.

SCALE 1:1

DIM

MIN MAX MIN MAX

INCHES

4.80 5.00 0.189 0.197

MILLIMETERS

B3.80 4.00 0.150 0.157

C1.35 1.75 0.053 0.069

D0.33 0.51 0.013 0.020

G1.27 BSC 0.050 BSC

H0.10 0.25 0.004 0.010

J0.19 0.25 0.007 0.010

K0.40 1.27 0.016 0.050

M0 8 0 8

N0.25 0.50 0.010 0.020

S5.80 6.20 0.228 0.244

−A−

−B−

0.25 (0.010)

−T−

0.25 (0.010) TSAS

XXX = Specific Device Code

A = Assembly Location

L = Wafer Lot

Y = Year

W = Work Week

G= Pb−Free Package

GENERIC

MARKING DIAGRAM

7 PL

____

*This information is generic. Please refer to

device data sheet for actual part marking.

Pb−Free indicator, “G” or microdot “ G”,

may or may not be present.

XXXXX

ALYWX

STYLES ON PAGE 2

1.52

0.060

7.0

0.275

0.6

0.024

1.270

0.050

4.0

0.155

ǒmm

inchesǓ

SCALE 6:1

*For additional information on our Pb−Free strategy and soldering

details, please download the ON Semiconductor Soldering and

Mounting Techniques Reference Manual, SOLDERRM/D.

SOLDERING FOOTPRINT*

MECHANICAL CASE OUTLINE

PACKAGE DIMENSIONS

ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.

ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding

the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically

disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the

rights of others.

98AON12199D

DOCUMENT NUMBER:

DESCRIPTION:

Electronic versions are uncontrolled except when accessed directly from the Document Repository.

Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.

PAGE 1 OF 2

7−LEAD SOIC

SOIC−7

CASE 751U−01

ISSUE E

DATE 20 OCT 2009

STYLE 4:

PIN 1. ANODE

2. ANODE

3. ANODE

4. ANODE

5. ANODE

6. ANODE

7. NOT USED

8. COMMON CATHODE

STYLE 1:

PIN 1. EMITTER

2. COLLECTOR

3. COLLECTOR

4. EMITTER

5. EMITTER

7. NOT USED

8. EMITTER

STYLE 2:

PIN 1. COLLECTOR, DIE, #1

2. COLLECTOR, #1

3. COLLECTOR, #2

4. COLLECTOR, #2

5. BASE, #2

6. EMITTER, #2

7. NOT USED

8. EMITTER, #1

STYLE 3:

PIN 1. DRAIN, DIE #1

2. DRAIN, #1

3. DRAIN, #2

4. DRAIN, #2

5. GATE, #2

6. SOURCE, #2

7. NOT USED

8. SOURCE, #1

STYLE 6:

PIN 1. SOURCE

2. DRAIN

3. DRAIN

4. SOURCE

5. SOURCE

7. NOT USED

8. SOURCE

STYLE 5:

PIN 1. DRAIN

2. DRAIN

3. DRAIN

4. DRAIN

7. NOT USED

8. SOURCE

STYLE 7:

PIN 1. INPUT

2. EXTERNAL BYPASS

3. THIRD STAGE SOURCE

4. GROUND

5. DRAIN

6. GATE 3

7. NOT USED

8. FIRST STAGE Vd

STYLE 8:

PIN 1. COLLECTOR (DIE 1)

2. BASE (DIE 1)

3. BASE (DIE 2)

4. COLLECTOR (DIE 2)

5. COLLECTOR (DIE 2)

6. EMITTER (DIE 2)

7. NOT USED

8. COLLECTOR (DIE 1)

STYLE 9:

PIN 1. EMITTER (COMMON)

2. COLLECTOR (DIE 1)

3. COLLECTOR (DIE 2)

4. EMITTER (COMMON)

5. EMITTER (COMMON)

6. BASE (DIE 2)

7. NOT USED

8. EMITTER (COMMON)

STYLE 10:

PIN 1. GROUND

2. BIAS 1

3. OUTPUT

4. GROUND

5. GROUND

6. BIAS 2

7. NOT USED

8. GROUND

STYLE 11:

PIN 1. SOURCE (DIE 1)

2. GATE (DIE 1)

3. SOURCE (DIE 2)

4. GATE (DIE 2)

5. DRAIN (DIE 2)

6. DRAIN (DIE 2)

7. NOT USED

8. DRAIN (DIE 1)

ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.

ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding

the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically

disclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor the

rights of others.

98AON12199D

DOCUMENT NUMBER:

DESCRIPTION:

Electronic versions are uncontrolled except when accessed directly from the Document Repository.

Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.

PAGE 2 OF 2

7−LEAD SOIC

www.onsemi.com

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ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability

arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.

Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,

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