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Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON
Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s
technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA
Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended
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August 2016
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7
FAN6961 —Boundary Mode PFC Controller
FAN6961
Boundary Mode PFC Controller
Features
Boundary Mode PFC Controller
Low Input Current THD
Controlled On-Time PWM
Zero-Current Detection
Cycle-by-Cycle Current Limiting
Leading-Edge Blanking instead of RC Filtering
Low Startup Current: 10 µA Typical
Low Operating Current: 4.5 mA Typical
Feedback Open-Loop Protection
Programmable Maximum On-Time (MOT)
Output Over-Voltage Clamping Protection
Clamped Gate Output Voltage 16.5 V
Applications
Electric Lamp Ballasts
AC-DC Switching Mode Power Converter
Open Frame Power Supplies and Power Adapters
Flyback Power Converters with ZCS / ZVS
Description
The FAN6961 is an 8-pin, boundary-mode, PFC
controller IC intended for controlling PFC pre-
regulators. The FAN6961 provides a controlled on-time
to regulate the output DC voltage and achieve natural
power factor correction. The maximum on-time of the
external switch is programmable to ensure safe
operation during AC brownouts. An innovative multi-
vector error amplifier is built in to provide rapid transient
response and precise output voltage clamping. A built-
in circuit disables the controller if the output feedback
loop is opened. The startup current is lower than 20 µA
and the operating current has been reduced to under
6 mA. The supply voltage can be up to 25 V,
maximizing application flexibility.
Ordering Information
Part Number
Operating Temperature
Range
Package
Packing Method
FAN6961SZ
-40°C to +125°C
8-Pin, Small Outline Package (SOP)(1)
Tape & Reel
FAN6961DZ
-40°C to +125°C
8-Pin, Dual In-line Package (DIP)
Tube
FAN6961SY
-40°C to +125°C
8-Pin, Small Outline Package (SOP)(1)
Tape & Reel
Note:
1. SZ &SY are for Eco status, please refer to https://www.fairchildsemi.com/products/power-management/power-
factor-correction/critical-bounary-conduction-mode-crcm/FAN6961.html.
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 2
FAN6961 — Boundary Mode PFC Controller
Application Diagram
FAN6961
Figure 1. Typical Application
Block Diagram
Figure 2. Function Block Diagram
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 3
FAN6961 — Boundary Mode PFC Controller
Marking Information
Figure 3. Marking Information
Pin Configuration
1 432
8 7 6 5
VCC GATE
MOT
ZCD
INV COMP CS
GND
Figure 4. DIP and SOP Pin Configuration (Top View)
Pin Definitions
Pin #
Name
Description
1
INV
Inverting Input of the Error Amplifier. INV is connected to the converter output via a resistive
divider. This pin is also used for over-voltage clamping and open-loop feedback protection.
2
COMP
Output of the Error Amplifier. To create a precise clamping protection, a compensation
network between this pin and GND is suggested.
3
MOT
Maximum On Time. A resistor from MOT to GND is used to determine the maximum on-time of
the external power MOSFET. The maximum output power of the converter is a function of the
maximum on time.
4
CS
Current Sense. Input to the over-current protection comparator. When the sensed voltage
across the sense resistor reaches the internal threshold (0.8 V), the switch is turned off to
activate cycle-by-cycle current limiting.
5
ZCD
Zero Current Detection. This pin is connected to an auxiliary winding via a resistor to detect the
zero crossing of the switch current. When the zero crossing is detected, a new switching cycle is
started. If it is connected to GND, the device is disabled.
6
GND
Ground. The power ground and signal ground. Placing a 0.1 µF decoupling capacitor between
VCC and GND is recommended.
7
GATE
Driver Output. Totem-pole driver output to drive the external power MOSFET. The clamped gate
output voltage is 16.5 V.
8
VCC
Power Supply. Driver and control circuit supply voltage.
F- Fairchild Logo
Z- Plant Code
X- Year Code
Y- Week Code
TT: Die Run Code
T: Package Type (S=SOP, D=DIP)
P: Z: Pb Free Y: Green Compound
M: Manufacture Flow Code
FAN6961
TPM
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 4
FAN6961 — Boundary Mode PFC Controller
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device
reliability. The absolute maximum ratings are stress ratings only. All voltage values, except differential voltage, are
given with respect to GND pin.
Symbol
Parameter
Min.
Max.
Unit
VVCC
DC Supply Voltage
30
V
VHIGH
Gate Driver
-0.3
30.0
V
VLOW
Others (INV, COMP, MOT, CS)
-0.3
7.0
V
VZCD
Input Voltage to ZCD Pin
-0.3
12.0
V
PD
Power Dissipation
SOP
400
mW
DIP
800
TJ
Operating Junction Temperature
-40
+125
C
θJA
Thermal Resistance (Junction-to-Air)
SOP
150
C/W
DIP
113
TSTG
Storage Temperature Range
-65
+150
C
TL
Lead Temperature (Wave Soldering or IR, 10 Seconds)
SOP
+230
C
DIP
+260
ESD
Human Body Model: JESD22-A114
2.5
KV
Machine Model: JESD22-A115
200
V
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol
Parameter
Min.
Typ.
Max.
Unit
TA
Operating Ambient Temperature
-40
+125
C
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 5
FAN6961 — Boundary Mode PFC Controller
Electrical Characteristics
Unless otherwise noted, VCC=15 V and TJ= -40°C to 125°C. Current is defined as positive into the device and
negative out of the device.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
VCC Section
VCC-OP
Continuous Operation Voltage
24.5
V
VCC-ON
Turn-On Threshold Voltage
11.5
12.5
13.5
V
VCC-OFF
Turn-Off Threshold Voltage
8.5
9.5
10.5
V
ICC-ST
Startup Current
VCC=VCC-ON – 0.16 V
10
20
µA
ICC-OP
Operating Supply Current
VCC=12 V, VCS=0 V,
CL=3 nF, fSW=60 KHz
4.5
6
mA
VCC-OVP
VDD Over-Voltage Protection Level
26.8
27.8
28.8
V
tD-VCCOVP
VDD Over-Voltage Protection Debounce
30
µs
Error Amplifier Section
VREF
Reference Voltage
2.475
2.500
2.525
V
Gm
Transconductance
125
μmho
VINVH
Clamp High Feedback Voltage
2.65
2.70
V
VINVL
Clamp Low Feedback Voltage
2.25
2.30
V
VOUT HIGH
Output High Voltage
4.8
V
VOZ
Zero Duty Cycle Output Voltage
1.15
1.25
1.35
V
VINV-OVP
Over Voltage Protection for INV Input
2.70
2.75
2.80
V
VINV-UVP
Under Voltage Protection for INV Input
0.40
0.45
0.50
V
ICOMP
Source Current
VINV=2.35 V, VCOMP=1.5 V
10
20
μA
VINV=1.5 V,
550
800
Sink Current
VINV=2.65 V, VCOMP=5 V
10
20
Current-Sense Section
VPK
Threshold Voltage for Peak Current Limit
Cycle-by-Cycle Limit
0.77
0.82
0.87
V
tPD
Propagation Delay
200
ns
tLEB
Leading-Edge Blanking Time
RMOT=24 kΩ, VCOMP=5 V
400
500
ns
RMOT=24 kΩ,
VCOMP=VOZ+50 mV
270
350
Gate Section
VZ-OUT
Output Voltage Maximum (Clamp)
VCC=25 V
14.5
16.0
17.5
V
VOL
Output Voltage Low
VCC=15 V, IO=100 mA
1.4
V
VOH
Output Voltage High
VCC=14 V, IO=100 mA
8
V
tR
Rising Time
VCC=12 V, CL=3 nF,
20~80%
80
ns
tF
Falling Time
VCC=12 V, CL=3 nF,
80~20%
40
ns
Continued on the following page…
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 6
FAN6961 — Boundary Mode PFC Controller
Electrical Characteristics
Unless otherwise noted, VCC=15 V and TJ=-40°C to 125°C. Current is defined as positive into the device and
negative out of the device.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
Zero Current Detection Section
VZCD
Input Threshold Voltage Rising Edge
VZCD Increasing
1.9
2.1
2.3
V
HYS of
VZCD
Threshold Voltage Hysteresis
VZCD Decreasing
0.35
V
VZCD-HIGH
Upper Clamp Voltage
IZCD=3 mA
12
V
VZCD-LOW
Lower Clamp Voltage
IZCD=-1.5 mA
0.3
V
tDEAD
Maximum Delay, ZCD to Output Turn-On
VCOMP=5 V,
fSW=60 KHz
100
400
ns
tRESTART
Restart Time
Output Turned Off by
ZCD
300
500
700
μs
tINHIB
Inhibit Time (Maximum Switching
Frequency Limit)
RMOT=24 kΩ
2.8
μs
VDIS
Disable Threshold Voltage
130
200
250
mV
tZCD-DIS
Disable Function Debounce Time
RMOT=24 kΩ,
VZCD=100 mV
800
μs
Maximum On Time Section
VMOT
Maximum On Time Voltage
1.25
1.30
1.35
V
tON-MAX
Maximum On Time Programming
(Resistor Based)
RMOT=24 kΩ,
VCS=0 V, VCOMP=5 V
25
μs
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 7
FAN6961 — Boundary Mode PFC Controller
Typical Performance Characteristics
2.475
2.485
2.495
2.505
2.515
2.525
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
Vref (V)
0.0
0.6
1.2
1.8
2.4
3.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
ICC-OP (mA)
Figure 5. VREF vs. TA
Figure 6. ICC-OP vs. TA
24.20
24.28
24.36
24.44
24.52
24.60
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
tON-MAX (μs)
11.0
11.6
12.2
12.8
13.4
14.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
Vth-ON (V)
Figure 7. tON-MAX vs. TA
Figure 8. Vth-ON vs. TA
8.5
8.9
9.3
9.7
10.1
10.5
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
Vth-OFF (V)
4.0
6.4
8.8
11.2
13.6
16.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
ICC-ST (μA)
Figure 9. Vth-OFF vs. TA
Figure 10. ICC-ST vs. TA
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 8
FAN6961 — Boundary Mode PFC Controller
Typical Performance Characteristics (Continued)
1.250
1.270
1.290
1.310
1.330
1.350
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
VMOT (V)
15.0
15.6
16.2
16.8
17.4
18.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
VZ-OUT (V)
Figure 11. VMOT vs. TA
Figure 12. VZ-OUT vs. TA
0.77
0.79
0.81
0.83
0.85
0.87
-40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature (℃)
VPK (V)
Figure 13. VPK vs. TA
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.7 9
FAN6961 — Boundary Mode PFC Controller
Functional Description
Error Amplifier
The inverting input of the error amplifier is referenced to
INV. The output of the error amplifier is referenced to
COMP. The non-inverting input is internally connected
to a fixed 2.5 V ± 2% voltage. The output of the error
amplifier is used to determine the on-time of the PWM
output and regulate the output voltage. To achieve a
low input current THD, the variation of the on time
within one input AC cycle should be very small. A multi-
vector error amplifier is built in to provide fast transient
response and precise output voltage clamping.
For FAN6961, connecting a capacitance, such as 1 µF,
between COMP and GND is suggested. The error
amplifier is a trans-conductance amplifier that converts
voltage to current with a 125 µmho.
Startup Current
Typical startup current is less than 20 µA. This ultra-low
startup current allows the usage of high resistance,
low-wattage startup resistor. For example,
1 MΩ/0.25 W startup resistor and a 10 µF/25 V (VCC
hold-up) capacitor are recommended for an AC-to-DC
power adaptor with a wide input range 85-265 VAC.
Operating Current
Operating current is typically 4.5 mA. The low operating
current enables a better efficiency and reduces the
requirement of VCC hold-up capacitance.
Maximum On-Time Operation
Given a fixed inductor value and maximum output
power, the relationship between on-time and line
voltage is:
2
2
rms
o
on VPL
t
(1)
If the line voltage is too low or the inductor value is too
high, tON is too long. To avoid extra low operating
frequency and achieve brownout protection, the
maximum value of tON is programmable by one resistor,
RI, connected between MOT and GND. A 24 kΩ
resistor RI generates corresponds to 25 µs maximum
on time:
skRt Ion
24
25
)(
(max)
(2)
The range of the maximum on-time is designed as 10 ~
50 µs.
Peak Current Limiting
The switch current is sensed by one resistor. The
signal is feed into CS pin and an input terminal of a
comparator. A high voltage in CS pin terminates a
switching cycle immediately and cycle-by-cycle current
limit is achieved. The designed threshold of the
protection point is 0.82 V.
Leading-Edge Blanking (LEB)
A turn-on spike on CS pin appears when the power
MOSFET is switched on. At the beginning of each
switching pulse, the current-limit comparator is disabled
for around 400ns to avoid premature termination. The
gate drive output cannot be switched off during the
blanking period. Conventional RC filtering is not
necessary, so the propagation delay of current limit
protection can be minimized.
Under-Voltage Lockout (UVLO)
The turn-on and turn-off threshold voltage is fixed
internally at 12 V/9.5 V. This hysteresis behavior
guarantees a one-shot startup with proper startup
resistor and hold-up capacitor. With an ultra-low startup
current of 20 µA, one 1 MΩ RIN is sufficient for startup
under low input line voltage, 85 Vrms. Power dissipation
on RIN would be less than 0.1 W even under high line
(VAC=265 Vrms) condition.
Output Driver
With low on resistance and high current driving
capability, the output driver can drive an external
capacitive load larger than 3000 pF. Cross conduction
current has been avoided to minimize heat dissipation,
improving efficiency and reliability. This output driver is
internally clamped by a 16.5 V Zener diode.
Zero-Current Detection (ZCD)
The zero-current detection of the inductor is achieved
using its auxiliary winding. When the stored energy of
the inductor is fully released to output, the voltage on
ZCD goes down and a new switching cycle is enabled
after a ZCD trigger. The power MOSFET is always
turned on with zero inductor current such that turn-on
loss and noise can be minimized. The converter works
in boundary-mode and peak inductor current is always
exactly twice of the average current. A natural power
factor correction function is achieved with the low-
bandwidth, on-time modulation. An inherent maximum
off time is built in to ensure proper startup operation.
This ZCD pin can be used as a synchronous input.
Noise Immunity
Noise on the current sense or control signal can cause
significant pulse-width jitter, particularly in the
boundary-mode operation. Slope compensation and
built-in debounce circuit can alleviate this problem.
Because the FAN6961 has a single ground pin, high
sink current at the output cannot be returned
separately. Good high-frequency or RF layout practices
should be followed. Avoiding long PCB traces and
component leads, locating compensation and filter
components near to the FAN6961, and increasing the
power MOSFET gate resistance improve performance.
© 2013 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6961 • Rev. 1.0.6 10
FAN6961 — Boundary Mode PFC Controller
Reference Circuit
Figure 14. Reference Circuit
8 5
41
NOTES:
A) THIS PACKAGE CONFORMS TO JEDEC MS-001 VARIATION BA WHICH DEFINES
B) CONTROLING DIMS ARE IN INCHES
C) DIMENSIONS ARE EXCLUSIVE OF BURRS, MOLD FLASH, AND TIE BAR EXTRUSIONS.
D) DIMENSIONS AND TOLERANCES PER ASME Y14.5M-2009
E) DRAWING FILENAME AND REVSION: MKT-N08MREV2.
0.400
0.355 [10.160
9.017 ]
0.280
0.240 [7.112
6.096]
0.195
0.115 [4.965
2.933]
MIN 0.015 [0.381]
MAX 0.210 [5.334]
0.100 [2.540]
0.070
0.045 [1.778
1.143]
0.022
0.014 [0.562
0.358]
0.150
0.115 [3.811
2.922]
C
0.015 [0.389] GAGE PLANE
0.325
0.300 [8.263
7.628]
0.300 [7.618]
0.430 [10.922]
MAX
(0.031 [0.786]) 4X
4X FOR 1/2 LEAD STYLE
FULL LEAD STYLE 4X
HALF LEAD STYLE 4X
0.10 C
SEATING PLANE
PIN 1 INDICATOR
0.031 [0.786] MIN 0.010 [0.252] MIN
8X FOR FULL LEAD STYLE
2 VERSIONS OF THE PACKAGE TERMINAL STYLE WHICH ARE SHOWN HERE.
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,
regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer
application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not
designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such
claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This
literature is subject to all applicable copyright laws and is not for resale in any manner.
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