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Is Now Part of
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of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. 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. 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
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January 2012
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
FL6961
Single-Stage Flyback and Boundary Mode PFC
Controller for Lighting
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: 10µA Typical
Low Operating Current: 4.5mA Typical
Feedback Open-Loop Protection
Programmable Maximum On-Time (MOT)
Output Over-Voltage Clamping Protection
Clamped Gate Output Voltage: 16.5V
Applications
General LED Lighting
Industrial, Commercial and Residential Fixtures
Outdoor Lighting: Street, Roadway, Parking,
Construction, and Ornamental LED Lighting
Description
The FL6961 is a general lighting power controller for
low- to high-power lumens applications requiring power
factor correction. It is designed for flyback or boost
converter operating in Boundary Mode.
The FL6961 provides a controlled on-time to regulate
the output DC voltage and achieves natural power factor
correction (PFC). The maximum on-time of the external
switch is programmable to ensure safe operation during
AC brownouts. An innovative multi-vector error amplifier
provides 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 20µA and the operating current is
less than 6mA. The supply voltage can be up to 25V,
maximizing application flexibility.
Ordering Information
Part Number Operating Temperature
Range Package Packing Method
FL6961MY -40°C to +125°C 8-Pin, Small Outline Package (SOP) Tape & Reel
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 2
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
Application Diagram
Figure 1. Typical Application Circuit for Step-up Converter
Figure 2. Typical Application Circuit for Single Stage PFC Converter
Block Diagram
UVLO
2.65V
2.3V
VOLTAGE
REGULATOR
2.5V
VCC_ON = 12V
VCC_OFF= 9.5V
9R
1R 2.75V
2.75V
0.45V
10V
2.1V/1.75V
SAWTOOTH
GENERATOR THD
OPTIMIZATION
INHIBIT
TIMER
VLIMIT
VCC
R
S
Q
LEB
DISABLE
INV
VCC
GND
ZCD
GATE
CS
4
7
5
6
8
1
3 2
MOT COMP
VZCDHYS = 0.35V
Internal
Supply
16.5V
VREF
OVP
Figure 3. Function Block Diagram
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 3
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
Marking Information
Figure 4. Marking Information
Pin Configuration
Figure 5. 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 (0.8V), 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 0.1µF 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 16.5V.
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 (M=SOP)
P: Z: Pb Free Y: Green Compound
M: Manufacture Flow Code
FL6961
TPM
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 4
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
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 660 mW
TJ Operating Junction Temperature -40 +150 C
θJA Thermal Resistance (Junction-to-Air) 150 C/W
θJC Thermal Resistance (Junction-to-Case) 39 C/W
TSTG Storage Temperature Range -65 +150 C
TL Lead Temperature (Wave Soldering or IR, 10 Seconds) +230 C
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
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 5
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
Electrical Characteristics
Unless otherwise noted, VCC=15V and TJ=-40°C to 150°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 – 0.16V 10 20 µA
ICC-OP Operating Supply Current VCC=12V, VCS=0V,
CL=3nF, fSW=60KHz 4.5 6 mA
VCC-OVP V
DD Over-Voltage Protection Level 26.8 27.8 28.8 V
tD-VCCOVP V
DD 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=2.35V, VCOMP=1.5V 10 20
μA
VINV=1.5V 550 800
Sink Current VINV=2.65V, VCOMP=5V 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=24kΩ, VCOMP=5V 400 500
ns
RMOT=24kΩ,
VCOMP=VOZ+50mV 270 350
Gate Section
VZ-OUT Output Voltage Maximum (Clamp) VCC=25V 14.5 16.0 17.5 V
VOL Output Voltage Low VCC=15V, IO=100mA 1.4 V
VOH Output Voltage High VCC=14V, IO=100mA 8 V
tR Rising Time VCC=12V, CL=3nF,
20~80% 80 ns
tF Falling Time VCC=12V, CL=3nF,
80~20% 40 ns
Continued on the following page…
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 6
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
Electrical Characteristics
Unless otherwise noted, VCC=15V and TJ=-40°C to 150°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=3mA 12 V
VZCD-LOW Lower Clamp Voltage IZCD=-1.5mA 0.3 V
tDEAD Maximum Delay, ZCD to Output Turn-On VCOMP=5V,
fSW=60KHz 100 400 ns
tRESTART Restart Time Output Turned Off by
ZCD 300 500 700 μs
tINHIB Inhibit Time (Maximum Switching
Frequency Limit) RMOT=24kΩ 2.8 μs
VDIS Disable Threshold Voltage 130 200 250 mV
tZCD-DIS Disable Function Debounce Time RMOT=24kΩ,
VZCD=100mV 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=24kΩ, VCS=0V,
VCOMP=5V 25 μs
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 7
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
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 (℃)
V
ref
(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 (℃)
I
CC-OP
(mA)
Figure 6.
V
REF vs. TA Figure 7. 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 (℃)
t
ON-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 (℃)
V
th-ON
(V)
Figure 8. tON-MAX vs. T A Figure 9.
V
th-ON vs. T A
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 (℃)
V
th-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 (℃)
I
CC-ST
(μA)
Figure 10.
V
th-OFF vs. T A Figure 11. ICC-ST vs. TA
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 8
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
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 (℃)
V
MOT
(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 (℃)
V
Z-OUT
(V)
Figure 12.
V
MOT vs. TA Figure 13.
V
Z-OUT vs. T A
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 (℃)
V
PK
(V)
Figure 14.
V
PK
v
s. TA
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 9
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
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 2.5V ±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.
Connecting a capacitance, such as 1µF, between
COMP and GND is suggested. The error amplifier is a
trans-conductance amplifier that converts voltage to
current with a 125µmho.
Startup Current
Typical startup current is less than 20µA. This ultra-low
startup current allows the usage of a high resistance,
low-wattage startup resistor. For example, 1MΩ/0.25W
startup resistor and a 10µF/25V (VCC hold-up) capacitor
are recommended for an AC-to-DC power adaptor with
a wide input range 85-265VAC.
Operating Current
Operating current is typically 4.5mA. The low operating
current enables 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 24kΩ resistor
RI generates corresponds to 25µs maximum on time:
skRt Ion
24
25
)(
(max) (2)
The range of the maximum on-time is 10 ~ 50µs.
Peak Current Limiting
The switch current is sensed by one resistor. The signal
is fed into the CS pin and an input terminal of a
comparator. A high voltage on the CS pin terminates
the switching cycle immediately and cycle-by-cycle
current limit is achieved. The designed threshold of the
protection point is 0.82V.
Leading-Edge Blanking (LEB)
A turn-on spike on the 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 voltages are fixed
internally at 12V and 9.5V, respectively. This hysteresis
behavior guarantees a one-shot startup with proper
startup resistor and hold-up capacitor. With an ultra-low
startup current of 20µA, one 1MΩ R
IN is sufficient for
startup under low input line voltage, 85Vrms. Power
dissipation on RIN would be less than 0.1W even under
high line (VAC=265Vrms) condition.
Output Driver
With low on resistance and high current driving
capability, the output driver can drive an external
capacitive load larger than 3000pF. Cross conduction
current has been avoided to minimize heat dissipation,
improving efficiency and reliability. This output driver is
internally clamped by a 16.5V 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 Boundary
Mode. Slope compensation and a built-in debounce
circuit can alleviate this problem. Because the FL6961
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
FL6961, and increasing the power MOSFET gate
resistance all improve performance.
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 10
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
Physical Dimensions
8°
0°
SEE DETAIL A
NOTES: UNLESS OTHERWISE SPECIFIED
A) THIS PACKAGE CONFORMS TO JEDEC
MS-012, VARIATION AA, ISSUE C,
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS DO NOT INCLUDE MOLD
FLASH OR BURRS.
D) LANDPATTERN STANDARD: SOIC127P600X175-8M.
E) DRAWING FILENAME: M08AREV13
LAND PATTERN RECOMMENDATION
SEATING PLANE
0.10 C
C
GAGE PLANE
x 45°
DETAIL A
SCALE: 2:1
PIN ONE
INDICATOR
4
8
1
C
MBA0.25
B
5
A
5.60
0.65
1.75
1.27
6.20
5.80
3.81
4.00
3.80
5.00
4.80
(0.33)
1.27
0.51
0.33
0.25
0.10
1.75 MAX
0.25
0.19
0.36
0.50
0.25
R0.10
R0.10
0.90
0.406 (1.04)
OPTION A - BEVEL EDGE
OPTION B - NO BEVEL EDGE
Figure 15. 8-Lead, SOIC, JEDEC MS-012, .150 Inch Narrow Body
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions,
specifically the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FL6961 • Rev. 1.0.2 11
FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting
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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