FL6961 Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Features 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. 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 Ordering Information Part Number Operating Temperature Range FL6961MY -40°C to +125°C © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 Package 8-Pin, Small Outline Package (SOP) Packing Method Tape & Reel www.fairchildsemi.com FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting January 2012 Figure 1. Figure 2. Typical Application Circuit for Step-up Converter Typical Application Circuit for Single Stage PFC Converter Block Diagram MOT COMP 3 2 2.65V OVP 2.75V 2.3V 0.45V INV 1 4 LEB 2.5V SAWTOOTH GENERATOR VCC 8 VOLTAGE REGULATOR CS VLIMIT THD OPTIMIZATION Internal Supply FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Application Diagram VREF VCC UVLO 9R R Q INHIBIT TIMER 2.1V/1.75V 1R VZCDHYS = 0.35V 2.75V VCC_ON = 12V VCC_OFF= 9.5V S 16.5V 7 GATE DISABLE GND 6 10V 5 ZCD Figure 3. Function Block Diagram © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 www.fairchildsemi.com 2 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 Figure 4. Marking Information Pin Configuration Figure 5. Pin Configuration (Top View) Pin Definitions Pin # Name Description 1 INV 2 COMP 3 MOT 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 cycleby-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 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. FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Marking Information Output of the Error Amplifier. To create a precise clamping protection, a compensation network between this pin and GND is suggested. 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. Power Supply. Driver and control circuit supply voltage. © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 www.fairchildsemi.com 3 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 VVCC DC Supply Voltage VHIGH Gate Driver Min. -0.3 Max. Unit 30 V 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 660 mW +150 C PD Power Dissipation TJ Operating Junction Temperature θJA Thermal Resistance (Junction-to-Air) 150 C/W θJC Thermal Resistance (Junction-to-Case) 39 C/W +150 C TSTG TL ESD -40 Storage Temperature Range -65 +230 C Human Body Model: JESD22-A114 2.5 KV Machine Model: JESD22-A115 200 V Lead Temperature (Wave Soldering or IR, 10 Seconds) 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 TA Parameter Min. Operating Ambient Temperature © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 -40 Typ. Max. Unit +125 C FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Absolute Maximum Ratings www.fairchildsemi.com 4 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 24.5 V VCC Section VCC-OP Continuous Operation Voltage 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 27.8 28.8 V VCC-OVP VDD Over-Voltage Protection Level 26.8 tD-VCCOVP VDD Over-Voltage Protection Debounce 30 µs Error Amplifier Section VREF Reference Voltage 2.475 Gm Transconductance 125 VINVH Clamp High Feedback Voltage 2.65 VINVL Clamp Low Feedback Voltage 2.25 VOUT HIGH Output High Voltage VOZ 2.500 2.525 V μmho 2.70 2.30 V V 4.8 V 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 VINV=2.35V, VCOMP=1.5V 10 20 VINV=1.5V 550 800 VINV=2.65V, VCOMP=5V 10 20 0.77 0.82 ICOMP Source Current Sink Current μA Current-Sense Section VPK Threshold Voltage for Peak Current Limit Cycle-by-Cycle Limit tPD Propagation Delay tLEB Leading-Edge Blanking Time 0.87 V 200 ns RMOT=24kΩ, VCOMP=5V 400 500 RMOT=24kΩ, VCOMP=VOZ+50mV 270 350 16.0 17.5 V 1.4 V FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Electrical Characteristics ns Gate Section VZ-OUT Output Voltage Maximum (Clamp) VCC=25V 14.5 VOL Output Voltage Low VCC=15V, IO=100mA VOH Output Voltage High VCC=14V, IO=100mA tR Rising Time VCC=12V, CL=3nF, 20~80% 80 ns tF Falling Time VCC=12V, CL=3nF, 80~20% 40 ns 8 V Continued on the following page… © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 www.fairchildsemi.com 5 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 1.9 2.1 2.3 V Zero-Current Detection Section VZCD HYS of VZCD Input Threshold Voltage Rising Edge VZCD Increasing Threshold Voltage Hysteresis VZCD Decreasing 0.35 VZCD-HIGH Upper Clamp Voltage IZCD=3mA VZCD-LOW Lower Clamp Voltage IZCD=-1.5mA 0.3 Maximum Delay, ZCD to Output Turn-On VCOMP=5V, fSW=60KHz 100 Restart Time Output Turned Off by ZCD 300 tINHIB Inhibit Time (Maximum Switching Frequency Limit) RMOT=24kΩ VDIS Disable Threshold Voltage tDEAD tRESTART tZCD-DIS Disable Function Debounce Time 12 V V 500 400 ns 700 μs 2.8 130 RMOT=24kΩ, VZCD=100mV V 200 μs 250 800 mV μs Maximum On Time Section VMOT tON-MAX Maximum On Time Voltage Maximum On Time Programming (Resistor Based) © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 1.25 RMOT=24kΩ, VCS=0V, VCOMP=5V 1.30 25 1.35 V μs FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Electrical Characteristics www.fairchildsemi.com 6 3.0 2.515 2.4 I CC-OP (mA) V ref (V) 2.525 2.505 2.495 2.485 1.8 1.2 0.6 2.475 0.0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 Temperature (℃) 20 35 50 65 80 95 110 125 Temperature (℃) Figure 6. VREF vs. TA Figure 7. ICC-OP vs. TA 24.60 14.0 24.52 13.4 V th-ON (V) t ON-MAX (μs) 5 24.44 24.36 24.28 12.8 12.2 11.6 24.20 -40 -25 -10 5 20 35 50 65 80 11.0 95 110 125 -40 -25 -10 5 Temperature (℃) 35 50 65 80 95 110 125 Temperature (℃) Figure 8. tON-MAX vs. TA Figure 9. Vth-ON vs. TA 10.5 16.0 10.1 13.6 I CC-ST (μA) V th-OFF (V) 20 9.7 9.3 8.9 FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Typical Performance Characteristics 11.2 8.8 6.4 8.5 4.0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 Temperature (℃) 20 35 50 65 80 95 110 125 Temperature (℃) Figure 10. Vth-OFF vs. TA © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 5 Figure 11. ICC-ST vs. TA www.fairchildsemi.com 7 18.0 1.330 17.4 V Z-OUT (V) V MOT (V) 1.350 1.310 1.290 1.270 16.2 15.6 1.250 15.0 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 Temperature (℃) 0.85 0.83 0.81 0.79 0.77 5 20 35 50 65 80 95 110 125 Temperature (℃) Figure 14. VPK vs. TA © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 20 35 50 65 Figure 13. VZ-OUT vs. TA 0.87 -40 -25 -10 5 80 Temperature (℃) Figure 12. VMOT vs. TA V PK (V) 16.8 95 110 125 FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Typical Performance Characteristics (Continued) www.fairchildsemi.com 8 Error Amplifier Leading-Edge Blanking (LEB) 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 multivector 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. 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 RIN 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. 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. 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. Operating Current Operating current is typically 4.5mA. The low operating current enables better efficiency and reduces the requirement of VCC hold-up capacitance. 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 lowbandwidth, 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. Maximum On-Time Operation Given a fixed inductor value and maximum output power, the relationship between on-time and line voltage is: t on 2 L Po (1) Vrms 2 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: t on (max) RI ( k ) 25 s 24 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. (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. © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Functional Description www.fairchildsemi.com 9 5.00 4.80 A 0.65 3.81 5 8 B 6.20 5.80 PIN ONE INDICATOR 1.75 4.00 3.80 1 5.60 4 1.27 (0.33) 0.25 M 1.27 C B A LAND PATTERN RECOMMENDATION 0.25 0.10 SEE DETAIL A 1.75 MAX 0.25 0.19 C 0.10 0.51 0.33 0.50 x 45° 0.25 R0.10 C OPTION A - BEVEL EDGE GAGE PLANE R0.10 OPTION B - NO BEVEL EDGE 0.36 NOTES: UNLESS OTHERWISE SPECIFIED 8° 0° 0.90 0.406 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 SEATING PLANE (1.04) DETAIL A SCALE: 2:1 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 FL6961 • Rev. 1.0.2 www.fairchildsemi.com 10 FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting Physical Dimensions FL6961 — Single-Stage Flyback and Boundary Mode PFC Controller for Lighting © 2010 Fairchild Semiconductor Corporation FL6961 • Rev. 1.0.2 www.fairchildsemi.com 11