FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Features Description Linearly Decreasing PWM Frequency Green Mode Under Light-Load and Zero-Load This highly integrated PWM controller provides several features to enhance the performance of low-power flyback converters. To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load and zero-load conditions. This green mode enables the power supply to meet international power conservation requirements. The supply voltage VDD is also used for feedback compensation, to regulate the output voltage without requiring a conventional TL431 and a photo-coupler. Another advantage of the FAN400A is that the typical startup current is only 8μA, while the typical operating current can be as low as 3.6mA. A large startup resistance can be used to achieve even higher power conversion efficiency. Conditions Constant Voltage (CV) and Constant Current (CC) No Secondary Feedback Low Startup Current: 8μA Low Operating Current: 3.6mA Leading-Edge Blanking Constant Power Limit Universal AC Input Range Synchronized Slope Compensation 140°C OTP Sensor with Hysteresis VDD Over-Voltage Clamping Cycle-by-Cycle Current Limiting Under-Voltage Lockout (UVLO) Fixed PWM Frequency with Hopping Gate Output Maximum Voltage Clamped at 17V Small SSOT-6 Package Applications General-purpose, switching mode, power supplies and flyback power converters, such as: Battery Chargers for Cellular Phones, Cordless Phones, PDAs, Digital Cameras, Power Tools Power Adapters for Ink Jet Printers, Video Game Consoles, Portable Audio Players Open-Frame SMPS for TV/DVD Standby and Auxiliary Supplies, Home Appliances, Consumer Electronics Replacement for Linear Transformers and RCC SMPS PC 5V Standby Power FAN400A integrates a frequency hopping function internally to reduce EMI emissions with minimum line filters. Built-in synchronized slope compensation maintains the stability of peak current-mode control. Proprietary internal compensation ensures constant output power limiting over a universal range of AC input voltages, from 90VAC to 264VAC. The FAN400A provides many protection functions. Pulse-by-pulse current limiting ensures constant output current, even if a short circuit occurs. The internal protection circuit disables PWM output if VDD exceeds 22.7V. The gate output is clamped at 17V to protect the power MOS from over-voltage damage. The built-in over-temperature protection (OTP) function shuts down the controller at 140°C with a 30°C hysteresis. The FAN400A is designed to provide a low-cost total solution for flyback converters. It is available in a smallfootprint, 6-pin, SSOT-6 package. Related Resources AN-400A Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Ordering Information Part Number Packing Method Operating Temperature Range Package FAN400ATY -40°C to +105°C SSOT-6 Green Tape & Reel FAN400ANY -40°C to +105°C DIP-8 Green Tube Eco Status For Fairchild’s definition of “green” please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 www.fairchildsemi.com FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback October 2008 V IN DO R IN D1 CO W AU X VDD G ATE C IN Q1 S EN SE GN D Figure 1. RS Typical Application Internal Block Diagram Figure 2. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 Functional Block Diagram VO FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Application Diagram www.fairchildsemi.com 2 XXX: AAT=FAN400A TT : Die run code . . . : Year code - - - : Week code 1’st line Z: Assembly plant code X: Year code Y: Week code TT: Die run code 3’rd line T: N=DIP P: Y=Green package M: Manufacture flow code Figure 3. Top Mark Pin Configuration DIP-8 SSOT-6 GND FB NC GND GATE GATE VDD VDD FB SENSE NC NC SENSE Figure 4. NC Pin Configurations Pin Definitions DIP Pin # SSOT Pin # Name Description 1 6 GATE The totem-pole output driver to drive the power MOSFET 2 5 VDD Power supply 3 4 NC 4 5 SENSE No connection Current sense senses the voltage across a sensed resistor. To provide overcurrent protection, PWM output is disabled if the voltage exceeds an internal threshold. This pin also provides current information for current-mode control. NC No connection 6 3 NC No connection 7 2 FB The FB pin provides feedback information to the internal PWM comparator. This feedback is used to control the duty cycle. When no feedback is provided, this pin is left open. 8 1 GND © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Marking Information Ground 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. Symbol Parameter Min. (1, 2) Max. Unit 30 V VVDD DC Supply Voltage VFB Input Voltage to FB Pin -0.3 7.0 V Input Voltage to Sense Pin -0.3 7.0 V +150 °C SSOT 263.3 °C/W DIP 135.7 °C/W +150 °C +260 °C 4 kV 200 V VSENSE TJ Operating Junction Temperature ΘJA Thermal Resistance (Junction-to-Air) TSTG Storage Temperature Range TL ESD -55 Lead Temperature (Wave Soldering or IR, 10 Seconds) Electrostatic Discharge Capability Human Body Model JESD22-A114 Machine Model JESD22-A115 Notes: 1. All voltage values, except differential voltages, are given with respect to GND pin. 2. Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Absolute Maximum Ratings www.fairchildsemi.com 4 Unless otherwise noted, VDD=15V and TA=25°C. Symbol Parameter Conditions Min. Typ. Max. Units 20 V 22.7 V VDD Section VDD-OP With Secondary Feedback Continuously Operation Voltage Without Secondary Feedback VDD-ON Turn-on Threshold Voltage 16 17 18 V VDD-OFF Turn-off Threshold Voltage 7.5 8.0 8.5 V IDD-ST Startup Current VDD=VDD-ON – 0.1V IDD-OP Operating Supply Current CL=1nF VDD-G OFF VDD Low-threshold Voltage to Exit Green-off Mode 8 20 μA 3.6 4.6 mA VDD-OFF+1.2 V 0.3 V/V 4.6 kΩ Feedback Input Section AV Input-Voltage to Current-Sense Attenuation ZFB Input Impedance VFB-OPEN VDD-FB IFB=0.1mA to 0.2mA Open-Loop Voltage 4.5 VDD Feedback Threshold Voltage V FB is Open 20.7 22.7 24.7 V IFB=0.4mA 18.4 20.4 22.4 V 100 150 ns Current-Sense Section tPD VSTHVA VSTHFL tLEB Propagation Delay Current Limit Valley Threshold Voltage Current Limit Flat Threshold Voltage VDD=18V 0.81 V VDD=15V 0.73 V VDD=10V 0.58 V VDD=18V 1.10 V VDD=15V 1.01 V VDD=10V 0.81 V Leading-Edge Blanking Time 250 Figure 5. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 310 370 ns FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Electrical Characteristics Saw Limit www.fairchildsemi.com 5 Unless otherwise noted, VDD=15V and TA=25°C. Symbol Parameter Conditions Min. Typ. Max. 60 65 70 ±4.1 ±4.6 ±5.1 Units Oscillator Section fOSC Frequency tHOP Hopping Period Center Frequency Hopping Range 4 kHz ms fOSC-G Green Mode Frequency 14.5 17.0 19.5 KHz VFB-N Green Mode Entry FB Voltage 2.3 2.6 2.9 V VFB-G Green Mode Ending FB Voltage VFB-Z Zero Duty Cycle FB Voltage SG Green Mode Modulation Slope 40 fDV Frequency Variation vs. VDD Deviation VDD=10 to 22V fDT Frequency Variation vs. Temperature Deviation TA=-20 to 85°C VFB-N 0.75 V 1.4 V 70 100 Hz/mV 2 % 1.5 5.0 % 73 78 % 1.5 V Output Section DCYMAX Maximum Duty Cycle 68 VGATE-L GATE Low Voltage IO=10mA VGATE-H GATE High Voltage IO=-10mA tr GATE Rising Time CL=1nF 150 200 250 ns tf GATE Falling Time CL=1nF 70 90 110 ns GATE Output Clamping Voltage VDD=20V 16 17 18 V VGATECLAMP 8 V Over Temperature Protection (OTP) TOTP TOTPRESTART Protection Junction Temperature 140 °C Restart Junction Temperature 110 °C © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Electrical Characteristics (Continued) www.fairchildsemi.com 6 8.6 16.8 8.4 V DD-OFF (V) V DD-ON (V) 17 16.6 16.4 16.2 8.2 8 7.8 16 7.6 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 T emperature (℃ ) Turn-on Threshold Voltage (VDD-ON) vs. Temperature Figure 7. 9 4 8 3.8 IDD-OP (mA) IDD-ST (μA) Figure 6. 7 6 5 35 50 65 80 95 110 125 Turn-off Threshold Voltage (VDD-ON) vs. Temperature 3.6 3.4 3.2 4 3 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 T emperature (℃ ) Figure 8. 20 35 50 65 80 95 110 125 T emperature (℃ ) Startup Current (IDD-ST) vs. Temperature Figure 9. Operating Supply Current (IDD-OP) vs. Temperature 75 68 67 74 66 DCY MAX (%) fOSC (KHz) 20 T emperature (℃ ) 65 64 73 72 71 63 62 70 -40 -25 -10 5 20 35 50 65 80 95 110 -40 125 -25 T emperature (℃ ) Figure 10. 5 20 35 50 65 80 95 110 125 T emperature (℃ ) Center Frequency (fOSC) vs. Temperature © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 -10 Figure 11. FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Typical Performance Characteristics Maximum Duty Cycle (DCYMAX) vs. Temperature www.fairchildsemi.com 7 2.2 2.8 2 V FB-G (V) V FB-N (V) 3 2.6 2.4 2.2 1.8 1.6 1.4 2 1.2 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 T emperature (℃ ) Figure 12. Green-Mode Entry FB Voltage (VFB-N) vs. Temperature Figure 13. 300 35 50 65 80 95 110 125 Green-Mode Ending FB Voltage (VFB-G) vs. Temperature 5 4.5 IDD-OP (mA) 280 tLEB (ns) 20 T emperature (℃ ) 260 240 220 4 3.5 3 2.5 2 200 -40 -25 -10 5 20 35 50 65 80 95 110 12 125 13 14 Figure 14. Leading-Edge Blanking Time (tLEB) vs. Temperature © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 15 16 17 18 19 20 21 22 23 V DD (V) Temperature (℃ ) Figure 15. Operating Supply Current vs. VDD Voltage 24 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Typical Performance Characteristics www.fairchildsemi.com 8 FAN400A devices integrate many useful functions for low-power switch-mode power supplies. The following descriptions highlight the key features of the FAN400A. Oscillator Operation Startup Current Leading-Edge Blanking (LEB) The required startup current is only 8μA. This allows a high-resistance, low-wattage startup resistor to supply the controller’s startup power. A 1.5 MΩ/0.25W startup resistor can be used over a wide input range (100V240VAC) with very little power loss. Each time the power MOSFET is switched on, a turn-on spike occurs at the sense-resistor. To avoid premature termination of the switching pulse, a 310ns leadingedge blanking time is built in. Conventional RC filtering is not necessary. During this blanking period, the current-limit comparator is disabled and cannot switch off the gate drive. The oscillation frequency is fixed at 65KHz. Operating Current The operating current is normally 3.6mA, which results in higher efficiency and reduces the required VDD holdup capacitance. A 10μF/25V VDD hold-up capacitor can be used over a wide input range (100V-240VAC) with very little power loss. Constant Output Power Limit When the SENSE voltage across the sense resistor RS reaches the threshold voltage (around 1.0V), the output GATE drive is turned off following a small propagation delay, tPD. This propagation delay introduces an additional current proportional to tPD•VIN/LP. The propagation delay is nearly constant regardless of the input line voltage VIN. Higher input line voltages result in larger additional currents. Under high input-line voltages the output power limit is higher than under low input-line voltages. Over a wide range of AC input voltages, the variation can be significant. To compensate for this, the threshold voltage is adjusted by adding a positive ramp (Vlimit_ramp). This ramp signal can vary from 0.73V to 1.01V and flattens out at 1.01V. A smaller threshold voltage forces the output GATE drive to terminate earlier, reducing total PWM turn-on time and making the output power equal to that of the low line input. This proprietary internal compensation feature ensures a constant output power limit over a wide range of AC input voltages (90VAC to 264VAC). Green-Mode Operation The proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load and zero-load conditions. The on-time is limited to provide better protection against brownouts and other abnormal conditions. Power supplies using the FAN400A can meet international restrictions regarding standby power-consumption. Constant Voltage (CV) and Constant Current (CC) without Feedback The FAN400A can tightly regulate the output voltage and provide over-current protection without requiring secondary-side feedback signals. For improved CV and CC accuracy, the transformer leakage inductance should be reduced as much as possible. Under Voltage Lockout (UVLO) The turn-on/turn-off thresholds are fixed internally at 17V and 8V. To enable the FAN400A during startup, the hold-up capacitor must first be charged to 17V through the startup resistor. The hold-up capacitor continues to supply VDD before energy can be delivered from the auxiliary winding of the main transformer. VDD must not drop below 8V during this startup process. This UVLO hysteresis window ensures that the hold-up capacitor can adequately supply VDD during startup. Over-Temperature Protection (OTP) The FAN400A has a built-in temperature sensing circuit to shut down PWM output once the junction temperature exceeds 140°C. While PWM output is shut down, the VDD voltage gradually drops to the UVLO voltage. Some of the internal circuits are shut down, and VDD gradually starts increasing again. When VDD reaches 17V, all the internal circuits, including the temperature sensing circuit, operate normally. If the junction temperature is still higher than 140°C, the PWM controller shuts down immediately. This situation continues until the temperature drops below 110°C. The PWM output is then turned back on. The temperature hysteresis window for the OTP circuit is 30°C. Gate Output The BiCMOS output stage is a fast totem-pole gate driver. Cross-conduction is avoided to minimize heat dissipation, increase efficiency, and enhance reliability. The output driver is clamped by an internal 17V Zener diode to protect the power MOSFET transistors against any harmful over-voltage gate signals. VDD Over-Voltage Clamping FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Operation Description VDD over-voltage clamping is built in to prevent damage from over-voltage conditions. When VDD exceeds 22.7V, PWM output is shut down. Over-voltage conditions may be caused by an open photo-coupler loop or a short circuit in the output. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 www.fairchildsemi.com 9 Slope Compensation Noise Immunity The sensed voltage across the current sense resistor is used for current mode control and pulse-by-pulse current limiting. The built-in slope compensation improves power supply stability. Furthermore, it prevents sub-harmonic oscillations that normally would occur because of peak current mode control. A positively sloped, synchronized ramp is activated with every switching cycle. The slope of the ramp is: 0.33 × Duty (1) Duty(max.) Noise from the current sense or the control signal may cause significant pulse-width jitter, particularly in continuous-conduction mode. Slope compensation helps alleviate this problem. Good placement and layout practices should be followed. The designer should avoid long PCB traces and component leads. Compensation and filter components should be located near the FAN400A. Finally, increasing the power-MOS gate resistance is advised. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Operation Description (Continued) www.fairchildsemi.com 10 Figure 16. Reference Circuit (without Secondary-Side Feedback) BOM Reference BD1 Component BD DI106 1A/600V Reference F1 Component R 1Ω/0.5W CX1 (Option) YC 4.7nF/400V (Y1) L1 Inductor 20mH 6*8mm CY1 (Option) YC 2.2nF/250V (Y1) L2 Inductor 10μH 6mm C1 EC 4.7μF/400V 105°C Q1 MOSFET 1A/600V C2 EC 4.7μF/400V 105°C R1,R2 R 750kΩ/1206 C3 CC 1nF/1kV R3,R4 R 47kΩ/1206 C4 EC 10μF/50V R5 R 47Ω/1206 C7 (Option) CC 1nF/100V 1206 R6 R 4.7Ω/0.5W C8 EC 470μF/10V 105°C R7 R 100Ω/0805 C9 EC 220μF/10V 105°C R8 R 10Ω/1206 D1 Diode FRI07 R10 (Option) R 10Ω/1206 D2 Diode FR102 T1 Transformer EE-16 D4 Diode SB360 U4 IC FAN400A (Green PWM IC) D5 (Option) ZD 6.8V/0.5W © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Applications Information www.fairchildsemi.com 11 Figure 17. Reference Circuit (with Secondary-Side Feedback) BOM Reference Component Reference Component BD1 BD DI106 1A/600V L2 Inductor 10μH 6mm CY1 (Option) YC 2.2nF/250V (Y1) Q1 MOSFET 1A/600V C1 EC 4.7μF/400V 105°C R1,R2 R 750kΩ/1206 C2 EC 4.7μF/400V 105°C R3,R4 R 47kΩ/1206 C3 CC 1nF/1kV R5 R 47Ω/1206 C4 EC 10μF/50V R6 R 4.7Ω/0.5W C6 CC 4.7nF/0805 R7 R 100Ω/0805 C7 (Option) CC 1nF/100V 1206 R8 R 10Ω/1206 C8 EC 470μF/10V 105°C R10 R 10Ω/1206 C9 EC 470μF/10V 105°C R11 R 100Ω/ 1/8W C10 CC 2.2nF/0805 R12 R 33kΩ/0805 D1 Diode FRI07 R13 R 33kΩ/ 1/8W D2 Diode FR102 R14 R 4.7kΩ/0805 D4 Diode SB360 T1 Transformer EE-16 D5 (Option) ZD 6.8V/0.5W U1 IC FAN400A (Green PWM IC) F1 R 1Ω/0.5W U2 IC PC817 L1 Inductor 20mH 6*8mm U3 IC TL431 © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Applications Information (Continued) www.fairchildsemi.com 12 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Physical Dimensions 9.83 9.00 6.67 6.096 8.255 7.61 3.683 3.20 5.08 MAX 7.62 0.33 MIN 3.60 3.00 (0.56) 2.54 0.56 0.355 0.356 0.20 1.65 1.27 9.957 7.87 7.62 NOTES: UNLESS OTHERWISE SPECIFIED A) THIS PACKAGE CONFORMS TO JEDEC MS-001 VARIATION BA B) ALL DIMENSIONS ARE IN MILLIMETERS. C) DIMENSIONS ARE EXCLUSIVE OF BURRS, MOLD FLASH, AND TIE BAR EXTRUSIONS. D) DIMENSIONS AND TOLERANCES PER ASME Y14.5M-1994 E) DRAWING FILENAME AND REVSION: MKT-N08FREV2. Figure 18. 8-Pin Dip-8 Package 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/. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 www.fairchildsemi.com 13 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback Physical Dimensions (Continued) Figure 19. 6-Pin SSOT-6 Package 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/. © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2 www.fairchildsemi.com 14 FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback 15 www.fairchildsemi.com © 2008 Fairchild Semiconductor Corporation FAN400A Rev. 1.0.2