Application circuit based on PFC controller L6564

Circuit explanation:

1. The input filter circuit plays a two-way filtering role, filtering out the interference from the power grid to the power circuit and the interference caused by the power circuit to the power grid.

interference;

2. The AC input mains rectified output half-sinusoidal voltage sampling circuit is used as the basis for input current waveform tracking. This requires that the filter capacitor capacity of the rectified output DC voltage cannot be large, otherwise the AC input mains rectified output half-sinusoidal voltage sampling cannot be completed. ;

3. Resistor R18, capacitors C8 and C9 form an RC compensation loop to ensure the stable operation of the amplifier circuit inside L6564;

4. Diode D2 is the output start-up diode. When the PFC output voltage has not yet been stably established, D2 supplies power to the output circuit. Once the PFC circuit is working normally and the output voltage is normal, D2 is cut off and does not work;

5. Resistor R1 is an output current limiting resistor, which is a PTC resistor. The greater the output current, the greater the heating of resistor R1 and the increased resistance, which plays the role of output current limiting;

6. Resistors R3, R6, R11 and R15 form the PFC output voltage overvoltage and undervoltage monitoring circuit. The detection signal is sent to pin 6 of L6564, which is a switch control signal;

7. Resistors R2, R8, R10, R12 and R14 form the PFC output voltage sampling circuit. The sampling voltage is compared with the internal reference voltage, and the output DC voltage is stable when passing through the internal control circuit;

8. Resistors R26 and R25 are PFC power switch tube source current sampling resistors. The sampling voltage is filtered by the filter circuit composed of R24 and C15 and sent to the 4th pin CS of L6564 to complete the sum of the PFC power switch tube source current line current. Overcurrent protection;

9. The PFC output control wiring strip can realize the output switch control function of the PFC output;

10. Capacitor C16 is the filter capacitor for the PFC output voltage overvoltage and undervoltage detection signals;

11. Q1 is the PFC power switch tube;

12. Capacitor C16 is the filter capacitor for the PFC output voltage overvoltage and undervoltage detection signals;

13. Resistor R24 ​​and capacitor C15 form the PFC power switch Q1 source current detection signal filter circuit to make the line current and overcurrent protection circuit inside L6564 work stably and reliably;

14. Resistor R32 and capacitor C13 form a sinusoidal waveform forming circuit. There should be a multiplier and a divider inside the L6564. After calculation, the output current of the PFC has nothing to do with the change of the AC input mains voltage;

15. Resistors R7, R16 and capacitor C10 form the startup circuit of L6564. Once L6564 completes the startup work, L6564 consists of the auxiliary power supply circuit (3-8 windings of inductor L2, capacitor C7, resistor R4, diode D4, capacitors C10, C11 and jumper Line JPX3 loop) power supply;

16. Inductor L2 is the output voltage boost inductor and auxiliary power supply winding;

17. The resistor R5 and the auxiliary winding circuit form the demagnetization detection circuit of the inductor L2 through the 7th pin of the L6564 to ensure that after the inductor L2 is demagnetized, the PFC power switch tube starts a new switching working cycle;

18. Diodes D4, D5, resistor R4 and capacitor C7 form the rectification and filtering circuit of the L6564's auxiliary power supply circuit;

19. Diode D3 is a PFC bootstrap voltage output rectifier diode;

20. Resistors R2, R8, R10, R12 and R14 form a PFC output voltage sampling circuit. The sampling voltage is compared with the internal reference voltage, and the output DC voltage is stable when passing through the internal control circuit;

21. Capacitors C10, C11 and jumper JPX3 form the RC filter circuit of the auxiliary power supply circuit.