Switching power supply circuit

1. A switching power supply circuit, comprising:

a power circuit;

a switching circuit including a first filter module, a power processing unit, a stability module, and a second filter module; and

a load;

wherein the first filter module receives a voltage signal from the power circuit and sends a filtered first voltage signal to the power processing unit; the power processing unit outputs a second voltage signal, the stability module stabilizes the second voltage signal and sends a third voltage signal to the second filter module; the second filter module filters the third voltage signal and sends a drive voltage to the load; and

in response to the second voltage signal instantaneously changing from high to low or low to high, during the change in current, power of the second voltage signal is stored in the stability module and released through the second filter module.

2. The switching power supply circuit as claimed in claim 1 , wherein the power processing unit includes an output terminal and a ground, the stability module includes a first inductor, a first capacitor and a first resistor, the first inductor, the first capacitor and the first resistor are connected in series between the output terminal and the ground.

3. The switching power supply circuit as claimed in claim 2 , wherein the second filter module includes a second inductor, a second capacitor, and a diode; the second inductor, the second capacitor, and the diode constituting a loop by which the power of the second voltage signal is released; wherein the first inductor and the second inductor are connected in series and the diode and the first capacitor are connected in parallel.

4. The switching power supply circuit as claimed in claim 3 , wherein the diode is a zener diode.

5. The switching power supply circuit as claimed in claim 4 , wherein the second filter module further includes a transformer including a primary winding and a secondary winding; the primary winding includes a first terminal and a second terminal, the secondary winding includes a third terminal and a fourth terminal; the first terminal is connected to the second capacitor; the second terminal is connected to an input terminal of the load; the third terminal and the fourth terminal are both connected to the ground.

6. The switching power supply circuit as claimed in claim 5 , wherein a third capacitor is connected between the second terminal and the ground.

7. The switching power supply circuit as claimed in claim 6 , wherein the first filter module includes a third inductor, a fourth capacitor, and a fifth capacitor; the third inductor and the fourth capacitor are connected between the power circuit and the ground; the fourth capacitor and the fifth capacitor are connected in parallel.

8. The switching power supply circuit as claimed in claim 6 , wherein the switching power supply circuit further includes a voltage divider circuit, the third voltage signal filtered by the filter module is divided into a feedback voltage through the voltage divider circuit; and the feedback voltage is input to a feedback terminal of the power processing unit.

9. The switching power supply circuit as claimed in claim 8 , wherein the power processing unit compares the feedback voltage with a reference voltage, and in response to the feedback voltage exceeding the reference voltage, the second voltage signal is forced into cutoff; and in response to the feedback voltage being lower than the reference voltage, the second voltage signal is forced into output.

10. The switching power supply circuit as claimed in claim 9 , wherein the reference voltage is equal to the drive voltage divided by the voltage divider circuit.

11. The switching power supply circuit as claimed in claim 2 , wherein the second filter module includes a diode, a transformer, and a second capacitor constituting a loop by which the power is released; wherein the diode is connected to the first inductor.

12. The switching power supply circuit as claimed in claim 11 , wherein the diode is a zener diode.

13. The switching power supply circuit as claimed in claim 12 , wherein the transformer includes a primary winding and a secondary winding; the primary winding includes a first terminal and a second terminal, the secondary winding includes a third terminal and a fourth terminal; the first terminal is connected to the zener diode; the second terminal is connected to an input terminal of the load; and the third terminal and the fourth terminal are both connected to the ground.

14. The switching power supply circuit as claimed in claim 13 , wherein the switching power supply circuit further includes a voltage divider circuit, the third voltage signal is divided into a feedback voltage through the voltage divider circuit; and the feedback voltage is input to a feedback terminal of the power processing unit.

15. The switching power supply circuit as claimed in claim 14 , wherein the power processing unit compares the feedback voltage with a reference voltage, and if the feedback voltage exceeds the reference voltage, the second voltage signal is forced into cutoff; and if the feedback voltage is lower than the reference voltage, the second voltage signal is forced into output.

16. The switching power supply circuit as claimed in claim 15 , wherein the reference voltage is equal to the drive voltage divided by the voltage divider circuit.

17. A switching power supply circuit, comprising:

a power circuit;

a switching circuit including a first filter module, a power processing unit, a stability module, and a second filter module; and

a load;

wherein the second filter module includes a loop; the first filter module receives a voltage signal from the power circuit and sends a filtered first voltage signal to the power processing unit; the power processing unit outputs a second voltage signal, the stability module stabilizes the second voltage signal and sends a third voltage signal to the second filter module; the second filter module filters the third voltage signal and sends a drive voltage to the load; and

in response to the second voltage signal instantaneously changing from high to low or low to high, during the change in current, power of the second voltage signal is stored in the stability module and released through the loop.

18. The switching power supply circuit as claimed in claim 17 , wherein the power processing unit includes an output terminal and a ground, and the stability module includes a first inductor, a first capacitor and a first resistor connected in series between the output terminal and the ground.

19. The switching power supply circuit as claimed in claim 18 , wherein the loop includes a second inductor, a second capacitor, and a diode; the first inductor and the second inductor are connected in series, the diode and the first capacitor are connected in parallel.

20. The switching power supply circuit as claimed in claim 19 , wherein the diode is a zener diode.

21. The switching power supply circuit as claimed in claim 18 , wherein the loop includes a diode, a transformer, and a second capacitor; the diode is connected to the first inductor.

22. The switching power supply circuit as claimed in claim 21 , wherein the diode is a zener diode.

23. The switching power supply circuit as claimed in claim 22 , wherein the transformer includes a primary winding and a secondary winding; the primary winding includes a first terminal and a second terminal, the secondary winding includes a third terminal and a fourth terminal; the first terminal is connected to the zener diode; the second terminal is connected to an input terminal of the load; and the third terminal and the fourth terminal are both connected to the ground.