Power converter with snubber

• US 20080169792A1
• Filed: 01/12/2007
• Published: 07/17/2008
• Est. Priority Date: 01/12/2007
• Status: Active Grant

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Potentia Semiconductor Corp. (Power Integrations Incorporated)
• Inventors: Orr, Raymond
• Granted Patent: US 7,579,814 B2
• Time in Patent Office: Days
• US Class Current: 323/222
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 3/155 using semiconductor devices only

Abstract

A buck or boost converter, which includes a first inductor, a controlled switch, a main diode, and an output capacitor, also includes a snubber circuit to reduce losses. The snubber circuit includes a second inductor in a path in series with the switch and main diode of the converter, a series-connected resistor and diode connected directly in parallel with the second inductor, and a capacitance in parallel with the main diode and which can be constituted partly or entirely by parasitic capacitance of the main diode.

Claims

1. A power converter comprising two input terminals, two output terminals, an output capacitor coupled between the two output terminals, a first inductor in a series path between the input and output terminals, a switch controlled by a control signal, and a first diode, the converter having a configuration for producing an output voltage at the output terminals from an input voltage supplied to the input terminals, the converter further comprising a second inductor, and a series-connected resistor and second diode in parallel with the second inductor, the second inductor and the series-connected resistor and second diode in parallel therewith being in a path in series with the switch and the first diode.

2. A power converter as claimed in claim 1 wherein the first inductor and the switch are coupled in series between the two input terminals, and the first diode is in said series path between the input and output terminals, to provide a boost configuration of the power converter.

3. A power converter as claimed in claim 2 wherein the second inductor is in series with the first diode in said series path between the input and output terminals.

4. A power converter as claimed in claim 2 wherein the second inductor is in series with the switch in a shunt path of the converter.

5. A power converter as claimed in claim 1 wherein the first inductor and the first diode are coupled in series between the two output terminals, and the switch is in said series path between the input and output terminals, to provide a buck configuration of the power converter.

6. A power converter as claimed in claim 5 wherein the second inductor is in series with the switch in said series path between the input and output terminals.

7. A power converter as claimed in claim 5 wherein the second inductor is in series with the diode in a shunt path of the converter.

8. A power converter as claimed in claim 1 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

9. A power converter as claimed in claim 3 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

10. A power converter as claimed in claim 4 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

11. A power converter as claimed in claim 6 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

12. A power converter as claimed in claim 7 and including a capacitor connected in parallel with the diode or the second diode in series with the resistor or the second diode.

13. A boost converter comprising two input terminals, a first inductor and a controlled switch coupled in series between the two input terminals, a first diode and an output capacitor coupled in series across the switch, a second inductor, and a series-connected resistor and second diode, the series-connected resistor and second diode being in parallel with the second inductor, the second inductor and the series-connected resistor and second diode in parallel therewith being in series with the first diode.

14. A boost converter as claimed in claim 13 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

15. A boost converter as claimed in claim 13 and including a capacitor connected in parallel with the first diode and a capacitor coupled in parallel with the resistor.

16. A boost converter comprising two input terminals, a first inductor and a controlled switch coupled in series between the two input terminals, a first diode and an output capacitor coupled in series across the switch, a second inductor, and a series-connected resistor and second diode, the series-connected resistor and a second diode being in parallel with the second inductor, the second inductor and the series-connected resistor and second diode in parallel therewith being in series with the switch, the converter further comprising a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

18. A boost converter as claimed in claim 16, wherein the capacitor is connected in parallel with the first diode and wherein the converter further comprises a further capacitor coupled in parallel with the resistor.

17. (canceled)

19. A buck converter comprising two input terminals, a controlled switch and a first diode coupled in series between the two input terminals, a first inductor and an output capacitor coupled in series across the first diode, a second inductor, and a series-connected resistor and second diode, the series-connected resistor and second diode being in parallel with the second inductor, the second inductor and the series-connected resistor and second diode in parallel therewith being in series with the switch.

20. A buck converter as claimed in claim 19 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

21. A buck converter as claimed in claim 19 and including a capacitor connected in parallel with the first diode and a capacitor coupled in parallel with the resistor.

22. A buck converter comprising two input terminals, a controlled switch and a first diode coupled in series between the two input terminals, a first inductor and an output capacitor coupled in series across the first diode, a second inductor, and a series-connected resistor and second diode, the series-connected resistor and second diode being in parallel with the second inductor, the second inductor and the series-connected resistor and second diode in parallel therewith being in series with the first diode.

23. A buck converter as claimed in claim 22 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

24. A buck converter as claimed in claim 22 and including a capacitor connected in parallel with the first diode and a capacitor coupled in parallel with the resistor.

25. A circuit arrangement comprising:

a first inductor through which a current flows in operation of the circuit arrangement;

a switch arranged to be opened and closed under the control of a control signal, the switch being arranged for conducting current of the first inductor when the switch is closed; and

a first diode arranged to be forward biased for conducting current of the inductor when the switch is open and for being reverse biased when the switch is closed;

wherein the circuit arrangement further comprises;

a second inductor, having an inductance much less than an inductance of the first inductor; and

a resistor and a second diode connected in series with the resistor, the series-connected resistor and second diode being connected in parallel with the second inductor;

the second inductor with the series-connected resistor and second diode in parallel therewith being in a path in series with the switch and the first diode.

26. A circuit arrangement as claimed in claim 25 and including a capacitor connected in parallel with the first diode or the second diode in series with the resistor or the second diode.

27. A circuit arrangement as claimed in claim 26 and forming a boost converter having input and output terminals, the first inductor coupling the input terminals to the switch, and the first diode coupling a junction between the first inductor and the switch to the output terminals.

28. A circuit arrangement as claimed in claim 26 and forming a buck converter having input and output terminals, the first inductor coupling the output terminals to the first diode, and the switch coupling a junction between the first inductor and the first diode to the input terminals.