Two terminals quasi resonant tank circuit

• US 7,764,515 B2
• Filed: 02/14/2007
• Issued: 07/27/2010
• Est. Priority Date: 02/14/2006
• Status: Active Grant

• Current Assignee: MyPAQ Holdings Ltd. (Transpacific IP Group Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Sharifipour, Bahmar, Jansen, Arian, Telefus, Mark
• Primary Examiner(s): Laxton; Gary L
• Application Number:
  US11/706,554
• Publication Number:
  US 20070263415A1
• Time in Patent Office: 1,259 Days
• Field of Search: 363/15, 363/16, 363/21.02, 363/21.03, 363/21.12, 363/97, 363/131
• US Class Current: 363/21.02
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power converter includes a transformer, a primary switch, an auxiliary switch, first and second resonance capacitors, and a secondary side rectification means. A switch mode power supply is formed to use reflected voltage and parasitic capacitance as an energy source for a transformer resonance. The auxiliary switch effectively exchanges energy between the primary inductance of the transformer and the first and second resonant capacitors. The auxiliary switch effectively switches the transformer resonance between two distinct frequencies. In one embodiment of the invention, the power converter can be, but is not limited to, a flyback converter and further includes a comparator and a driver. The comparator is for detecting the voltage across the second resonance capacitor and the driver is configured to drive the auxiliary switch based on the output state of the comparator. The resonant nature of the converter provides zero voltage (ZVS) for the primary switch as well as for the auxiliary switch.

Claims

1. A power converter comprising:

a transformer;

a resonant type circuit coupled to the transformer, a primary switch, an auxiliary switch, first and second resonance capacitors, and a rectifier located near a secondary side of the transformer; and

a flyback type converter, wherein the flyback type converter includes;

a comparator to detect the voltage across the second resonance capacitor, and

a driver to drive the auxiliary switch based on the output state of the comparator.

2. The converter of claim 1, wherein the resonant type circuit, via a commutation of the auxiliary switch, forms the energy exchange between the primary inductance of said transformer and said first and second resonant capacitors, respectively, wherein the commutation comprises an ON-OFF cycle for the auxiliary switch.

3. The converter of claim 1, further comprising:

a resonant type circuit switching between two resonant frequencies via the auxiliary switch, wherein the two resonant frequencies are based on the values of the first and second resonant capacitors.

4. The converter of claim 1, wherein the power converter is configured to provide Zero Voltage Switching (ZVS) for at least one of the primary switch and the auxiliary switch.

5. The converter of claim 1, the power converter configured for circulating energy stored in a parasitic capacitance in a resonance cycle, the parasitic capacitance associated with at least one of:

the primary switch, the secondary switch, and the transformer.

6. The converter of claim 1, further comprising:

a primary driver for the primary switch, and

an auxiliary driver for the auxiliary switch, the auxiliary driver independent from the primary driver.

7. The converter of claim 1, wherein the power converter is configured to extract energy from a driver for the auxiliary switch from a main resonance cycle, whereby the auxiliary switch is substantially self driven.

8. A power converter comprising:

a transformer;

a resonant type circuit coupled to the transformer, the resonant type circuit comprising;

a first capacitor coupled to the transformer for operating at a first resonance frequency, and

a second capacitor selectively coupled in parallel to the first capacitor for operating at a second resonance frequency; and

a flyback type converter, wherein the flyback type converter includes;

a comparator to detect the voltage across the second capacitor, and

a driver to drive the auxiliary switch based on the output state of the comparator.

9. A power converter comprising:

a transformer;

a main switch;

a first resonance capacitor coupled to the transformer to form a resonant circuit with the primary inductance of said transformer;

a second resonance capacitor coupled to the transformer through an auxiliary switch to form a resonant circuit with the primary inductance of said transformer;

a switching cycle comprising a first resonant cycle and a second resonant cycle, wherein energy in the first resonant capacitor is substantially transferred to the second resonance capacitor through the first and second resonant cycles;

a comparator; and

driving means to drive the auxiliary switch,

wherein the auxiliary switch switches over when most of the resonant energy is stored in the transformer.

10. The converter of claim 9, wherein the first and second resonance capacitors consist, at least in part, of parasitic capacitances.

11. The converter of claim 9, wherein the first resonant cycle comprises a higher frequency than the second resonant cycle.

12. The converter of claim 9, wherein the converter is of the flyback type.

13. The converter of claim 9, wherein the converter is of the forward type.

14. The converter of claim 9, wherein the converter is of the quasi resonant type.

15. The converter of claim 9, wherein the main switch includes a MOSFET.

16. The converter of claim 9, wherein the main switch includes a bipolar transistor.

17. The converter of claim 9, wherein the auxiliary switch includes a MOSFET.

18. The converter of claim 9, wherein the auxiliary switch includes a bipolar transistor.

19. The converter of claim 9, wherein at least one of the first and second resonance cycles provides substantial zero voltage switching for the main switch.

20. A power converter comprising:

a transformer;

a main switch;

a first resonance capacitor coupled to the transformer to form a resonant circuit with the primary inductance of said transformer;

a second resonance capacitor coupled to the transformer through an auxiliary switch to form a resonant circuit with the primary inductance of said transformer;

a switching cycle comprising a first resonant cycle and a second resonant cycle, wherein the auxiliary switch is driven from a resonant cycle;

a flyback transformer topology; and

a parametric circuit coupled to the transformer, wherein the parametric circuit is configured to be driven by voltage developed across the transformer during a magnetic flux reset cycle in the flyback transformer topology.

21. The converter of claim 20, wherein a driving circuit for the auxiliary switch comprises two diodes and a capacitor.

22. The converter of claim 20, wherein a driving circuit for the auxiliary switch comprises three diodes and a capacitor.

23. A power converter comprising:

a transformer;

a resonant type circuit coupled to the transformer, the resonant type circuit for providing a switching cycle for the transformer, the switching cycle comprising a first cycle and a second cycle, wherein the resonant type circuit is configured to store and release electromagnetic energy from a set of parasitic and non parasitic components;

a flyback transformer topology; and

a parametric circuit coupled to the transformer, wherein the parametric circuit is configured to be driven by voltage developed across the transformer during a magnetic flux reset cycle in the flyback transformer topology.

24. The converter of claim 23, wherein the set of parasitic and non parasitic components forms an inductor-capacitor (LC) quasi resonant type circuit.

25. The converter of claim 23, further comprising:

a source; and

a load, wherein the power converter is configured to store and release energy from the parasitic and non parasitic components to the load and back to the source in a resonant type operation.

26. The converter of claim 23, wherein the circuit is configured for high frequency operation.

27. The converter of claim 23, wherein the first cycle is a high frequency cycle.

28. The converter of claim 23, wherein the second cycle is a low frequency cycle.

29. The converter of claim 23, wherein the resonant circuit is configured to provide the switching cycle to the transformer without the need for external control.

30. The converter of claim 23, wherein the resonant circuit is energy efficient.

31. The converter of claim 23, wherein the resonant circuit is parametrically adaptive.

32. The converter of claim 23, wherein the resonant circuit is self oscillating.

33. The converter of claim 23, wherein the resonant circuit is a quasi resonant tank type circuit (QRTC).

34. The converter of claim 23, wherein the resonant circuit comprises a MOSFET.

35. The converter of claim 23, wherein the resonant circuit provides zero voltage switching, and zero current switching, for a plurality of conditions, and without the need for external control.

36. The converter of claim 23, wherein the resonant circuit allows an increase of the switching frequency to minimize a magnetic effect.

37. The converter of claim 23, wherein the resonant circuit is configured to eliminate a switching loss.

38. The converter of claim 23, wherein the resonant circuit is configured to minimize a stress factor for a switching component.

39. The converter of claim 23, wherein the resonant circuit is configured to minimize a stress factor for a filter component.

40. The converter of claim 23, further comprising a low voltage application coupled to the secondary coil of the transformer.

41. The converter of claim 23, further comprising:

a resonance current;

a zero voltage switch loop for circulating the resonance current.

42. The converter of claim 23, further comprising:

a forward converter bridge configured to provide a resonant reset for the transformer.

43. The converter of claim 23, further comprising an active clamp.

44. The converter of claim 23, further comprising integration with a controller for providing control to the resonance circuit.

45. The converter of claim 23, further comprising more than two terminal nodes.

46. The converter of claim 23, wherein the converter is implemented for motor control.