High power converter architecture

• US 9,019,724 B2
• Filed: 07/27/2012
• Issued: 04/28/2015
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Telefus, Mark
• Primary Examiner(s): Laxton, Gary L
• Assistant Examiner(s): Moody, Kyle J
• Application Number:
  US13/560,847
• Publication Number:
  US 20140029312A1
• Time in Patent Office: 1,005 Days
• Field of Search: 363/16, 363 20- 2118
• US Class Current: 363/21.01
• CPC Class Codes: H02M 1/342 Active non-dissipative snubbers
• 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: 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

The power converter is an integration of three topologies which include a forward converter topology, a flyback converter topology, and a resonant circuit topology. The combination of these three topologies functions to transfer energy using three different modes. A first mode, or forward mode, is a forward energy transfer that forwards energy from the input supply to the output load in a manner similar to a forward converter. A second mode, or flyback mode, stores and releases energy in a manner similar to a flyback converter. A third mode, or resonant mode, stores and releases energy from the resonant tank using a resonant circuit and a secondary side forward-type converter topologies. An output circuit of the power converter is configured as a forward-type converter including two diodes and an inductor. The output circuit is coupled to a secondary winding of a converter transformer.

Claims

1. A power converter circuit comprising:

a transformer having a primary winding coupled to an input power supply and a secondary winding;

an output circuit coupled to the secondary winding, wherein the output circuit comprises a first diode, a second diode, an inductor, and a capacitor, further wherein the first diode and the second diode are coupled to the secondary winding of the transformer such that when the first diode is forward biased, the second diode is reverse biased, and when the first diode is reverse biased, the second diode is forward biased;

a primary switch coupled in series to the primary winding;

a sense resistor coupled in series with the primary switch on the opposite side as the primary winding;

a resonant circuit including an auxiliary switch serially coupled to a tank capacitor that are together coupled in parallel to the primary winding, wherein when the primary switch is OFF the tank capacitor and the primary winding form a resonant tank; and

a controller coupled to the primary switch and coupled to a node between the primary switch and the sense resistor such that the controller is able to sense voltage or current conditions within the power converter circuit;

wherein the power converter circuit is configured to;

forward energy from the input power supply to the output circuit;

store energy from leakage inductance, magnetizing inductance, and parasitic capacitances as resonant energy in the resonant tank; and

deliver stored resonant energy to the output circuit.

2. The power converter circuit of claim 1 wherein the power converter circuit is configured to forward energy from the input power supply to the output circuit when the primary switch is ON.

3. The power converter circuit of claim 1 wherein the parasitic capacitances comprise parasitic capacitances from the auxiliary switch and the primary switch.

4. The power converter circuit of claim 1 wherein the resonant energy is delivered over an entire resonant cycle of the resonant tank, wherein the resonant cycle comprises a positive primary winding current flow and a negative primary winding current flow.

5. The power converter circuit of claim 1 wherein energy delivered to the output circuit comprises a summation of energy forwarded from:

the input power supply;

resonant energy stored and released by the resonant tank; and

parasitic capacitances and leakage inductance stored and released as additional resonant energy by the resonant tank.

6. The power converter circuit of claim 1 wherein the auxiliary switch comprises a parametrically controlled auxiliary switch.

7. The power converter circuit of claim 6 further comprising driving circuitry coupled to the auxiliary switch and to the primary switch, wherein the driving circuitry is configured to parametrically control the auxiliary switch according to a voltage condition of the primary switch.

8. The power converter circuit of claim 1 wherein the resonant circuit, the transformer, and the output circuit are configured to store and release the resonant energy according to a flyback mode of energy conversion.

9. The power converter circuit of claim 8 wherein during the flyback mode of energy conversion, the primary switch is OFF.

10. The power converter circuit of claim 1 wherein an anode of the first diode is coupled to a first terminal of the secondary winding, an anode of the second diode is coupled to a second terminal of the secondary winding, a cathode of the first diode and a cathode of the second diode are each coupled to a first terminal of the inductor, and a second terminal of the inductor is coupled to the capacitor.

11. The power converter circuit of claim 1 wherein a primary winding current rises linearly to a peak value when the primary switch is ON.

12. A power converter circuit comprising:

a transformer having a primary winding coupled to an input power supply and a secondary winding;

an output circuit coupled to the secondary winding, wherein the output circuit comprises a first diode, a second diode, an inductor, and a capacitor, further wherein the first diode and the second diode are coupled to the secondary winding of the transformer such that when the first diode is forward biased, the second diode is reverse biased, and when the first diode is reverse biased, the second diode is forward biased;

a primary switch coupled in series to the primary winding;

a sense resistor coupled in series with the primary switch on the opposite side as the primary winding;

a resonant circuit including an auxiliary switch serially coupled to a tank capacitor that are together coupled in parallel to the primary winding, wherein when the primary switch is OFF the tank capacitor and primary winding form a resonant tank;

driving circuitry coupled to the auxiliary switch and to the primary switch, wherein the driving circuitry is configured to parametrically control the auxiliary switch according to a voltage condition of the primary switch; and

a controller coupled to the primary switch and coupled to a node between the primary switch and the sense resistor such that the controller is able to sense voltage or current conditions within the power converter circuit;

wherein the power converter circuit is configured to;

forward energy from the input power supply to the output circuit;

store energy from leakage inductance, magnetizing inductance, and parasitic capacitances as resonant energy in the resonant tank; and

deliver stored resonant energy to the output circuit.

13. The power converter circuit of claim 12 wherein an anode of the first diode is coupled to a first terminal of the secondary winding, an anode of the second diode is coupled to a second terminal of the secondary winding, a cathode of the first diode and a cathode of the second diode are each coupled to a first terminal of the inductor, and a second terminal of the inductor is coupled to the capacitor.

14. A method of transferring energy using a power converter, the method comprising:

configuring the power converter comprising a transformer having a primary winding coupled to an input power supply and a secondary winding, an output circuit having an inductor coupled to the secondary winding, and a primary switch coupled in series between the primary winding and a sense resistor;

controlling operation of the primary switch with a controller coupled to the primary switch based on a sensed voltage or current at a node between the primary switch and the sense resistor to which the controller is coupled;

forwarding energy from the input power supply to the output circuit while the primary switch is ON;

forming a resonant tank including an auxiliary switch serially coupled to a tank capacitor that are together coupled in parallel to the primary winding when the primary switch is OFF, wherein the resonant tank includes resonant energy derived from stored magnetizing inductance, stored leakage inductance and parasitic capacitances; and

delivering the resonant energy in the resonant tank to the output circuit while the primary switch is OFF.

15. The method of claim 14 wherein energy is continuously transferred from a primary side of the power converter to the output circuit while the primary switch is both ON and OFF.

16. The method of claim 14 wherein the parasitic capacitances comprise parasitic capacitances from the auxiliary switch and the primary switch.

17. The method of claim 14 wherein the resonant energy is delivered over an entire resonant cycle of the resonant tank, wherein the resonant tank includes the primary winding and the resonant cycle comprises a positive primary winding current flow and a negative primary winding current flow.

18. The method of claim 17 wherein the auxiliary switch turns ON and OFF according to a voltage condition of the primary switch.

19. The method of claim 14 wherein energy delivered to the output circuit comprises a summation of energy forwarded from:

the input power supply;

resonant energy stored and released by the resonant tank; and

parasitic capacitances and leakage inductance stored and released as additional resonant energy by the resonant tank.

20. The method of claim 14 further comprising controlling the auxiliary switch through self-commutation.

21. The method of claim 20 wherein during the flyback mode of energy conversion, the primary switch is OFF.

22. The method of claim 14 wherein the resonant energy is stored and delivered according to a flyback mode of energy conversion.

23. The method of claim 14 wherein the output circuit comprises a first diode, a second diode, and a capacitor, the first diode and the second diode are coupled to the secondary winding of the transformer such that when the first diode is forward biased, the second diode is reverse biased, and when the first diode is reverse biased, the second diode is forward biased.

24. The method of claim 14 wherein a primary winding current rises linearly to a peak value when the primary switch is ON.