Soft-switching DC/DC converter having relatively better effectiveness

• US 20070007933A1
• Filed: 05/31/2006
• Published: 01/11/2007
• Est. Priority Date: 07/05/2005
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Chang, Yu-Ming, Chan, Chih-Chiang
• Granted Patent: US 7,433,209 B2
• Time in Patent Office: Days
• US Class Current: 323/235
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/33538 of the forward type H02M3/3353, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33569 having several active switching elements H02M3/3353 takes precedence
• CPC Class Codes: H02M 3/33573 Full-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

The proposed soft-switching DC/DC converter includes a converter circuit including a main switch having a first, a second and a control terminals for converting an input DC voltage to an output DC voltage, a resonant circuit electrically connected to the converter circuit, and an energy transferring circuit including an auxiliary switch having a first, a second and a control terminals and magnetically coupled to the resonant circuit. In which, the main switch is turned on under a specific voltage across the first and the second terminals of the main switch and the auxiliary switch is turned off under a specific current flowing through the first and the second terminals of the auxiliary switch both controlled by the resonant circuit through a resonance effect so as to accomplish a soft-switching of the converter.

Claims

1. A soft-switching DC/DC converter, comprising:

a converter circuit comprising a main switch having a first, a second and a control terminals for converting an input DC voltage to an output DC voltage;

a resonant circuit electrically connected to said converter circuit; and

an energy transferring circuit comprising an auxiliary switch having a first, a second and a control terminals and magnetically coupled to said resonant circuit,

wherein said main switch is turned on under a specific voltage across said first and said second terminals of said main switch and said auxiliary switch is turned off under a specific current flowing through said first and said second terminals of said auxiliary switch both controlled by said resonant circuit through a resonance effect so as to accomplish a soft-switching of said converter.

2. The converter according to claim 1, wherein said main switch comprises a transistor.

3. The converter according to claim 1, wherein said auxiliary switch comprises a transistor.

4. The converter according to claim 1, wherein said converter circuit comprises a buck converter.

5. The converter according to claim 4, wherein said buck converter comprises said main switch, an input capacitor having a first and a second terminals, an inductor having a first and a second terminals, a diode having an anode and a cathode and an output capacitor having a first and a second terminals, said first terminal of said main switch is electrically connected to said first terminal of said input capacitor, said first terminal of said inductor is electrically connected to said second terminal of said main switch and said cathode of said diode, said second terminal of said inductor is electrically connected to said first terminal of said output capacitor, and said anode of said diode is electrically connected to said second terminals of said input and said output capacitors.

6. The converter according to claim 1, wherein said converter circuit comprises a boost converter.

7. The converter according to claim 6, wherein said boost converter comprises said main switch, an input capacitor having a first and a second terminals, an inductor having a first and a second terminals, a diode having an anode and a cathode and an output capacitor having a first and a second terminals, said first terminal of said inductor is electrically connected to said first terminal of said input capacitor, said first terminal of said main switch is electrically connected to said second terminal of said inductor and said anode of said diode, said second terminal of said main switch is electrically connected to said second terminals of said input and said output capacitors, and said cathode of said diode is electrically connected to said first terminal of said output capacitor.

8. The converter according to claim 1, wherein said converter circuit comprises a buck-boost converter.

9. The converter according to claim 8, wherein said buck-boost converter comprises said main switch, an input capacitor having a first and a second terminals, an inductor having a first and a second terminals, a diode having an anode and a cathode and an output capacitor having a first and a second terminals, said first terminal of said main switch is electrically connected to said first terminal of said input capacitor, said first terminal of said inductor is electrically connected to said second terminal of said main switch and said cathode of said diode, said second terminal of said inductor is electrically connected to said second terminal of said input capacitor and said first terminal of said output capacitor, and said anode of said diode is electrically connected to said second terminal of said output capacitor.

10. The converter according to claim 1 further comprising a first and a second input terminals, a first and a second output terminals and a transformer having a primary winding with a first and a second terminals and a secondary winding with a first and a second terminals, wherein said first terminal of said main switch is electrically connected to said first input terminal, and said converter circuit is electrically connected to said second input terminal and said first and said second output terminals.

11. The converter according to claim 10, wherein said resonant circuit comprises said secondary winding of said transformer, a resonant inductor having a first and a second terminals, a resonant diode having an anode and a cathode and a flywheel diode having an anode and a cathode, said first terminal of said secondary winding is electrically connected to said cathode of said flywheel diode and said first terminal of said inductor, said second terminal of said inductor is electrically connected to said second terminal of said main switch, said second terminal of said secondary winding is electrically connected to said cathode of said resonant diode, and said anode of said resonant diode is electrically connected to said anode of said flywheel diode and said second input and said second output terminals of said converter.

12. The converter according to claim 10, wherein said energy transferring circuit further comprises said primary winding of said transformer, a clamping diode having an anode and a cathode, a clamping capacitor having a first and a second terminals and a discharging resistor having a first and a second terminals, said first terminal of said discharging resistor is electrically connected to said first input terminal, said first terminal of said clamping capacitor and said first terminal of said primary winding, said second terminal of said discharging resistor is electrically connected to said second terminal of said clamping capacitor and said cathode of said clamping diode, said anode of said clamping diode is electrically connected to said first terminal of said auxiliary switch and said second terminal of said primary winding, and said second terminal of said auxiliary switch is electrically connected to said second input and said second output terminals of said converter.

13. The converter according to claim 10, wherein said energy transferring circuit comprises a dual switch forward DC/DC converter.

14. The converter according to claim 13, wherein said dual switch forward DC/DC converter comprises a pair of switches, a first switch being said auxiliary switch and a second switch having a first, a second and a control terminals, a first diode having an anode and a cathode, a second diode having an anode and a cathode and said primary winding of said transformer, said anode of said first diode is electrically connected to said second terminal of said first switch and said second input and said second output terminals of said converter, said cathode of said first diode is electrically connected to said second terminal of said second switch and said first terminal of said primary winding, said second terminal of said primary winding is electrically connected to said anode of said second diode and said first terminal of said first switch, and said cathode of said second diode is electrically connected to said first input terminal of said converter and said first terminal of said second switch.

15. The converter according to claim 10, wherein said energy transferring circuit is electrically connected to said first and said second output terminals of said converter in parallel.

16. The converter according to claim 1, wherein said energy transferring circuit comprises a push-pull DC/DC converter.

17. The converter according to claim 1, wherein said energy transferring circuit comprises a full-bridge DC/DC converter.

18. The converter according to claim 1, wherein said specific voltage is zero volt.

19. The converter according to claim 1, wherein said specific current is one close to zero amp.

20. A soft-switching DC/DC converter, comprising:

a converter circuit comprising a main switch for converting an input DC voltage to an output DC voltage;

a resonant circuit electrically connected to said converter circuit; and

an energy transferring circuit comprising an auxiliary switch magnetically coupled to said resonant circuit,

wherein said main switch is turned on under a specific voltage and said auxiliary switch is turned off under a specific current both controlled by said resonant circuit through a resonance effect so as to accomplish a soft-switching of said converter.