Multiphase zero-volt-switching resonant DC-DC regulator

• US 6,487,095 B1
• Filed: 10/31/2001
• Issued: 11/26/2002
• Est. Priority Date: 10/31/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ngo, Thai Q., Strand, Scott D., Malik, Randhir Singh, Hemena, William
• Primary Examiner(s): Sterrett, Jeffrey
• Assistant Examiner(s): Laxton, Gary L.
• Application Number:
  US10/002,754
• Time in Patent Office: 391 Days
• Field of Search: 363/24, 363/25, 363/65, 363/82, 363/84, 363/89, 363/90, 363/127, 363/133
• US Class Current: 363/25
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 7/4818 with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuits
• 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 multiphase zero-volt switching, zero volt switch resonant DC-DC regulator includes: a zero-volt switch zero volt switch; a DC output voltage means; a variable resonant circuit; a synchronous rectifier; and a sensing circuit. The sensing circuit senses a DC output voltage at the DC output of the regulator. The regulator uses the resonant circuit in conjunction with the sensing circuit to provide a substantially constant DC output voltage at a fixed frequency. If the sensing circuit senses a change in the DC output voltage, then a resonant frequency of the regulator is changed by the variable resonant circuit. This allows the oscillator of the regulator to maintain a fixed frequency, thus ensuring the availability of zero-volt switching over the full range of operation. The regulator also has the advantages of low power loss, reduced ripple, and a very fast transient response time.

Claims

1. A multiphase direct current DC-DC regulator, the regulator including a DC output, the regulator comprising:

a zero volt switch

a DC output voltage means coupled to the zero volt switch and the DC output;

a variable resonant circuit coupled to the DC output voltage means;

a synchronous rectifier coupled to the DC output voltage means and the variable resonant circuit; and

a sensing circuit coupled to the DC output and the variable resonant circuit, wherein the sensing circuit senses changes in a DC output voltage at the DC output,

wherein if the sensing circuit senses an increase in the DC output voltage, then a resonant frequency of the regulator is decreased by the variable resonant circuit,

wherein if the sensing circuit senses a decrease in the DC output voltage, then a resonant frequency of the regulator is increased by the variable resonant circuit.

2. The regulator of claim 1, wherein the zero volt switch comprises:

a set of push-pull transistors coupled to a DC input; and

a transformer coupled to the set of push-pull transistors and the DC input.

3. The regulator of claim 1, wherein the DC output voltage means comprises:

a high frequency transformer coupled to the variable resonant circuit;

an output inductor coupled to the high frequency transformer; and

an output capacitor coupled to the output inductor and the DC output.

4. The regulator of claim 1, wherein the variable resonant circuit comprises:

a resonant inductor coupled to a high frequency transformer of the DC output voltage means; and

a resonant capacitor coupled to the resonant inductor and the high frequency transformer.

5. The regulator of claim 1, wherein the synchronous rectifier comprises:

a synchronization driver; and

a set of synchronization transistors, wherein gates of the synchronization transistors are coupled to the synchronization driver, wherein drains of the synchronization transistors are coupled to the variable resonant circuit, wherein sources of the synchronization transistors are grounded.

6. The regulator of claim 1, wherein the sensing circuit comprises:

an error amplifier, wherein an output of the error amplifier is coupled to a resonant inductor of the variable resonant circuit; and

at least one sensing resistor coupled to the DC output and the error amplifier, wherein the at least one sensing resistor provides the error amplifier with a sense signal concerning the DC output voltage.

7. The regulator of claim 6, wherein the error amplifier compares the sense signal with a reference voltage,

wherein if the sense signal increases as compared with the reference voltage, then an output voltage of the error amplifier increases,

wherein if the sense signal decreases as compared with the reference voltage, than an output voltage of the error amplifier decreases.

8. A multiphase DC-DC regulator, the regulator including a DC output, the regulator comprising:

zero volt switch

a DC output voltage means coupled to the zero volt switch and the DC output;

a variable resonant circuit coupled to the DC output voltage means, the variable resonant circuit comprising;

a resonant inductor coupled to the DC output voltage means, and

a resonant capacitor coupled to the resonant inductor and the DC output voltage means;

a synchronous rectifier coupled to the DC output voltage means and the variable resonant circuit; and

a sensing circuit coupled to the DC output and the resonant inductor of the variable resonant circuit, wherein the sensing circuit senses changes in a DC output voltage at the DC output,

wherein if the sensing circuit senses an increase in the DC output voltage, then a resonant frequency of the DC output voltage means is decreased by the variable resonant circuit,

wherein if the sensing circuit senses a decrease in the DC output voltage, then a resonant frequency of the DC output voltage means is increased by the variable resonant circuit.

9. The regulator of claim 8, wherein the zero volt switch comprises:

a set of push-pull transistors coupled to a DC input; and

a transformer coupled to the set of push-pull transistors and the DC input.

10. The regulator of claim 8 wherein the DC output voltage means comprises:

a high frequency transformer coupled to the resonant inductor and the resonant capacitor of the variable resonant circuit;

an output inductor coupled to the high frequency transformer; and

an output capacitor coupled to the output inductor and the DC output.

11. The regulator of claim 8, wherein the synchronous rectifier comprises:

a synchronization driver; and

a set of synchronization transistors, wherein gates of the synchronization transistors are coupled to the synchronization driver, wherein drains of the synchronization transistors are coupled to the variable resonant circuit, wherein sources of the synchronization transistors are grounded.

12. The regulator of claim 8, wherein the sensing circuit comprises:

an error amplifier, wherein an output of the error amplifier is coupled to the resonant inductor of the variable resonant circuit; and

at least one sensing resistor coupled to the DC output and the error amplifier, wherein the at least one sensing resistor provides the error amplifier with a sense signal concerning the DC output voltage.

13. The regulator of claim 12, wherein the error amplifier compares the sense signal with a reference voltage,

wherein if the sense signal increases as compared with the reference voltage, then an output voltage of the error amplifier increases,

wherein if the sense signal decreases as compared with the reference voltage, than an output voltage of the error amplifier decreases.

14. A multiphase DC-DC regulator, the regulator including a DC output, the regulator comprising:

an oscillator;

a phase one circuit coupled to the oscillator, the phase one circuit comprising;

a first zero volt switch

a first DC output voltage means coupled to the first zero volt switch and the DC output,

a first variable resonant circuit coupled to the first DC output voltage means, and

a first synchronous rectifier coupled to the first DC output voltage means and the first variable resonant circuit;

a phase two circuit coupled to the oscillator, the phase two circuit comprising;

a second zero volt switch

a second DC output voltage means coupled to the second zero volt switch and the DC output,

a second variable resonant circuit coupled to the second DC output voltage means, and

a second synchronous rectifier coupled to the second DC output voltage means and the second variable resonant circuit,

wherein an operation of the phase two circuit is out of phase with an operation of the phase one circuit; and

a sensing circuit coupled to the DC output, the first variable resonant circuit, and the second variable resonant circuit, wherein the sensing circuit senses changes in a DC output voltage at the DC output,

wherein if the sensing circuit senses an increase in the DC output voltage, then a resonant frequency of the regulator is decreased by the first and second variable resonant circuits,

wherein if the sensing circuit senses a decrease in the DC output voltage, then a resonant frequency of the regulator is increased by the first and second variable resonant circuits.

15. The regulator of claim 14, wherein the first zero volt switch comprises:

a first set of push-pull transistors coupled to a DC input; and

a first transformer coupled to the first set of push-pull transistors and the DC input.

16. The regulator of claim 14, wherein the second zero volt switch comprises:

a second set of push-pull transistors coupled to a DC input; and

a second transformer coupled to the second set of push-pull transistors and the DC input.

17. The regulator of claim 14, wherein the first DC output voltage means comprises:

a first high frequency transformer coupled to the first variable resonant circuit;

a first output inductor coupled to the first high frequency transformer; and

a first output capacitor coupled to the first output inductor and the DC output.

18. The regulator of claim 14, wherein the second DC output voltage means comprises:

a second high frequency transformer coupled to the second variable resonant circuit;

a second output inductor coupled to the second high frequency transformer; and

a second output capacitor coupled to the second output inductor and the DC output.

19. The regulator of claim 14, wherein the first variable resonant circuit comprises:

a first resonant inductor coupled to a first high frequency transformer of the first DC output voltage means; and

a first resonant capacitor coupled to the first resonant inductor and the first high frequency transformer.

20. The regulator of claim 14, wherein the first synchronous rectifier comprises:

a first synchronization driver; and

a first set of synchronization transistors, wherein gates of the first synchronization transistors are coupled to the first synchronization driver, wherein drains of the first synchronization transistors are coupled to the first variable resonant circuit, wherein sources of the first synchronization transistors are grounded.

21. The regulator of claim 14, wherein the second synchronous rectifier comprises:

a second synchronization driver; and

a second set of synchronization transistors, wherein gates of the second synchronization transistors are coupled to the second synchronization driver, wherein drains of the second synchronization transistors are coupled to the second variable resonant circuit, wherein sources of the second synchronization transistors are grounded.

22. The regulator of claim 14, wherein the sensing circuit comprises:

an error amplifier, wherein an output of the error amplifier is coupled to a first resonant inductor of the first variable resonant circuit and to a second resonant inductor of the second variable resonant circuit; and

at least one sensing resistor coupled to the DC output and the error amplifier, wherein the at least one sensing resistor provides the error amplifier with a sense signal concerning the DC output voltage.

23. The regulator of claim 22, wherein the error amplifier compares the sense signal with a reference voltage,

wherein if the sense signal increases as compared with the reference voltage, then an output voltage of the error amplifier increases,

wherein if the sense signal decreases as compared with the reference voltage, than an output voltage of the error amplifier decreases.