Method and apparatus for auto-interleaving synchronization in a multiphase switching power converter

• US 20040041543A1
• Filed: 04/25/2003
• Published: 03/04/2004
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Inventors: Brooks, Steven W., Pickle, Paul
• Granted Patent: US 6,965,219 B2
• Time in Patent Office: Days
• US Class Current: 323/212
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A plurality of single-phase synchronizing converter automatically synchronize on a peer-to-peer basis. Each synchronizing converter is configured as a DC-to-DC converter. The synchronizing converters operate in parallel as a multi-phase converter. A common bus between the synchronizing converters includes a sync line and a common phase control line. Proper phasing automatically occurs when power is applied, and the phasing changes automatically as converters are added or removed. When the system powers up, the converters arbitrate for phase position. The phasing positions are random, but the phasing is relatively symmetrical regardless of the number of phases. Preferably, a hot-swappable converter module can be plugged into any location of a parallel multiphase bus to produce a common output voltage. When an additional module is plugged in, the converters readjust their phases to maintain phase symmetry. Preferably, each module shares a substantially equal portion of the output load.

Claims

1. A power supply system comprising a first single-phase synchronizing converter that produces output power having a first phase, the first single-phase synchronizing converter configured to automatically synchronize with at least one other power converter to produce phase symmetry between the first phase and one or more phases of the at least one other power converter.

2. The power supply system of claim 1, further comprising a common phase control bus, wherein the first single-phase synchronizing converter provides a channel pulse to the common phase control bus.

3. The power supply system of claim 1, further comprising a common phase control bus, wherein the first single-phase synchronizing converter provides a pulse to the common phase control bus, the pulse indicating a phase of the single-phase synchronizing converter.

4. The power supply system of claim 3, wherein the single-phase synchronizing converter uses a tri-state driver to provide the pulse to the common phase control bus.

5. The power supply system of claim 3, wherein the common phase control bus carries time and amplitude information.

6. The power supply system of claim 1, further comprising a sync bus, wherein the single-phase synchronizing converter provides a sync pulse to the sync bus to indicate a start of a cycle of the power supply system.

7. The power supply system of claim 1, further comprising a loadshare bus, wherein the first single-phase synchronizing converter provides a signal to the loadshare bus to indicate an amount of current the first single-phase synchronizing converter is supplying to a load connected to the power supply system.

8. A power supply system comprising a first single-phase synchronizing converter that produces output power having a first phase, the first single-phase synchronizing converter configured to automatically synchronize on a peer-to-peer basis with at least one other single-phase power converter to produce phase symmetry between the first phase at least one phase of the at least one other single-phase power converter to produce a multi-phase converter.

9. The power supply system of claim 8, wherein the first single-phase synchronizing converter is provided to a sync line and to a common phase control line.

10. The power supply system of claim 8, wherein the single-phase synchronizing converter comprises a feedback loop to control the first phase by adjusting the first phase to fall between a previous power pulse produced by a first peer of the single-phase synchronizing converter and a subsequent power pulse produced by a second peer of the single-phase synchronizing converter.

11. A method for adjusting a phase of an output power pulse of a power module, comprising controlling the phase by a feedback loop configured to adjust the first phase to fall between a previous power pulse produced by a first peer of the power module and a subsequent power pulse and a subsequent power pulse produced by a at least one other power module.

12. A power supply system comprising:

a first converter that produces output power according to a first phase; and

a second converter that produces output power according to a second phase, the first and second converters each configured to automatically synchronize on a peer-to-peer basis to produce phase symmetry between the first phase and the second phase.

13. The power supply system of claim 12, further comprising a common phase control bus, wherein the first converter provides a first channel pulse to the common phase control bus and the second converter provides a second channel pulse to the common phase control bus.

14. The power supply system of claim 13, wherein the first converter uses a tri-state driver to provide the first channel pulse to the common phase control bus.

15. The power supply system of claim 12, further comprising a sync bus, wherein a faster of the first converter and the second converter provides a sync pulse to the sync bus to indicate a start of a cycle of the power supply system.

16. The power supply system of claim 12, further comprising a loadshare bus, wherein:

the first converter provides a signal to the loadshare bus to indicate an amount of current the first single-phase synchronizing converter is supplying to a load connected to the power supply system; and

the second converter provides a signal to the loadshare bus to indicate an amount of current the second synchronizing converter is supplying to the load.

17. The power supply system of claim 12, further comprising a shutdown bus, wherein the first converter provides a signal to the shutdown bus to shutdown the first converter and the second converter.

18. The power supply system of claim 12, wherein the first converter is configured to start a first timer at the end of a first second-channel pulse produced by the second converter, the first converter further configured to end the first timer and start a second timer at a start of a first-channel pulse produced by the first converter, the first converter further configured to stop the second timer at a start of a second second-channel pulse produced by the second converter, the first converter configured to adjust a timing of the first-channel pulse to approximately equalize times measured by the first timer and the second timer.

19. The power supply system of claim 12, wherein the first converter produces first channel pulses and the second channel produces second channel pulses, the first channel configured to adjust a phase of the first channel pulses to fall between the second channel pulses.

20. The power supply system of claim 12, wherein the first converter produces first channel pulses and the second channel produces second channel pulses, the first channel configured to adjust a phase of the first channel pulses to fall between the second channel pulses, the second channel configured to adjust a phase of the second channel pulses to fall between the first channel pulses.

21. The power supply system of claim 12, wherein the first converter produces first channel pulses and the second channel produces second channel pulses, the first channel configured to adjust a phase of the first channel pulses to produce phase symmetry with respect to the second channel pulses.

22. An auto-interleaving multiphase switching converter, comprising:

at least a first inductor and a second inductor having respective input terminals and respective output terminals, the output terminals connected together;

at least a first switch circuit connected to the input terminal of the first inductor, and at least a second switch circuit coupled to the input terminal of the second inductor;

at least one voltage source coupled to the first and second switch circuits; and

a first controller to control operations of the first switch circuit and a second controller to control operations of the second switch circuit, the first and second controllers configured to alternately connect the input terminals of the respective inductors to the respective voltage source and ground, the first and second controllers configured to adjust duty cycles of respective voltage waveforms across the respective inductors to achieve substantially equal sensed voltages representative of respective voltages at the input terminals of the inductors, the first and second controllers further configured to adjust a phase of operation of the respective first and second switch circuits to achieve approximate phase symmetry.

23. The auto-interleaving multiphase switching converter of claim 22, wherein the voltages at the respective input terminals are lowpass filtered to produce the respective sensed voltages.

24. The auto-interleaving multiphase switching converter of claim 22, wherein the switch circuits are implemented by metal-oxide-semiconductor-field-effect-transistors.

25. The auto-interleaving multiphase switching converter of claim 22, wherein:

the first controller comprises a control voltage circuit and at least two pulse-width modulation circuits; and

the control voltage circuit produces control voltages to control duty cycles of respective outputs of the respective pulse-width modulation circuits.

26. The auto-interleaving multiphase switching converter of claim 25, wherein the control voltage circuit further comprises:

an error amplifier configured to compare a feedback voltage proportional to an output voltage with a reference voltage;

a first feedback amplifier configured to buffer an output of the error amplifier and provide a first control voltage;

an offset amplifier configured to compare a first sensed voltage with a second sensed voltage; and

a second feedback amplifier configured to sum an output of the offset amplifier with an output of the error amplifier and provide a second control voltage.

27. The auto-interleaving multiphase switching converter of claim 26, wherein:

the error amplifier and the offset amplifier are integrating amplifiers; and

the feedback amplifiers are unity gain amplifiers.

28. The auto-interleaving multiphase switching converter of claim 22, wherein at lest one of said first controller and said second controller is configured to dither said respective phase of operation to avoid phase overlap between output pulses of said first inductor and said second inductor.

29. A method of auto-interleaving each channel in a multiphase switching converter, comprising:

starting a first timer in a first channel;

resetting the first timer if a second channel outputs a second-channel pulse;

stopping the first timer and starting a second timer when the first channel generates a first-channel pulse;

stopping the second timer when a third channel outputs a third-channel pulse; and

adjusting a time of the first-channel pulse to cause the first-channel pulse to start approximately halfway between an end of the second-channel pulse and a start of the third-channel pulse.

30. The method of claim 29, further comprising:

converting voltages at respective input terminals of inductors into sensed voltages, wherein the sensed voltages are proportional to respective duty cycles of respective voltage waveforms across the respective inductors, one of the sensed voltages being a reference sensed voltage, the others of the sensed voltages being slave sensed voltages;

comparing the slave sensed voltages to the reference sensed voltage;

generating respective offset voltages based on respective differences between each of the slave sensed voltages and the reference sensed voltage; and

adjusting duty cycles of the voltage waveforms in accordance with respective offset voltages to achieve equal sensed voltages.

31. A multiphase switching converter, comprising:

means for sensing a start of a converter cycle;

means for producing a sync pulse at the start of each converter cycle; and

means for adjusting phases to achieve phase symmetry within a converter cycle through peer-to-peer arbitration.

32. A multiphase switching converter, comprising:

means for converting voltage waveforms at respective input terminals of respective inductors into respective sensed voltages;

means for comparing the sensed voltages;

means for adjusting duty cycles of the respective voltage waveforms to achieve equal sensed voltages; and

means for adjusting phases of the respective voltage waveforms to produce phase symmetry.