Multi-channel driver interface circuit for increasing phase count in a multi-phase DC-DC converter

• US 20050088156A1
• Filed: 07/09/2004
• Published: 04/28/2005
• Est. Priority Date: 10/27/2003
• Status: Active Grant

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Cheung, Chun, Harris, Matthew B.
• Granted Patent: US 7,026,798 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A reduced pin count, dual channel driver interface is configured to interface a supervisory controller with a plurality of multi-phase output channel switching circuits of a multi-phase DC-DC regulator. Each dual channel driver is configured for placement relatively close to output channel sense points, so as to effectively reduce the distance that would otherwise have to be traversed by noise sensitive voltage signals. Sensed current representative signals are processed within the dual driver for current balance between a respective multi driver pair, and are combined to supply the controller with the average current signal of the dual channels. The controller uses this average current-information to adjust respective pulse width modulation signals that are supplied to the dual channel drivers.

Claims

1. A multiphase DC-DC converter comprising:

a plurality of switched converter channels, outputs of which are combined to provide a composite output DC voltage waveform for delivery to a load;

a multiphase driver interface coupled to receive a single pulse width modulation (PWM) signal from a converter controller and being operative to generate therefrom a plurality of PWM signals mutually separated in time, and being coupled to control switching of respective ones of said plurality of switched converter channels;

a current sensing circuit which is operative to sense current conditions at selected portions of said plurality of switched converter channels, and to produce a single output representative of said current conditions sensed at said selected portions of said plurality of switched converter channels; and

a single conductor through which said single output from said current sensing circuit is coupled to a current sense port of said converter controller.

2. The multiphase DC-DC converter according to claim 1, wherein said multiphase driver interface is coupled to receive said single pulse width modulation (PWM) signal from said converter controller and is operative to delay said single PWM signal by a prescribed delay as a delayed PWM signal, and to control switching of respective ones of said plurality of switched converter channels in accordance with said single PWM signal and said delayed PWM signal.

3. The multiphase DC-DC converter according to claim 2, wherein said multiphase driver interface operative to control pulse width of said delayed PWM signal in accordance with the operation of said current sensing circuit.

4. The multiphase DC-DC converter according to claim 1, wherein said current sensing circuit is operative to differentially sense current conditions at said selected portions of said plurality of switched converter channels, and to produce said single output representative of said current conditions differentially sensed at said selected portions of said plurality of switched converter channels.

5. The multiphase DC-DC converter according to claim 4, wherein said current sensing circuit is operative to generate voltages representative of said differentially sensed current conditions at said selected portions of respectively different ones of said plurality of switched converter channels, and to combine said voltages into a composite from which said single output is produced.

6. The multiphase DC-DC converter according to claim 3, wherein said current sensing circuit is operative to generate voltages representative of said differentially sensed current conditions at said selected portions of respectively different ones of said plurality of switched converter channels, and to differentially combine said voltages to produce an error signal for adjusting the pulse width of said delayed PWM signal.

7. The multiphase DC-DC converter according to claim 6, wherein said current sensing circuit includes an integrating differential amplifier to which said voltages representative of said differentially sensed current conditions at said selected portions of respectively different ones of said plurality of switched converter channels are coupled, and being operative to produce said error signal for adjusting the pulse width of said delayed PWM signal.

8. The multiphase DC-DC converter according to claim 1, wherein said current sensing circuit is operative to sense current conditions at selected portions of said plurality of switched converter channels, and to produce a single output current representative of said current conditions sensed at said selected portions of said plurality of switched converter channels, said single output current being coupled over said single conductor to said current sense port of said converter controller.

9. The multiphase DC-DC converter according to claim 1, wherein said multiphase driver interface is coupled to receive said single PWM signal from said converter controller and is operative to delay said single PWM signal by a first delay as a first delayed PWM signal associated with signal propagation delay through components of said multiphase driver interface, and to delay said single PWM signal by a second delay associated with the number of said plurality of switched converter channels as a second delayed PWM signal, and to control switching of respective ones of said plurality of switched converter channels in accordance with said first and second delayed PWM signals.

10. The multiphase DC-DC converter according to claim 9, wherein said multiphase driver interface is operative to control switching of a first converter channel in accordance with said first delayed PWM signal and to control switching of a second converter channel in accordance with said second delayed signal that is controllably offset in time relative to a selected one of a leading edge and a falling edge of said single PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

11. The multiphase DC-DC converter according to claim 10, wherein said second delayed signal is controllably offset in time relative to said leading edge of said single PWM signal.

12. The multiphase DC-DC converter according to claim 10, wherein said second delayed signal is controllably offset in time relative to said trailing edge of said single PWM signal.

13. The multiphase DC-DC converter according to claim 9, wherein said multiphase driver interface is operative to control switching of a first converter channel in accordance with said first delayed PWM signal and to control switching of a second converter channel in accordance with said second delayed signal, and wherein said first and second delayed signals are controllably offset in time relative to a selected one of a leading edge and a falling edge of said single PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

14. A dual phase DC-DC converter comprising:

first and second switched converter channels, outputs of which are combined to provide a dual phase output voltage for delivery to a load;

a converter controller which is operative to produce a pulse width modulation (PWM) signal, and being operative to controllably adjust said PWM signal in accordance with monitored current conditions at selected portions of said first and second switched converter channels;

a dual phase driver interface, coupled to receive said PWM signal via a first conductor from said converter controller, and being operative to generate therefrom first and second PWM signals, which are mutually separated in time and are coupled to control switching of said first and second switched converter channels, said dual phase driver interface including a current sensing circuit, which is operative to sense current conditions at selected portions of said first and second switched converter channels, and producing a single output representative of said current conditions sensed at said selected portions of said plurality of switched converter channels; and

a second conductor through which said single output from said current sensing circuit is coupled to a current sense port of said converter controller, said converter controller being operative to controllably adjust said PWM signal in accordance with said single output from said current sensing circuit as coupled to said current sense port.

15. The dual phase DC-DC converter according to claim 14, wherein said dual phase driver interface is coupled to receive said PWM signal from said converter controller and is operative to delay said PWM signal by a prescribed delay as a delayed PWM signal, and to control switching of said first and second switched converter channels in accordance with said PWM signal and said delayed PWM signal, respectively.

16. The dual phase DC-DC converter according to claim 15, wherein said dual phase driver interface operative to control the pulse width of said delayed PWM signal in accordance with the operation of said current sensing circuit.

17. The dual phase DC-DC converter according to claim 16, wherein said current sensing circuit is operative to differentially sense current conditions at said selected portions of said first and second switched converter channels, and to produce said single output representative of said current conditions differentially sensed at said selected portions of said first and second switched converter channels.

18. The dual phase DC-DC converter according to claim 14, wherein said dual phase driver interface is coupled to receive said PWM signal from said converter controller and is operative to delay said single PWM signal by a first delay as a first delayed PWM signal, and to delay said PWM signal by a second delay as a second delayed PWM signal, and to control switching of said first and second of switched converter channels in accordance with said first and second delayed PWM signals, respectively.

19. The dual phase DC-DC converter according to claim 18, wherein said multiphase driver interface is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal that is controllably offset in time relative to a selected one of a leading edge and a falling edge of said PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

20. The dual phase DC-DC converter according to claim 19, wherein said second delayed signal is controllably offset in time relative to said leading edge of said single PWM signal.

21. The dual phase DC-DC converter according to claim 19, wherein said second delayed signal is controllably offset in time relative to said trailing edge of said single PWM signal.

22. The dual phase DC-DC converter according to claim 18, wherein said multiphase driver interface is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal, and wherein said first and second delayed signals are controllably offset in time relative to a selected one of a leading edge and a falling edge of said single PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

23. A multiphase DC-DC converter comprising:

a plurality of switched converter channels, outputs of which are combined to provide a multiphase output voltage for delivery to a load;

a converter controller which is operative to produce a plurality of pulse width modulation (PWM) signals, and to controllably adjust said PWM signals in accordance with monitored current conditions at selected portions of said plurality of switched converter channels; and

a plurality of dual channel driver interfaces, a respective dual phase driver interface being coupled to receive one of said PWM signals from said converter controller, and being operative to generate therefrom first and second PWM signals, which are mutually separated in time in accordance with the number of phases of said multiphase DC-DC converter, and are coupled to control switching of a respective pair of switched converter channels, said dual phase driver interface including a current sensing circuit, which is operative to sense current conditions at selected portions of said respective pair of switched converter channels, and producing a single output representative of said current conditions sensed at said selected portions of said respective pair of switched converter channels, said single output from said current sensing circuit being coupled to an associated current sense port of said converter controller, said converter controller being operative to controllably adjust a respective PWM signal in accordance with outputs from current sensing circuits of said plurality of dual channel driver interfaces.

24. The multiphase phase DC-DC converter according to claim 23, wherein said respective dual phase driver interface is coupled to receive a respective one of said plurality of PWM signals from said converter controller, and is operative to delay said respective PWM signal by a prescribed delay as a delayed PWM signal, and to control switching of said first and second ones of said respective pair of switched converter channels in accordance with said respective PWM signal and said delayed PWM signal, respectively.

25. The multiphase DC-DC converter according to claim 24, wherein said respective dual phase driver interface operative to control the pulse width of said delayed PWM signal in accordance with the operation of said current sensing circuit.

26. The multiphase DC-DC converter according to claim 25, wherein said current sensing circuit is operative to differentially sense current conditions at said selected portions of said first and second switched converter channels, and to produce said single output representative of said current conditions differentially sensed at said selected portions of said first and second switched converter channels.

27. The multiphase DC-DC converter according to claim 23, wherein said respective dual phase driver interface is coupled to receive a PWM signal from said converter controller and is operative to delay said single PWM signal by a first delay as a first delayed PWM signal, and to delay said PWM signal by a second delay as a second delayed PWM signal, and to control switching of said first and second of switched converter channels in accordance with said first and second delayed PWM signals, respectively.

28. The multiphase DC-DC converter according to claim 27, wherein said multiphase driver interface is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal that is controllably offset in time relative to a selected one of a leading edge and a falling edge of said PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

29. The multiphase DC-DC converter according to claim 28, wherein said second delayed signal is controllably offset in time relative to said leading edge of said single PWM signal.

30. The multiphase DC-DC converter according to claim 28, wherein said second delayed signal is controllably offset in time relative to said trailing edge of said single PWM signal.

31. The multiphase DC-DC converter according to claim 27, wherein said multiphase driver interface is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal, and wherein said first and second delayed signals are controllably offset in time relative to a selected one of a leading edge and a falling edge of said single PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

32. A dual channel interface for a multiphase DC-DC converter having a plurality of switched converter channels, outputs of which are combined to provide a multiphase output voltage for delivery to a load, comprising

an input port coupled to receive a pulse width modulation (PWM) signal from a converter controller, which is operative to controllably adjust said PWM signal in accordance with monitored current conditions at selected portions of said plurality of switched converter channels;

and

a dual channel driver coupled to receive said PWM signal from said converter controller, and being operative to generate therefrom first and second PWM signals, which are mutually separated in time in accordance with the number of phases of said multiphase DC-DC converter, and are coupled to control switching of a respective pair of switched converter channels, said dual channel driver including a current sensing circuit, which is operative to sense current conditions at selected portions of said respective pair of switched converter channels, and producing a single output representative of said current conditions sensed at said selected portions of said respective pair of switched converter channels, said single output from said current sensing circuit being coupled to an associated current sense port of said converter controller, and wherein said dual channel driver is operative to define parameters of said first and second PWM signals in a manner that is effective to balance current flow in said respective pair of switched converter channels.

33. The dual channel interface according to claim 32, wherein said dual channel driver is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal that is controllably offset in time relative to a selected one of a leading edge and a falling edge of said PWM signal in a manner that is effective to balance current flow between said first and second converter channels.

34. The dual channel interface according to claim 33, wherein said second delayed signal is controllably offset in time relative to said leading edge of said single PWM signal.

35. The dual channel interface according to claim 33, wherein said second delayed signal is controllably offset in time relative to said trailing edge of said single PWM signal.

36. The dual channel interface according to claim 32, wherein said dual channel driver is operative to control switching of said first converter channel in accordance with said first delayed PWM signal and to control switching of said second converter channel in accordance with said second delayed signal, and wherein said first and second delayed signals are controllably offset in time relative to a selected one of a leading edge and a falling edge of said single PWM signal in a manner that is effective to balance current flow between said first and second converter channels.