Multiphase power regulator with load adaptive phase control

• US 7,492,134 B2
• Filed: 07/03/2006
• Issued: 02/17/2009
• Est. Priority Date: 07/02/2004
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Primarion Incorporated (Infineon Technologies AG)
• Inventors: Steffen, Nicholas R., Pierson, Richard C., Carroll, Robert T., Tang, Benjamim
• Primary Examiner(s): Han; Jessica
• Assistant Examiner(s): PHAM, EMILY P
• Application Number:
  US11/480,715
• Publication Number:
  US 20070013350A1
• Time in Patent Office: 960 Days
• Field of Search: 323/283, 323/241, 323/242, 323/910, 363/36, 363/87
• US Class Current: 323/241
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

Disclosed is a power regulator for providing precisely regulated power to a microelectronic device such as a microprocessor. Improved power regulation is accomplished by optimizing the power efficiency of the power regulator. In particular, in a multiphase system, the number of active phases is increased or decreased to achieve optimum power efficiency. The multiphase voltage regulator adapts the operating mode to maximize efficiency as the load current demand of the load device changes by adjusting the number of active phases to maximize efficiency. The total value of current provided by the regulator and the total number of active phases is determined, the total number of active phases is compared with the number of active phases required to provide the total value of current at maximum efficiency; and the number of active phases is adjusted to provide the total value of current at maximum efficiency.

A current sense circuit senses the current at each phase, a summing circuit coupled to the output of the current sense circuit provides the total current value of all the measured phases, a circuit coupled to the output of the summing circuit provides the time averaged total current value to a threshold detecting circuit that determines the number of phases at which the voltage regulator should be operating for maximum efficiency, and a circuit for comparing the number of phases that are operating to the number of phases at which the voltage regulator should be operating adjusts the number of active phases to the number of phases at which the voltage regulator should be operating for maximum efficiency.

Claims

1. A multiphase voltage regulator that adapts the operating mode to maximize efficiency as the load current demand of the load device changes, comprising:

a current sense circuit for sensing the current at each phase;

a summing circuit coupled to the output of the current sense circuit for providing the total current value of all the measured phases;

a circuit coupled to the output of the summing circuit for providing the time averaged total current value to a threshold detecting circuit that determines the number of phases at which the voltage regulator should be operating for maximum efficiency; and

a circuit for comparing the number of phases that are operating to the number of phases at which the voltage regulator should be operating and adjusting the number of active phases to the number of phases at which the voltage regulator should be operating for maximum efficiency.

2. A multiphase voltage regulator as in claim 1, wherein said circuit coupled to the output of the summing circuit further provides an update signal to said threshold detecting circuit to reduce the effect of system noise.

3. A multiphase voltage regulator as in claim 1, wherein said threshold detecting circuit comprises:

a plurality of comparator circuits; and

a plurality of latch circuits coupled to said plurality of comparator circuits and providing an output signal representing the number of phases at which the voltage regulator should be operating for maximum efficiency.

4. A multiphase voltage regulator as in claim 1, wherein said circuit for comparing comprises:

circuits for determining whether a slow drop, slow add, or fast add function is required; and

a state machine coupled to the output of the circuits for determining and providing a phase control signal to adjust the number of active phases.

5. A multiphase voltage regulator as in claim 1, wherein said circuit for comparing comprises a slow drop circuit.

6. A multiphase voltage regulator as in claim 5, wherein said slow drop circuit comprises:

a counter that counts the number of average current readings in a row that are below the phase drop threshold; and

a comparator circuit for receiving the output of the counter.

7. A multiphase voltage regulator as in claim 1, wherein said circuit for comparing comprises a slow add circuit.

8. A multiphase voltage regulator as in claim 7, wherein said slow add circuit comprises:

a counter that counts the number of average current readings in a row that are above the phase drop threshold; and

a comparator circuit for receiving the output of the counter.

9. A multiphase voltage regulator as in claim 1, wherein said circuit for comparing comprises a fast add circuit.

10. A multiphase voltage regulator as in claim 9, wherein said fast add circuit comprises:

a comparator circuit for providing a signal to turn all phases on whenever a predetermined threshold is sensed.

11. In a multiphase voltage regulator that adapts the operating mode to maximize efficiency as the load current demand of the load device changes, the method of adjusting the number of active phases to maximize efficiency, comprising the steps of:

determining the total value of current provided by the regulator;

determining the total number of active phases;

comparing the total number of active phases with the number of active phases required to provide the total value of current at maximum efficiency; and

adjusting the number of active phases to provide the total value of current at maximum efficiency.

12. In a multiphase voltage regulator as in claim 11, in which the step of adjusting the number of active phases comprises the step of:

dropping active phases slowly.

13. In a multiphase voltage regulator as in claim 12, in which the step of adjusting the number of active phases comprises the step of:

dropping active phases one at a time.

14. In a multiphase voltage regulator as in claim 11, in which the step of adjusting the number of active phases comprises the step of:

direct dropping active phases slowly.

15. In a multiphase voltage regulator as in claim 11, in which the step of adjusting the number of active phases comprises the step of:

adding active phases slowly.

16. In a multiphase voltage regulator as in claim 11, in which the step of adjusting the number of active phases comprises the step of:

adding active phases quickly.

17. In a multiphase voltage regulator as in claim 16, in which the step of adjusting the number of active phases by adding active phases quickly occurs when a transient amplitude passes multiple thresholds.

18. In a multiphase voltage regulator as in claim 11, in which the step of adjusting the number of active phases comprises the step of:

adjusting non-overlap time between the active phases providing the total value of current at maximum efficiency.