Multiphase regulator with self-test

1. A multiphase regulator, comprising:

a plurality of output phases each operable to deliver a phase current through a separate inductor to a load connected to the output phases via the inductors and an output capacitor; and

a voltage mode controller operable to regulate a voltage delivered to the load by adjusting the phase currents delivered to the load by the output phases, monitor the phase currents delivered to the load by the output phases, and determine if the monitored phase currents indicate any of the individual output phases, any of the individual inductors or the output capacitor are faulty even if a total current delivered by the multiphase regulator to the load is within specified limits,

wherein the voltage mode controller is further operable to determine an allocation of the total load current between one or more active ones of the output phases, adjust the phase currents of each active output phase to match the allocation, and detect if any of the phase currents delivered by the one or more active output phases do not match the allocation for that active output phase,

wherein the voltage mode controller is further operable to test if the one or more active output phases react to a known change in the allocation in a predetermined way in a test mode of the multiphase regulator, and detect if the phase currents delivered by the one or more active output phases in the test mode respond to the known change in the allocation by rebalancing the phase currents in the predetermined way.

2. The multiphase regulator of claim 1 , wherein the voltage mode controller is further operable to disable each output phase determined to be faulty or each output phase that is connected to an inductor that is determined to be faulty.

3. A method of operating a multiphase regulator having a plurality of output phases each for delivering a phase current through a separate inductor to a load connected to the plurality of output phases via the inductors and an output capacitor, the method comprising:

regulating a voltage delivered to the load by adjusting the phase currents delivered to the load by the output phases via voltage mode control;

monitoring the phase currents delivered to the load by the output phases;

determining if the monitored phase currents indicate any of the individual output phases, any of the individual inductors or the output capacitor are faulty even if a total current delivered by the multiphase regulator to the load is within specified limits;

determining an allocation of the total load current between one or more active ones of the output phases;

adjusting the phase currents of each active output phase to match the allocation;

detecting if any of the phase currents delivered by the one or more active output phases do not match the allocation for that active output phase;

testing if the one or more active output phases react to a known change in the allocation in a predetermined way in a test mode of the multiphase regulator; and

detecting if the phase currents delivered by the one or more active output phases in the test mode respond to the known change in the allocation by rebalancing the phase currents in the predetermined way.

4. The method of claim 3 , further comprising disabling each output phase determined to be faulty or connected to an inductor determined to be faulty.

5. A device configured to control a multiphase regulator having a plurality of output phases each for delivering a phase current through a separate inductor to a load connected to the plurality of output phases via the inductors and an output capacitor, the method comprising:

means for regulating a voltage delivered to the load by adjusting the phase currents delivered to the load by the output phases via voltage mode control;

means for monitoring the phase currents delivered to the load by the output phases;

means for determining if the monitored phase currents indicate any of the individual output phases, any of the individual inductors or the output capacitor are faulty even if a total current delivered by the multiphase regulator to the load is within specified limits;

means for determining an allocation of the total load current between one or more active ones of the output phases;

means for adjusting the phase currents of each active output phase to match the allocation;

means for detecting if any of the phase currents delivered by the one or more active output phases do not match the allocation for that active output phase;

means for testing if the one or more active output phases react to a known change in the allocation in a predetermined way in a test mode of the multiphase regulator; and

means for detecting if the phase currents delivered by the one or more active output phases in the test mode respond to the known change in the allocation by rebalancing the phase currents in the predetermined way.