Method and apparatus for multiphase regulator with thermal adaptive phase add/drop control
A multiphase regulator having a variable number of phases in operation and nominal current thresholds for indicating when to add or drop a phase is provided. A digital controller for the regulator includes digital circuitry configured to adjust the nominal current thresholds based on a measured or estimated temperature of the regulator, to yield adjusted current thresholds which are a function of temperature. The digital circuitry is further configured to modify the number of phases in operation based on the adjusted current thresholds and a measured or estimated current in the regulator. The regulator can be included in an electronic component having a load, power stages for providing phase currents to the load, and at least one fan for cooling the power stages and load. The digital controller controls operation of the regulator, including adaptive control of the number of phases in operation. Corresponding control methods are also provided.
1. A method of controlling a multiphase regulator having a variable number of phases in operation and nominal current thresholds for indicating when to add or drop a phase in operation, the method comprising:
measuring or estimating a current in the multiphase regulator;
measuring or estimating a temperature of the multiphase regulator;
adjusting the nominal current thresholds based on the temperature to yield adjusted current thresholds which are a function of temperature; and
modifying the number of phases of the multiphase regulator in operation based on the current and the adjusted nominal current thresholds,
wherein the nominal current thresholds comprise a first per-phase nominal current threshold for indicating when to add a phase of the multiphase regulator in operation and a second per-phase nominal current threshold for indicating when to drop a phase of the multiphase regulator in operation,
wherein adjusting the nominal current thresholds based on the temperature comprises reducing the first and second per-phase nominal current thresholds responsive to the temperature exceeding a first temperature level.
2. The method of claim 1 , wherein reducing the first and second per-phase nominal current thresholds responsive to the temperature exceeding the first temperature level comprises:
linearly reducing the first and second per-phase nominal current thresholds with a negative slope which is a function of increasing temperature.
3. The method of claim 1 , further comprising:
operating the multiphase regulator with a maximum number of phases while preventing dropping of any phases of the multiphase regulator in operation responsive to the temperature exceeding a second temperature level above the first temperature level and below a maximum temperature limit.
4. The method of claim 1 , further comprising:
operating the multiphase regulator with a maximum number of phases while preventing any of the phases from being dropped, responsive to the temperature exceeding a second temperature level above the first temperature level and below a maximum temperature limit.
5. A digital controller for a multiphase regulator having a variable number of phases in operation and nominal current thresholds for indicating when to add or drop a phase of the multiphase regulator, the digital controller comprising digital circuitry configured to:
adjust the nominal current thresholds based on a measured or estimated temperature of the multiphase regulator, to yield adjusted current thresholds which are a function of temperature; and
modify the number of phases of the multiphase regulator in operation based on the adjusted nominal current thresholds and a measured or estimated current in the multiphase regulator,
wherein the nominal current thresholds comprise a first per-phase nominal current threshold for indicating when to add a phase of the multiphase regulator in operation and a second per-phase nominal current threshold for indicating when to drop a phase of the multiphase regulator in operation, and wherein the digital circuitry is configured to reduce the first and second per-phase nominal current thresholds responsive to the temperature exceeding a first temperature level.
6. The digital controller of claim 5 , wherein the digital circuitry is configured to operate the multiphase regulator with a maximum number of phases while preventing any of the phases from being dropped, responsive to the temperature exceeding a second temperature level above the first temperature level and below a maximum temperature limit.
7. The digital controller of claim 5 , wherein the digital circuitry is configured to operate the multiphase regulator with a maximum number of phases while preventing any of the phases from being dropped, responsive to the temperature exceeding a second temperature level above the first temperature level and below a maximum temperature limit.
8. The digital controller of claim 5 , wherein the digital circuitry comprises a microcontroller and firmware configured to adjust the nominal current thresholds based on the temperature to yield the adjusted nominal current thresholds which are a function of temperature.
9. A multiphase regulator, comprising:
a plurality of power stages each configured to provide a phase of the multiphase regulator to a load; and
a digital controller configured to:
store nominal current thresholds for indicating when to add or drop a phase of the multiphase regulator;
adjust the nominal current thresholds based on a measured or estimated temperature of the multiphase regulator, to yield adjusted current thresholds which are a function of temperature; and
modify the number of phases of the multiphase regulator in operation based on the adjusted nominal current thresholds and a measured or estimated current in the multiphase regulator,
wherein the nominal current thresholds comprise a first per-phase nominal current threshold for indicating when to add a phase of the multiphase regulator in operation and a second per-phase nominal current threshold for indicating when to drop a phase of the multiphase regulator in operation,
wherein the digital controller is configured to reduce the first and second per-phase nominal current thresholds responsive to the temperature exceeding a first temperature level.
10. An electronic component, comprising:
a board;
a load attached to the board;
a plurality of power stages attached to the board and each configured to provide a phase current to the load;
at least one fan configured to cool the plurality of power stages and the load; and
a digital controller configured to:
store nominal current thresholds for indicating when to add or drop a phase of the multiphase regulator;
adjust the nominal current thresholds based on a measured or estimated temperature of the multiphase regulator, to yield adjusted current thresholds which are a function of temperature; and
modify the number of phases of the multiphase regulator in operation based on the adjusted nominal current thresholds and a measured or estimated current in the multiphase regulator,
wherein the nominal current thresholds comprise a first per-phase nominal current threshold for indicating when to add a phase of the multiphase regulator in operation and a second per-phase nominal current threshold for indicating when to drop a phase of the multiphase regulator in operation,
wherein the digital controller is configured to reduce the first and second per-phase nominal current thresholds responsive to the temperature exceeding a first temperature level.
11. The electronic component of claim 10 , wherein the digital controller is configured to increase the number of phases in operation based on the adjusted nominal current thresholds in a light-load condition when demand from the load is low, even if the nominal current thresholds indicate that fewer phases should be in operation.
12. A method of controlling a multiphase regulator having a variable number of phases in operation and nominal current thresholds for indicating when to add or drop a phase in operation, the method comprising:
measuring or estimating a current in the multiphase regulator;
measuring or estimating a temperature of the multiphase regulator;
adjusting the nominal current thresholds based on the temperature to yield adjusted current thresholds which are a function of temperature;
modifying the number of phases of the multiphase regulator in operation based on the current and the adjusted nominal current thresholds; and
operating the multiphase regulator with a maximum number of phases while preventing any of the phases from being dropped, responsive to the temperature exceeding a high temperature level, the high temperature level being below a maximum temperature limit.
13. A digital controller for a multiphase regulator having a variable number of phases in operation and nominal current thresholds for indicating when to add or drop a phase of the multiphase regulator, the digital controller comprising digital circuitry configured to:
adjust the nominal current thresholds based on a measured or estimated temperature of the multiphase regulator, to yield adjusted current thresholds which are a function of temperature;
modify the number of phases of the multiphase regulator in operation based on the adjusted nominal current thresholds and a measured or estimated current in the multiphase regulator; and
operate the multiphase regulator with a maximum number of phases while preventing any of the phases from being dropped, responsive to the temperature exceeding a second temperature level above the first temperature level and below a maximum temperature limit.