SENSORLESS SELF-TUNING DIGITAL CURRENT PROGRAMMED MODE (CPM) CONTROLLER WITH MULTIPLE PARAMETER ESTIMATION AND THERMAL STRESS EQUALIZATION

• US 20120223692A1
• Filed: 03/03/2011
• Published: 09/06/2012
• Est. Priority Date: 03/03/2011
• Status: Active Grant

• Current Assignee: Exar Corporation (Maxlinear Incorporated)
• Original Assignee: Exar Corporation (Maxlinear Incorporated)
• Inventors: ZHAO, ZHENYU, PRODIC, ALEKSANDAR, LUKIC, ZDRAVKO, AHSANUZZAMAN, S M
• Granted Patent: US 8,536,842 B2
• Time in Patent Office: Days
• US Class Current: 323/283
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel

Abstract

A multiphase controller for a DC-to-DC power supply includes logic to estimate parameters for multiple phases that provide a combined output at a load. The estimated parameters include a current estimate and an effective resistance estimates for each phase so that a power estimate for each phase can be produced. The logic adjusts the operation of the phases using the power estimate for each phase.

Claims

1. A multiphase controller for a DC-to-DC power supply comprising:

logic to estimate parameters for multiple phases that provide a combined output at a load, the estimated parameters including a current estimate and an effective resistance estimate for each phase so that a power loss estimate for each phase can be produced, wherein the logic adjusts the operation of the phases using the power estimate for each phase.

2. The multiphase controller of claim 1, wherein the power losses for each of the phases are made more equal using the power estimate for each phase.

3. The multiphase controller of claim 2, wherein the equalization of power losses of the phases effectively equalizes the temperature of the phases without using a temperature sensor.

4. The multiphase controller of claim 1, wherein the controller also estimates inductor values for the phases and output capacitance, the inductor and capacitance estimates being used to control the response of the phases to load transients.

6. The multiphase controller of claim 1, wherein an input voltage and an output voltage are sampled to produce the current estimate.

7. The multiphase controller of claim 6, wherein the input voltage is sampled before the high side and low side switches of each phase and duty cycle values for the phases are used in the current estimates.

8. The multiphase controller of claim 7, wherein a current offset is compensated for by making preliminary current estimates at multiple frequencies.

9. The multiphase controller of claim 1, wherein a selectable current sink is used to make the parameter estimates for the phases.

10. The multiphase controller of claim 1, wherein current sharing logic produces reference current values provided to current loop logic associated with the multiple phases.

11. The multiphase controller of claim 10, wherein the reference current values are different for each phase and used to equalize the power losses of each phase.

12. The multiphase controller of claim 10, wherein the current loop logic for each phase uses at least one estimated parameter to produce duty cycle values for each phase.

13. The multiphase controller of claim 1, wherein each phase is calibrated individually by freezing any other phase.

5. (canceled)

14. A current estimator that uses an internal value indicative of switching in a circuit to produce a current estimate, the current estimator producing preliminary current estimates at multiple frequencies.

15. The current estimator of claim 14, wherein the use of the preliminary current estimates at multiple frequencies compensates for switching delays in the circuit.

16. The current estimator of claim 14, wherein the internal value is a duty cycle value and the circuit is part of a DC-to-DC converter which uses the duty cycle value to switch high side and low side switches of the DC-to-DC converter.

17. The current estimator of claim 16, wherein an input voltage before high side and low side switches of the DC-to-DC converter and an output voltage are used to produce the current estimate.

18. The current estimator of claim 16, wherein the circuit is a phase of a multiphase DC-to-DC controller.

19. The circuit estimator of claim 14, wherein the relative switching delay is proportional to the frequency and an offset current is calculated to determine the effect of the switching delay at a normal frequency.

20. The current estimator of claim 19, wherein a preliminary current estimate at twice the normal frequency and a preliminary current estimate at the normal frequency are used to determine the current offset.

21. The current estimator of claim 20, wherein the preliminary current estimate for the normal frequency is subtracted from the preliminary current estimate at twice the normal frequency to determine the current offset.