Controller including a common current-sense device for power switches of a power converter

• US 9,240,712 B2
• Filed: 12/13/2012
• Issued: 01/19/2016
• Est. Priority Date: 12/13/2012
• Status: Active Grant

• Current Assignee: Power Systems Technologies Company Limited (Flex, Ltd.)
• Original Assignee: Power Systems Technologies Company Limited (Flex, Ltd.)
• Inventors: Chandrasekaran, Sriram
• Primary Examiner(s): Berhane, Adolf
• Assistant Examiner(s): Mehari, Yemane
• Application Number:
  US13/714,095
• Publication Number:
  US 20140169049A1
• Time in Patent Office: 1,132 Days
• Field of Search: 323/207, 323/222, 323/268, 323/272, 323283-285
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A controller for a power converter includes a current-sense device couplable in series with switched terminals of power switches of interleaved switching regulators and configured to produce a current-sense signal. The controller also includes an error amplifier configured to produce an error signal as a function of a characteristic of the power converter. The controller also includes a duty-cycle controller configured to sample the current-sense signal at mid-points of duty cycles of the power switches and regulate the characteristic as a function of the error signal and the current-sense signal.

Claims

1. A controller for use with a power converter formed with interleaved switching regulators, comprising:

a common current-sense device couplable in series with switched terminals of power switches of said interleaved switching regulators and configured to produce a current-sense signal representative of currents in said power switches;

an error amplifier configured to produce an error signal as a function of a characteristic of said power converter; and

a duty-cycle controller configured to sample said current-sense signal at mid-points of duty cycles of said power switches and regulate said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.

2. The controller as recited in claim 1, wherein said current-sense device is a common current-sense resistor.

3. The controller as recited in claim 1, wherein said characteristic of said power converter is an output voltage.

4. The controller as recited in claim 1, wherein said error amplifier is configured to produce said error signal as a function of a reference voltage.

5. The controller as recited in claim 1, further comprising a comparator configured to produce an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.

6. The controller as recited in claim 5, wherein said duty-cycle controller is configured to produce drive signals for and to control said duty cycles of said power switches as a function of said average current signal.

7. The controller as recited in claim 1, wherein a sampled current-sense signal represents a current through a switched terminal of one of said power switches when a current flowing through a switched terminal of another of said power switches is substantially zero.

8. A method for use with a power converter formed with interleaved switching regulators, comprising:

producing a current-sense signal with a common current-sense device in series with switched terminals of power switches of said interleaved switching regulators, said current-sense signal being representative of currents in said power switches;

producing an error signal as a function of a characteristic of said power converter;

sampling said current-sense signal at mid-points of duty cycles of said power switches; and

regulating said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.

9. The method as recited in claim 8, wherein producing said error signal is a function of a reference voltage.

10. The method as recited in claim 8, further comprising producing an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.

11. The method as recited in claim 10, further comprising producing drive signals for and to control said duty cycles of said power switches as a function of said average current signal.

12. The method as recited in claim 8, wherein a sampled current-sense signal represents a current through a switched terminal of one of said power switches when a current flowing through a switched terminal of another of said power switches is substantially zero.

13. A power converter, comprising:

a first interleaved switching regulator including a first power switch;

a second interleaved switching regulator including a second power switch; and

a controller, comprising;

a common current-sense device couplable in series with switched terminals of said first and second power switches and configured to produce a current-sense signal representative of currents in said first and second power switches;

an error amplifier configured to produce an error signal as a function of a characteristic of said power converter; and

a duty-cycle controller configured to sample said current-sense signal at mid-points of duty cycles of said first and second power switches and regulate said characteristic as a function of said error signal and said current-sense signal sampled at said mid-points.

14. The power converter as recited in claim 13, wherein said current-sense device is a common current-sense resistor.

15. The power converter as recited in claim 13, wherein said characteristic of said power converter is an output voltage.

16. The power converter as recited in claim 13, wherein said error amplifier is configured to produce said error signal as a function of a reference voltage.

17. The power converter as recited in claim 13, wherein said controller further comprises a comparator configured to produce an average current signal as a function of said current-sense signal sampled at said mid-points and said error signal.

18. The power converter as recited in claim 17, wherein said duty-cycle controller is configured to produce drive signals for and to control said duty cycles of said first and second power switches as a function of said average current signal.

19. The power converter as recited in claim 13, wherein a sampled current-sense signal represents a current through a switched terminal of said first power switch when a current flowing through a switched terminal of said second power switch is substantially zero.

20. The power converter as recited in claim 13, wherein said first interleaved switching regulator is controlled with a duty cycle 180 degrees out of phase with respect to said second interleaved switching regulator.