Controller for a Power Converter and Method of Operating the Same

• US 20120039098A1
• Filed: 08/10/2011
• Published: 02/16/2012
• Est. Priority Date: 01/22/2010
• Status: Active Grant

• Current Assignee: MyPAQ Holdings Ltd. (Transpacific IP Group Limited)
• Original Assignee: Power Systems Technologies Company Limited (Flex, Ltd.)
• Inventors: Berghegger, Ralf Schroeder genannt
• Granted Patent: US 9,246,391 B2
• Time in Patent Office: Days
• US Class Current: 363/21.13
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• 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 and method of operating the same. In one embodiment, the controller includes a peak detector, coupled to a circuit element of the power converter, configured to produce a signal corresponding to a peak current through a circuit element. The controller also includes an adjustable reference circuit responsive to a difference between the signal and a reference signal corresponding to a desired peak current to produce a corrected signal corresponding to the peak current.

Claims

1. A controller employable with a power converter, comprising:

a peak detector, coupled to a circuit element of said power converter, configured to produce a signal corresponding to a peak current through said circuit element; and

an adjustable reference circuit responsive to a difference between said signal and a reference signal corresponding to a desired peak current to produce a corrected signal corresponding to said peak current.

2. The controller as recited in claim 1 wherein said circuit element is a power switch and said controller further comprises a comparator coupled to said peak detector and said adjustable reference circuit configured to disable conductivity of said power switch when said signal exceeds said corrected signal.

3. The controller as recited in claim 1 wherein said peak detector comprises a current sensor, an amplifier, a diode, and a capacitor.

4. The controller as recited in claim 3 wherein said current sensor comprises a resistor.

5. The controller as recited in claim 3 wherein said peak detector further comprises a resistor and a peak detector switch with conductivity switched at a frequency related to a switching frequency of said power converter to provide a discharge path for said capacitor.

6. The controller as recited in claim 1 wherein said adjustable reference circuit comprises an amplifier including a feedback capacitor.

7. The controller as recited in claim 1 wherein said adjustable reference circuit comprises digital logic and a digital-to-analog converter.

8. The controller as recited in claim 1 wherein said digital logic comprises an up-down counter.

9. The controller as recited in claim 1 wherein said corrected signal is limited by a first diode in an output path of said adjustable reference circuit and a second diode in a feedback path of said adjustable reference circuit.

10. The controller as recited in claim 1 wherein said corrected signal is limited by a first switch in an output path of said adjustable reference circuit and a second switch in a feedback path of said adjustable reference circuit.

11. A method employable with a power converter, comprising:

producing a signal corresponding to a peak current through a circuit element of said power converter;

producing a reference signal corresponding to a desired peak current associated with said circuit element; and

produce a corrected signal corresponding to said peak current responsive to a difference between said signal and said reference signal.

12. The method as recited in claim 11 wherein said circuit element is a power switch and further comprising disabling conductivity of said power switch when said signal exceeds said corrected signal.

13. The method as recited in claim 11 wherein said corrected signal is produced with digital logic and a digital-to-analog converter.

14. The method as recited in claim 11 further comprising limiting said corrected signal with a feedback circuit.

15. A power converter, comprising:

a circuit element coupled to an input of said power converter; and

a controller, coupled to said circuit element, comprising;

a peak detector configured to produce a signal corresponding to a peak current through said circuit element, and

an adjustable reference circuit responsive to a difference between said signal and a reference signal corresponding to a desired peak current to produce a corrected signal corresponding to said peak current.

16. The power converter as recited in claim 15 wherein said circuit element is a power switch and said controller further comprises a comparator coupled to said peak detector and said adjustable reference circuit configured to disable conductivity of said power switch when said signal exceeds said corrected signal.

17. The power converter as recited in claim 15 wherein said peak detector comprises a current sensor, an amplifier, a diode, and a capacitor.

18. The power converter as recited in claim 15 wherein said adjustable reference circuit comprises an amplifier including a feedback capacitor.

19. The power converter as recited in claim 15 wherein said adjustable reference circuit comprises digital logic and a digital-to-analog converter.

20. The power converter controller as recited in claim 15 wherein said corrected signal is limited by a first diode or switch in an output path of said adjustable reference circuit and a second diode or switch in a feedback path of said adjustable reference circuit.