Controller for a switch and method of operating the same

• US 8,792,256 B2
• Filed: 01/27/2012
• Issued: 07/29/2014
• Est. Priority Date: 01/27/2012
• Status: Active Grant

• Current Assignee: Power Systems Technologies Company Limited (Flex, Ltd.)
• Original Assignee: Power Systems Technologies Company Limited (Flex, Ltd.)
• Inventors: genannt Berghegger, Ralf Schroeder, Frey, Michael
• Primary Examiner(s): Behm, Harry
• Application Number:
  US13/360,516
• Publication Number:
  US 20130194826A1
• Time in Patent Office: 914 Days
• Field of Search: 363/21.13, 327/109, 327/419, 326/82
• US Class Current: 363/21.13
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only

Abstract

A controller for a switch and a method of operating the same. In one embodiment, the controller is configured to measure a voltage of a control terminal of the switch and select a first mode of operation if the voltage of the control terminal is greater than a threshold voltage, and a second mode of operation if the voltage of the control terminal is less than the threshold voltage.

Claims

1. A controller for a switch configured to measure a voltage of a control terminal of said switch and select a first mode of operation if said voltage of said control terminal is greater than a threshold voltage, and a second mode of operation if said voltage of said control terminal is less than said threshold voltage, wherein said first mode of operation signifies that said switch is a field-effect transistor and said second mode of operation signifies that said switch is a bipolar transistor.

2. The controller as recited in claim 1 further comprising a voltage limiter configured to limit a voltage for said control terminal of said switch to a voltage limit during said first mode of operation.

3. The controller as recited in claim 1 further comprising a current limiter configured to limit a current for said control terminal of said switch to a current limit during said second mode of operation.

4. The controller as recited in claim 1 wherein an under-voltage lockout level is configured to be set to a higher level during said first mode of operation than during said second mode of operation.

5. The controller as recited in claim 1 further comprising a timer configured to produce a pulse-width modulated signal.

6. The controller as recited in claim 1 wherein said controller is configured to control a duty cycle of said switch to regulate an output voltage of a power converter.

7. The controller as recited in claim 1 wherein said controller is configured to initiate operation in said first mode of operation at startup.

8. A method, comprising:

measuring a voltage of a control terminal of a switch; and

selecting a first mode of operation if said voltage of said control terminal is greater than a threshold voltage, and a second mode of operation if said voltage of said control terminal is less than said threshold voltage, wherein said first mode of operation signifies that said switch is a field-effect transistor and said second mode of operation signifies that said switch is a bipolar transistor.

9. The method as recited in claim 8 further comprising limiting a voltage for said control terminal of said switch to a voltage limit during said first mode of operation.

10. The method as recited in claim 8 further comprising limiting a current for said control terminal of said switch to a current limit during said second mode of operation.

11. The method as recited in claim 8 further comprising setting an under-voltage lockout level to a higher level during said first mode of operation than during said second mode of operation.

12. The method as recited in claim 8 further comprising producing a pulse-width modulated signal.

13. The method as recited in claim 8 further comprising controlling a duty cycle of said switch to regulate an output voltage of a power converter.

14. The method as recited in claim 8 further comprising initiating operation in said first mode of operation at startup.

15. A power converter, comprising:

a power switch coupled to an input of said power converter;

a transformer interposed between said power switch and an output of said power converter; and

controller for said power switch configured to measure a voltage of a control terminal of said power switch and select a first mode of operation if said voltage of said control terminal is greater than a threshold voltage, and a second mode of operation if said voltage of said control terminal is less than said threshold voltage, wherein said first mode of operation signifies that said power switch is a field-effect transistor and said second mode of operation signifies that said power switch is a bipolar transistor.

16. The power converter as recited in claim 15 wherein said controller comprises a voltage limiter configured to limit a voltage for said control terminal of said switch to a voltage limit during said first mode of operation.

17. The power converter as recited in claim 15 wherein said controller comprises a current limiter configured to limit a current for said control terminal of said switch to a current limit during said second mode of operation.

18. The power converter as recited in claim 15 wherein an under-voltage lockout level is configured to be set to a higher level during said first mode of operation than during said second mode of operation.

19. The power converter as recited in claim 15 wherein said controller comprises a timer configured to produce a pulse-width modulated signal.

20. The power converter as recited in claim 15 wherein said controller is configured to initiate operation in said first mode of operation at startup.