Temperature protection circuit for power converter and method of operation thereof

• US 6,078,511 A
• Filed: 12/01/1998
• Issued: 06/20/2000
• Est. Priority Date: 12/01/1998
• Status: Expired due to Term

• Current Assignee: ABB Power Electronics Inc. (ABB Ltd.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Le, Nhon D., He, Jin, Fasullo, Greg H., Jorgenson, Greg P.
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/203,444
• Time in Patent Office: 567 Days
• Field of Search: 363/50, 361/103, 361/106, 361/27
• US Class Current: 363/50
• CPC Class Codes: H02H 5/042 using temperature dependent resistors
• CPC Class Codes: H02H 7/1203 Circuits independent of the type of conversion
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/327 against abnormal temperatures

Abstract

A temperature protection circuit, a method of protecting a power converter and a power converter employing the circuit or the method. In one embodiment, the circuit includes: (1) a temperature sensor, located in thermal communication with the power converter, that produces a signal based on a temperature associated with the power converter and (2) a current controller, coupled to the temperature sensor, that reduces an output current of the power converter to an intermediate level based on the signal.

Claims

1. For use with a power converter, a temperature protection circuit, comprising:

a temperature sensor, located in thermal communication with said power converter, that produces a signal based on a temperature associated with said power converter; and

a current controller, coupled to said temperature sensor, that reduces an output current of said power converter to an intermediate level based on said signal and a temperature-dependent output capacity of said power converter.

2. The circuit as recited in claim 1 wherein said current controller linearly reduces said output current as a function of said signal.

3. The circuit as recited in claim 1 wherein said current controller further reduces said output current to zero when said signal attains a predetermined value.

4. The circuit as recited in claim 1 wherein said temperature sensor is located proximate a power switch in said power converter.

5. The circuit as recited in claim 1 wherein said temperature sensor is coupled to a heat sink associated with a power switch in said power converter.

6. The circuit as recited in claim 1 wherein said temperature sensor is a thermistor.

7. The circuit as recited in claim 1 wherein said current controller is embodied as a sequence of instructions executable in a microcontroller associated with said power converter.

8. A method of providing temperature protection to a power converter, comprising:

producing a signal based on a temperature associated with said power converter; and

reducing an output current of said power converter to an intermediate level based on said signal and a temperature-dependent output capacity of said power converter.

9. The method as recited in claim 8 wherein said reducing comprises linearly reducing said output current as a function of said signal.

10. The method as recited in claim 8 wherein said reducing comprises further reducing said output current to zero when said signal attains a predetermined value.

11. The method as recited in claim 8 wherein said producing comprises sensing said temperature with a temperature sensor located proximate a power switch in said power converter.

12. The method as recited in claim 8 wherein said producing comprises sensing said temperature with a temperature sensor coupled to a heat sink associated with a power switch in said power converter.

13. The method as recited in claim 8 wherein said producing comprises sensing said temperature with a thermistor.

14. The method as recited in claim 8 wherein said reducing comprises executing a sequence of instructions executable in a microcontroller associated with said power converter.

15. A power converter, comprising:

a power switch;

a converter controller that toggles said power switch to control an output current of said power converter; and

a temperature protection circuit associated with said converter controller and including;

a temperature sensor, located in thermal communication with said power switch, that produces a signal based on a temperature associated with said power switch, and a current controller, coupled to said temperature sensor, that reduces said output current to an intermediate level based on said signal and a temperature-dependent output capacity of said power converter.

16. The converter as recited in claim 15 wherein said current controller linearly reduces said output current as a function of said signal.

17. The converter as recited in claim 15 wherein said current controller further reduces said output current to zero when said signal attains a predetermined value.

18. The converter as recited in claim 15 wherein said temperature sensor is coupled to a heat sink associated with said power switch.

19. The converter as recited in claim 15 wherein said temperature sensor is a thermistor.

20. The converter as recited in claim 15 wherein said current controller is embodied as a sequence of instructions executable in a microcontroller associated with said power converter.