Method of protecting power amplifiers

• US 20060003713A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Black Sand Technologies, Inc. (Qualcomm, Inc.)
• Inventors: Ouzillou, Mendy M., Bocock, Ryan M.
• Granted Patent: US 7,751,784 B2
• Time in Patent Office: Days
• US Class Current: 455/117
• CPC Class Codes: H04B 1/0466 Fault detection or indication H04B1/0483 takes precedence

Abstract

In a power amplifier, techniques are provided for protecting the power amplifier from temperature extremes resulting from conditions such as load mismatches. After sensing the temperature of the power amplifier, the operation of the RF power amplifier is controlled accordingly. In one example, the power amplifier is shut down when the sensed temperature reaches a threshold value, which can be set to a value just below the point where permanent damage would occur. In another example, when a threshold temperature is reached, the operation of the power amplifier is changed, to prevent the temperature of the power amplifier from rising to a level that would damage the power amplifier.

Claims

1. A method of protecting an RF power amplifier comprising:

sensing the temperature in an RF power amplifier; and

changing the operation of the RF power amplifier when the sensed temperature reaches a threshold value.

2. The method of claim 1, further comprising shutting down the RF power amplifier in response to the threshold value being reached.

3. The method of claim 1, further comprising decreasing the output power of the RF power amplifier in response to the threshold value being reached.

4. The method of claim 1, further comprising decreasing the duty cycle of the output of the RF power amplifier in response to the threshold value being reached.

5. The method of claim 1, wherein the RF power amplifier is used in a mobile communication system, the method further comprising dropping a call in response to the threshold value being reached.

6. The method of claim 1, further comprising sending a message to a user of the RF power amplifier in response to the threshold value being reached.

7. The method of claim 6, wherein the message instructs the user to take an action.

8. The method of claim 7, wherein the message instructs the user to move.

9. The method of claim 1, wherein sensing the temperature in the RF power amplifier includes comparing a temperature dependent signal with a reference signal to determine when the sensed temperature reaches the threshold value.

10. The method of claim 9, wherein the reference signal is a temperature independent voltage signal.

11. The method of claim 9, wherein the reference signal is a bandgap reference signal.

12. The method of claim 1, wherein changing the operation of the RF power amplifier when the sensed temperature reaches a threshold value includes an action that attempts to reduce the temperature of the RF power amplifier.

13. The method of claim 12, further comprising shutting down the power amplifier when the sensed temperature reaches a second threshold value.

14. A method of protecting an RF power amplifier comprising:

establishing a first temperature threshold value;

establishing a second temperature threshold value;

sensing the temperature in the RF power amplifier;

changing the operation of the RF power amplifier when the sensed temperature reaches the first temperature threshold value; and

shutting down the RF power amplifier when the sensed temperature reaches the second temperature threshold value.

15. The method of claim 14, wherein the RF power amplifier generates an RF output signal, the method further comprising decreasing the power of the RF output signal in response to the first temperature threshold being reached.

16. The method of claim 14, wherein the RF power amplifier generates an RF output signal, further comprising decreasing the duty cycle of the RF output signal in response to the first temperature threshold being reached.

17. The method of claim 14, wherein the RF power amplifier is used in a mobile communication system, the method further comprising dropping a call in response to the first temperature threshold being reached.

18. The method of claim 14, further comprising sending a message to a user of the RF power amplifier in response to the first temperature threshold being reached.

19. The method of claim 18, wherein the message instructs the user to take an action.

20. The method of claim 19, wherein the message instructs the user to move.

21. The method of claim 14, further comprising determining when the first temperature threshold value is reached by comparing a temperature dependent signal with a first reference signal.

22. The method of claim 14, further comprising determining when the second temperature threshold value is reached by comparing a temperature dependent signal with a second reference signal.

23. The method of claim 22, wherein the first and second reference signals are temperature independent signals.

24. The method of claim 23, further comprising using a bandgap reference circuit to derive the first reference signal.

25. The method of claim 24, further comprising using a bandgap reference circuit to derive the second reference signal.