PROTECTION CIRCUIT FOR RADIO FREQUENCY POWER AMPLIFIER

• US 20110292554A1
• Filed: 05/24/2011
• Published: 12/01/2011
• Est. Priority Date: 05/26/2010
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: TriQuint Semiconductor Incorporated (Qorvo, Inc.)
• Inventors: Hu, Peter, Yao, Jingshi, Lin, Barry Jia-Fu, Sun, Xiaopeng, Mokalla, Mehra
• Granted Patent: US 8,487,705 B2
• Time in Patent Office: Days
• US Class Current: 361/56
• CPC Class Codes: H03F 1/52 Circuit arrangements for protecting such amplifiers monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74
• CPC Class Codes: H03F 2200/15 the supply or bias voltage or current at the drain side of a FET being continuously controlled by a controlling signal
• CPC Class Codes: H03F 2200/21 Bias resistors are added at the input of an amplifier
• CPC Class Codes: H03F 2200/555 A voltage generating circuit being realised for biasing different circuit elements
• CPC Class Codes: H03F 2200/78 A comparator being used in a controlling circuit of an amplifier
• CPC Class Codes: H03F 2203/7203 the gated amplifier being switched on or off by a switch in the bias circuit of the amplifier controlling a bias current in the amplifier
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H04B 1/0466 Fault detection or indication H04B1/0483 takes precedence

Abstract

Embodiments of circuits, apparatuses, and systems for a protection circuit to protect against overdrive or overvoltage conditions. Other embodiments may be described and claimed.

Claims

1. A circuit comprising:

a transmission line configured to transmit a radio frequency (RF) signal;

a primary power transistor having a base coupled with the transmission line, wherein the primary power transistor is configured to amplify the RF signal; and

a protection circuit coupled with the transmission line and configured to detect an overdrive or overvoltage condition and to reduce a current or voltage at the power amplifier based on a detection of the overdrive or overvoltage condition.

2. The circuit of claim 1, wherein the protection circuit comprises:

a compensator configured to compensate for an amplitude or phase of the RF signal; and

two transistors coupled with the transmission line via the compensator and a shunt line.

3. The circuit of claim 2, wherein the two transistors are arranged in a Darlington configuration.

4. The circuit of claim 2, wherein the compensator is configured to compensate for the phase of the RF signal to increase linearity of a response profile of the primary power transistor.

5. The circuit of claim 2, wherein the protection circuit further comprises:

a detector configured to track a trigger voltage and to provide a biasing voltage to the two transistors that is proportional to the trigger voltage.

6. The circuit of claim 5, wherein the detector comprises a voltage divider coupled with an emitter of a first transistor of the two transistors and further coupled with a base of a second transistor of the two transistors.

7. The circuit of claim 6, wherein the detector further comprises:

a capacitor coupled with the emitter of the first transistor.

8. The circuit of claim 4, wherein the detector is coupled with a bias voltage node that is configured to provide a bias voltage, through an input bias network, to the base of the primary power transistor.

9. The circuit of claim 4, wherein the detector is coupled with a control voltage node that is configured to provide a bias voltage, through an output bias network, to a collector of the primary power transistor.

10. The circuit of claim 1:

wherein the protection circuit is coupled with the transmission line via an emitter follower;

wherein the protection circuit further comprises an operational amplifier;

wherein the sensing resistor is coupled with a voltage control node of the operational amplifier and is coupled with the transmission line via a collector of the emitter follower; and

wherein an output of the operational amplifier is coupled with a base of the emitter follower.

11. A system comprising:

a transceiver configured to provide a radio frequency (RF) signal;

amplification circuitry coupled with the transceiver, the amplification circuitry including a primary power transistor configured to receive and amplify the RF signal;

a transmission line configured to transmit the RF signal from the transceiver to a base of the primary power transistor; and

a protection circuit coupled with the transmission line and configured to detect an overdrive or overvoltage condition and to reduce a current or voltage at the primary power transistor based on a detection of the overdrive or overvoltage condition.

12. The system of claim 11, wherein the protection circuit comprises:

a compensator configured to compensate for an amplitude or phase of the RF signal; and

two transistors coupled with the transmission line via the compensator and a shunt line.

13. The system of claim 12, wherein the protection circuit further comprises:

a detector configured to track a trigger voltage and to provide a biasing voltage to the two transistors that is proportional to the trigger voltage.

14. The system of claim 13, wherein the detector comprises a voltage divider coupled with an emitter of a first transistor of the two transistors and further coupled with a base of a second transistor of the two transistors.

15. The system of claim 14, wherein the detector further comprises:

a capacitor coupled with the emitter of the first transistor.

16. The system of claim 13, wherein the detector is coupled with a voltage node that is configured to provide a bias voltage through an input bias network to the base of the primary power transistor or through an output bias network to a collector of the primary power transistor.

17. A method comprising:

generating, by a transceiver, a radio frequency (RF) signal;

transmitting, by the transceiver, the RF signal along a transmission line to a primary power transistor;

detecting, by a protection circuit coupled with the transmission line, an overdrive condition or an overvoltage condition; and

reducing, by the protection circuit, a current or voltage at the primary power transistor based on said detecting.

18. The method of claim 17, wherein said reducing comprises shunting at least a portion of the RF signal via the protection circuit.

19. The method of claim 17, wherein said detecting comprises:

tracking, with a detector of the protection circuit, a trigger voltage; and

providing a biasing voltage to two transistors of the protection circuit that is proportional to the trigger voltage.

20. The method of claim 17, further comprising:

compensating, with the protection circuit, for a phase of the RF signal to increase linearity of a response profile of the primary power transistor.