RFIC with dynamically controlled power amplifier

• US 20080139128A1
• Filed: 04/16/2007
• Published: 06/12/2008
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Liao, Hsin-Hsing
• Granted Patent: US 7,787,839 B2
• Time in Patent Office: Days
• US Class Current: 455/68
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

A radio frequency (RF) front-end includes a power amplifier module and a power amplifier control module. The power amplifier module is coupled to amplify an outbound RF signal in accordance with a control signal to produce an amplified outbound RF signal. The power amplifier control module is coupled to generate the control signal based on at least one of forward power of the amplified outbound RF signal and reflected power of the amplified outbound RF signal.

Claims

1. A radio frequency (RF) front-end comprises:

a power amplifier module coupled to amplify an outbound RF signal in accordance with a control signal to produce an amplified outbound RF signal; and

power amplifier control module coupled to generate the control signal based on at least one of forward power of the amplified outbound RF signal and reflected power of the amplified outbound RF signal.

2. The RF front-end of claim 1, wherein the power amplifier control module comprises:

a directional coupler coupled to provide the amplified outbound RF signal to an antenna structure;

forward power detection circuitry coupled to the directional coupler, wherein the forward power detection circuitry detects the forward power of the amplified outbound RF signal;

reflected power detection circuitry coupled to the directional coupler, wherein the reflected power detection circuitry detects the reflected power of the amplified outbound RF signal; and

control circuitry to generate the control signal based on the at least one of the forward power and the reflected power.

3. The RF front-end of claim 2, wherein the control circuitry further functions to:

generate the control signal to turn off the power amplifier module when the reflected power compares unfavorably to a reflected power threshold.

4. The RF front-end of claim 2, wherein the control circuitry further functions to:

determine a difference between the forward power and the reflected power; and

generate the control signal to adjust output impedance of the power amplifier module to reduce the reflected power and to increase the forward power.

5. The RF front-end of claim 2, wherein the control circuitry further functions to:

generate the control signal to adjust biasing of the power amplifier module based on the forward power.

6. The RF front-end of claim 2, wherein the forward power detection circuitry comprises:

a forward rectifying circuit coupled to rectify the amplified outbound RF signal received by the directional coupler to produce a rectified forward outbound RF signal, wherein the rectified forward outbound RF signal is representative of the forward power.

7. The RF front-end of claim 6, wherein the reflected power detection circuitry comprises:

a reflected rectifying circuit coupled to rectify the amplified outbound RF signal outputted by the directional coupler to produce a rectified reflected outbound RF signal, wherein the rectified reflected outbound RF signal is representative of the reflected power; and

a comparison module coupled to compare the rectified reflected outbound RF signal with a reflected power threshold and to output an over power indication when the rectified reflected outbound RF signal compares unfavorably with the reflected power threshold.

8. The RF front-end of claim 7, wherein the control circuitry comprises:

a first circuit to generate the control signal as a bias adjust signal based on an interpretation of the rectified forward outbound RF signal; and

a second circuit to generate the control signal as a power down signal for the power amplifier module based on the over power indication.

9. The RF front-end of claim 8, wherein the first circuit comprises:

a mathematical module to generate a mathematical representation of the rectified forward outbound RF signal;

a second comparison module coupled to compare the mathematical representation of the rectified forward power with operational parameters of the power amplifier module; and

a first control module coupled to generate the control signal as the bias adjust signal based on the comparison of the mathematical representation of the rectified forward power with operational parameters of the power amplifier module.

10. The RF front-end of claim 9, wherein the first circuit further comprises:

a second mathematical module to generate a mathematical representation of the rectified reflected outbound RF signal;

a third comparison module coupled to compare the mathematical representation of the rectified forward power with the mathematical representation of the rectified reflected outbound RF signal; and

a second control module coupled to generate the control signal as an impedance adjust signal based on the comparison of the mathematical representation of the rectified forward power with the mathematical representation of the rectified reflected outbound RF signal, wherein the impedance adjust signal is provided to at least one of the power amplifier module and an antenna interface.

11. A radio frequency integrated circuit (RFIC) comprises:

a baseband processing module coupled to;

convert outbound data into an outbound symbol stream in accordance with a wireless communication protocol; and

convert an inbound symbol stream into inbound data in accordance with the wireless communication protocol;

a receiver section coupled to convert an inbound radio frequency (RF) signal into the inbound symbol stream in accordance with a receiver local oscillation;

an up-conversion module coupled to convert the outbound symbol stream into an outbound RF signal in accordance with a transmitter local oscillation;

a power amplifier module coupled to amplify an outbound RF signal in accordance with a control signal to produce an amplified outbound RF signal; and

power amplifier control module coupled to generate the control signal based on at least one of forward power of the amplified outbound RF signal and reflected power of the amplified outbound RF signal.

12. The RFIC of claim 11, wherein the power amplifier control module comprises:

a directional coupler coupled to provide the amplified outbound RF signal to an antenna structure;

forward power detection circuitry coupled to the directional coupler, wherein the forward power detection circuitry detects the forward power of the amplified outbound RF signal;

reflected power detection circuitry coupled to the directional coupler, wherein the reflected power detection circuitry detects the reflected power of the amplified outbound RF signal; and

control circuitry to generate the control signal based on the at least one of the forward power and the reflected power.

13. The RFIC of claim 12, wherein the control circuitry further functions to:

generate the control signal to turn off the power amplifier module when the reflected power compares unfavorably to a reflected power threshold.

14. The RFIC of claim 12, wherein the control circuitry further functions to:

determine a difference between the forward power and the reflected power; and

generate the control signal to adjust output impedance of the power amplifier module to reduce the reflected power and to increase the forward power.

15. The RFIC of claim 12, wherein the control circuitry further functions to:

generate the control signal to adjust biasing of the power amplifier module based on the forward power.

16. The RFIC of claim 12, wherein the forward power detection circuitry comprises:

a forward rectifying circuit coupled to rectify the amplified outbound RF signal received by the directional coupler to produce a rectified forward outbound RF signal, wherein the rectified forward outbound RF signal is representative of the forward power.

17. The RFIC of claim 16, wherein the reflected power detection circuitry comprises:

a reflected rectifying circuit coupled to rectify the amplified outbound RF signal outputted by the directional coupler to produce a rectified reflected outbound RF signal, wherein the rectified reflected outbound RF signal is representative of the reflected power; and

a comparison module coupled to compare the rectified reflected outbound RF signal with a reflected power threshold and to output an over power indication when the rectified reflected outbound RF signal compares unfavorably with the reflected power threshold.

18. The RFIC of claim 17, wherein the control circuitry comprises:

a first circuit to generate the control signal as a bias adjust signal based on an interpretation of the rectified forward outbound RF signal; and

a second circuit to generate the control signal as a power down signal for the power amplifier module based on the over power indication.

19. The RFIC of claim 18, wherein the first circuit comprises:

a mathematical module to generate a mathematical representation of the rectified forward outbound RF signal;

a second comparison module coupled to compare the mathematical representation of the rectified forward power with operational parameters of the power amplifier module; and

a first control module coupled to generate the control signal as the bias adjust signal based on the comparison of the mathematical representation of the rectified forward power with operational parameters of the power amplifier module.

20. The RFIC of claim 19, wherein the first circuit further comprises:

a second mathematical module to generate a mathematical representation of the rectified reflected outbound RF signal;

a third comparison module coupled to compare the mathematical representation of the rectified forward power with the mathematical representation of the rectified reflected outbound RF signal; and

a second control module coupled to generate the control signal as an impedance adjust signal based on the comparison of the mathematical representation of the rectified forward power with the mathematical representation of the rectified reflected outbound RF signal, wherein the impedance adjust signal is provided to at least one of the power amplifier module and an antenna interface.