Current-mode control for radio-frequency power amplifiers

Patent metadata

Field	Value
Publication number	US-2016190994-A1
Application number	US-201514809227-A
Country	US
Kind code	A1
Filing date	Jul 26, 2015
Priority date	Aug 15, 2012
Publication date	Jun 30, 2016
Grant date	—

Abstract

Current-mode control for radio-frequency (RF) power amplifiers. In some embodiments, an RF power amplifier control circuit can include a sensor configured to measure a base current of a power amplifier and generate a sensed current. The control circuit can further include a sensing node configured to receive a reference current and perform a current-mode operation with the sensed current to yield an error current. The control circuit can further include a control loop configured to generate a control signal based on the error current to adjust an operating parameter of the power amplifier.

First claim

What is claimed is:

1 . A radio-frequency power amplifier control circuit, comprising:
a sensor configured to measure a base current of a power amplifier and generate a sensed current; a sensing node configured to receive a reference current and perform a current-mode operation with the sensed current to yield an error current; and a control loop configured to generate a control signal based on the error current to adjust an operating parameter of the power amplifier.

2 . The control circuit of claim 1 wherein the power amplifier includes a gallium arsenide (GaAs) heterojunction bipolar transistor (HBT) power amplifier.

3 . The control circuit of claim 2 wherein the GaAs HBT power amplifier is configured to operate in GSM/GPRS communication protocols.

4 . The control circuit of claim 1 wherein the sensor includes a finger sensor configured to sense the base current of the power amplifier to yield the sensed current.

5 . The control circuit of claim 1 wherein the current-mode operation includes subtracting the sensed current from the reference current to yield the error current.

6 . The control circuit of claim 1 wherein the power amplifier control circuit is substantially free of a sense resistor between the sensor and the sensing node.

7 . The control circuit of claim 1 wherein the reference current is obtained from an external analog control voltage.

8 . The control circuit of claim 1 wherein the sensing node is configured to be regulated to substantially maintain a voltage that tracks a battery voltage.

9 . The control circuit of claim 1 wherein the control loop includes a trans-impedance amplifier configured to amplify the error current.

10 . The control circuit of claim 1 wherein the control loop includes a closed control loop.

11 . The control circuit of claim 1 wherein the power amplifier control circuit is substantially free of an external bypass capacitor to thereby reduce cost and size associated with the power amplifier circuit.

12 . The control circuit of claim 1 further comprising a pre-charging system configured to pre-charge a selected node of the control circuit.

13 . The control circuit of claim 12 wherein the pre-charging system including a sensor circuit configured to generate a control signal based on comparison of a base voltage of the PA and a reference voltage selected to be lower than a threshold voltage of the PA, the pre-charging system further including an actuator circuit in communication with the sensor circuit, the actuator circuit configured to receive the control signal from the sensor circuit, the actuator circuit further configured to enable or disable, based on the control signal, a pre-charge current for pre-charging the selected node of the control circuit.

14 . A method for controlling a radio-frequency power amplifier, the method comprising:
measuring a base current of a power amplifier to generate a sensed current; performing a current-mode operation between a reference current and the sensed current to yield an error current; generating a control signal based on the error current; and adjusting an operating parameter of the power amplifier based on the control signal.

15 . The method of claim 14 wherein performing the current-mode operation includes subtracting the sensed current from the reference current to yield the error current.

16 . The method of claim 14 wherein generating the control signal includes amplifying the error current with a trans-impedance amplifier.

17 . The method of claim 14 wherein at least some of the generating and adjusting are facilitated by a closed control loop.

18 . A radio-frequency (RF) module comprising:
a packaging substrate configured to receive a plurality of components; a power amplifier (PA) disposed over the packaging substrate; a control circuit disposed over the packaging substrate and interconnected to the PA, the control circuit including a sensor configured to measure a base current of the PA and generate a sensed current, a sensing node configured to receive a reference current and perform a current-mode operation with the sensed current to yield an error current, and a control loop configured to generate a control signal based on the error current to adjust an operating parameter of the PA; and a plurality of connectors configured to provide electrical connections between the PA, the control circuit, and the packaging substrate.

19 . The RF module of claim 18 wherein the PA is disposed on a first die and the control circuit is disposed on a second die, each of the first die and the second die being mounted on the packaging substrate.

20 . The RF module of claim 18 wherein the control circuit further includes a pre-charging system configured to pre-charge a selected node of the control circuit, the pre-charging system including a sensor circuit configured to generate a control signal based on comparison of a base voltage of the PA and a reference voltage selected to be lower than a threshold voltage of the PA, the pre-charging system further including an actuator circuit in communication with the sensor circuit, the actuator circuit configured to receive the control signal from the sensor circuit and enable or disable, based on the control signal, a pre-charge current for pre-charging the selected node of the control circuit.

Assignees

• Skyworks Solutions Inc

Inventors

• Shi Ying
• Oz Onder

Classifications

• H03F2200/423

  Amplifier output adaptation especially for transmission line coupling purposes, e.g. impedance adaptation · CPC title

• H03F2200/462

  the current being sensed · CPC title

• H03G3/3042 Primary

  in modulators, frequency-changers, transmitters or power amplifiers · CPC title

• H03F3/195

  in integrated circuits · CPC title

• H03F1/0233 Primary

  by using a signal derived from the output signal, e.g. bootstrapping the voltage supply · CPC title