Systems and methods providing loadline modulation of a power amplifier
AssigneeQUALCOMM Incorporated
InventorJose Cabanillas
Life of this patent
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Abstract
A circuit including: a power amplifier configured to provide amplified signals to a load; an impedance matching network disposed between the power amplifier and the load, the impedance matching network comprising an adjustable impedance unit; and a feedback loop comprising a rectifier, the rectifier being coupled with an output of the power amplifier, the feedback loop further comprising and impedance control circuit configured to receive a signal from the rectifier and to control the adjustable impedance unit in response to the signal from the rectifier.
Claims15
A circuit comprising:
- a power amplifier configured to provide amplified signals to a load;
- an impedance matching network disposed between the power amplifier and the load, the impedance matching network comprising an adjustable impedance unit;
- and
- a feedback loop comprising a rectifier, the rectifier being coupled with an output of the power amplifier, the feedback loop further comprising an impedance control circuit configured to receive a signal from the rectifier and to control the adjustable impedance unit in response to the signal from the rectifier, wherein the impedance control circuit comprises a weighting block configured to receive a rectified load voltage, and configured to generate a control signal for the adjustable impedance unit that is a function of the signal from the rectifier and the rectified load voltage.
A method performed at a radio frequency (RF) power amplifier (PA) system, the method comprising:
- sampling a voltage swing at an output terminal of the PA, wherein the PA provides an amplified RF signal to a load;
- generating a first control signal in response to the voltage swing;
- applying the first control signal to a comparator to generate a second control signal, wherein the comparator receives a reference signal corresponding to a voltage swing threshold;
- and
- adjusting an impedance of a matching network of the PA in response to the second control signal, wherein generating the first control signal comprises:
- receiving a first rectified voltage from a first rectifier sampling the voltage swing;
- receiving a second rectified voltage from a second rectifier sampling a voltage at the load;
- and
- generating the first control signal as a function of the first rectified voltage and the second rectified voltage.
A method performed in a radio frequency (RF) circuit having a power amplifier (PA), the method comprising:
- providing an amplified RF signal from an output terminal of the PA to a load;
- demodulating the amplified RF signal to generate an envelope signal;
- processing the envelope signal to generate a control signal that is a function of the envelope signal;
- and
- applying the control signal as a bias to an adjustable impedance element of a matching network, wherein the matching network is coupled between the output terminal of the PA and the load, further comprising applying a low pass filter to the control signal before applying the control signal as the bias to the adjustable impedance element.
Dependencies are inferred from the claim text.