Qualcomm Incorporated

Guoqing Fu

Xiangdong Zhang

Xinwei Wang

Yan Kit Gary Hau

Jing-Hwa Chen

Chenliang Du

Jisun Ryu

Junzhi Yu

An amplifier circuit includes an amplifier configured to receive a radio frequency (RF) input signal from an input node, a bias circuit comprising a reference transistor coupled between a reference current source and ground, and a bias transistor coupled to the reference transistor and configured to generate a main bias current to bias the amplifier, an input power sense circuit coupled to the input node, and an additional transistor coupled to the input power sense circuit and to the bias transistor, the additional transistor configured to generate an additional bias current to bias the amplifier, the additional bias current responsive to a power level of the RF input signal.

Radio frequency (RF) amplifier bias circuit

Certain aspects of the present disclosure are directed to an amplifier. The amplifier may include a transistor coupled to an output of the amplifier, and a resonator coupled between the output of the amplifier and a reference potential node, a resonant frequency of the resonator being set to be at a subharmonic of a fundamental frequency of the amplifier, and an impedance of the resonator being greater than a load impedance of the amplifier at the fundamental frequency of the amplifier.

Stability improvement circuit for radio frequency (RF) power amplifiers

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Medford, MA, United States of America

Guoqing Fu