Power amplifier devices that improve amplifier linearity using accumulator variable capacitors

Abstract

A power amplifier device for amplifying an input signal includes a first-stage amplifier circuit, a second-stage amplifier circuit, and an accumulating variable capacitor electrically connected to each other. The first-stage amplifier circuit amplifies the input signal into an amplified signal and outputs it. The second-stage amplifier circuit amplifies the amplified signal into an output signal and outputs it, having an input capacitance value that varies with voltage amplitude. The accumulating variable capacitor has a compensation capacitance value that varies with voltage amplitude, and the change in the compensation capacitance value is complementary to the change in the input capacitance value. By adding an accumulating variable capacitor between the electrically connected first-stage and second-stage amplifier circuits, the input capacitance value plus the compensation capacitance value can be maintained within a stable range, thereby improving the linearity of the amplifier.

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