POWER AMPLIFIER

摘要

A power amplifier includes an amplification transistor which performs power amplification, a bias circuit which outputs a bias voltage to a base of the amplification transistor, a control terminal to which a control voltage is applied for controlling switching between an operating state and a stopping state of the bias circuit, and a bias voltage adjustment circuit connected to the control terminal. The bias voltage adjustment circuit includes a variable capacitance element which is connected to the control terminal and whose capacitance value decreases as the control voltage increases, a discharge circuit which discharges electric charge accumulated in the variable capacitance element to the control terminal, and a control circuit which is connected to the bias circuit and controls the bias voltage. The bias voltage adjustment circuit outputs, to the bias circuit, a bias voltage adjustment signal which increases the bias voltage for a predetermined period after the control voltage is applied.

主权项

1. A power amplifier comprising:
an amplification transistor which performs power amplification; a bias circuit which outputs a bias voltage to a base of the amplification transistor; a control terminal to which a control voltage is applied for controlling switching between an operating state and a stopping state of the bias circuit; and a bias voltage adjustment circuit connected to the control terminal, wherein the bias voltage adjustment circuit includes:
a variable capacitance element which is connected to the control terminal and whose capacitance value decreases as the control voltage increases;a discharge circuit which discharges electric charge accumulated in the variable capacitance element to the control terminal; anda control circuit which is connected to the bias circuit and controls the bias voltage, and the bias voltage adjustment circuit outputs, to the bias circuit, a bias voltage adjustment signal which increases the bias voltage for a predetermined period after the control voltage is applied.