Patent ID: 8692619
Filing Date: 2014-04-08
Classification: H03F

Abstract:
1. A high frequency power amplifier comprising: a first transistor that performs power amplification of a high frequency signal; a bias circuit that supplies a bias to the first transistor according to a reference voltage; a power-supply circuit that applies the reference voltage to the bias circuit, the reference voltage controlling an amount of bias supplied to the first transistor from the bias circuit; a control voltage terminal to which a control signal is applied, the control signal controlling start-up and stopping of the bias circuit; and a speed-up circuit that increases the amount of bias supplied to the first transistor from the bias circuit by transiently increasing the reference voltage output from the power-supply circuit during rise of the control voltage, wherein the speed-up circuit includes: the overshoot control circuit determines an increasing amount of the reference voltage output from the power-supply circuit when the reference voltage is transiently increased according to a charge amount charged in the capacitor, and the time-constant control circuit determines a time constant in charging and discharging the capacitor through the time-constant control circuit and the overshoot control circuit.