Patent ID: 9654063
Date: 2017-05-16
CPC Classifications: H03F

Claim:
1. A bias circuit for use with an amplifier circuit, comprising: a first circuit comprising a first resistor and a decoupling capacitor, the first circuit supplying a bias voltage to the amplifier circuit; a bias voltage generation circuit comprising a first transistor and charges the decoupling capacitor through the first resistor, the first transistor being connected to the first circuit and generating the bias voltage; one or more switches for changing the amount of a current flowing through the first transistor; a first replica circuit comprising a second circuit and a second transistor, the second circuit comprising a second resistor and a capacitor, the second transistor being connected to the second circuit and generating a pseudo-bias voltage; a second replica circuit comprising a third transistor that generates a reference voltage; a comparator for comparing the pseudo-bias voltage with the reference voltage and outputting a comparison result signal based on a result of the comparison; and a control circuit for controlling the one or more switches based on the comparison result signal to reduce the amount of the current flowing through the first transistor when the pseudo-bias voltage reaches or exceeds the reference voltage.