Patent ID: 9240760
Filing Date: 2016-01-19
CPC Classification: H03F

Claim Text:
1. A power amplifier module comprising: a first amplification transistor configured to amplify and output a radio frequency signal; a second amplification transistor connected in parallel to the first amplification transistor and having a smaller size than the first amplification transistor; a bias circuit configured to supply a bias voltage or a bias current to the first and second amplification transistors; a current detector circuit configured to detect a current flowing in the second amplification transistor; a bias control circuit configured to control the bias voltage or the bias current supplied from the bias circuit to the first and second amplification transistors depending on the detection result of the current detector circuit; and a reference voltage generator circuit configured to generate a predetermined reference voltage, wherein the current detector circuit includes a detection resistor connected in series to the second amplification transistor, the detection resistor being configured to generate a detection voltage corresponding to the current flowing in the second amplification transistor, and wherein the bias control circuit includes a comparator circuit configured to compare the detection voltage with the reference voltage, and a first bias-reducing circuit configured to reduce the bias voltage or the bias current when the detection voltage is greater than the predetermined reference voltage on the basis of the comparison result of the comparator circuit.