Patent ID: 8736376

Claim:
A power amplifier module having a bias circuit, the power amplifier module comprising: an amplifier unit receiving a bias power to amplify an input signal; and a bias unit supplying the bias power to the amplifier wherein the bias unit includes at least one transistor group having: a first NMOS transistor connected between the input signal terminal and the ground, and having a source and a gate connected to the ground; a second NMOS transistor having a source and a gate connected to a drain and the gate of the first NMOS transistor and a drain connected to the input signal terminal together with the gate; a third NMOS transistor connected between the input signal terminal and the reference power terminal, and having a source and a gate connected to the input signal terminal; a fourth NMOS transistor having a source and a gate connected to a drain and the gate of the third NMOS transistor and a drain connected to the reference power terminal together with the gate; a first switch connected in parallel to the first NMOS transistor, and turned on according to a control signal to bypass a power to be applied to the first NMOS transistor; and a second switch connected in parallel to the third NMOS transistor, and turned on according to the control signal to bypass a power to be applied to the third NMOS transistor.