Patent ID: 6972627

Claim:
A high frequency power amplifier module, comprising: a first transistor which performs current amplification in response to an input signal received at a base terminal thereof, the base terminal being biased based on a first bias control signal; a first bias control circuit having an input which receives a bias voltage and an output which generates the first bias control signal, wherein the first bias control circuit includes: a first current conversion unit which converts the bias voltage into a first converted current; and a first buffer amplifier having an input coupled to an output of the current conversion unit and an output coupled to the output of the first bias control circuit; a first low-pass filter coupled between the output of the first bias control circuit and the base terminal of the first transistor; and a first reference voltage generating unit which receives the first converted current from the first current conversion unit and which generates a first reference voltage based on the first converted current, wherein the first reference voltage is amplified by the first buffer amplifier and is provided to the first low-pass filter, wherein the first current conversion unit comprises: an op amplifier having a voltage follower configuration; a first MOS transistor which has a gate connected to an output portion of the op amplifier and which is coupled in series between a power supply voltage and a reference potential to generate a first current; and a second MOS transistor whose gate is coupled to the output portion of the op amplifier and which is coupled in series between the power supply voltage and the first reference voltage generating unit to generate a second current of the same level as the first current, and wherein the first buffer amplifier includes a voltage follower-coupled op amplifier.