US 11,855,587 B2
Power amplifier circuit
Takashi Soga, Kyoto (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed on Jun. 26, 2020, as Appl. No. 16/913,585.
Claims priority of application No. 2019-119379 (JP), filed on Jun. 27, 2019.
Prior Publication US 2020/0412304 A1, Dec. 31, 2020
Int. Cl. H03F 1/30 (2006.01); H03F 3/21 (2006.01); H03F 1/32 (2006.01)
CPC H03F 1/302 (2013.01) [H03F 1/32 (2013.01); H03F 3/21 (2013.01); H03F 2200/447 (2013.01); H03F 2200/451 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A power amplifier circuit comprising:
an amplifier transistor configured to amplify an input signal;
a resistance element connected in series with a base of the amplifier transistor;
a bias transistor configured to supply a bias current from an emitter or a source of the bias transistor to the base of the amplifier transistor through the resistance element; and
a positive feedback circuit configured to change a base voltage or a gate voltage of the bias transistor based on a change in the bias current, wherein the positive feedback circuit comprises a current mirror circuit connected to the bias transistor and an offset circuit.