US 12,334,882 B2
Radio-frequency amplifier circuit
Takayuki Tsutsui, Kyoto (JP); and Satoshi Tanaka, Kyoto (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed on Jul. 13, 2021, as Appl. No. 17/374,403.
Claims priority of application No. 2020-141019 (JP), filed on Aug. 24, 2020.
Prior Publication US 2022/0060157 A1, Feb. 24, 2022
Int. Cl. H03F 1/30 (2006.01); H03F 1/56 (2006.01); H03F 3/21 (2006.01)
CPC H03F 3/211 (2013.01) [H03F 1/56 (2013.01); H03F 2200/222 (2013.01); H03F 2200/451 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A radio-frequency amplifier circuit comprising:
a first amplifier transistor configured to amplify and output a radio-frequency signal supplied to a base of the first amplifier transistor;
a first bias transistor that is connected to the first amplifier transistor, thereby forming a current mirror, and that is configured to supply a first bias to the base of the first amplifier transistor;
a second bias transistor that is connected to the base of the first amplifier transistor via a bias supply node, thereby forming an emitter follower, and that is configured to supply a second bias to the base of the first amplifier transistor; and
a first capacitor having a first end connected to the base of the first amplifier transistor and a second end connected to an emitter of the second bias transistor via the bias supply node,
wherein a part of the radio-frequency signal is supplied to the bias supply node via the first capacitor.