US 11,996,811 B2
Power amplifier circuit
Masafumi Kazuno, Kyoto (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed on Jun. 8, 2021, as Appl. No. 17/341,953.
Claims priority of application No. 2020-101104 (JP), filed on Jun. 10, 2020.
Prior Publication US 2021/0391835 A1, Dec. 16, 2021
Int. Cl. H03F 3/195 (2006.01); H03F 3/24 (2006.01)
CPC H03F 3/245 (2013.01) [H03F 3/195 (2013.01); H03F 2200/451 (2013.01); H03F 2200/541 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A power amplifier circuit comprising:
a first amplifier configured to amplify an input signal;
a first transformer including a first primary coil connected to an output of the first amplifier, and a first secondary coil coupled to the first primary coil via a first electromagnetic field;
a second amplifier connected to a first end of the first secondary coil;
a third amplifier connected to a second end of the first secondary coil;
a second transformer including a second primary coil having a first end connected to an output of the second amplifier, and a second end connected to an output of the third amplifier, and a second secondary coil coupled to the second primary coil via a second electromagnetic field;
a first capacitance element between the second secondary coil and a ground; and
a second capacitance element having a first end connected to a first end of the second secondary coil, and a second end connected to a second end of the second secondary coil,
wherein the second end of the second secondary coil is connected to a node between the first capacitance element and the second capacitance element.