Patent ID: 11967934
Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A power amplifier circuit which is a Doherty type power amplifier circuit including a main amplifier and a peak amplifier to which a first input signal and a second input signal branched off from one input signal are respectively input, and configured to synthesize and output a first output signal from the main amplifier and a second output signal from the peak amplifier,
wherein the peak amplifier includes:
a first transistor including a first source terminal, a first drain terminal and a first control terminal, the first source terminal being connected to a first constant potential line, the first drain terminal being connected to a first node connected to the first constant potential line via a third alternating current coupling circuit, the first control terminal being connected to a first bias voltage application circuit configured to apply a first bias voltage to the first control terminal, and the second input signal being input to the first control terminal via a first alternating current coupling circuit; and
a second transistor including a second source terminal, a second drain terminal and a second control terminal, the second source terminal being connected to the first node, the second drain terminal being connected to a second constant potential line having a higher potential than the first constant potential line, the second control terminal being connected to a second bias voltage application circuit configured to apply a second bias voltage to the second control terminal, and the second control terminal being connected to the first node via a second alternating current coupling circuit, and
a second node between the second drain terminal and the second constant potential line is connected to a fourth alternating current coupling circuit and outputs the second output signal via the fourth alternating current coupling circuit,

wherein the first bias voltage has a magnitude such that the first transistor is in a pinch-off state when power of a signal input to the first control terminal does not exceed a first level, and the first transistor is in an ON state when the power of the signal input to the first control terminal exceeds the first level.