Patent ID: 9369090
Filing Date: 2016-06-14
CPC Classification: H03F

Claim Text:
1. A high-frequency amplifier circuit comprising: a high-frequency amplifying element including an input end and an output end; a bias circuit that is connected to the high-frequency amplifying element and that supplies a first bias voltage to an input side of the high-frequency amplifying element; and a bias adjusting circuit that is connected between the input end and the bias circuit and that adjusts the first bias voltage based on a high-frequency signal inputted to the input end, the bias adjusting circuit including a lumped element and an active element, wherein the bias adjusting circuit includes a signal detecting circuit and a switching circuit; the signal detecting circuit is connected to the input end and the switching circuit, detects the high-frequency signal, and outputs a detected value to the switching circuit; and the switching circuit is connected to the bias circuit and reduces the first bias voltage when the detected value is greater than or equal to a threshold.