Patent ID: 11901867
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A differential amplifier circuit comprising:
a first amplifier and a second amplifier that output a differential signal in a radio-frequency band;
a first inductor having a first end connected to an output end of the first amplifier, and a second end;
a second inductor having a first end connected to an output end of the second amplifier, and a second end,
the second end of the first inductor and the second end of the second inductor being connected to each other;
a choke inductor connected to the second end of the first inductor and the second end of the second inductor;
a first capacitor having a first end connected to the second end of the first inductor and the second end of the second inductor, and a second end connected to a reference potential;
a second capacitor; and
a switch that selectively connects the second capacitor in parallel to the first capacitor or terminates a parallel connection of the first capacitor and the second capacitor, wherein
the first inductor or the second inductor is connected in series with the first capacitor to form a resonant circuit having a first resonant frequency, and the first inductor or the second inductor is connected in series with the first capacitor and the second capacitor that are connected in parallel to form a resonant circuit having a second resonant frequency, the first resonant frequency and the second resonant frequency being different from each other, and
the first resonant frequency and the second resonant frequency correspond to second harmonic frequencies of the differential signal.