| 摘要 |
A photodetecting circuit includes an adder that selectively adds outputs of a plurality of circuits for photodetection. Each of the circuits for photodetection includes: a element for photodetecting; a transimpedance amplifier for photodetection, with a first input terminal connected to the photodetecting element; a transconductance amplifier, with a first input terminal connected to an output terminal of the transimpedance amplifier; and a feedback circuit, connected between the output terminal of the transimpedance amplifier for photodetection and the first input terminal of the transimpedance amplifier for photodetection and applying feedback to keep fixed an output voltage of the transimpedance amplifier for photodetection. |
