Light reception circuit and light reception device

摘要

A light reception circuit includes a direct current (DC) level shift circuit that shifts a DC voltage level of a first signal or a second signal and outputs a third signal or a fourth signal, or outputs both of the third signal and the fourth signal so that a DC voltage level of the first signal output from a cathode of a photodiode that generates a signal by photo conversion and a DC voltage level of the second signal output from an anode of the photodiode agree, and a differential amplifier that amplifies a difference between the third signal and the second signal, between the first signal and the fourth signal, or the third signal and the fourth signal, based on the third signal, the forth signal output from the DC level shift circuit, impedance of the DC level shift circuit being lower than input impedance of the differential amplifier.

主权项

1. A light reception circuit, comprising:
a direct current (DC) level shift circuit that shifts a DC voltage level of a first electric signal and outputs a third electric signal, shifts a DC voltage level of a second electric signal and outputs a fourth electric signal, or outputs both of the third electric signal and the fourth electric signal so that a DC voltage level of the first electric signal output from a cathode of a photodiode that generates an electric signal by photoelectric conversion and a DC voltage level of the second electric signal output from an anode of the photodiode agree; a differential amplifier that amplifies a difference between the third electric signal and the second electric signal when the DC level shift circuit outputs the third electric signal, amplifies a difference between the first electric signal and the fourth electric signal when the DC level shift circuit outputs the fourth electric signal, or amplifies a difference between the third electric signal and the fourth electric signal when the DC level shift circuit outputs both the third electric signal and the fourth electric signal; and a bias circuit that applies an opposite directional bias between the anode of the photodiode and the cathode of the photodiode, impedance of the DC level shift circuit being lower than input impedance of the differential amplifier.