Patent ID: 8258452
Filing Date: 2012-09-04
Classification: H03F

Abstract:
1. A light receiving circuit comprising: a photodiode that outputs a photocurrent in response to a received light signal; a first amplifier including a feedback resistor connected between an input terminal and an output terminal of an inverting amplifier, and having an input terminal connected to a cathode of the photodiode; a second amplifier having a configuration similar to that of the first amplifier, and having an input terminal connected to an anode of the photodiode; a capacitor element connected between an output terminal of the first amplifier and the input terminal of the second amplifier; and a bias current control circuit that outputs a bias current to the input terminal of the second amplifier according to a current value of the photocurrent, and controls an output voltage signal according to an output of the second amplifier by using the bias current to adjust sensitivity of the light receiving circuit, wherein the bias current control circuit changes the sensitivity according to the output of the second amplifier.