Patent ID: 7408141

Claim:
A light-receiving amplifier circuit comprising: a photodiode which converts an optical signal into a current signal; an operation amplifier circuit which converts and amplifies the current signal into a voltage signal, and outputs the voltage signal; and a clipping circuit which clips the voltage signal outputted by said operation amplifier circuit to a predetermined value by clipping an input voltage of an output amplifier stage of said operation amplifier circuit, when the voltage signal outputted by said operation amplifier circuit reaches the predetermined value, wherein the current signal is converted into the voltage signal through a conversion resistance connected between an output terminal and an inverting input terminal of said operation amplifier circuit, wherein said clipping circuit includes a voltage source and a switch element which detects a change of the voltage signal outputted by said operation amplifier circuit, and when turned on, said switch element applies a voltage in accordance with a voltage of said voltage source to an input of said output amplifier stage of said operation amplifier circuit.