Patent ID: 7557333

Claim:
An optical signal receiving circuit comprising: a current-voltage converting circuit receiving a current signal output from a photoelectric converting circuit, and converting the current signal into a voltage signal, the photoelectric converting circuit receiving an optical signal and converting the optical signal into the current signal; a voltage generating circuit receiving the voltage signal output from said current-voltage converting circuit and generating a DC voltage based on the voltage signal; and a first differential circuit receiving the voltage signal output from said current-voltage converting circuit and the DC voltage output from said voltage generating circuit and generating a differential voltage signal based on the voltage signal and the DC voltage, wherein said first differential circuit includes a pair of differential transistors and a current source commonly connected to the pair of transistors, wherein the current source consists of at least one passive element, wherein said voltage generating circuit includes a low-pass filter, and wherein said voltage generating circuit further includes a second differential circuit having said low-pass filter coupled with one of differential inputs of said second differential circuit.