Patent ID: 7105797

Claim:
An optical receiving circuit, comprising: a current-voltage converting circuit for converting an input current signal into a voltage signal so as to output the voltage signal; a single-differential converting circuit for converting the voltage signal from said current-voltage converting circuit into differential signals so as to output the differential signals; a first low-pass filter for inputting one signal output from said single-differential converting circuit; a second low-pass filter for inputting the other signal output from said single-differential converting circuit; a voltage-current converting circuit for converting a difference between the output signal from said first low-pass filter and the output signal from said second low-pass filter into a current signal; and a hold capacitor for receiving the current signal from said voltage-current converting circuit so as to hold the current signal as a voltage, wherein said current-voltage converting circuit inputs the voltage held in said hold capacitor as a control signal so as to convert the input current signal into the voltage signal using a current-voltage converting gain according to the control signal.