Patent ID: 8155537

Claim:
An optical receiver circuit comprising: a first light-receiving element operable to convert an optical signal to a current signal; a first transimpedance amplifier operable to output a first voltage signal in response to input of the current signal; a first voltage source operable to supply a second voltage signal serving as a reference voltage for determining pulse switching of the first voltage signal; a second voltage source operable to supply a third voltage signal serving as a reference voltage for generating a shift control signal in comparison with the first voltage signal; a level shift circuit operable to output a voltage signal generated by subtracting a level shift voltage from the first voltage signal in response to the shift control signal; a comparator having a first terminal for receiving the voltage signal from the level shift circuit and a second terminal for receiving the second voltage signal, the comparator being operable to convert the first voltage signal to a pulse; and a controller detecting that the first voltage signal has exceeded the third voltage signal, and operable to output the shift control signal, the controller outputting the shift control signal that is operable to output the level shift voltage and shift the first voltage signal to a low-level side by the level shift circuit when the first voltage signal exceeds the third voltage signal, and the controller outputting the shift control signal that returns the voltage signal from the level shift circuit to a high-level side after the output of the level shift circuit is lowered below the second voltage signal.