Patent ID: 7427738

Claim:
A light-receiving amplifier circuit comprising: a pre-differential amplifier circuit of voltage-parallel-feedback type, to which circuit a light-receiving element is connected; a differential amplifier circuit for amplifying differential between an output voltage from said pre-differential amplifier circuit and a first reference voltage; and an output voltage expanding circuit, wherein said pre-differential amplifier circuit includes a differential amplifier and plural feedback resistors provided in parallel to said differential amplifier, each of which resistors has an end connected to one of input terminals of said differential amplifier; an amplification factor of said differential amplifier circuit is less than 1; and said output voltage expanding circuit is for (i) expanding an output voltage range from said differential amplifier and (ii) supplying the expanded output voltage range to the differential amplifier circuit, and is connected to another end of at least one of said plural feedback resistors and an output terminal of said differential amplifier.