Patent ID: 7442913
Filing Date: 2008-10-28
Classification: H03F

Abstract:
1. A photocurrent amplifier circuit comprising: a differential amplifier circuit which is configured to have an input unit including amplifier devices which are connected in parallel; device selector switches, each of which is connected to an input of an associated one of said amplifier devices and is operable to apply an input voltage to said associated amplifier device, the input voltage inactivating said associated amplifier device; gain resistors, each of which is connected between an input of an associated one of said amplifier devices and an output of said differential amplifier circuit; and light receiving devices, each of which is connected to an input of an associated one of said amplifier devices and is operable to cause a photocurrent in accordance with an amount of received light, wherein the photocurrent flowing from each of the light receiving devices into an associated one of said gain resistors is amplified into a voltage signal by said differential amplifier circuit.