Patent attributes
A photocurrent amplifier circuit which can be realized as a simple and downsized photocurrent amplifier circuit is capable of selectively amplifying, in an amplifier circuit in an output stage, one or more of current signals which are respectively obtainable from light receiving circuits. The photocurrent amplifier circuit includes: light receiving circuits; amplifier devices associated with the light receiving circuits; device selector switches which apply input voltages, which deactivate the amplifier devices, to the associated amplifier devices; and a differential amplifier circuit having an inverting input unit configured of the amplifier devices which are connected in parallel. The inputs of the amplifier devices and the output of the differential amplifier circuit are connected by gain resistors. The differential amplifier circuit amplifies, into voltage signals, current signals flowing from the light receiving circuits which are respectively associated with the gain resistors.
