Multi-beam laser light-intensity control circuit and optical scanning apparatus including the same

摘要

A multi-beam laser light-intensity control circuit includes laser diodes; a light-receiving element for receiving a laser beam emitted from each laser diode and outputting a current corresponding to the light intensity of the received laser beam; and an automatic power control circuit for automatically controlling output power of each laser diode based on the current output from the light-receiving element. The automatic power control circuit includes a current/voltage conversion unit for converting the current output from the light-receiving element into a voltage; an error amplifying circuit for amplifying a difference voltage between the voltage output from the current/voltage conversion unit and a predetermined reference voltage; storing circuits each configured to store the difference voltage output from the error amplifying circuit in association with the corresponding laser diode; and drive current generating units each configured to generate a drive current for the corresponding laser diode based on the difference voltage.