Automatic power controller for semiconductor laser

摘要

A controller for controlling the output intensity of a semiconductor laser used in a laser printer or the like in such a manner that the desired adjustment value is obtained, even in the presence of noise in a signal PD indicating the value of the detected intensity. An adjustment value is provided depending on the results of a comparison between the signal PD and a set value PS. The adjustment value is decreased when PS<PD and increased when PD<PS. The current through the semiconductor laser is adjusted in accordance with this set value.