| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress gain variation due to element variation in an optical apparatus provided with a light emission output controller for performing APC control. <P>SOLUTION: A light-receiving element 114 detects the optical output of a light-emitting element 112, and a current/voltage converter 132 converts the detected current Im into a detected voltage signal Vm. A variable gain amplifier 142 is provided between a differential amplifier 170 for controlling the driving of a current driver 120 for supplying current to the light-emitting element 112 and the current/voltage converter 132. A variable gain amplifier 152 amplifies a light-emitting element control voltage Vset for canceling variation in light emission output due to variation in individual light-emitting element 112 or the light-receiving element 114. The difference amplifier 154 adjusts control gains of the variable gain amplifiers 142, 152, based on the difference between a reference signal Vref and a light-emitting element control voltage Vset 1 to be output from the variable gain amplifier 152 so that an opening loop gain of a control loop may not change. <P>COPYRIGHT: (C)2007,JPO&INPIT |
