| 摘要 |
PURPOSE:To prevent an over current from being fed to a laser diode when a power supply is turned OFF. CONSTITUTION:A power supply voltage detecting means 103 detects the reduction of a power supply in voltage and outputs a detection signal. A stop means 101 shuts off the feed of a drive electric power to a laser diode 104 according to the detection signal concerned. As mentioned above, when a power supply drops in voltage with the shutoff of a power supply, a laser diode 104 is can be prevented from starting to operate and protected against damage. |
