| 摘要 |
PROBLEM TO BE SOLVED: To control a semiconductor laser driven with the high voltage by a transistor of low breakdown voltage. SOLUTION: A protecting circuit 33 is connected between a terminal 20 whereto the semiconductor laser LD and the transistor 7 for driving the semiconductor laser LD are connected, and a control terminal 25 of the semiconductor laser for each other. By this protecting circuit 33, the voltage of the terminal 20 is controlled to the breakdown voltage of the transistor 7 or lower. |
