| 摘要 |
PROBLEM TO BE SOLVED: To prevent runaway of a semiconductor light emitting device due to malfunction of an APC control system. SOLUTION: When photocurrent becomes zero due to malfunction of an APC control system, the output voltage of a current-voltage converting part 3 becomes maximum and higher than a reference voltage Vth2 and the output level of an anomaly detecting part 5 becomes high. Then intermittent operation signals from an intermittent operation signals generating part 6 appear at the output of an AND gate 7 and at the output of a NOR gate 8. In response to the intermittent operation signals, a transistor 901 of a bias current controlling part 9 is intermittently driven and a transistor 1103 of a modulation current controlling part 11 is also intermittently driven. |
