| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a circuit and a method for light output control that can control light output of a semiconductor light emitting device according to operation temperature, based upon a driving current of the semiconductor light emitting device. <P>SOLUTION: In the light output control circuit as an embodiment, a light emission efficiency arithmetic section calculates light emission efficiency SE through operation based upon desired light emission intensity Ptar and extinction ratio ER, a mark rate M of an input modulated signal, and a modulating current Im. A threshold generator generates a threshold through quotient operation between designated permissible light emission intensity Pmax and the light emission efficiency SE. Further, in this light output control circuit, a driving current calculator calculates the driving current Iop of the semiconductor light emitting device. When the driving current Iop exceeds the threshold, the light output control circuit stops the light output of the semiconductor light emitting device. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
