| 摘要 |
In an optical power control device for a semiconductor light emitting element, a voltage corresponding to a write power set value is modified with write data and then is averaged. The resultant averaged voltage is subtracted from the averaged voltage of the optical power detection voltage, so that the drive current of the semiconductor light emitting element is controlled in accordance with the difference of the resultant subtraction voltage from the read power set value. As a result, even when the write power has been outputted for a long period of time, it can be switched over to the read power instantaneously. By employing simple switching circuitry, the control device is free from the occurrence of drifts or the adjustment of offsets.
|
