| 摘要 |
<p>PURPOSE:To drive at a high speed and to eliminate noise in a driving current by connecting means for supplying a bias current to an anode end irrespective of ON/OFF of the current. CONSTITUTION:A laser diode driving current is outputted from a emitter of N-P-N transistors 4 and 5, and supplied to an anode terminal of a laser diode 7. A cathode terminal of the diode 7 is connected to an CND 9 point. A bias current setting resistor 10 is connected to the anode terminal of the diode 7. The other end of the resistor 10 is connected to a power source VCC 8. Thus, a connecting capacity of a semiconductor light emitting element is previously charged, and a connecting capacity charge current can be eliminated irrespective of a length of an OFF time. As a result, spike noise of a rise of a current waveform depending upon the OFF time suppresses deterioration of a rising speed.</p> |
