| 摘要 |
PURPOSE:To effectively drive at a high speed with an optical signal having severe variation by providing bias means having resistor group. CONSTITUTION:If a control input signal is a low level, the output, i.e., a connecting point B of a switching circuit 2 becomes a high level, a light emitting diode 1 is turned OFF, and an optical semiconductor element is not driven. When a control input signal becomes a high level, the point B becomes a low level. Since a transient current flows to the circuit 2 through speedup capacitor 3, and a resistor 4 of the diode 1 from a power source voltage at the transient time upon change of state of the point B, the switching time of the diode 1 is shortened to improve rising characteristic. When the signal becomes a low level, the point B becomes a high level, and remaining charge near the diode 1 is discharged and absorbed by transient current from the circuit 2 at the transient time. Thus, an optical semiconductor element can be effectively driven at a high speed for the signal including high frequency component of severe variation. |
