| 摘要 |
PURPOSE:To drive a high speed signal with an optional pulse width by using two current changeover switches and connecting a capacitor between a semiconductor light emitting element connected to each current changeover switch and a resistor. CONSTITUTION:When a binary signal is fed to a signal input terminal 1,the signal is fed to the 1st and 2nd current changeover switches 11, 14 through a gate circuit 10 and when a signal is at a high level, transistors (TRs) 12, 14 are conductive,a current from constant current sources 19, 20 flows and TRs 13, 16 are turned off. When a signal is at a low level, the TRs 13, 15 are turned on. In selecting a resistor 18 larger than the internal resistance of the semiconductor light emitting element 6, the current flowing to the semiconductor light emitting element 6 has a waveform subjected to peaking its leading and trailing, resulting that the leading and trailing time of the optical output waveform is quickened. |
