1st driver null

摘要

PROBLEM TO BE SOLVED: To improve the operability of the ON resistance regulation of a photoconductive switch by reducing dissipation power and decreasing the leakage current at the time of high output impedance of a driver. ;SOLUTION: Only one main constant-current source 8 and bias constant current source 11 are adopted. The respective current sources are selectively connected to laser diodes LDi by a driver output voltage selector 21 and bias switching circuit 22. A low leakage current mode is provided separately from a normal high speed mode, the bias currents of LDi at the time of high output impedance of a drive are all set to zero to suppress the leakage current of a PCSW. The LDi at the time of ON of the PCSWi is driven only by the main current Iai, and no bias current flows. Accordingly, the ON resistance Roni of the PCSW can be regulated in a short time by variably setting distribution ratio of the main current distributor ADi.;COPYRIGHT: (C)1997,JPO