SEMICONDUCTOR RELAY CIRCUIT

摘要

PURPOSE:To improve the responsiveness at both on/off operations by using an enhancement type MOS transistor (TR) at the on-operation so as to charge the gate capacitance and using a depletion type MOS TR at the off-operation so as to discharge the gate electric charge. CONSTITUTION:The 1st photo diode array 2 and the 2nd photo diode array 3 receiving an optical output of a light emitting diode 1 and generating a photoelectromotive force are connected oppositely in series. A small signal MOS TR having a comparatively small drain-gate capacitance is used at the on-operation to apply high speed charge to the drain-gate capacitance of an outputting MOS TR 5. A depletion type MOS TR 7 having a small effective on-resistance is used at the off-operation to discharge the electric charge of the gate of the outputting MOS TR, and the gate voltage of the outputting MOS TR is decreased quickly by discharging the electric charge of the gate of the enhancement type MOS TR 6 via a diode 5 to decrease a switching time.