ONE-ELEMENT TYPE OPTICAL RECEPTION CIRCUIT

摘要

PURPOSE:To prevent the effect of an output voltage fluctuation of a preamplifier at changeover of light emission/light reception in the one-element optical reception circuit using a light emitting element for a light receiving element. CONSTITUTION:The one-element type light receiving circuit using a light emitting element 1 for a light receiving element and providing an output via a preamplifier 3 is provided with a differential amplifier system provided with a dummy preamplifier circuit 5 whose input connects to an equivalent resistor 6 and equivalent capacitance 7 of the light emitting element 1 and with a differential amplifier 4. Since the equivalent resistor 6 and equivalent capacitance 7 of the light emitting element 1 simulate a Twitching time response of light emission/light reception of the light emitting element and an output of the dummy preamplifier 5 is inputted to the differential amplifier 4 at the same transient response as that of an output of the preamplifier 3, the effect of the switching of the light emission/light reception of the light emitting element 1 is reduced.