SHIFT REGISTER AND IMAGE SENSOR EMPLOYING IT

摘要

PURPOSE:To prevent insufficient scanning of an image sensor at low cost. CONSTITUTION:PNP transistors 2a-2f and NPN transistors 3a-3f having interconnected collectors and bases constitute a plurality of stages of thyristor which constitute a shaft register along with interstage coupling transistors 4a-4f. A first diode circuit is inserted into a jumper line communicating the common connection line of cathodes in the thyristors at odd stages and one input terminal of two-phase shift clock pulse. A second diode circuit 20 is inserted into a jumper line communicating the common connecting line of the cathodes in thyristors at even stages and the other input terminal of two-phase shift clock pulse. Since the L level potential of shift clock pulse increases by a level corresponding to the built-in voltage of one diode, erroneous turn ON of parasitic thyristor can be prevented.