BIDIRECTIONAL SIGNAL TRANSMISSION CIRCUIT ROBUST TO SIGNAL VARIATIONS ON RISING AND FALLING EDGES

摘要

PURPOSE: A bi-directional signal transmission circuit is provided to reduce erroneous operations of a shift register by reducing signal variations at rising edges or falling edges. CONSTITUTION: A bidirectional signal transmission circuit(23) includes a buffer element(24) for reducing the impedance of a signal line, a signal line arranged between input terminals in both ends of the bidirectional signal transmission circuit, and a signal line between output terminals in both ends of the bidirectional signal transmission circuit. The signal lines between output terminals are installed to be parallel to each other. A signal supplied from outside of the bidirectional signal transmission circuit is sequentially transmitted from one end to the other and is outputted from the other end. The bidirectional signal transmission circuit confirms the sequential transmission at outside. The transmitting direction is switchable both ends of the bidirectional signal transmission circuit according to a switching signal supplied from outside. The buffer element disposed in at least one end of the signal line between the output terminals reduces the impedance of the signal line.