DRIVER CIRCUIT DEVICE

PROBLEM TO BE SOLVED: To realize the differential amplitude in terms of AC which is sufficiently received by a receiver by charging/discharging charges in a parasitic capacitance caused pins of a package at a sufficiently higher speed to ensure a high speed transmission operation in a constant current driver used for an LVDS interface. SOLUTION: The device is made up of a transmission circuit consisting of transistors (TRs) 52, 53, 56, 57 to send a signal by switching a direction of a signal current flowing to a couple of transmission lines connecting to output terminals 13, 13B and TRs 54, 75 forming a constant current source to control a current of the transmission circuit. Then a signal current flowing to the output terminals 13, 13B is limited by using either of the TRs 54, 75 for the constant current source based on a control signal from control signal input terminals 24, 25 connecting to gates of TRs 76, 77 connecting in series with the TRs 54, 75 to suppress power consumption. On the other hand, in the case of transmission of the high speed signal, both the TRs 54, 75 are used to form the constant current source thereby increasing the signal current flowing to the output terminals 13, 13B to allow the device to have provision for a high speed signal.