CONSTANT CURRENT DRIVER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a constant current driver circuit capable of quickly controlling the on/off switching of output currents. SOLUTION: A constant current driver circuit 40 is provided with first and second MOS transistors Q11 and Q12 whose gates are connected to each other, and output currents Iout being a value at a fixed rate against reference currents Iref1 to be supplied to the first MOS transitory Q11 are obtained from the second MOS transistor Q12. Then, a switch circuit 46 connected to the second MOS transistor Q12 is on/off controlled based on an input signal Sin so that the output currents Iout can be on/off controlled. A bias circuit 44 supplies a bias voltage VB generated so that the fluctuation of a gate voltage Vg2 of the second MOS transitory Q12 at the time of turning on the output currents Iout can be reduced to the gate of the second MOS transistor Q12.