DRIVE CIRCUIT FOR LIGHT-EMITTING DIODE

摘要

PROBLEM TO BE SOLVED: To provide a drive circuit which is capable of quickly changing a light-emitting diode from a luminous state to a quenching state and vice versa, corresponding to a sharp change in level of drive indication signal. SOLUTION: Drive signals DRV for driving a light-emitting diode 900 are the sum of the output current signal I1 of an output buffer circuit 210 and a current signal I2 obtained by differentiating the current signal I2 with a capacitor element 220, provided between the input terminal 211 of the output buffer circuit 210 and an output terminal 213 which outputs signals of the same phase with the signals inputted into the input terminal 211. As a result, a current that flows when the light-emitting diode 900 is changed from an off-state to an on-state in larger than that which flows when the diode 900 is normally kept in an on-state later, and a current that flows when the light-emitting diode 900 is changed from an on-state to an off-state is smaller than that which flows when the diode 900 is kept in an off-state or negative in polarity.