Patent ID: 8253343

Claim:
A drive circuit to adjust a luminance of a light emitting element based on a PWM signal, comprising: a PWM signal generating circuit to generate the PWM signal; an operational amplifier to compare a voltage applied to a first input terminal with a reference voltage applied to a second input terminal; a transistor, having an output connected to the first input terminal of the operational amplifier, to supply a current to the light emitting element depending on a comparison result of the operational amplifier; and a switch to switch, based on the PWM signal, between a first state of conduction of a path providing the comparison result of the operational amplifier to the transistor and non-conduction of a path providing a predetermined voltage to the transistor to turn on the transistor, and a second state of non-conduction of the path providing the comparison result of the operational amplifier to the transistor and conduction of the path providing the predetermined voltage to the transistor to turn off the transistor.