| 摘要 |
By means of a PWM pulse setting device (10), a PWM pulse with a pulse width corresponding to a requested lighting time is supplied to an LED. In a constant-current driver (6), current to be fed to the LED (2) is adjusted within a PWM pulse width set by the PWM pulse setting device (10) and for a predetermined constant current. In this case, by means of a current breaking adjuster (15), an output that turns off an operation by the constant-current driver (6) is provided before the time when the PWM pulse of a minimum lighting time is turned off.
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