| 摘要 |
A driver circuit of a light emitting element is improved in efficiency. The driver circuit is to drive a white LED and includes a charge transfer device, a capacitor connected to the charge transfer device and a booster circuit that converts a power supply voltage inputted to the charge transfer device to a drive voltage of 1.5 times of the power supply voltage according to a clock applied to the capacitor. The drive voltage from the booster circuit is supplied to the white LED. The driver circuit also includes a pulse detection circuit that detects a brightness adjustment pulse BP and a switching circuit that controls a drive current to the white LED in order to adjust brightness of the white LED. The driver circuit includes a divider that reduces a frequency of the clock corresponding to a reduction in the drive current due to the brightness adjustment made by the switching circuit.
|
