| 摘要 |
In a high luminance area having a target luminance L of not lower than a preset reference luminance L 0 , the light emitting element driver of the invention adopts a direct current drive mode and enables the function of a constant current driving circuit to drive an LED or light emitting diode. In a low luminance area having the target luminance L of lower than the preset reference luminance L 0 , on the other hand, the light emitting element driver adopts a pulse width modulation drive mode and enables the function of a pulse width modulation driving circuit to drive the LED. This control procedure enables the luminance adjustment by the pulse width modulation drive control in the low luminance area, while ensuring the high power efficiency by the direct current drive control in the high luminance area. The advantage of this arrangement simultaneously satisfies both the luminance adjustment in a wide range including the low luminance area and the high power efficiency.
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