| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform accurate LED lighting control without suffering from malfunction in spite of generation of excessive current and excessive voltage. Ž<P>SOLUTION: In an LED lighting control device performing constant current control for lighting of an LED and having a protection circuit protecting malfunction for lighting control of the LED, current flowing in the LED and voltage across the LED are first detected. Then, a reset signal for resetting actions of a constant current control circuit driving a first transistor which supplies current to the LED with an input enable-signal is generated by the protection circuit on the basis of detected results. Meanwhile, a pulse signal is output for a fixed period according to state transition of a LED control signal for controlling lighting-up and lights-out of the LED with a second transistor, and an AND operation of the pulse signal and the reset signal is carried out by an AND gate. Then, a reset action of the constant current control circuit is controlled according to an output signal from the AND gate obtained from results of the AND operation. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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