| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an indicator drive system having small flickering and brightness variation by using both an indicator and night illumination by one system indicator light source and preventing a duty ratio of a control signal from excessively lowering even when controlling light in small brightness. <P>SOLUTION: The indicator drive system is provided with a branch drive route LB having current limit loads D3, R4 for night light reduction branched from a main drive route without controlling the duty ratio of dimming control by only a first switch element Tr1 on the main drive route LM. In night light control, the indicator light source LED is driven via the branch drive route LB by a second switch element Tr4. Since the branch drive route LB decreases a current capacity by the current limit loads D3, R4 for the night light reduction, an output duty ratio is largely secured when obtaining low brightness output in a night light reduction state and flickering or brightness variation is effectively suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT |
