| 摘要 |
PROBLEM TO BE SOLVED: To make a power loss of the load driving device small, and to make the device excellent in controllability with a simple circuit structure, by providing a means for varying ON-time and OFF-time lengths of a switching circuit according to a scanning pattern of the switching circuit. SOLUTION: A part of LED1 to LED16 arranged in a matrix form, two pieces of the LEDs, are connected in series. And, ON-time and OFF-time lengths of transistor switching circuits Q1 to Q3 are decided by a software processing of a microcomputer U1, to drive the transistor switching circuits Q1 to Q3. Since a part of the LEDs, two pieces, are thus connected in series, it is possible to reduce a power loss through a resister connected in series with the LED at the time of driving, and since ON-time and OFF-time lengths of the corresponding transistor switching circuits are made to be variable so that a mean current value flowing through each LED takes a prescribed value, the current value of each LED can freely be set, and the controllability can be improved.
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