| 摘要 |
PURPOSE:To prevent the breakdown of a load by outputting a voltage lower than a prescribed voltage in the noncontrol state. CONSTITUTION:This controller consists of a switching element 10, its driving part 11, a transformer 20, a rectifying element 21, etc., and the turn-on/off operation time of the element 10 is controlled to adjust output voltage and current applied to a load 16. In this case, a reference voltage source 17 is provided in an inverted terminal (r) of an error amplifier 18, and a photodetector 13 is provided in series between the base of the element 10 and the driving part 11. If the potential difference of a voltage detecting resistance 14 is larger than the reference voltage source 17 (non-control state) when the prescribed voltage is supplied to the load as the output voltage, light emission of alight emitting element 19 is stopped through the error amplifier 18 and the light receiving element 13 is turned off, and the element 10 is turned off. As the result, a voltage higher than the prescribed voltage is not applied in the non- control state by the element 10 to prevent the breakdown of the load 16.
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