| 摘要 |
PURPOSE:To protect the input power source by a method wherein the output overload thereof is simply detected even when the tolerance of input voltage is relatively wide by detecting the input power and limiting the output of the overload. CONSTITUTION:A current detecting resistor 25 is inserted in series with a transistor 14. When an overload state occurs due to the variation in load 21, the voltage at a junction point 28 exceeds the reference voltage of a constant voltage element 32 and the output of a comparator is inversed. The output of comparator 29 is latched by a latch circuit 36, a transistor 37 is turned to conductive, and between the base and the emitter of the transistor 14, which is a switching element, is short-circuited. Accordingly, the transistor 14 is maintained in OFF state, and the load 21 and the power source can be protected. |
