| 摘要 |
PROBLEM TO BE SOLVED: To protect easily at low cost an equipment connected to a step-down converter from overvoltage. SOLUTION: Between output terminals of a converter, a thyristor SCR7 is connected. The voltage across the converter is detected by a voltage-detecting circuit 10. When the detected voltage becomes an abnormal voltage set value or above, the voltage-detecting circuit 10 outputs a signal and the SCR7 is turned into a conduction state by a thyristor igniting circuit 11. As a result, the input terminal of the converter is shorted through two conducting thyristors out of SCRs 1-6, so that either of fuses 9R-9T is melted and the input of power is cut out. |
