| 摘要 |
PURPOSE:To immediately detect the damage of a GTO thyristor by comparing a reverse bias voltage between the gate and the cathode of a GTO thyristor with the OFF command signal of a gate drive circuit during OFF period of the thyristor. CONSTITUTION:In a defect detector 3, a voltage comparator 301 detects the presence or absence of a reverse bias between the gate and the cathode of a GTO thyristor 1, the output signal of the comparator 301 is input together with an OFF command signal of the thyristor 1 to an exclusive OR circuit 303, and the output is fed through a film circuit to a voltage comparator 307. If the reverse bias voltage is not present between the gate and the cathode even if the OFF command signal is present, a light emitting diode 313 is fired. |
