| 摘要 |
PURPOSE:To shorten the discharging time of a capacitor by inserting the capacitor into a current path where both a gate forward current and a gate backward current flow and connecting a diode in the flowing direction of the gate backward current in parallel to the capacitor. CONSTITUTION:When the 1st transistor(TR) 4 is turned off and the 2nd TR 8 is also turned on at time t2, the gate backward current is flowed from the cathode K of a GTO 1 to the gate electrode G by the 2nd DC power source 9, but this current flows through the capacitor 6 as along as there is charges with a polarity left in the capacitor 6 and when the charges in the capacitor 6 are all discharged, the current flows to a by-pass diode 10. Consequently, capacitor charges which are charged with the gate forward current of several amperes are discharged forcibly and smoothly with the gate backward current which is normally >=10 times the gate forward current by next turn-on time t3. |
