| 摘要 |
PURPOSE:To protect each high-speed switching element by adding a diode and a parallel circuit composed of a resistor and a capacitor between both poles of the high speed switching element of each series stage constituting a serial- parallel circuit. CONSTITUTION:When a diode 12, a capacitor 13 and a resistor 14 are added, a voltage at both ends of the capacitor 13 is Voff when a FET 11 is turned off. Then a voltage Vn is going to rise at a time t0 and the capacitor 13 starts charging through the diode 12 and a voltage at both ends of the capacitor 13 is boosted according to a flowing charge. Thus, the voltage at both ends of the capacitor 13 is gradually boosted and since the voltage applied to the FET 11 is equal to the voltage at both ends of the capacitor 13, till the FET 11 is turned on at a time t1, the voltage is boosted gradually. Thus, even when the on-timing of the FET 11 is delayed, the drain-source voltage is not rapidly boosted and the FET 11 is protected. |
