TRANSISTOR SWITCH CIRCUIT

摘要

PURPOSE:To suppress the displacement potential of a transistor and to reduce the loss of a snubber circuit, by using the 1st snubber circuit connected in parallel to the transistor and the 2nd snubber circuit connected in parallel to a diode to constitute an arm. CONSTITUTION:When an arm 2 is turned on, an arm 1 is held at power supply voltage E. At the same time, a snubber capacitor C11 of a TR1 is also charged up to the voltage E. The capacitor C11 is discharged with a capacitor C12 charged respectively when the arm 2 is turned off and an adversely parallel diode D12 of the arm 1 conducts. The voltage of the C11 is not reduced down to zero and can be freely changed by the ratio between C11 and C12. Therefore, the sudden forward voltage is applied to the TR1 when the D12 is turned off. However no displacement current is produced since said sudden forward voltage is restricted within a high voltage region. This process can reduce the capacity of the C11 and therefore reduces greatly the loss of a snubber circuit.