| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size and loss in a suppression circuit for suppressing each element voltage unbalance in switching, in a semiconductor switching circuit comprising connection of a plurality of voltage drive type semiconductor devices (semiconductor devices) in series. SOLUTION: A transition voltage balance circuit B1 is connected to the semiconductor devices Q1, Q2 with the shortest distance, and a steady voltage balance circuit B2 is connected to a position that is apart form the semiconductor devices Q1, Q2 and is structurally optimum. In this case, the reason why the distance is made shortest is that it is required that the capacity of a capacitor in the circuit B1 should be increased further, since the time constant of voltage unbalance is very small in a mode, immediately after switching in transition and hence parasitic inductance becomes large, when wiring length is lengthened. Voltage balance results in terms of DC in the unbalance mode of a leakage current, which is not related to the inductance, so that connection is made to an optimum arbitrary position. COPYRIGHT: (C)2005,JPO&NCIPI
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