| 摘要 |
PROBLEM TO BE SOLVED: To protect serially connected semiconductor switching elements from overvoltage, while minimizing power loss and to equalize shared voltages. SOLUTION: A serial circuit of a first diode and a first capacitor is connected to both ends of serially connected individual semiconductor switching elements, a nonlinear circuit having a characteristic for making current flow when a clamp voltage is exceeded, is connected parallelly to both ends of the first capacitor, and the clamp voltage is made to have minimum essential margin with respect to the shared voltage of the individual semiconductor switching elements corresponding to a power supply voltage that increases, when an accident occurs. |
