| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable detection of a short fault in switches for power source cutoff, and reduce the number of signal lines and connector terminals used for fault detection. <P>SOLUTION: A protection circuit has switches 21 and 22 connected in series to a power supply line of a driving circuit in a semiconductor switching element, and monitoring means (a CPU 13) that monitors power source voltage from an output side of the series circuits. The protection circuit turns off the switches 21 and 22 with a cutoff signal generated in the event of an abnormality of a power conversion device to cut the supply of a driving circuit power source off. The protection circuit has buffer ICs 14 and 15 with enable signals that are connected to the path of the cutoff signal, and control means (the CPU 13) that controls the buffer ICs 14 and 15 to turn off the switches 21 and 22 individually. The monitoring means determines that a switch to be turned off by one of the buffer ICs 14 and 15 has a short fault when the driving circuit power source voltage is a normal value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
