| 摘要 |
<P>PROBLEM TO BE SOLVED: To make the power consumption of an overvoltage protection circuit more suitable. <P>SOLUTION: A pulse signal is input to a gate terminal of a transistor 12 of an overvoltage protection circuit 3 connected in parallel to a motor 4, and the carrier frequency f of the pulse signal is controlled, whereby the switching loss of a transistor 12 can be adjusted by controlling the switching frequency f of a transistor 12 of the overvoltage protection circuit 3, so that even if the power consumption of a discharge resistance 13 changes, the power consumption of the overvoltage protection circuit 11 can be made more suitable as a whole. <P>COPYRIGHT: (C)2008,JPO&INPIT |
