| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the heat radiation of a control element in a brushless motor driving circuit. <P>SOLUTION: An n-channel-type MOSFET 7U is arranged on the side of the power source Vs of a brushless motor 1, and a p-channel-type MOSFET 8U is arranged on the side of a ground GND. A bootstrap circuit 11 is connected, as a boosting circuit which makes higher potential than the power source Vs, to the gate of an FET7U. A bootstrap circuit 12 is connected, as a minus potential generating circuit which makes a lower potential than the ground GND, to the gate of the FET 8U. An initial charge circuit 17, which charges bootstrap capacitors 15 and 16, is arranged at the prestage of the boost lap circuits 11 and 12. FETs are placed on one heat spreader, with their drain terminals shared, on both the power source side and the ground side. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
