| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection circuit for a brushless DC electric motor that can protect the switching element of an inverter circuit, without increasing the size of a protection device. SOLUTION: A circuit between the collector and emitter of transistors Qau- Qaw for protection is connected between drive signal output terminals 6u-6w of a control IC 6, for outputting a drive signal for driving transistors Qu-Qw and Qx-Qz of an inverter circuit 2 and the ground, and the transistors Qau-Qaw are turned on when a DC voltage VB for driving is applied, thus preventing a noise signal from being fed from the control IC 6 to the side of the inverter circuit 2 before a DC voltage Vc for control reaches an operation-enable level. When the DC voltage for control reaches the operation-enable level, a transistor Qb is turned on, thus turning off the transistors Qau-Qaw and canceling a protection operation. |
