| 摘要 |
PURPOSE:To make it possible to prevent an instantaneous interruption of a coil current by slowly discharging an electric charge of a capacitor and to effectively protect circuit elements even though the output of a current feedback amplifier is interrupted by the operation of a heat protection circuit in a brushless motor drive circuit having a noise interrupting capacitor for coil current and a heat protection circuit. CONSTITUTION:In a brushless motor drive circuit with a noise interrupting capacitor Co connected to an input terminal of a current feedback amplifier A2, a heat protection circuit 10 interrupting energization of drive coils Lu, Lv and Lw is connected to control signal routes located ahead of the connecting points of the capacitor Co when the temperature of circuit elements rises above a constant value, thereby slowly discharging the electric charge of the capacitor Co when the heat protection circuit 10 has operated, so that the generation of a spike-shaped voltage at the output end of drive coils Lu, Lv and Lw are prevented. |
