| 摘要 |
PURPOSE:To prevent the damage of a transistor due to damage of Hall elements by interrupting the energization of a motor when the levels of the signals of a plurality of Hall elements for deciding the energizing order of motor coils all coincide. CONSTITUTION:The outputs of Hall elements H1-H3 provided around a rotor are supplied through differential amplifiers A11-A13 to an output circuit 3, and driven by determining the energizing order of motor coils (u), (v), (w). At this time, the output of the amplifier A is applied together with the reference voltage VREF to a detector 11 which has transistors Q1-Q5, a constant current circuit CS11, and an output circuit 3 is controlled through a controller 2. Accordingly, at the normal time a current is flowed to any of Q1-Q3 to interrupt the controller 2. When the Hall elements are damaged, Q1-Q3 are all turned OFF to interrupt the output circuit 3, thereby protecting the drive transistor. |
