Patent attributes
A braking device for an electrically driven rotor comprises a drive signal generating circuit for an electrically driven rotor, an output stage, a motor for the electrically driven rotor, driven by the output stage, and a monitor circuit for detecting interruption of an electric power supply for the motor. The output stage has a MOSFET of an upper stage side and a MOSFET of a lower side, and a diode inserted between a gate of the MOSFET of the lower stage side and the electric power supply. An electromagnetic brake is generated and applied on the electrically driven rotor when the MOSFET of the upper stage side is turned OFF and the MOSFET of the lower stage side is turned ON by a control signal from the monitor circuit, and an exciter coil of the motor is shorted when the electric power supply is interrupted.
