Patent ID: 6222333
Filing Date: 2001-04-24
Classification: H02P

Abstract:
A motor control for driving a half-wave DC brushless motor having first and second motor stator coils, stator and rotor poles and a sensor disposed in the motor for sensing the position of the rotor comprisinghigh and low voltage DC power supplies,a microprocessor having input and output ports, a gate drive conditioner coupled to an output of the microprocessor and controlled by pre-drive signals therefrom for providing gate drive signals to a final drive and flyback circuit including a MOSFET transistor having a breakdown voltage V.sub.breakdown for each coil winding, each MOSFET transistor providing a coil drive signal for a respective stator coil when gated on by a gate drive signal, current flowing through a respective coil when a MOSFET transistor is gated on and when the MOSFET transistor is gated off the energy within the respective coil collapsing tending to create a large voltage potential V.sub.flyback across the MOSFET transistor, the flyback circuit including a SIDAC serially connected to a diode connected across a respective coil, the SIDACs selected to trigger at a selected voltage higher than V.sub.emf and lower than V.sub.breakdown so that when the flyback voltage reaches V.sub.breakdown and the respective SIDAC is triggered, the SIDAC acts like a diode to clamp the flyback energy to a few volts and when not triggered the respective SIDAC allows V.sub.emf to float.