Design Of A Newly Developed Stepper Motor Driving Circuit

The stepper motor is an electromechanical device that converts electrical pulses signal into discrete step angle. Because of having the advantage of precise positioning and non-cumulative movement error, stepper motor is being applied widely in many fields compared to the other motors. The subdividing drive is a kind of driving technology that can effectively improve the step precision and characteristic of low frequency. It is the most important technique to provide for increased step resolution. The basic principle of subdividing drive is to produce many neutralities in synthesize magnetic field for subdivision by controlling the motor current ascend or descend in given rule. The thesis particularly presents the technique of subdividing drive, and analyses the mathematics models of hybrid stepper motor. The circuits were designed on this theory.The thesis designs a two-phase stepper motor driver IC, which has PWM chopper and subdividing control function. The outputs are rated for continuous output currents to 1.5A and operating voltages to 36V. PWM current control combined with an internal three-bit nonlinear digital-to-analog converter allow the motor current to be controlled in full-, half-, quarter-, or microstepping modes, and this can drive the motor to work in different step angle. The motors can operate in a fast current-decay mode, slow current-decay mode or in a mixed current-decay mode to optimize their performances in micro stepping/sinusoidal stepper-motor drive applications. Internal circuit protection includes thermal shutdown and under voltage lock out.The thesis expatiates the module circuits of the driver and presents the simulation results. The results simulated by cadence spectre indicate that the performances of IC have realized the target. At same time, we completed the design of layout and confirmed its validity.