Abstract: Based on mixed-signal ISP flash MCU C8051F005 and full-bridge pulse width modulation(PWM) integrated circuit 3955, a microstepping driver with high performance, simple structure and ultra small size was designed for two-phases hybrid stepping motors. The driver utilized advanced sinusoidal current subdivided technique and fixed off-time PWM current control. Adjustable mixed current decay mode optimized the output current further. The stepping motor system provided selectable subdividing up to 256, and offered functions including direction control, half current control, enable/disable option, etc. It also had the ability of simulation and update program on system. In addition, over voltage, under voltage, over current and over temperature protections were also included for the driver′s high reliability. System design, generation of reference voltage for the phase current in different resolution and armature current control technique were detailed descried. The experiment results confirm that the microstepping driver has the characteristic of high performance, high reliability and good torque/frequency characteristic.