The project presented here is a bipolar stepper motor driver. It is based on BD63731EFV chip which is a low-consumption driver that is driven by a PWM signal. The power supply voltage of the project is 8 to 28V DC, and the rated output current is 3A. CLK-IN driving mode is adopted for the input interface, and excitation mode is corresponding to FULL STEP mode (2 types), HALF STEP mode (2 types), QUARTER STEP mode (2 types), 1/8 STEP mode, and 1/16 STEP mode via a built-in DAC. In terms of current decay, the SLOW DECAY/FAST DECAY ratio may be set without any limitation, and all available modes may be controlled in the most appropriate way. In addition, the power supply may be driven by one single system, which simplifies the design.