The control scheme and circuit of bidirectional counter structure indexer for stepper motor driver

Based on the analysis of the operating principle of the stepper motor, an indexer structure combining the counter and digital-analog signal converter (DAC) is proposed and designed in this paper. Through the digital-analog signal converter, the digital signal output of the counter is converted into analog signal to accurately control the current flowing through the stepper motor. By the control of the indexer, six types of asynchronous long stepper motor working mode including the 1/32 subdivision, 1/16 subdivision, 1/8 subdivision, 1/4 subdivision, 1/2 subdivision and full step can be realized. Only a few number of control signals are needed to realize the switching of the working mode and the motor steering. The function and feasibility of the indexer are verified by simulation.