DC motor control and rotation sensing circuit - uses dual polarity pulse width modulated fixed frequency supply with pulse width controlled from sawtooth generator via two comparators

摘要

The circuit controlling the couple and direction of rotation of DC motors allows their output and cooling to be optimised. Operation is based on a dual polarity DC supply with a fixed reference voltage, the motor receiving the supply via a variable pulse width, fixed frequency, pulse generator. One motor terminal is fed by parallel power amplifiers, the two polarities corresponding to the two rotational directions. The second motor terminal is ground via a low resistance and is supplied with the reference voltage. Pulse width is controlled from a sawtooth generator followed by two comparators working about the reference level, one comparator being fed via an inverter. Two gate circuits interconnect the comparators and amplifiers, width control being a function of an input control voltage and feedback from the grounded motor connection.