| 摘要 |
<p>A stepping motor exciting system comprises coils (21A, 21 B) wound on respective poles of a motor. One coil (21A) is connected to four transistors (22A,23A,24A and 25A) which are driven by drive circuits (29A,31A). The coil current is sensed by a resistor (27A1, and the resulting voltage is divided by one of four values in a control circuit (28A). The output of the control circuit (28A) is supplied to one input of a comparator (34A), the other input of which receives a reference voltage V<Sub>s</Sub> and the output of the comparator is supplied to the drive circuits (29A, 31A). A similar circuit is associated with the other coil (21 B). Drive and control circuits (29A. 31A and 28A) also receives input signals from a ROM (32) which is addressed a mode signal (45) and a counter (42) clocked by pulses (41).</p><p>In operation, for linear operation the coils (21A. 21 B) are driven with pseudo-sinusoidal currents and for stepwise operation the coils are driven with pseudo-trapezoidal currents.</p> |
