JPS5583498A - Driving device for stepping motor - Google Patents

Abstract

PURPOSE:To eliminate an initial torque shortage and make the device compact by improving the maximum drive clock frequency capable of making the starting rotation in following the clock pulses, which are the maximum self starting frequency of the stepping motor. CONSTITUTION:Drive clock pulses P produced by drive clock pulse generator 101 are shaped like drive signal P1 by drive pulse generator 102 and control the opening and closing of switching element 103. Drive clock pulses P are inputted to frequency divider 301 and are shaped like output signal P2. Frequency divider 301 outputs output signal P2, which becomes L during the interval of the initial four pulses of clock pulses P and turns switching element 302 off. By this, the output of comparator 304 becomes H, and excitation current limiting switching circuit 305 is turned on for the interval of the initial four pulses of clock pulses P; and excitation boil 17 is impressed with voltage V, and Ic excitation current IH flows which is several times as large as rated excitation current.