| 摘要 |
PURPOSE:To reduce noises from a stepping motor, and to improve resolving power thereof by storing a data corresponding to exciting-coil currents to a ROM and minutely controlling a stepping angle. CONSTITUTION:A pulse input is converted into a 4-bit signal by a counter 1, an address in a ROM 2 is set by the 4-bit signal, and a corresponding data is outputted. One parts of outputs from the ROM 2 are used as phase signals for changing over the directions of output currents from PWM constant-current circuits 5, 6. The residual outputs of the ROM 2 are inputted to D/A converters 3, 4, converted into analog voltage (b), (d) changing in a stepped manner by the D/A converters 3, 4, and applied as reference voltage for setting the currents of the PWM constant-current circuits 5, 6. Output currents IA, IB from the PWM constant-current circuits 5, 6 are made variable in the stepped manner. |
