| 摘要 |
PROBLEM TO BE SOLVED: To positively drive an FET for allowing a coil current to flow without requiring any minus power supply, by constantly maintaining a coil current that flows from a drive part to a stepping motor, and controlling the grounding potential of the drive part. SOLUTION: Vref when current is constant is given to a control part 1 from a control signal input terminal 7, and the rotary speed of a motor 6 is set, thus starting the motor. The excitation pattern signal for driving the motor is generated according to an instruction from the control part 1, thus outputting a+ to e+ and a-to e-. Each excitation pattern signal enters pull-up A part 4 and B part 20, is set to a proper voltage, and allows a current to flow to the coil of the motor 6 according to an excitation pattern being inputted to an FET in a drive part 5 for rotation. In this case, a middle-point potential being applied to the drive part 5 is adjusted to Vadj at a potential adjustment part 30, a-side potential is adjusted, a voltage being applied between + and-is minimized according to speed and current values, and the FET can be turned on within the range. |
