| 摘要 |
PURPOSE:To improve holding torque characteristics and to prevent the discrepancy in stopping position of a stepping motor, by impressing a high voltage upon the stepping motor for a fixed time in response to the loading of a magnetic head also. CONSTITUTION:A front edge detecting circuit 22 detects the front end of a head load signal and sends the detected signal to an OR gate 23 of the next stage. A re-triggerable type monostable multivibrator 24 is triggered by a step signal and front-edge detecting pulse obtained from the OR gate 23, and generates a pulse of 30-50ms. The output of the multivibrator 24 is supplied to the base of a transistor Q1 through an invertor 25. This magnetic disk device is constituted in such a way that a high voltage (+12V) is impressed upon a motor voltage supplying circuit 26 when the step signal is generated and the head signal is generated and a low voltage of about 4.3V which is obtained by subtracting the drop of a diode D1 from +5V is impressed upon the circuit 26 at the other time of maintaining the stopping position. |
