| 摘要 |
PURPOSE:To drive a stepping motor under optimum condition at the time of respective operating by changing over a surge voltage absorption factor to high side at the time of operating a tracking servo, and changing it over to low side at the time of accessing. CONSTITUTION:When a tracking servo is applied, a switch SW is turned on and a surge voltage absorption factor is set high side by a changing-over signal from a stepping motor driving circuit. An exciting current by a motor driving voltage Vm is supplied through switching elements Tr1 and Tr2 to a coil L of a stepping motor, and rotated step by step. When a magnetic head is accessed to a desired track, the switch SW is turned off and the surge voltage absorption factor is set lower. Thus, the stepping motor is rotated at a high speed and the magnetic head is quickly moved. Consequently, respective actions are executed under the optimum condition. |
