| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a magnetic disk control device capable of performing retraction operation in a short time and cutting electric power consumption during the retraction operation. <P>SOLUTION: A retraction drive circuit RETDV1, for example, alternately performs an operation to apply drive voltage to a voice coil motor VCM through a power MOS transistor M1 and the operation to detect a reverse electromotive voltage (BEMF) generated in the VCM in accordance with a control from a retraction control circuit RETC1. The RETC1 controls a switch SW1 to be turned off and, at the same time, specifies a threshold voltage Vref in order to make the RETDV1 compare a magnitude relation between the Vref and the BEMF. Then, the RETC1 sets a drive voltage value that the RETDV1 applies to the VCM by appropriately setting a value of resistance R2 based on the comparison result and controlling the switch SW1 to be turned on. <P>COPYRIGHT: (C)2012,JPO&INPIT |
