Title:
モータドライバ及び磁気ディスク装置
Document Type and Number:
Japanese Patent JP4462871
Kind Code:
B2
Abstract:
A back electromotive force detection circuit 12 incorporates an A/D conversion circuit 14 that converts the output from a differential amplifier circuit A 2 into a digital signal and an offset calculation circuit 15 that sets the resistance value of a variable resistor R 2 according to the output from the A/D conversion circuit 14 . Based on the difference between the output from the A/D conversion circuit 14 as obtained when the drive current fed to a motor coil L equals zero and the output from the A/D conversion circuit 14 as obtained when the drive current fed to a motor coil L equals a predetermined value, the offset calculation circuit 15 sets the resistance value of the variable resistor R 2.
Inventors:
Mitsuaki Oho
Application Number:
JP2003297858A
Publication Date:
May 12, 2010
Filing Date:
August 21, 2003
Export Citation:
Assignee:
ROHM Co., Ltd.
International Classes:
G11B21/08; G11B5/55; H02P7/288
Domestic Patent References:
| JP5244790A | ||||
| JP2000014190A | ||||
| JP2002208238A |
Attorney, Agent or Firm:
Shizuo Sano