| US 7,460,324 B2 | ||
| Head amplifier circuit with function for degaussing residual magnetism of recording head | ||
| Yusuke Ohinata, Tachikawa (Japan); Hiroyuki Naka, Ome (Japan); and Yuji Sakai, Ome (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Aug. 31, 2005, as Appl. No. 11/215,020. | ||
| Claims priority of application No. 2004-380301 (JP), filed on Dec. 28, 2004. | ||
| Prior Publication US 2006/0139787 A1, Jun. 29, 2006 | ||
| Int. Cl. G11B 5/03 (2006.01) | ||
| U.S. Cl. 360—66 [360/46; 360/67; 360/68; 360/75] | 2 Claims |
| 1. A head amplifier circuit for use in a hard disk drive having a recording head which magnetically records data on a magnetic
disk medium, comprising:
a driver circuit configured to supply, in a data-recording mode, the recording head with a recording current corresponding
to write data and serving as a first recording current, and to supply, in a degaussing mode, the recording head with a degaussing
current serving as a second recording current, the second recording current being a recording current of a square wave which
has a rising period and a falling period set longer than a rising period and a falling period of the first recording current;
and a control circuit configured to control switching from the data-recording mode to the degaussing mode to control the driver
circuit,
wherein:
write data of one sector recorded to the magnetic disk medium by the recording head includes user data and a postamble that
forms a rear end of the write data; and the control circuit switches the driver circuit from the data-recording mode to the
degaussing mode while part of the postamble is recorded on the magnetic disk medium, thereby controlling the recording of
the remaining part of the postamble on the magnetic disk medium by the magnetic recording head, based on the degaussing current
generated by the driver circuit.
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