The present invention is generally related to hard disk drives (HDDs), and more particularly to HDD write drivers.
In the process of manufacturing hard disk drives (HDD) the servo track data must be written to the disk surfaces. In order to speed up this process, manufacturers commonly write more than one disk surface at a time, and up to the total number of surfaces (up to eight) at the same time. The preamps must have the ability to enter the Servo Write mode to enable writing to several heads simultaneously. Write drivers typically dissipate a lot of power due to the high-speed and high-current writing requirements of today's HDDs. It is not practical to turn on eight of these power-hungry writers at the same time. Since servo writing is done at a much lower data rate (such as less than 500 Mb/s) than normal data writing (such as 1.5 Gb/s), an approach to accommodate simultaneous writing of many surfaces has been to incorporate a lower performance and lower power write driver with each head which operates only during Servo Write mode. The object of these servo writers is to dissipate as little power as possible and to consume as little silicon area as possible.
The present invention achieves technical advantages as a HDD write driver circuit having a boost current overshoot programmed by a plurality of pull-up devices. The pull-up strength of an inverter is adjustably selected by programming pull-up PMOS devices, and less power is dropped across a resistor such that there is less overshoot when an overshoot MSB is low.
Referring to
Though the invention has been described with respect to a specific preferred embodiment, many variations and modifications will become apparent to those skilled in the art upon reading the present application. It is therefore the intention that the appended claims be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.
This application is a continuation-in-part of co-pending commonly assigned U.S. patent application Ser. No. 10/118,782 filed Apr. 9, 2002, entitled “System and Method for Enhancing Write Driver Performance”.
Number | Date | Country | |
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Parent | 10118782 | Apr 2002 | US |
Child | 10977412 | Oct 2004 | US |