Overshoot control for a hard disk drive write head
AssigneeTexas Instruments Incorporated
InventorPatrick M. Teterud
Life of this patent
Estimating the term…
Abstract
An improved write drive circuit which includes a discharge circuit added to the base of the bottom transistors of the H-bridge to prevent excessive overshoot and ringing while allowing for higher data rates. The discharge circuit is turned on after the head voltage or current reaches an overshoot condition. In preferred embodiments, the discharge circuit includes variable discharge capability by selecting one or more parallel drive transistors or varying a variable delay in the discharge circuit or any combination of both variables. Both can be controlled by a word written to the disk drive pre-amp over the serial control port.
Claims17
A hard disk drive for a computer system comprising:
- a. one or more platters having magnetic media on one or more surfaces;
- b. a write head associated with at least one of said surfaces having magnetic media;
- c. an H-bridge circuit capable of driving a current through said write head, said H-bridge circuit comprising two upper transistors and two lower transistors;
- and
- d. a discharge circuit connected to at least one of said transistors to discharge the base/gate drive of said at least one transistor, which ultimately decreases that transistors drive current during a period when the current is reversed through the write head.
An integrated circuit for driving a write head of a hard disk drive comprising:
- a. an H-bridge circuit capable of driving a current through said write head, said H-bridge circuit comprising two upper transistors and two lower transistors;
- and
- b. a discharge circuit connected to at least one of said transistors to discharge the base/gate drive of said at least one transistor and wherein said discharge circuit discharges the base/gate drive after said current through said head reaches an overshoot condition.
Dependencies are inferred from the claim text.