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US 8,134,792 B2Granted
Preamplifier and method for synchronization with bit patterned media
AssigneeTexas Instruments Incorporated
InventorIndumini Ranmuthu
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AssigneeTexas Instruments Incorporated
InventorIndumini Ranmuthu
Estimating the term…
A preamplifier and method writes data synchronized with the passing of a write head in a magnetic storage device over bit islands in discrete patterned recording media. The preamplifier contains a write pre-driver that conditions write data, a synchronization circuit that accepts a delay offset value and a write clock and produces a delayed clock, and a write output driver that is gated by the delayed clock to produce write pulses for magnetizing the bit islands. Gating the write output driver using the delayed clock results in more accurate synchronization than delaying the write data into the preamplifier due to the reduction of the overall length and variability of interconnects and transistors in the intervening circuitry. Write clock generation circuitry, as well as bit position sensor circuitry for use with bit position signals produced by a read head or by a separate bit position sensor, are optionally integrated into the preamplifier, close to the write output driver and write head, for further improvements in delay accuracy and stability. Write pulses produced by the preamplifier are thus well aligned with the bit islands, resulting in higher magnetization and an improved bit error rate.
A preamplifier for a magnetic storage device, the storage device having a recording medium patterned into discrete magnetizable bit islands and a write head and a read head passing over the bit islands, the preamplifier comprising:
A method for synchronization of write pulses to bit islands of a patterned media disk drive used to store data for a host system, the disk drive having (a) a magnetic recording medium rotating at a rotation rate, and having at least one circumferential data track patterned into discrete magnetizable bit islands with a density along the track, the density of bit islands and the rotation rate determining a bit frequency;
Dependencies are inferred from the claim text.
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Recording, reproducing, or erasing methods; Read, write or erase circuits therefor: digital recording
Nanotechnology for information processing, storage or transmission
Circuits: synchronisation; Clocking
For track following on disks: aligning for runout, eccentricity or offset compensation
About 3 years 3 months of term left · ends 17 Jan 2030 (estimated)
1. Field of the Invention
The present invention relates generally to the field of magnetic recording disk drives, and more particularly, to a preamplifier and method for synchronizing write pulses with bit islands in discrete bit patterned recording media.
2. Description of the Related Art
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram depicting a data storage system according to an embodiment of the present invention;
FIG. 2 is a block diagram depicting a preamplifier according to an embodiment of the present invention in which a write clock is provided from an external source;
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
Referring now to FIG. 1, a block diagram of a representative data storage system 100 according to the present invention is shown. A host system 102, which may be a computer system, a music player, a game system, a network-connected server, or other data processing system is connected through a digital system input/output interface 120 to a hard disk drive (HDD) 104. HDD 104 may be physically contained within the host system 102, or be housed in a separate external enclosure. Interface 120 is typically a high-speed data peripheral interface designed specifically for high-speed data transfer from a storage device such as hard disk drive 104, and may be a parallel interface as indicated by the block arrows in this diagram. Hard disk drive 104 contains several principal electronic components shown here explicitly that are related to writing and reading data to and from the magnetic media, in addition to other components (not shown) including the media disk platter or platters themselves, each having one or both surfaces coated with a recording medium made of a magnetic material, electromechanical components including a motor to rotate a spindle serving as an axle for the platter or platters, a voice coil actuator (motor) for head positioning, interconnects and enclosures, and electronics primarily related to spindle motor control, head positioning, and data buffering.
Shown within hard disk drive 104 in FIG. 1 are an HDD controller 106, which may be implemented in a system-on-chip (SOC), which contains mainly digital circuitry to process read and write data in the digital domain, a preamplifier 108, which operates mostly in the analog domain to amplify read and write data signals, and a head subassembly 110. Head subassembly 110 typically includes a read head 112 and a write head 114, and may optionally include a bit position sensor 116 specifically intended to read synchronization data from bit patterned media. The head subassembly 110 may also include a head carrier or slider, mountings, flexible circuit (flex) interconnects, as well as the heads and sensors shown here. Furthermore, there may be more than one head subassembly, such that one or more is associated with each surface of a platter or multiple platters. The HDD controller 106 may be integrated into a single system-on-chip SOC as shown, or implemented on a printed circuit board (PCB) with some of the functions of the controller performed in separately packaged integrated circuits (ICs). For example, a read channel IC containing the circuitry for conversion of amplified analog read signal to digital data, clock recovery and sampling thereof, and multiplexing or serialization/deserialization may be a separate IC, or alternatively, these functions could be integrated onto preamplifier (preamp) IC 108. As shown here, read clock recovery may be performed by a phase-locked loop (PLL) 118 within HDD SOC controller IC 106, which may generate a clock signal Clk 140 from incoming read data RD 138.