KR100370760B1 - Head device for improving signal-to-noise ratio - Google Patents

Abstract

PURPOSE: A head device for improving a signal-to-noise ratio is provided to minimize a noise included in read signals by filtering the signals read from a head and improve the signal-to-noise ratio of the read signals. CONSTITUTION: In the case that a host computer orders to read data, signals read from a head(12) are applied to a low pass filter(36) through conductive lines. The low pass filter connected between the head and a read signal preamplifier(16) low pass filters the signals, so that only pure data signals written at a magnetic disk are output to the read signal preamplifer. The read signal preamplifer amplifies the filtered read signals. The amplified signals are applied to a read buffer(38) to be buffered. The head, the low pass filter, and the read signal preamplifer are mounted at one head slider.

Description

Head unit to improve signal-to-noise ratio

The present invention relates to a hard disk drive, and more particularly, to a head device for improving a signal to noise ratio (S / N ratio).

In general, a hard disk drive includes a head for writing or reading data recorded on a magnetic disk. When driving the hard disk drive, the head will fly on the track on the magnetic disk while maintaining a constant flight altitude. At this time, the actuator moves the head radially on the disk during the track search, and fixes the head on the track during the track following. Typically, disks of a hard disk drive using a multi-platter method are installed in one spindle, and each disk surface corresponds to one head. Thus all the heads are moved together by the movement of the actuator.

1 shows a schematic block diagram of a general hard disk drive. The magnetic disk 10, which is a recording medium, is rotated by a spindle motor 32. As shown in FIG. The heads 12 are located on the surface of the corresponding one of the disks 10 and are mounted on a vertically extending support arm 14 of the arm assembly of the actuator 28. The preamplifier 16 preamplifies the signal picked up by the head 12 during data read and applies the analog read signal to the read / write channel circuit 18. Encoded write data applied from the read / write channel 18 circuit is written onto the magnetic disk 10 via a corresponding one of the heads 12. The read / write channel 18 circuit detects and decodes a data pulse from a read signal applied from the preamplifier 16 and applies it to a DDC (Disk Data Controller) (DDC) 20, which is applied from the DDC 20. The write data is encoded and applied to the preamplifier 16. The DDC 20 is controlled by the microcontroller 24 and writes data received from the host computer to or reads from the disk 10 through the read / write channel 18 circuit and the preamplifier 16. The transmitted data to the host computer. The DDC 20 also interfaces the communication between the host computer and the microcontroller 24. The microcontroller 24 controls the DDC 20 in response to a read or write command received from the host computer and controls track search and track following. The servo driver 26 generates a driving current for driving the actuator 28 by a signal for position control of the heads 12 generated from the microcontroller 24 to generate a voice coil of the actuator 28. ) Is applied. The actuator 28 moves the heads 12 on the disks 10 in correspondence with the direction and level of the driving current applied from the servo driver 26. The spindle motor driver 30 rotates the disks 10 by driving the spindle motor 32 in accordance with a control value for rotation control of the disks 10 generated from the microcontroller 24. The disk signal controller 22 generates various timing signals necessary for read / write, decodes the servo information, and applies it to the microcontroller 24. In the conventional hard disk drive having the above-described configuration, the preamplifier 16 is integrated with a read / write channel circuit 18 in one integrated circuit chip (IC Chip). An example of such a chip is the SSI 32R2210R, a thin film lead / write device from Silicon Systems. The read / write channel circuit 18 is largely divided into a head switching circuit, a read buffer and a write circuit, and the head switching circuit selects a specific head among a plurality of heads by a signal applied from the DDC 20. Each of the read buffer and the write circuit is a circuit for buffering a signal read from the head selected by the head switching circuit or applying a current corresponding to the write signal applied from the DDC 20 to the specific head. Meanwhile, the preamplifier 16 is connected between the head switching circuit and the read / write circuit. In the hard disk drive having the above-described configuration, the signal read by the head 12 in accordance with the magnetic change on the magnetic disk 10 is very weak. Therefore, the preamplifier 16 amplifies the signal read from the head 12 and outputs the read / write channel circuit 18. However, the signal amplified by the preamplifier includes various noises. For example, the noise inside the head, the noise on the magnetic disk, the electrical resistance on the lead signal transmission path, and the noise caused by the variability of the preamplifier 16 are amplified together with the read signal to generate a read / write channel circuit ( 18) is entered. Therefore, a large amount of noise is introduced into the signal read from the head 12, thereby lowering the signal-to-noise ratio, thereby degrading the reliability of the hard disk drive.

Accordingly, an object of the present invention is to provide a head device capable of improving the signal-to-noise ratio by removing noise included in the read data during the data read operation of the hard disk drive.

The present invention for achieving the above object is a head device for improving the signal-to-noise ratio of a hard disk drive,

A head mounted on the head slider body of the hard disk drive to read written data;

Noise removing means mounted to the head slider body to remove noise of a signal generated from the head;

And amplifying means mounted on the head slider body to amplify and output the signal output from the noise removing means.

Hereinafter, exemplary operations of the present invention will be described in detail with reference to the accompanying drawings. In the following description, it should be noted that the same elements in the figures represent the same reference signs wherever possible. Also in the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention, such as specific head and slider configurations. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 is a block diagram of the head device 40 for improving the signal-to-noise ratio according to the present invention. The head device 40 includes a head 12 for reading and writing data on the magnetic disk 10. ), A LPF (Low Pass Filter) 36 for filtering the noise contained in the signal read from the head 12 before amplification, and a read signal preamplifier 16. Referring to FIG. 2, when there is a data read command from the host computer, signals read from the head 12 are applied to the LPF 36 through conductive lines, respectively. The LPF 36 connected between the head 12 and the lead signal preamplifier 16 conducts low pass filtering of the signal read from the head 12 to conduct only pure data signals written to the magnetic disk 10. The read signal preamplifier 16 is output through the line. Thereafter, the low pass filtered read signal is amplified by the read signal preamplifier 16 and applied to the read buffer 38 to be buffered. That is, by connecting the LPF 36 between the head 12 and the preamplifier 16, various external noises included in the signal read from the head 12 can be minimized. Hereinafter, a process of forming the head 12, the LPF 36, and the read signal preamplifier 16 described above with reference to FIG. 3 on one head slider will be described. The head slider means a main body to which a head can be attached, and the head and the head slider are usually named together in some cases. In the following description, the sensor 44 and the gold pad 46, which are the core parts of the head 12, constitute the head 12, and the head 12 is combined with the slider body. Define as configuring the head slider.

3 shows a perspective view of the head device 40 for explaining the process of forming the head 12, the LPF 36, and the lead signal preamplifier 16 in one slider body 42 by a semiconductor process. will be. 3A is a perspective view of the head slider 42 made by the semiconductor process, wherein the ABS (Air Bearing Surface) of the head slider 42 is determined according to the model type. In this case, the head slider 42 is designed to be equipped with the above-described lead signal preamplifier 16 and the LPF 36 using semiconductor manufacturing techniques. On the other hand (3b) is a perspective view of the head 12 made by the wafer process, the head 12 is a thin film head and a sensor 44 for detecting a change in the magnetic signal read from the magnetic disk 10 and It consists of a gold pad 46. (3c) shows a perspective view of the head slider provided with the head device 40 according to the present invention. The head slider body 42 of the above-mentioned 3a and the head 12 of the 3b are combined. At this time, the input terminal of the LPF 36 mounted in the head slider body 42 and the gold pad 46 of the head 12 are connected by a magnet wire. Therefore, the signal read from the sensor 44 of the head 12 flying on the magnetic disk 10 at a certain inlet height is input to the LPF 36 in the head slider body 42. As a result, noise generated by internal or external factors such as the head 12 and the magnetic disk 10 is filtered out of the LPF 36 so that only pure read data is read through the read signal preamplifier 16 through the read buffer ( 38).

As described above, the present invention has the advantage of minimizing noise included in the read signal by filtering the signal read from the head, thereby improving the signal-to-noise ratio of the read signal amplified and output through the read signal preamplifier. There is this.

1 is a schematic block diagram of a general hard disk drive.

2 is a diagram illustrating a connection state between the head 12, the LPF 36, and the read signal preamplifier 16 for improving the signal-to-noise ratio according to the present invention.

3 is a perspective view of the head device 40 according to the present invention.

Claims (3)

In the head device for improving the signal-to-noise ratio of the hard disk drive, A head mounted on the head slider body of the hard disk drive to read written data; Noise removing means mounted to the head slider body to remove noise of a signal generated from the head; And a read signal amplifying means mounted on the head slider body to amplify and output the signal output from the noise removing means. The head device as set forth in claim 1, wherein the head is a thin film head. The head device as set forth in claim 1, wherein said noise removing means and read signal amplifying means are mounted in said head slider body by a semiconductor manufacturing process.