KR100365614B1 - Method for controlling write current of magnetic disk recording apparatus - Google Patents

Abstract

PURPOSE: A method for controlling a write current of a magnetic disk recording apparatus is provided to adaptively control the write current in the case of assembling different heads or disks with one PCBA(Printed Circuit Board Assembly). CONSTITUTION: A microcontroller confirms a write current ID from servo information read from a disk(400). A write current control value corresponding to the confirmed write current ID is loaded from a ROM to be set as a write current control value of the corresponding hard disk drive(402). The microcontroller executes an HDA(Head Disk Assembly) function test while applying an amount of write current corresponding to the write current value to a head(404). The write current control value is recorded at a maintenance cylinder on the disk as a default(406).

Description

Recording Current Control Method of Magnetic Disk Recording Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk recording apparatus, and more particularly to a write current control for controlling a write current applied to a head (or data transducer) when writing data on a magnetic disk. It is about a method.

Generally, magnetic disk recording devices such as hard disk drives (hereinafter referred to as "HDD") and floppy disk drives ("FDD") are widely used as auxiliary storage devices in computer systems. have. Among them, NDD not only can stably store large amounts of data but also has the advantage of fast access.

At present, the HDD has a trend of increasing the recording density on the disk in order to increase the storage capacity of the disk, and accordingly, the head is also highly precise, and therefore sensitive to the recording current. As the recording density becomes higher and the head becomes higher in accuracy, the recording current value applied to the head when data is recorded on the disk has emerged as a more important and sensitive variable in the performance of the HDD. In HDD, not only HDDs such as recording current but also one HDD should be appropriately changed depending on the type and characteristics of each head and disk.

Accordingly, techniques have been proposed to automatically set the optimal recording current to the HDD or head characteristics of each HDD. One such technology is Patent Application No. 95-53518, filed by the present applicant with the Korean Patent Office on December 21, 1995, "Recording current control circuit of magnetic disk recording apparatus and its optimization method." The patent application No. 95-53518 sets the optimum value of the recording current control value adaptively to the respective head and disk characteristics, and has a duty corresponding to the recording current control value set as described above when writing data on the disk. Disclosed is a technique for adjusting a recording current by a (Pulse Width Modulation) signal.

The patent application No. 95-53518 describes a single printed circuit of a head disk assembly (hereinafter referred to as "HDA") that includes a head and a disk, each of which has the same type or does not have a large difference in characteristics when the HDD is assembled. It is suitable for assembling to a printed circuit board assembly (hereinafter referred to as "PCBA"). However, if the type of head or disk is completely different, the ROM stores the microcode corresponding to the recording current control value which changes the resistance element for selecting the recording current value or determines the recording current value in the PCBA. You must change the Read Only Memory. In general, in HDD, PCBA means a portion composed of all circuit elements assembled on a PCB, and HDA means a portion composed of all the components except the PCBA. Hence HDA includes a head and a disk.

For example, suppose that the head is produced by assembling one PCBA using two heads, one of a thin film head and a double Mig head, but the characteristics of the head are completely different. As a result, data errors occur naturally using the same write current resistance element and ROM in PCBA. Therefore, if the type of head or disk is completely different or the characteristic difference is large, the PCBA must be changed and assembled for each HDA. At this time, the circuits of the PCBA except for the write current resistance element and the ROM are the same, but since the write current resistance element and the ROM are different, the HDD manufacturer must manage the revision of the PCBA and the microcode differently in each case.

As described above, when HDAs are produced by assembling HDAs with different heads or disks or having different characteristics with a single PCBA, the hardware must be changed and the PCBA and microcode revisions are managed separately. There was a hassle and trouble to do.

Accordingly, it is an object of the present invention to provide a recording current control method capable of adaptively controlling the recording current without changing the hardware when assembling heads or disks having a completely different type or a large characteristic difference with one PCBA.

The present invention for achieving the above object is provided with a ROM having a recording current control value set corresponding to the type / characteristics of the head and disk, and means for stepwise adjusting the amount of recording current according to a predetermined recording current control value, When recording servo information on the disc for each HDA, recording current ID (identification) to distinguish the type and characteristics of the head and the disc is included in the servo information differently depending on the head and the disc included in the corresponding HDA. Recording and checking the recording current ID from the servo information read from the disk, and loading the corresponding recording current control value from the ROM and setting it as the recording current control value of the magnetic disk recording apparatus.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 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 processing flows, servo information recording formats, and the like. 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.

FIG. 1 shows a block diagram of an HDD to which the present invention is applied, and shows an example having two disks 10 and four heads 12, one on each side thereof. In addition, the HDD shown in FIG. 1 has a function to adjust the recording current step by step through the recording current adjusting circuit 38 under the control of the microcontroller 24. Examples of such technology in HDDs include the aforementioned patent application No. 95-53518 or patent application No. 91-2820, filed in the Republic of Korea by the present applicant in 1991, with "recording current control circuit of a magnetic recording apparatus". There is. Patent application No. 91-2820 discloses a technique for controlling a recording current value differently according to a region on a disc by using a digital to analog converter (DAC). In the embodiment of the present invention, an example using the aforementioned patent application No. 95-53518 is described.

Referring to FIG. 1, the configuration and operation of a HDD useful for understanding the present invention will now be described.

The disk 10 is installed as a stack on one spindle and rotated by the spindle motor 34. Each of the heads 12 is located on a corresponding one of the disks 10, and is an E-block assembly 14 coupled with a rotary voice coil actuator 30. Respectively corresponding to a support arm extended from the disk 10 toward the disk 10.

The read / write circuit 16 connected to the head 12 transposes the signal picked up by one of the heads 12 during readout to read / write the analog read signal. Recording data is recorded on the disc 10 by applying a recording current according to the encoded recording data applied from the read / write channel circuit 18 to one of the heads 12 selected during recording. Be sure to At this time, the read / write circuit 16 includes a head switching circuit for selecting one of the heads 12 to perform head switching by a selection signal applied from the disk signal controller 36. In addition, the read / write circuit 16 generally uses a one chip integrated circuit (IC), for example, SSI 32R221OR / 2211R / 2212R, which is a read / write device of silicon systems of the United States of America. . The read / write circuit has a write current control terminal WC provided for controlling the write current from the outside, and the write current value is determined by the resistance value of the external resistance element connected to the write current control terminal WC. Therefore, the read / write circuit 16 applies the write current of the value corresponding to the amount of current of the write current control terminal WC to the head in accordance with the write data when writing data on the disc 10.

The read / write channel circuit 18 detects and decodes a data pulse from a read signal applied from the read / write circuit 16 and applies it to a disk data controller (DDC) 20, and applies it from the DDC 20. The recorded data is encoded and applied to the read / write circuit 16.

The DDC 20 is controlled by the microcontroller 24 and read / write channel circuit 18 and read / write circuit 16 to read data received from a host computer such as a personal computer (PC). Recording on the disk 10 or reading data from the disk 10 and sending it to the host computer. The DDC 20 also interfaces the communication between the host computer and the microcontroller 24. A random access memory (RAM) 22 temporarily stores data transferred between the host computer, the microcontroller 24 and the read / write channel circuit 18.

The microcontroller 24 controls the DDC 20 in response to a read or write command received from a host computer and controls track search and track following. The microcontroller 24 also adjusts the write current value applied from the read / write circuit 16 to the head 12 through the write current adjustment circuit 38. At this time, the microcontroller 24 generates a PWM signal having a duty corresponding to a preset recording current control value in order to determine the recording current amount. The write current adjusting circuit 38 is connected between the write current control terminal WC of the read / write circuit 16 and the PWM output terminal of the microcontroller 24 and writes the read / write circuit 16 to correspond to the duty of the PWM signal. Adjust current amount of current control terminal WC. The ROM 26 stores the execution program of the microcontroller 24 and various setting values.

The servo driver 28 generates a driving current for driving the actuator 30 by the signal for controlling the position of the head 12 generated from the microcontroller 24 and applies it to the actuator 30. The actuator 30 moves the head 12 on the disk 10 in response to the direction and level of the drive current applied from the servo driver 28. The spindle motor driver 32 drives the spindle motor 34 to rotate the disk 10 according to a control value for rotation control of the disk 10 generated from the microcontroller 24. The disk signal controller 36 decodes servo information from the read data output from the read / write channel circuit 18 to the microcontroller 24 and applies various control signals necessary for read / write from the DDC 20. The signal is generated and controlled by the microcontroller 24 and applied to the read / write circuit 16, the read / write channel circuit 18, the DDC 20, and the like. The disk signal controller 36 typically uses an ASIC (Application Specifie Integrated Circuit) designed for each HDD.

According to the present invention applied to the HDD as described above, when the servo information is recorded by the servo writer on the disk of the HDA in the state where the assembly of the HDA is completed, the type of the head and the disk used for the HDA / The recording current ID for distinguishing characteristics is included in the servo information differently according to the head and the disk, and the recording current ID is described in detail as follows.

First, in the HDD, to selectively position the head on a particular track, it is necessary to know the current head position relative to the tracks. As such, servo information informing the head position relative to the tracks is provided by using a particular servo pattern that is read on the disc by the head. This servo pattern is permanently recorded on the disk in advance by the servo writer when assembling the HDD. This servo pattern is used as track position information by being detected by the head when accessing data on the disk. One example of a method for providing servo information is an embedded servo method. In the embedded servo method, servo information is arranged between data feeds which are data areas in each track on the disc.

A typical recording format of such servo information is shown in FIG. 2 as an example of an embedded servo method, and is an example of one track and is not an accurate scale. In FIG. 2, servo information consisting of a servo address mark, an index, a track address, a burst, and the like is recorded in a servo feed on a disc. The servo address mark is a signal of a specific pattern indicating the start of the servo feed. The index is information for determining the reference of each track. For example, when the index bit is a logic "1", it indicates that the corresponding servo feed is the first servo feed in the track. The track address is track position information and indicates position information of the track and the servo sector. Burst is information for controlling the position of the head, which is used to on-track the head when following a track.

In the conventional servo information recording format as shown in FIG. 2, the recording current ID according to the present invention is included to configure the servo information recording format as shown in FIG. FIG. 3 also shows an example of one track as in FIG. 2 and is not an accurate scale. In the embodiment of the present invention, the write current ID is located between the index and the track address as shown in FIG. At this time, the position of the recording current ID is positioned after the index to facilitate detection, but may be different. As described above, the recording current ID is used to distinguish the type / characteristic of the head and the disk used in the HDA to be assembled with one PCBA, and is set to different values according to the type / characteristic of the head and the disk.

As described above, the microcode corresponding to each of the recording current control values set by including the recording current ID in the servo information and set correspondingly to the types / characteristics of the head and the disk in the ROM 26 in FIG. Save them. At this time, each of the microcodes are classified according to the above-described recording current ID.

In the function test for the HDAs in the above state, the microcontroller 24 performs the operation according to the flowchart of FIG.

First, the microcontroller 24 checks the recording current ID from the servo information read from the disk 10 in step 400. At this time, the disc signal controller 36 inputs encoded data, which is data read from the disc 10, from the read / write channel circuit 18, decodes the servo information shown in the read data, and provides the decoded servo information to the microcontroller 24.

When the recording current ID is confirmed as described above, the microcontroller 24 loads the recording current control value corresponding to the recording current ID from the ROM 26 in step 402 to the recording current control value of the corresponding HDD. Set it. Accordingly, when writing data on the disc 10, the microcontroller 24 outputs a PWM signal having a duty corresponding to the write current control value and is applied to the write current adjustment circuit 38. The write current adjustment circuit 38 then adjusts the amount of current in the write current control terminal WC of the read / write circuit 16 corresponding to the duty of the PWM signal, and as a result, the write current value applied to the head 12 is determined.

Next, the microcontroller 24 executes the normal HDA function test while applying the recording current amount corresponding to the recording current control value to the head 12 in step 404.

After the HDA function test is completed, the recording current control value is recorded as a default value in a maintenance cylinder on the disk 10. The maintenance area usually uses the outermost cylinder on the disk 10, and is an area in which unique information for maintaining the HDD is recorded. Such unique information includes, for example, a defect list for two sectors on the disc 10, spare sector information, parameters of read / write channels, and the like. Typically, in the HDD, the microcontroller 24 reads out variables of the read / write channel from the ROM 26 and writes them to the maintenance area on the disk 10, and uses data read / write on the disk 10.

As described above, the recording current control value recorded in the maintenance area on the disk 10 is a recording current control value suitable for the corresponding HDD, and then the consumer decides the amount of recording current when writing data using the HDD.

Therefore, HDAs with different heads or disks, or large characteristic differences, are assembled with a single PCBA so that the hardware does not need to be changed.

As described above, the present invention has the advantage that the recording current can be adaptively controlled without changing the hardware when assembling the heads or disks of which the kind or the characteristic difference is large with one PCBA.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. In particular, although the HDD has been described as an example, all of them can be applied to the magnetic disk recording apparatus such as the FDD as well as the HDD without any special modification. Therefore, the scope of the invention should not be defined by the described embodiments, but should be defined by the equivalents of the claims and the claims.

1 is a block diagram of an HDD to which the present invention is applied.

2 is a conventional servo information recording format diagram.

3 is a servo information recording format diagram according to the present invention.

4 is a flow chart according to the present invention

Claims (4)

The recording current of the magnetic disk recording apparatus having a ROM having a recording current control value set corresponding to the type / characteristics of the head and the disk, and means for adjusting the amount of recording current applied to the head in accordance with a predetermined recording current control value. In the control method, The recording current ID for distinguishing the type / characteristic of the head and disk is included in the servo information differently depending on the head and disk included in the head disk assembly when recording the servo information on the disk for each head disk assembly. The process of recording Confirming the recording current ID from the servo information read out from the disk; Loading a write current control value corresponding to the checked write current ID from the ROM; And setting the loaded recording current control value as the recording current control value of the corresponding magnetic disk recording apparatus. The recording current control method according to claim 1, further comprising the step of recording the loaded recording current control value as a default value in a maintenance area on the disk. The recording current control method according to claim 2, further comprising: performing a functional test on the head disk assembly while applying the recording current amount corresponding to the loaded recording current control value to the head. The recording current control method according to claim 2, wherein the recording current control value recorded in the maintenance area on the disk is used when data is recorded on the disk.