JP2010176840A - Head amplifier of disk storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk storage device capable of attaining magnetization testing function for automatically executing a test mode for detecting the magnetization state of a write head. <P>SOLUTION: In a perpendicular magnetic recording mode disk drive, HDC 9 executes a magnetization test mode to detect the magnetization state of the write head, by using a degauss control circuit 62 and a degauss circuit 63 mounted on a head amplifier circuit 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a head amplifier device applied to a perpendicular magnetic recording type disk storage device.

  Generally, in a perpendicular magnetic recording type disk storage device (hereinafter referred to as a disk drive), a single pole type head (SPT) suitable for perpendicular magnetic recording is used as a write head (recording head). in use.

  In such a disk drive, after the data signal is perpendicularly magnetically recorded on the disk medium by the write head, even if the recording current applied to the write head is made zero, the write head remains magnetized and becomes magnetized. It becomes a state.

  Due to the residual magnetization of the write head, there is a problem that after the write operation (data recording) is completed, the recording data of the data sector on the disk medium and the servo data recorded on the servo sector are erroneously erased. Such a problem does not occur in a longitudinal magnetic recording type disk drive.

  As a prior art for solving such a problem, a data writing circuit having a demagnetization circuit (also called a degaussing circuit or a degauss circuit) that removes residual magnetization of a magnetic head has been proposed (see, for example, Patent Document 1). . This demagnetization circuit is a circuit that attenuates and erases a write current (recording current) at a constant time constant in accordance with the fall of data after the write gate is closed. A disk drive having a read / write channel including a degauss circuit has been proposed (see, for example, Patent Document 2).

Japanese Patent Publication No. 5-84564 JP-A-7-134804

  Along with the degauss circuit that removes the remanent magnetization of the write head, the disk drive has a function that automatically executes a test mode that detects the magnetization state of the mounted write head at the time of manufacture or operation after shipping as a product (magnetic test). Function) is useful. By incorporating such a function as a self-diagnosis function of a disk drive, for example, one of SMART (Self-Monitoring Analysis and Reporting Technology System) functions, the host system can grasp the magnetic state of the write head. .

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a head amplifier device applied to a disk storage device that can realize a magnetic field test function.

  A head amplifier device according to an aspect of the present invention is a head amplifier device applied to a disk storage device having a magnetic head including a write head that performs perpendicular magnetic recording for recording write data on a disk medium, A degauss circuit for generating a degauss signal for executing a degaussing operation for removing residual magnetization of the write head, write driver means for supplying write data or a recording current corresponding to the degauss signal to the write head, and the degauss circuit And control means for controlling the output of the recording current from the write driver means, the control means in accordance with an instruction for data recording from the outside, And a write current corresponding to the degauss signal is output from the write driver means. The write driver means outputs a recording current according to a test write sequence for setting invalid and valid timings of the write data and the degauss signal in response to an external magnetic test instruction. Configured to control.

  According to the present invention, it is possible to provide a head amplifier device that is applied to a disk storage device that can realize a magnetic field test function.

1 is a block diagram showing a main part of a perpendicular magnetic recording type disk drive according to each embodiment of the present invention. The block diagram which shows the structure of the degauss control circuit regarding 1st Embodiment. 6 is a timing chart for explaining the operation of the head amplifier circuit in a normal data recording / reproducing mode according to the first embodiment. 4 is a timing chart for explaining the operation of the head amplifier circuit in a magnetic test mode according to the first embodiment. The block diagram which shows the structure of the degauss control circuit regarding 2nd Embodiment. 9 is a timing chart for explaining the operation of the head amplifier circuit according to the second embodiment. The block diagram which shows the structure of the degauss control circuit regarding 3rd Embodiment. 10 is a timing chart for explaining the operation of the head amplifier circuit according to the third embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

(Disk drive configuration)
FIG. 1 is a block diagram showing a main part of a perpendicular magnetic recording type disk drive according to each embodiment.

  As shown in FIG. 1, the disk drive of the present embodiment includes a disk medium 1, a magnetic head 2, a spindle motor (SPM) 3 that rotates the disk medium 1, and an actuator that mounts the magnetic head 2. It has a drive mechanism and a control / signal processing circuit system.

  The disk medium 1 is a recording medium capable of perpendicular magnetic recording. As will be described later, a large number of tracks 100 including tracks for a magnetic field test mode (test recording areas) are provided on the outermost or innermost periphery. . The magnetic head 2 has a write head composed of a single pole head (SPT head) for performing perpendicular magnetic recording, and a read head for reproducing a recording data signal from the disk medium 1.

  The actuator includes an arm (including a suspension) 4 on which the magnetic head 2 is mounted, and a voice coil motor (VCM) 5 that generates a driving force. The actuator moves the magnetic head 2 in the radial direction on the disk medium 1 by servo control of the microprocessor (CPU) 10 to position it at a target position (target track).

  The control / signal processing circuit system is roughly divided into a head amplifier circuit 6, a motor driver 7, a read / write channel 8, a disk controller (HDC) 9, a CPU 10, and a memory 11.

  The motor driver 7 includes an SPM driver 70 that supplies a drive current to the SPM 3 and a VCM driver 71 that supplies a drive current to the VCM 5 under the control of the CPU 9. The read / write channel 8 is a read / write signal processing circuit, which outputs a write data signal WD28 to the head amplifier circuit 6, and inputs a read data signal (reproduction signal) RS29 from the head amplifier circuit 6.

  The HDC 9 constitutes an interface between the disk drive and a host system (personal computer or digital device), and executes read / write transfer control of user data with the host system.

  The HDC 9 controls the read / write operation of the read / write channel 8 via the bidirectional control signal line RC22 including the bus I / F. The HDC 9 transmits / receives write data and read data (WD / RD25) having a predetermined format to / from the read / write channel 8 in synchronization with the write gate WG23 and the read gate RG24.

  Further, the HDC 9 controls the read / write operation of the head amplifier circuit 6 and sends the write gate WGA 21 to the head amplifier circuit 6 via the bidirectional control signal line AC 20 formed of a serial I / F.

  Here, the write gate WGA 21 is transmitted at the same time as the write gate WG 23, and is a gate signal whose timing is adjusted according to the write data signal WD 28 transmitted from the read / write channel 8. The read / write channel 8 sends a write data signal WD28 (encoded signal of the write data WD25) to the head amplifier circuit 6 with a certain timing delay in a predetermined format according to the write gate WG23 and the write data WD25 from the HDC 9. To do.

  Furthermore, the HDC 9 sends a servo gate SG26 to the read / write channel 8 and receives servo data SD27 for head positioning decoded from the reproduction signal RS29.

  The CPU 10 is a main control device for the disk drive, and is a main element of a servo system for executing positioning control (servo control) of the magnetic head 2. The CPU 10 controls the seek operation and the track following operation in accordance with the servo data SD27 received via the HDC 9. Specifically, the CPU 10 controls the drive of the VCM 5 of the actuator by controlling the input value (control voltage value) of the VCM driver 71. Further, the CPU 10 controls the HDC 9 to execute the magnetization test mode of the present embodiment.

  The memory 11 includes a RAM, a ROM, and a flash EEPROM, and stores a control program for the CPU 10 and various control data.

  The head amplifier circuit 6 includes a write driver 61, a read amplifier 60, a degaussing control circuit 62, a degauss signal generation circuit (hereinafter simply referred to as a degauss circuit) 63, and a switch 64.

  The write driver 61 supplies a write current WS34 according to the write data signal WD28 or the degauss signal DS31 to the write head included in the magnetic head 2. The read amplifier 60 amplifies the read data signal 33 from the read head included in the magnetic head 2 and sends it to the read / write channel 8 as a reproduction signal RS29.

  The degauss circuit 63 generates a degauss (demagnetization or demagnetization) signal DS31 having a constant frequency at which the signal amplitude attenuates linearly or exponentially, for example. The switch 64 transfers one of the degauss signal DS31 and the write data signal WD28 to the write driver 61 in accordance with the write gate WGA21 from the HDC9.

  The degauss control circuit 62 outputs a gate signal DG30 for controlling the generation of the degauss signal DS31 of the degauss circuit 63, and a gate for controlling the output of the recording current signal WS34 to the write head to the write driver 61. The signal WGB32 is output.

  The head amplifier circuit 6 has a normal data recording / reproducing mode and a write head magnetic test mode, and each mode is switched by a mode switching instruction transferred from the HDC 9 via the amplifier control signal AC20. Is called.

  Specifically, the degauss control circuit 62 includes a flip-flop (F / F) 621, an inverter 622, AND gate circuits 623 and 624, and an OR gate circuit 625, as shown in FIG.

  As will be described later with reference to FIG. 4, the degauss control circuit 62 performs gate timing control and signal control for realizing a write sequence for executing the magnetic field test mode.

  Specifically, the flip-flop 621 is initialized by the CLR signal 45 when the head amplifier circuit 6 is switched from the HDC 9 through the AC 20 to the head amplifier circuit 6 and is switched to the write sequence operation enabled state. It is done. Thereafter, the head amplifier circuit 6 executes a write sequence operation in the magnetic test mode in accordance with the write gate WGA 21 sent from the HDC 9.

(Normal data recording / playback mode)
The operation of the head amplifier circuit 6 in the normal data recording / reproducing mode will be described below with reference to the timing chart of FIG.

  First, as shown in FIG. 3A, a track 100 includes a servo sector 110 in which servo data is recorded at regular intervals in the circumferential direction, and a plurality of data sectors (user data recording areas) between the servo sectors 110. 120 is provided.

  In the normal data recording / reproducing mode, as shown in FIGS. 3C and 3E, the degauss signal DS31 is always applied to the write driver 61 immediately after the end of the write data WD28.

  Specifically, in the head amplifier circuit 6, in synchronization with the fall of the write gate WGA 21 (WG 23) from the HDC 9, the degauss control circuit 62 outputs the degauss signal generation control gate signal DG 30 having a predetermined time width to the degauss. Output to the circuit 63. The degauss circuit 63 generates a degauss signal DS31 according to the control gate signal DG30 and outputs it to the switch 64 (see FIGS. 3B, 3D, and 3E).

  The switch 64 switches from the write data WD28 to the degauss signal DS31 in synchronization with the write gate WGA21 and outputs it to the write driver 61. The write driver 61 supplies a write current signal WS34 composed of the write data WD28 and the degauss signal DS31 to the write head in synchronization with the gate signal WGB32 output from the degauss control circuit 62 (FIG. 3C, ( E), (F), (G)).

(Magnetic test mode)
Next, the operation in the magnetic field test mode according to this embodiment will be described.

  The write head magnetism test is a test for detecting the magnetism state of the write head, that is, detecting that the residual magnetization exceeds the allowable range. In principle, when the degauss function (demagnetization function) of the degauss circuit 63 is enabled (turned on), the possibility of erasure of subsequent data becomes extremely low after data recording by the write head. On the other hand, when data recording is performed with the degauss function disabled (off), the fact that the possibility of erasure of subsequent data is increased is utilized.

  Specifically, the magnetic disk test mode track (test recording area) is provided on the outermost or innermost periphery of the disk medium 1 of the present embodiment. In this track, as shown in FIG. 4A, a plurality of data sectors 120 are provided between servo sectors 110 in the same manner as a normal recording area (see FIG. 3A). In each data sector 120, test data is recorded in advance.

  The HDC 9 outputs an instruction to switch from the normal data recording / reproducing mode to the magnetic test mode to the head amplifier circuit 6 via the AC 20. Further, the HDC 9 issues a write gate WGA 21 for accessing (recording operation) the L data sectors 120 that are continuous between the servo sectors 110 when executing the magnetic test mode (see FIG. 4B). .

  Here, L is “L = M + N + 1” and means “M is an integer of M ≧ 1 and N is an integer of N ≧ 0”. The HDC 9 invalidates the degauss operation of the degauss circuit 63 and records the test data in M (≧ 1) data sectors 120 when the magnetism test mode is executed. Further, neither the data recording nor the degauss operation is performed on the subsequent N (≧ 0) data sectors 120. Further, a degauss operation (or both data recording and degauss operation) is performed on the last one data sector 120 subsequent thereto.

  Note that (N + 1) or N data sectors that are not subjected to the data recording are recorded with test data in the normal data recording / reproducing mode and with the degauss operation enabled at the initial stage of the test operation. Keep it. The degauss control circuit 62 controls the validity or invalidity of the degauss operation of the degauss circuit 63 by the control gate signal DG30 (see FIGS. 4I and 4J).

  After the end of the test write operation (recording operation), the HDC 9 outputs the read gate RG24 and reproduces the recording data signal from the data sector 120 of the test mode track by the read head. Specifically, the recording data signal is reproduced from (N + 1) or N data sectors where data recording is not performed following M data sectors where data recording is performed with the degauss operation disabled.

  The CPU 10 detects the magnetic state of the write head based on the amplitude value or error rate of the reproduction signal transferred from the HDC 9. That is, when the amplitude value or error rate of the reproduction signal is lower than the allowable range, it is determined that the magnetic state of the write head exceeds the allowable range.

  Note that the HDC 9 may transfer the amplitude value or error rate of the reproduction signal in the magnetic test mode to the host system as information for detecting the magnetic state of the write head. Based on the information, the host system determines whether or not the magnetic state of the write head exceeds an allowable range.

  Here, the HDC 9 writes so as to issue P (multiple of L) WGAs 21 between the servo sectors so that the degauss operation is always valid in the last data sector in which the recording operation is executed between the servo sectors 110. Perform gate control.

  Hereinafter, the operation of the head amplifier circuit 6 of the present embodiment, that is, the test write sequence in the magnetic field test mode in the disk drive will be described with reference to the timing chart of FIG.

  Here, the present embodiment is a case of the magnetic field test mode of L = 2, M = 1, and N = 0. FIG. 4 is a timing chart of various gates and signals of the head amplifier circuit 6 and the degauss control circuit 62 when the HDC 9 issues P (multiple of 2) write gates WGA 21 between servo sectors.

  That is, the HDC 9 issues a write gate WGA 21 continuously with L = 2, and executes a test in units of two data sectors 120. Data is recorded in the first data sector with the degauss operation disabled (see FIGS. 4K and 4L).

  That is, the HDC 9 outputs the write gate WGA21 and the write data WD28 (see FIGS. 4B and 4C). The degauss control circuit 62 turns off the gate control signal DGA41 of the AND gate 624 shown in FIG. 2 and turns off the control gate signal DG30 (see FIGS. 4D and 4I). As a result, the degauss operation of the degauss circuit 63 becomes invalid, and the degauss signal DS31 is not output (see FIG. 4J).

  Further, the HDC 9 does not perform data recording on the subsequent second data sector, but only performs a degauss operation. That is, the degauss control circuit 62 turns on the gate control signal DGA41, the control gate signal DG30, and the gate signal WGB32 (see FIGS. 4D, 4I, 4J, and 4K). As a result, the degauss operation of the degauss circuit 63 is enabled, and the degauss signal DS31 is output and supplied to the write driver 61 as the recording current WS34 (see FIG. 4L).

  Then, the HDC 9 reproduces a recording data signal (recorded in advance as test data) of the second data sector that has not been recorded. The CPU 10 detects the magnetic state of the write head based on the amplitude value or error rate of the reproduction signal transferred from the HDC 9.

  Here, the magnetic head state may be detected by reproducing all data sectors including data sectors that were not recorded in the test mode and measuring the error rate reduction.

  As described above, according to the present embodiment, after the disk drive product is shipped, the degauss control circuit 62 and the degauss circuit 63 of the head amplifier circuit 6 are used when a command from the host system is given or a predetermined time is used. A magnetization test mode for detecting the magnetization state is executed. Therefore, the disk drive or the host system can monitor the magnetic state of the write head and avoid the occurrence of data erasure due to the residual magnetization of the write head that is likely to occur in perpendicular magnetic recording. In other words, the disk drive of the present embodiment realizes a function of monitoring the magnetic state of the write head as one of the self-diagnosis functions of the drive, for example, a SMART (Self-Monitoring Analysis and Reporting Technology System) function. be able to.

  It should be noted that the disk drive according to the present embodiment executes the magnetism test mode, for example, when executing a failure diagnosis function due to a data reproduction error, or at every elapse of a certain operation time of the drive, other than an instruction from the host system.

  Further, when the magnetic field test mode is executed at the time of manufacturing the disk drive, it is not necessary to provide a test recording area on the disk medium 1, and an arbitrary recording area on the disk medium 1 may be used.

(Second Embodiment)
5 and 6 are diagrams for explaining the second embodiment.

  In this embodiment, the write gate control is executed so that the HDC 9 issues P (a multiple of 3) write gates WGA 21 between servo sectors when executing the magnetic test mode of L = 3, M = 1, and N = 1. It is the structure to do.

  Specifically, the degauss control circuit 62 of the present embodiment includes flip-flops 621A, 621B, inverters 622, 627, 628, AND gate circuits 623, 624, 626, a NAND gate circuit 629 and an OR gate circuit 625, as shown in FIG. Have

  Hereinafter, the operation of the head amplifier circuit 6 of the present embodiment, that is, the test write sequence in the magnetic field test mode in the disk drive will be described with reference to the timing chart of FIG.

  When the head amplifier circuit 6 is instructed to switch to the magnetic test mode from the HDC 9 through the AC 20, the flip-flop 621 A is initialized by the CLR signal 56 in the degauss control circuit 62, and the write sequence operation is possible. Is switched to. Thereafter, the head amplifier circuit 6 executes a write sequence operation in the magnetic test mode in accordance with the write gate WGA 21 sent from the HDC 9.

  The HDC 9 continuously issues the write gate WGA 21 with L = 3, and executes a test in units of three data sectors 120. Data is recorded in the first data sector with the degauss operation disabled (see FIGS. 6K and 6L).

  That is, the HDC 9 outputs the write gate WGA 21 and the write data WD 28 (see FIGS. 6B and 6C). The degauss control circuit 62 turns off the gate control signal DGA52 of the AND gate 624 shown in FIG. 5 and turns off the control gate signal DG30 (see FIGS. 6D and 6I). As a result, the degauss operation of the degauss circuit 63 becomes invalid, and the degauss signal DS31 is not output (see FIG. 6J).

  Further, the HDC 9 does not perform data recording on the subsequent second data sector, but only performs a degauss operation. That is, the degauss control circuit 62 turns on the gate control signal DGA52, the control gate signal DG30, and the gate signal WGB32 (see FIGS. 6D, 6I, 6J, and 6K). As a result, the degauss operation of the degauss circuit 63 is enabled, and the degauss signal DS31 is output and supplied to the write driver 61 as the recording current WS34 (see FIG. 6L).

  After the end of the test write operation (recording operation), the HDC 9 outputs the read gate RG24 and reproduces the recording data signal from the data sector 120 of the test mode track by the read head. Specifically, a recording data signal (recorded in advance as test data) is reproduced from the second and third data sectors where data recording was not performed.

  The CPU 10 detects the magnetic state of the write head based on the amplitude value or error rate of the reproduction signal transferred from the HDC 9. Alternatively, the HDC 9 may transfer the amplitude value or error rate of the reproduction signal in the magnetic test mode to the host system as information for detecting the magnetic state of the write head. Based on the information, the host system determines whether or not the magnetic state of the write head exceeds an allowable range.

  Here, the magnetic head state may be detected by reproducing all data sectors including data sectors that were not recorded in the test mode and measuring the error rate reduction.

  Also in the present embodiment described above, as in the first embodiment described above, the degauss control circuit 62 and the degauss circuit 63 of the head amplifier circuit 6 when a command is given from the host system or at a predetermined time after the disk drive is shipped. Is used to execute a magnetization test mode for detecting the magnetization state of the write head. Therefore, the disk drive or the host system can monitor the magnetic state of the write head and avoid the occurrence of data erasure due to the residual magnetization of the write head that is likely to occur in perpendicular magnetic recording. In other words, the disk drive of the present embodiment realizes a function of monitoring the magnetization state of the write head as one of the self-diagnosis functions of the drive, for example, a SMART (Self-Monitoring Analysis and Reporting Technology System) function. be able to.

  It should be noted that the disk drive according to the present embodiment executes the magnetism test mode, for example, when executing a failure diagnosis function due to a data reproduction error, or at every elapse of a certain operation time of the drive, other than an instruction from the host system.

  Further, when the magnetic field test mode is executed at the time of manufacturing the disk drive, it is not necessary to provide a test recording area on the disk medium 1, and an arbitrary recording area on the disk medium 1 may be used.

(Third embodiment)
7 and 8 are diagrams for explaining the third embodiment.

  In the present embodiment, as in the second embodiment described above, when the magnetic field test mode of L = 3, M = 1, and N = 1 is executed, the HDC 9 causes P (a multiple of 3) write gates between servo sectors. In this configuration, the write gate control is executed so that the WGA 21 is issued.

  Hereinafter, mainly different items from those in the second embodiment will be described.

  As shown in FIG. 7, the degauss control circuit 62 of this embodiment includes flip-flops 621A and 621B, inverters 622, 627, and 628, AND gate circuits 623, 624, and 626, a NAND gate circuit 629, and an OR gate circuit 625. The input configuration of the AND gate circuit 623 is different from the degauss control circuit 62 shown in FIG.

  The HDC 9 outputs a write gate WGA21 and write data WD28 (see FIGS. 8B and 8C). The degauss control circuit 62 turns off the gate control signal DGA62 of the AND gate 624 shown in FIG. 7 and turns off the control gate signal DG30 (see FIGS. 8D and 8I). As a result, the degauss operation of the degauss circuit 63 becomes invalid, and the degauss signal DS31 is not output (see FIG. 8J).

  Further, the HDC 9 does not perform either data recording or degauss operation on the second data sector that follows. That is, the degauss control circuit 62 turns off the gate control signal DGA62, the control gate signal DG30, and the gate signal WGB32 (see FIGS. 8D, 8I, J, and K). As a result, the degauss operation of the degauss circuit 63 becomes invalid, and no recording current is supplied to the write driver 61 (see FIG. 8L).

  Further, the HDC 9 performs data recording and degauss operations on the subsequent third data sector. That is, the degauss control circuit 62 turns on the gate control signal DGA62, the control gate signal DG30, and the gate signal WGB32 (see FIGS. 8D, 8I, J, and K). Thus, after the data recording is completed, the degauss operation of the degauss circuit 63 becomes valid, and the degauss signal DS31 is output and supplied to the write driver 61 as the recording current WS34 (see FIG. 8 (L)).

  After completion of the test write operation (recording operation), the HDC 9 outputs the read gate RG24 to reproduce the recording data signal from the data sector 120 of the test mode track by the read head. Specifically, a recording data signal (recorded in advance as test data) is reproduced from the second data sector where data recording was not performed.

  Also in the present embodiment described above, as in the second embodiment described above, the degauss control circuit 62 and the degauss circuit 63 of the head amplifier circuit 6 are provided at the time of an instruction from the host system or at a predetermined time after the disk drive is shipped. Is used to execute a magnetization test mode for detecting the magnetization state of the write head. Therefore, the disk drive or the host system can monitor the magnetic state of the write head and avoid the occurrence of data erasure due to the residual magnetization of the write head that is likely to occur in perpendicular magnetic recording. In other words, the disk drive of the present embodiment realizes a function of monitoring the magnetic state of the write head as one of the self-diagnosis functions of the drive, for example, a SMART (Self-Monitoring Analysis and Reporting Technology System) function. be able to.

  In each of the first to third embodiments, the head amplifier circuit 6 controls the validity or invalidity of the degauss function of the degauss circuit 63 by the internal degauss control circuit 62, so that the control is performed from the outside. A control signal line is not required.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 ... disk medium, 2 ... magnetic head (write head and read head),
3 ... Spindle motor (SPM), 4 ... Arm, 5 ... Voice coil motor (VCM),
6 ... head amplifier circuit, 7 ... motor driver, 8 ... read / write channel,
9 ... Disk controller (HDC), 10 ... Microprocessor (CPU),
11 ... Memory, 60 ... Read amplifier, 61 ... Write driver,
62 ... Degauss control circuit, 63 ... Degauss signal generation circuit (Degauss circuit)
64 ... Switcher.

Claims (4)

A head amplifier device applied to a disk storage device having a magnetic head including a write head for performing perpendicular magnetic recording for recording write data on a disk medium,
A degauss circuit for generating a degauss signal for performing a degaussing operation to remove residual magnetization of the write head;
Write driver means for supplying a write current corresponding to write data or the degauss signal to the write head;
Control means for controlling the output of the degauss signal from the degauss circuit, and for controlling the output of the recording current from the write driver means,
The control means includes
In response to an external data recording instruction, control is performed so that write data and a recording current corresponding to the degauss signal are output from the write driver means,
Control to output a recording current from the write driver means in accordance with a test write sequence for setting invalid and valid timings of the write data and the degauss signal in accordance with an external magnetic test instruction. Head amplifier device characterized by this. The control means includes
Receiving a write gate signal for setting the timing of the write operation of the write data in accordance with the instruction of the magnetic test,
Controlling the output of the degauss signal from the degauss circuit in response to the write gate signal;
The write driver unit is controlled to output a valid write data according to the test write sequence or a valid recording current corresponding to the valid degauss signal in accordance with the write gate signal. The head amplifier device according to 1. The control means includes
Receives a write gate signal for setting the write data recording operation timing in accordance with the magnetic test instruction, selects one of the write data and the degauss signal in accordance with the write gate signal, and supplies it to the write driver means Switching means for
Controlling the output of the degauss signal from the degauss circuit to the switching means in accordance with the write gate signal;
The write driver unit is controlled to output a valid write data according to the test write sequence or a valid recording current corresponding to the valid degauss signal in accordance with the write gate signal. 2. The head amplifier device according to 2. The magnetic head includes a read head for reproducing data from the disk medium;
The read amplifier according to any one of claims 1 to 3, further comprising: a read amplifier for sending data reproduced from the disk medium by the read head in response to an instruction of the magnetic field test. Head amplifier device.

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