JPH01263904A - magnetic head device - Google Patents

Abstract

PURPOSE:To correct bit asymmetry with a simple method by using a terminal to connect the write dumping resistance of a read/write IC, and making imbalanced a write current applied to each separated coil of a magnetic head. CONSTITUTION:By using a terminal 13 to connect the write dumping resistance of the read/write IC, a write current applied to each separated coil 45 of a magnetic head 41 is made imbalanced. Thus, a direct current magnetic field generated by an erasing head 42 is canceled, the write current to be applied to each coil separated by a center tap 45a of the R/W head coil 45 can be made imbalanced, and the correction of the bit asymmetry is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to the field of flexible disk drives.

[Prior Art] The most basic function of a flexible disk drive is to record a predetermined signal and read it without error. Many magnetic disk drives employ a peak detection method, which determines whether a peak in the read waveform exists within a certain time frame or not, but the position of the peak may shift due to various factors. . One of the factors is bit asymmetry.

For example, ideally, the magnetization pattern on the medium for a constant frequency signal should be as shown in (a) of Figure 3(a).
When this pattern becomes longer in the right direction and shorter in the left direction as shown in (a) of (b), the output waveform becomes (b).
) is distorted as shown in (b), and the interval of the digital output becomes asymmetric as shown in (c), such that tl<t2 during one cycle. This phenomenon is called bit asymmetry (BA). , 13A) jj There are various causes, but leakage of the erase magnetic field is one of the causes. Figure 4 shows a 1llf1 diagram of the magnetic head. The magnetic head consists of a read/write (R/W) head 41 that records and reproduces data on a medium, and an erase head 42 that creates a guard band with no data between tracks. The write magnetic field by the R/W head 41 during writing is (!!+) in FIG. 3(a).
It is fine if N and S are completely symmetrical as shown in (b), but if the erase magnetic field 43 jumps to the R/W head side during writing and a leakage DC erase magnetic field 44 is formed, the recording magnetic field is biased and the N Since the strengths of and S are no longer the same, A as shown in Fig. f53 (b) occurs.Therefore, as shown in Utility Model Application No. 59-39423, a demagnetizing field is generated to cancel the leakage magnetic field due to the erase head. Therefore, methods have been taken to correct the unbalance of magnetization strength on a circuit.

[Problems to be Solved by the Invention] However, nowadays, recording circuits that record on flexible disks and playback circuits that play back signals recorded on flexible disks have become more integrated, and one read/write Since it is used as an IC, it is not possible to directly control the write current.
SUMMARY OF THE INVENTION The present invention solves these problems, and its purpose is to provide a BA correction method when a read/write IC is used.

[Means for Solving the Problems] A flexible disk drive of the present invention includes: a main shaft motor that rotationally drives a flexible disk; a magnetic head that records and reproduces information on the flexible disk; and a carriage that supports the magnetic head. A read/write IC including a carriage position control circuit that controls the positioning mechanism of the magnetic head and carriage, a recording circuit that records on a flexible disk, and a reproduction circuit that reproduces signals recorded on the flexible disk. The flexible disk drive is characterized in that the write current flowing to each separated coil of the magnetic head is made unbalanced by using the terminal connecting the write damping resistor of the read/write IC. do.

[Function] According to the above configuration of the present invention, even when a read/write IC is used, it is possible to make the write current flowing to each separated coil of the magnetic head unbalanced, and BA correction is possible. Become.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows an embodiment of the present invention, in which read/write I
FIG. 3 is a block diagram during a CO write operation. During writing, the write current IO is applied to the center tap 45 of the R/W head coil 45.
It is alternately poured into one side of a, causing magnetization reversal. Also, in the guard band erase during writing, direct current is applied to the erase head 42 through the rad coil 46.
and generates an erasure magnetic field. As mentioned above, this erase magnetic field also leaks to the vicinity of the gap of the R/W head 41, resulting in a DC bias being applied to the recording magnetic field, so the strength of the magnetic field increases depending on the magnetization direction, causing BA. Therefore, in order to cancel the DC magnetic field generated by the erase head 42, correction can be made by unbalancing the write current flowing to each coil separated by the center tap 45a of the R/W head coil 45. be.

The following method was implemented as a specific method when using a read/write IC. A terminal 13 for connecting a write damping resistor is provided from the read/write IC to connect between current lines flowing to each coil separated by the center tap 45a of the R/W head coil 45. By connecting one of these to a constant voltage source through the BA111i positive resistor 12, a current Δ1 determined by its resistance value and voltage value flows through the BA correction resistor 12. *Since the current source of the stray current is a constant current source, the write current IO-Δi flows through the coil to which the BA correction resistor 12 is connected. Therefore, the center tap 4 of the R/W head coil 45
The write current to each coil separated by 5a becomes unbalanced, and the write magnetic field in the same direction as the leakage magnetic flux from the erase head 42 becomes weaker, so that it is balanced with the write magnetic field in the opposite direction. BA is corrected. The size of the BA value is
Since it is determined by the magnitude of leakage magnetic flux, the unbalance ratio of the write current can be corrected appropriately by changing the resistance value of the BA correction positive resistor 12 according to the magnitude of BA. The relationship between BAjlt2-tl shown in FIG. 3(b) and the BAA positive resistance value that corrects it is roughly shown in FIG. 2, so the value of the BAA positive resistance 12 can be determined according to the generated BA. BA4111i correctness when using a read/write IC was realized by making the value 0 or more.

〔Effect of the invention〕

As described above, according to the present invention, the read/write IC
Even when using this method, there is an effect that BA correction can be performed using a simple method. Furthermore, since BA correction can be easily performed, it is also effective in improving yield in production of flexible disk drives.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 4 is an explanatory diagram of bit asymmetry, and FIG. 4 is a schematic diagram of a magnetic head. 12...BAA positive resistance 13...Light damping connection terminal 41...R/
W head 42...Erase head 43...Erase magnetic field 44...Leakage DC erase magnetic field 45,...R/W head coil 45a...Center tap 46,...From the Rad coil to erase 2 Applicants: Seiko Epson Agent Patent Attorney Co., Ltd. Kizobe Suzuki (and 1 other person) Light Taihi 6'/Rio, Isao" Concubine Night Piece ψ Shima No. 1
Figure 2 Figure 4

Claims (1)

[Claims] A main shaft motor for rotationally driving a flexible disk, a magnetic head for recording and reproducing information on the flexible disk, a carriage for supporting the magnetic head, a carriage position control circuit for controlling a positioning mechanism for the magnetic head and the carriage, and a flexible disk. In a flexible disk drive comprising a recording circuit for recording on a disk and a read/write IC including a reproducing circuit for reproducing signals recorded on the flexible disk, a write damping resistor of the read/write IC is connected. A magnetic head device characterized in that the write currents flowing to the separated coils of the magnetic head are made unbalanced by using terminals.