JPH065570B2 - Magnetic head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head that is provided in a magnetic disk device, a magnetic recording device such as a magnetic tape, or the like and performs writing and reading on the magnetic recording medium. is there.

[Prior Art] FIG. 6 shows an electrical circuit diagram of a conventional magnetic head provided in a magnetic recording device, for example, a magnetic disk device. In the figure, (1) is a magnetic head, (2) is a head core constituting the magnetic head (1), and has a core gap (5). (3)
Is a head coil wound around the head core (2) and has a three-terminal coil configuration in which both ends are connected to the terminals H ₁ and H ₂ , respectively, and the intermediate position of the winding is connected to the terminal H ₃ . .

(4) is a writing circuit connected to the head coil (3) through the terminals H ₁ , H ₂ and H ₃ , and the terminal H ₃
To the source circuit (6), the sink circuit (7a) connected to the terminal H ₁ and the sink circuit (7) connected to the terminal H _2.
b).

Although not shown here, the source circuit (6) includes a plurality of magnetic heads (1) in the magnetic recording device, that is, a head coil.
When a plurality of (3) are provided, it has a function of selecting one of them and a function of setting a write current value necessary for writing.

The sink circuits (7a) and (7b) have a function of switching the write current of the head coil (3) in either direction, that is, arrow A or B.

(8) is a preamplifier circuit connected between both ends of the head coil (3), which inputs the voltage induced in the head coil (3) at the time of reading, amplifies it, and then outputs it as read data.

Next, the operation of the magnetic head (1) shown in FIG. 6 will be described with reference to the write timing chart shown in FIG.

First, during the write operation, the source circuit (6) is in the operating state and is synchronized with the drive pulse (FIGS. 7 (a) and 7 (b)) input to the sink circuits (7a) and (7b). Then, a write signal is input from the outside, and a write current according to this is applied to the head coil (3) through the terminal H ₃ of the head coil (3) in the arrow directions A and B, and the sink circuits (7a) and ( 7b).
As a result, a magnetic flux is generated in the gap (5), and the magnetic medium (not shown) facing the gap (5) by this magnetic flux.
Write data to. Of the write currents supplied from the source circuit (6), the write current that contributes to actual recording has a waveform as shown in FIG. 7 (e), and the current values of (cd) are equal.

During the read operation, the magnetic flux of the data written on the magnetic disk (not shown) is guided from the gap (5) to the head core (2), and the voltage induced in the head coil (3) is applied to the preamplifier circuit. It is input to (8), amplified, and output as read data.

Next, problems with the conventional magnetic head will be described.

As is well known, a magnetic recording device equipped with such a magnetic head must read binary "1" and "0" data written on a disk as an external storage device of an electronic computer without error. Generally, a magnetic recording device is required to have high reliability such that an error of 1 bit is allowed when reading 10 ¹⁰ bits of data. The table below shows the timing loss factors that occur during writing and reading in a normal magnetic recording device.

As shown in the table, there are 12 major timing loss factors.
There is an item, and in designing a magnetic recording device, it is important to satisfy the condition that a data error does not occur even if these exist alone or in plural. Normally, the timing loss due to the pattern peak shift and the overwriting noise is larger than the other timing losses, so how to reduce these is important for ensuring the reliability of the magnetic recording device. Such timing loss depends on the recording medium, the magnetic head, and the mutual relationship between the two, and is therefore a major factor in determining the recording density of the magnetic recording device.

In the magnetic recording devices that have been commercialized so far, the timing loss due to the pattern peak shift is 10% or less with respect to the window width for judging "1" and "0" of data, and the loss due to overwriting is It is required to be 2 to 3% or less.

By the way, the Institute of Electronics and Communication Engineers, Magnetic Recording Study Group materials (MR75-1
0) "A study of recording correction in digital magnetic recording"
According to the publication, the E-type correction method and the IBM-type correction method are effective for reducing the timing loss of the magnetic head.

In this E-type correction method, as shown in FIG. 8 (a), a non-square wave correction current is added before and after the main current of the write current of the magnetic head is inverted, so that the waveform from the dotted line to the solid line is changed. The rising of the write current is corrected in the waveform. That is, the correction effect is obtained by adding the unsaturated recording element to the saturated recording element.

On the other hand, the IBM correction method corrects the rising of the write current from the waveform of the dotted line to the waveform of the solid line by adding the correction current after the main current is inverted, as shown in FIG. 8 (c). . This correction method also has the same effect as the above E-type correction method. However, quantitatively, the E-type correction method is considered to be more advantageous than the IBM-type correction method.

8 (b) and 8 (d) show the E-type correction method and IBM.
The waveform of the read signal of the magnetic head obtained when the data written by the type correction method is read is shown. As is clear from the figure, the read signal (solid line) has a sharper read waveform compared to the read signal (dotted line) when no correction is performed by any of the methods, and the peak point is accurately positioned at a predetermined position. It is possible to generate.

[Problems to be Solved by the Invention] Since the conventional magnetic head is configured as described above,
There is a problem that the timing loss cannot be sufficiently reduced, and therefore it is not easy to increase the recording density on the recording medium and to improve the data reliability of the magnetic recording device.

Further, it has been found that the IBM type correction method and the IBM type correction method described above are effective for reducing the timing loss of the magnetic head, but it is difficult to realize this with the conventional magnetic head. .

The present invention has been made to solve the above problems, and the E-type correction method and the IBM-type correction method described above can also be applied, and the timing loss can be easily reduced and the reliability can be improved. An object of the present invention is to obtain a magnetic head that can easily realize a high-performance magnetic recording device.

[Means for Solving the Problems] In the magnetic head according to the present invention, an additional current for correcting the main current of the write current is connected to each connection point so as to draw out a plurality of winding positions of the head coil. The flow is selectively made from the connection point.

[Operation] In the magnetic head according to the present invention, since a plurality of winding positions of the head coil are respectively connected to the connection points, the additional current for correcting the main current of the write current is selectively supplied from these connection points. To improve the rising of the write current and reduce the timing loss.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, (9) is a connection point provided at an intermediate position in the winding of the head coil (3), and (10) and (11) are located outside the connection point (9) to supply additional current. Connection points of the head coil (3) provided at predetermined winding positions, and connection points (12) and (13) at both ends of the head coil (3) guide the main current of the write current. H _{1 to} H ₅ are connection points (10)
Terminals for drawing out the head coil (3) connected to (13) to (13).

FIG. 3 is a circuit diagram showing an example of first and second write circuits and read circuits connected to the magnetic head of the present invention shown in FIG. In the figure, D _{1 to} D ₆ are diodes, which have a function as a switch for setting the magnetic head (1) in a writing operation or a reading operation state.

T ₁ is a transistor connected between the power source and the terminal H _3, switch function for turning on and off the write current through the terminal H ₃ of the head coil (3), thus the magnetic head (1) a plurality equipped When it is displayed, it has a function of selecting any one of them.

T ₂ and T ₃ are transistors connected to the terminals H ₄ and H ₂ via the ground and the resistors R ₈ and R ₉ and the diodes D ₂ and D _1, and turn on the additional currents i ₁ and i ₂ . -Has a switch function to turn off.

R _{1 to} R ₇ are resistors for applying a reverse bias voltage to the diodes D _{1 to} D ₆ from the power supply. Diode D ₁ ~
To turn off the D ₆ is achieved by applying a reverse bias voltage from a power source between these anode and the cathode through a resistor R ₁ to R _7.

T ₄ and T ₅ are transistors connected to the terminals H ₅ and H ₁ via the ground and the resistors R ₁₀ and R ₁₁ and the diodes D ₄ and D _3, and turn on the main currents i ₃ and i ₄ . -Has a switch function to turn off.

Here, the resistance R ₈ to R ₁₁ have the function of limiting values and rise time of the current a current i ₁ through i _4, the value corresponds to the electromagnetic conversion characteristics of the recording medium and a magnetic head (1) Selected.

The transistors T ₂ , T ₃ and the resistors R ₈ and R described above
Reference numeral ₉ constitutes a first writing circuit (20a), and transistors T ₄ , T ₅ and resistors R ₁₀ and R ₁₁ constitute a second writing circuit (20b).

C ₁ and C ₂ are capacitors, and R ₁₂ and R ₁₃ are resistors. These constitute an AC coupling circuit between the head coil (3) and the preamplifier circuit (8), and the reverse bias voltage applied to the diodes D ₅ and D ₆ is the preamplifier circuit.
This is cut off so as not to be applied to (8), and only a minute read signal output from the head coil (3) is passed. That is, it is intended to prevent saturation of the preamplifier circuit (8) which makes it impossible to amplify the read signal due to such a reverse bias voltage. Here, the transistor T ₆ , the diodes D ₅ , D ₆ and the capacitor C
₁ , C ₂ , resistors R ₅ , R ₆ , R ₁₂ , R ₁₃ and the preamplifier circuit (8) form a read circuit (30). next,
The operation of the magnetic head (1) having the above configuration will be described. In FIG. ₁ , additional currents i ₁ and i _{2 of the} write current flow from the connection point (9) to the connection points (10) and (11), respectively, and from the connection point (9) to the connection points (12) and (13). The main currents i ₃ and i _{4 of the} write current respectively flow in the.

Switching for selecting the write operation or the read operation is performed by the transistor T ₆ together with the diodes D _{1 to} D _3.
Is turned on or off. Transistor T ₂ through T ₅ without turning on or off, when the turned on transistor T _6, since the read signal from the magnetic head (1) is guided to the pre-amplifier circuit (8), which is amplified, read It is output as data.

In the waveform diagram shown in FIG. 2, (a) and (d) are additional currents i ₁ and i
₂ , (b) (e) shows the main currents i ₃ and i ₄ , and (c) (f) shows the addition currents i ₁ and i ₂ and the main currents i ₃ and i ₄ , i ₁ + I ₃ and i ₂ + i ₄ are shown.

Further, (g) is a write current (i ₁ + i ₃ ) − obtained by combining the additional currents i ₁ and i ₂ and the main currents i ₃ and i ₄ flowing from the connection point (9) to the left and right of the head coil ( ₃ ) − (I ₂ + i ₄ ), which is the write current corrected by the E-type correction method described above.

FIG. 4 is a waveform diagram of voltage and current in each stage of the write circuits (20a) (20b) and the read circuit (30) shown in FIG. In the figure, (a), (b), (c) and (d) respectively indicate drive signals input to the bases of the transistors T ₅ , T ₄ , T ₃ and T ₂ of FIG. ₃ , and these drive signals are "H". It is turned on at the "level" and turned off at the drive signal "L" level.

Also, e, f, g and h are transistors T ₅ , T ₄ and
The main currents i ₄ , i ₃ and the additional currents i ₂ , i ₁ flowing through the head coil (3) as T ₃ and T ₂ are turned on and off are shown respectively. i is the write current (i ₄ + i ₂ ) − (i ₂ +
i ₄ ), which is the write current of the head coil (3) corrected for the timing loss.

In the above embodiment, the head coil (3) is provided with a plurality of connection points and the lead lines are connected to these, respectively. However, as shown in FIG. 5, each head coil (3) has a plurality of connection points. Alternatively, the windings may be composed of individual windings, and the terminals thereof may be connected to each other via the terminals H _{2 to} H ₄ , and the same effect as that of the above-described embodiment is obtained.

Further, in the above-described embodiment, the case of the E-type correction method has been described, but the correction method of the write current may be the IBM-type correction method or another correction method, and any of them has the same effect as that of the above-described embodiment. .

As described above, according to the present invention, the plurality of winding positions of the head coil are connected to the respective terminals, so that the write current is applied to the head coil of the magnetic head through these terminals. There is an effect that an additional current for correcting the main current of 1 can be selectively flown, and therefore, timing loss can be easily reduced.

[Brief description of drawings]

1 is an electrical equivalent circuit of a head coil of a magnetic head according to an embodiment of the present invention, FIG. 2 is a current waveform diagram shown in FIG. 1, and FIG. 3 is a magnetic head diagram shown in FIG. Circuit diagrams of a write circuit and a read circuit connected, FIG. 4 is a waveform diagram for explaining the operation of the circuit shown in FIG. 3, and FIG.
FIG. 6 is an electrical equivalent circuit of a magnetic head according to another embodiment of the present invention, FIG. 6 is a circuit diagram of a conventional magnetic head and its write / read circuit, and FIG. 7 shows the operation of the magnetic head shown in FIG. FIG. 8 is a waveform diagram for explaining, and FIG. 8 is a waveform diagram of the write current for explaining the E compensation and IBM type correction methods for the magnetic head. In the figure, (3) is a head coil, (9) to (13) are connection points,
(20a) (20b) are write circuits, (30) are read circuits, H ₁
~H ₅ is a terminal. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. In a magnetic head of a magnetic recording apparatus for writing and reading data to and from a magnetic recording medium, an intermediate position, first and second winding positions which are symmetrical with respect to the intermediate position, and from the intermediate position. 5 connected to each terminal so as to draw out five winding positions, which are the third and fourth winding positions located outside the first and second winding positions.
A head coil having a plurality of connection points, and a switch circuit for turning on / off a write current at the connection point at the intermediate position, and a first write circuit at the connection point at the first and second winding positions, The second at the connection point of the third and fourth winding positions
A magnetic head characterized in that the write circuit and the read circuit of are connected respectively. 2. The first write circuit supplies an additional current for correcting the main current of the write current, and the second write circuit supplies the main current of the write current. The magnetic head according to claim 1.