JPH0442406A - Recording/reproducing integrated circuit for magnetic head and magnetic head assembly - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording/reproducing integrated circuit for a magnetic head having a center tap and a magnetic head assembly equipped with the integrated circuit.

[Conventional technology]

2. Description of the Related Art Waveform asymmetry may occur in magnetic disk devices, especially small-sized large-capacity magnetic disk devices, when reproducing data recorded on a disk. This waveform asymmetry is the first
This is a phenomenon in which when data recorded on a disk is reproduced using a write data pulse as shown in FIG. 2(a), the read signal waveform becomes asymmetrical as shown in FIG. 2(b). The read pulse obtained by detecting the peak of the read 1m signal becomes a read pulse whose phase is shifted from the read I-data pulse as shown in FIG. 2 (,). In order to correct such waveform asymmetry, conventional methods have been
There is 6105. As shown in Fig. 3, a damping resistor 4 is connected in parallel to each coil of the magnetic head having a center-tapped coil 3, with the center tap as the starting point, and the ratio of the resistance to each coil is determined. l! ! and freely change the recording current to prevent waveform asymmetry.

[Problem to be solved by the invention]

In recent years, magnetic disk drives have a fourth disk drive to save space.
As shown in the figure, the recording/reproducing circuit is integrated into an integrated circuit.

It is mounted on the magnetic head assembly.

It is difficult to integrate the recording/reproducing circuit shown in FIG. 3 of the prior art because the variable damping resistor 4 is used. Even if the variable damping resistor 4 is attached externally to the integrated circuit.

It is difficult to mount it on a magnetic head assembly. Furthermore, in the conventional recording/reproducing circuit, it is difficult to adjust the recording current unless the direction and magnitude of the waveform asymmetry are known.

An object of the present invention is to adjust the rise and fall times of a recording current using a recording/reproducing integrated circuit that can be mounted on a magnetic head assembly.

[Means for resolving issues]

The above object can be achieved by adjusting the resistance value of a clamp voltage generating circuit in a magnetic head recording/reproducing integrated circuit having a center-tapped coil.

[Effect]

In the recording/reproducing integrated circuit of the present invention, as shown in FIG. 5, the recording current oscillates when the rise and fall times of the recording current are faster than a certain time due to the inductance. When the recording current waveform oscillates as shown by the solid line in FIG. 6, the duty of the recording current shifts, so that the signal recorded on the magnetic disk has an asymmetrical waveform.

Therefore, the rise and fall times of the recording current are set to be slower than a certain time by the inductance of the magnetic head so that the recording current does not oscillate, and as shown by the dotted line in the figure, recording B without duty shift can be achieved.
Signals can be recorded using electric current.

Here, the rise and fall times of the recording current are shown in Figure 1(d).
This can be adjusted by changing the value of the resistor 5 of the clamp voltage generating circuit 6. By this method, a recording/reproducing integrated circuit without waveform asymmetry can be provided.

〔Example〕

An embodiment of the present invention is shown in FIG. 1 below. FIG. 1r and 1. at 10% and 90%. stipulates. Next, the amount of waveform asymmetry ΔT=IA−Bl is shown in FIG. (hereinafter abbreviated as ΔT). Figure (c) shows the relationship between the inductance of the magnetic head and jrejf, assuming that ΔT is constant. According to this diagram, when a certain inductance is 2.5 μH, for example, ΔT is desired to be 5 ns or less. If LtvLt is 15ns
Here, the relationship between LtvLt and flyback voltage is t.

ty =C/V1. II (VL near-back voltage, C: constant) Therefore, when the inductance is constant, tr+ty increases when the flyback voltage is decreased. In recent years, as this type of integrated circuit has become more dense, the speed has increased and the circuit can operate in several nanoseconds.On the other hand, the inductance of a magnetic head is less than 1 μH for a thin film head, but it can be several μH for a conventional monolithic type. In the case of a monolithic head from a certain value of 0 or more, the waveform asymmetry will not be less than the generally allowable 5 ns on the graph of FIG. 1(c).

I The flyback voltage vt is VL=-L7 (L: head inductance, I: head recording current.

t: rise and fall time of head recording current), and L and 1 are determined by the usage conditions.

VL is determined by dt and therefore by the integrated circuit. In order to suppress this VL, a suppression circuit 7, ie, a clamp voltage generation circuit 6, shown in FIG. 1(d) is provided in the integrated H path. The flyback voltage VL generated by the head inductance is transmitted through transistors Q, Q2, and diode D.
1 to D4, VL is suppressed. Depending on the reversal of the head current, Dl, Q,, D2 or D,, Q,.

D4 releases the flyback voltage VL.

The emission level of the flyback voltage vL is determined by the base voltage Vl (clamp voltage) of Q, , Q,.

From the above, by reducing the clamp voltage (18), the flyback voltage (2) is suppressed, and as a result, the rise and fall times tr+jf of the head recording current are increased, and the waveform asymmetry Δ'1' can be reduced. Furthermore, clamp voltage (v8)
As an example of the generation circuit 6, a resistor 5 shown in FIG. 1(d) is used.
This can be realized by the current source i.

Assuming that the current flowing through the resistor 5 is constant, when the resistor 5 is increased, (1) decreases and jr+tf increases.

With this method, even if the number of turns of the coil wound around the core slider is changed, 8T can be made small. Further, it is easy to integrate the circuit shown in FIG. 2(d). Resistor R1 Current source i or voltage ■
Voltage VH can be adjusted by providing terminal 8, one terminal of resistor R, and one terminal of current source i outside the integrated circuit. Therefore, it becomes possible to adjust the flyback voltage vL, the rise and fall times of the current, and the asymmetry of the read waveform can be reduced. The above integrated circuit can be mounted on a magnetic head assembly as shown in FIG.

〔Effect of the invention〕

According to the present invention, if the inductance of the magnetic head is known in advance, a recording/reproducing integrated circuit without waveform asymmetry can be created by simply setting the value of the resistor for adjusting the flyback voltage to a certain value.

[Brief explanation of drawings]

FIG. 1 (a) is a regulation diagram of Lr + tf, (b) is a regulation diagram of ΔT, (c) is a relation diagram between inductance and T r + T f that explains the present invention in detail, and (d) is a diagram of the regulation of the present invention. 2 is a waveform diagram explaining the 8T, FIG. 3 is a conventional circuit diagram, FIG. 4 is a diagram showing a magnetic head assembly equipped with the recording/reproducing integrated circuit of the present invention, and FIG. The figure shows whether the recording current oscillates depending on the inductance and T r T T f, and FIG. 6 shows the recording current waveform with or without oscillation. l...recording current waveform, 2...reading signal waveform, 3
... Coil with center tap, 4... Damping resistor, 5... Resistor, 6... Clamp voltage generation circuit, 7...
... Inhibition circuit, 8 ... Core slider, 9 ... Recording/reproduction integrated circuit, 1O ... Flexible printed circuit board, 11 ...
-Magnetic head support, 12...Vacancies in the magnetic head support.纂 j fig. 4 fig. 5 fig. 1% 6 'X 纂 2 fig. 3 V

Claims (1)

[Scope of Claims] 1. A recording/reproducing integrated circuit for a magnetic head having a center-tapped coil, which includes a clamp voltage generation circuit for suppressing a flyback voltage that adjusts the rise and fall times of a recording current; A recording/reproducing integrated circuit for a magnetic head, characterized in that it has a function of making it adjustable. 2. A magnetic head assembly equipped with the recording/reproducing integrated circuit according to claim 1, characterized in that it is possible to prevent asymmetry of a read waveform.