JPH07192203A - Rotary reproducing device - Google Patents

Abstract

PURPOSE:To obtain a high output under a narrow track by providing a rectifier circuit at a rotary transformer for rectifying an AC or a pulse current from power source. CONSTITUTION:A power source 2 for driving an MR element 1 is supplied through a rotary transformer RT 1, and a regenerated signal from the MR element 1 is detected through a rotary transformer RT 2. One rotary transformer RT 1 is a channel for supplying a driving current from the power source 2 to the MR element 1, and the other rotary transformer RT 2 transmits the regenerated signal from the MR element 1. The MR element 1 functions as the reproducing head to show a resistance value change by impressing an external magnetic field, and this MR element 1 is parallelly connected between the rotary transformer RT 1 connected on the power source 2 side and the rotary transformer RT 2 connected on the output side. Thus, since the rectifier circuit is provided inside the rotary transformer, the MR head to provide the high output under the narrow track can be applied to a helical scan recording system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel rotary reproducing apparatus in which a signal is transmitted / received to / from a magnetoresistive effect element (hereinafter simply referred to as an MR element) via a rotary transformer.

[0002]

2. Description of the Related Art In recent years, along with the demand for higher recording density in magnetic recording, there has been a demand for a narrower track width of a magnetic head used in a helical scan recording system (helical scan recording / reproducing system). ing.

Conventionally, in the helical scan recording system, there are a method of performing both recording and reproduction by the same magnetic head, and a method of performing recording and reproduction by separate magnetic heads. A so-called induction type magnetic head is generally used as a magnetic head used in such a helical scan recording system.

When this induction type magnetic head is used as a reproducing head, the track width is narrowed in principle, so that the magnetic flux flowing from the medium is reduced and the S / N is finally deteriorated. There was a certain limit to.

On the other hand, in a hard disk device for high-density recording, the induction type magnetic head has a limit for the purpose of reproducing a narrow track for the same reason as above. Under such conditions, it has been verified that it is advantageous to use a magnetoresistive effect magnetic head (hereinafter simply referred to as an MR head) that utilizes a magnetoresistive effect that requires energy from the outside. , Recently, it has been partially put into practical use.

[0006]

However, in principle M
It is obvious that the R head can be applied to a tape type magnetic recording device, but a DC current is required to drive the MR element, and a signal is transmitted via a rotary transformer that cannot transmit DC. At present, it has not been applied to a helical scan recording system that needs to exchange data.

Therefore, the present invention has been proposed in view of the above circumstances, and provides a rotary reproducing apparatus which can obtain a high output even under a narrow track and can be applied to a helical scan recording system. The purpose is to

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a rotary reproducing apparatus which supplies power for driving an MR element through a rotary transformer and detects a reproduction signal from the MR element through the rotary transformer. In the above, the above-mentioned problem is solved by providing the rotary transformer with a rectifying circuit for rectifying an alternating current or a pulse current from a power source.

[0009]

In order to operate the MR element, a direct current is required, but since the rectifier circuit is provided in the rotary transformer, the alternating current or pulse current from the power source is rectified.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. As shown in the basic configuration of FIG. 1, the rotary reproducing apparatus of the present embodiment supplies a power source 2 for driving the MR element 1 via a rotary transformer RT1 and outputs a reproduction signal from the MR element 1 to the rotary transformer RT2. It is designed to be detected via.

One rotary transformer RT1 is a channel for supplying a drive current from the power supply 2 to the MR element 1. The other rotary transformer RT2 is a channel for transmitting the reproduction signal from the MR element 1.

The MR element 1 functions as a reproducing head which changes its resistance value when an external magnetic field is applied. The MR element 1 is connected in parallel between the rotary transformer RT1 connected to the power supply 2 side and the rotary transformer RT2 connected to the output side.

The MR element 1 is composed of a giant magnetoresistive material made of permalloy, an artificial lattice, or a granular material, which has been widely known in the past, and a known material such as a spin valve.

Normally, the MR element 1 has a so-called shield type structure in which it is sandwiched between a pair of shield magnetic bodies. Besides, the MR element 1 has a so-called yoke type configuration by being provided between the pair of yokes.

The power source 2 is for driving the MR element 1 and is connected to one rotary transformer RT2. An alternating current or a pulse current is used for the power source 2 in order to transmit a sense current to the MR element 1 via the rotary transformer RT1. When the power supply 2 is pulsed, it is desirable that the power supply 2 is bipolar in consideration of the saturation characteristics of the core of the rotary transformer RT1.

The frequency of the alternating current or the pulse can be set arbitrarily, but in order to reduce the capacity of the capacitor for removing the ripple after rectification, which will be described later, MH
High frequencies in the z band are advantageous.

In particular, in this rotary reproducing apparatus, a rectifying circuit for rectifying the alternating current or pulse current from the power source 2 is provided in the rotary transformer. The rectifying circuit is composed of, for example, a rectifying diode 3.

The rectifying diode 3 is provided between the MR element 1 and the rotary transformer RT1 connected to the power source 2, and the anode is connected to one end of the rotary transformer RT1 and the cathode is connected to one end of the MR element 1. . It is desirable to use, for example, a Schottky barrier diode having a low forward voltage drop and a high-speed response as the rectifying diode 3 for rectifying a high frequency current.

The one end of the capacitor 4 is connected to the cathode of the rectifying diode 3 in parallel with the MR element 1. The capacitor 4 is
The pulsating current of the rectified current is removed.

As described above, the configuration in which the rectifying circuit is provided in the rotary transformer makes it possible to support a helical scan recording system that transmits and receives signals via the rotary transformers RT1 and RT2. That is, a direct current is required to drive the MR element 1. However, in the above configuration, since a rectifying circuit for rectifying an alternating current or a pulse current is provided in the rotary transformer, the direct current is transmitted to the MR element 1. You can Therefore, an MR head that can obtain a high output under a narrow track is
It can be applied to a helical scan recording system that sends and receives signals via a rotary transformer.

The above is a description of the components that are basically necessary to implement the present invention, and the configuration of each part is not limited to that shown in FIG. For example, the rectifier circuit here shows a half-wave rectifier circuit, but it is essentially necessary to exhibit a rectifying action, and this part is a commonly known double-wave or full-wave rectifier circuit. Good. Also, a rotary transformer RT connected to the power supply 2
A double-wave rectification circuit in which the secondary side of 2 has a center tap may be used.

In addition, the capacitor 4 is provided essentially for the purpose of filtering the pulsating current, and the same operation can be achieved as an LC filter circuit by connecting an inductance immediately after the diode. .

[0023]

As is apparent from the above description, in the rotary reproducing apparatus of the present invention, since the rectifier circuit for rectifying the alternating current or the pulse current from the power source is provided in the rotary transformer, the narrow track MR with high output
The head can be applied to a helical scan recording system.

Further, in the rotary reproducing apparatus of the present invention, it becomes possible to reproduce a signal having a sufficient S / N even if the track width is several μm, which is very difficult to realize with the induction type magnetic head. Density recording can be easily realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a basic configuration of a rotary reproducing apparatus.

[Explanation of symbols]

 1 ... MR element 2 ... Power supply 3 ... Rectifying diode 4 ... Capacitor RT1, RT2 ... Rotary transformer

Claims (1)

[Claims] 1. A rotary reproducing apparatus, wherein a power source for driving a magnetoresistive effect element is supplied through a rotary transformer and a reproduction signal from the magnetoresistive effect element is detected through the rotary transformer. The rotary reproducing device, wherein the transformer is provided with a rectifying circuit for rectifying an alternating current or a pulse current from a power source.