JP3236161B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing technique, and more particularly to an inductive head for recording information on a magnetic recording medium and a reproducing MR head utilizing a magnetoresistance effect for reproducing information. The present invention relates to a technique which is effective when applied to a magnetic recording / reproducing apparatus using a composite recording / reproducing-type composite magnetic head.

[0002]

2. Description of the Related Art A read / write separated magnetic recording / reproducing system for reproducing information from a recording medium in which information is recorded in a magnetization reversal form by an inductive head by a magnetoresistive read head (hereinafter referred to as an MR head) is used. It is being done. For this recording / reproducing method, a composite head in which the above-mentioned recording head and reproducing head are integrated is used. As described above, since the composite head includes a head for recording and reproduction, as shown in FIG. 9, the number of lead wires from the recording / reproducing circuit system to the composite head is conventionally smaller than that of the individual composite head. 2 for the recording signal and 2 for the reproduction signal each time, for a total of 4
It had a book configuration.

On the other hand, as one of means for increasing the recording density of a magnetic disk drive, a method of reducing the flying height of a magnetic head has been adopted. In order to reduce the flying height, it is necessary to reduce the size of the slider on which the composite magnetic head is mounted, and to have a structure that can easily follow irregularities on the medium surface. However, when the slider size is reduced, the followability is affected even when a weak external force is applied. One of the causes of this weak external force is the rigidity of the lead wire.

[0004]

As one of the measures for reducing the rigidity of such a lead wire, the wire diameter has been reduced. However, since the number of lead wires is as large as four for each composite magnetic head, the effect of reducing external force is small. Therefore, it is conceivable to reduce the number of lead wires. However, reduction of the number of lead wires connecting the composite magnetic head and the recording / reproducing circuit system has not been considered in the past.

As a similar technique relating to the line number reduction method, for example, as shown in FIG. 10, a transmission line from a recording / reproducing circuit 9 (RW-IC) to a subsequent signal processing circuit is connected to a recording system. In addition, the transmission line 45 (FPC (2)) having two lines for each of the reproduction system is used, and the transmission line for the recording signal and the reproduction signal is made common. It is conceivable to adopt a configuration in which the recording / reproducing circuit 9 is connected via (3)).

That is, in FIG. 10, in the RW-IC 9 operated by the RW-IC power supply 47A, the control unit 1
7, one of the plurality of MR composite heads 12 is selected. Further, the recording / reproducing control signal 41 selects between recording and reproducing. When the recording / reproduction control signal 41 indicates a recording state, the recording signal 43 from the recording circuit 7 is output to the recording induction type head 37 of the target composite head by the power supplied from the recording current source 46.

On the other hand, in the case of reproduction, a head selection signal 41A is output from the control unit 17, and the corresponding MR composite head 12 is selected. Further, if the recording / reproduction control signal 41 indicates a reproduction state, a signal from the reproduction MR head 38 for performing the reproduction operation using the bias current of the MR sense current source 47 is transmitted to the reproduction signal 42 via the RW-IC 9. Is output to the reproducing circuit 13.

According to such a conventional idea, in order to reduce the number of lead wires provided along a supporting member such as a head arm for supporting the composite head, the RW-IC 9 is disposed on the MR composite head 12. It will be. But R
Attached signal lines such as a W-IC power supply 48 and a recording / reproducing mode switching signal are required, and eventually the number of lines increases. If the RW-IC 9 is mounted on a smaller slider, the recording side amplifier circuit of the RW-IC 9 consumes a large amount of power.

It is an object of the present invention to provide a magnetic recording / reproducing technique capable of reducing the rigidity of a support structure for supporting a composite magnetic head on an actuator and thereby narrowing a floating gap of the composite magnetic head with respect to a magnetic recording medium. To provide.

Another object of the present invention is to alleviate or eliminate the band limitation on a transmission line serving as an information transmission path between a composite magnetic head and a recording / reproducing circuit, thereby realizing higher-speed data transfer. An object of the present invention is to provide a possible magnetic recording / reproducing technique.

[0011]

According to the magnetic recording / reproducing apparatus of the present invention, for example, when a composite magnetic head is constituted by a recording induction type head and a reproducing MR head using a magnetoresistive element, a recording / reproducing circuit is provided. (1) First stage of reproduction amplifier circuit (MR resistance change detection circuit) (2) Divide into two parts, the recording side and the latter stage of reproduction amplifier circuit. Then, the first stage resistance change detection circuit on the reproduction side of (1) is mounted on the MR composite magnetic head,
The part (2) is attached to the carriage or the actuator.

The first and second transmission lines are shared by the reproducing magnetic head and the recording magnetic head constituting the composite magnetic head by using the current signal transmission method for recording and reproducing signals.

In order to mount the first stage resistance change detecting circuit on the reproducing side in the composite magnetic head, the power supply line of the circuit is also shared with the first and second transmission lines. In this case, since the current for the circuit power supply is always a constant value and the signal current changes, it is possible to separate them. Therefore, the line of the signal and the power supply can be shared.

Further, there is provided switching means for switching between a recording time and a reproduction time so that the recording current does not leak to the recording side and the reproduction signal leaks to the recording side. The switching means can be constituted by a switch control circuit that operates by a potential difference between the first and second transmission lines.

[0015] Also, two first and second transmission lines are:
It is possible to adopt a configuration that also serves as a support member for supporting the composite magnetic head on the actuator.

[0016]

According to the magnetic recording / reproducing apparatus of the present invention, the number of transmission lines is reduced from the conventional four to two of the first and second transmission lines, so that the influence of the external force on the flying characteristics can be reduced.
The floating gap with respect to the magnetic recording medium can be further reduced. As a result, the recording density can be improved by lowering the flying height of the composite magnetic head.

Further, since the resistance change detection circuit at the first stage on the reproduction signal side is mounted near the composite magnetic head, the transmission of the reproduction signal is performed as in the case where the resistance change detection circuit is arranged at a position separated from the composite magnetic head. The first and second transmission lines can be used as high-speed data transfer channels without being subject to band limitation by the route.

[0018]

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

FIGS. 1 and 2 are conceptual diagrams showing an example of the configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

The magnetic recording / reproducing apparatus of the present invention uses a magneto-resistive head (MR head) such as a magnetic disk device, a magnetic tape device, a floppy disk device, or a digital VTR device or a magnetic card reader. Although the present invention can be applied to any reproducing apparatus, this embodiment will exemplify a case in which the present invention is applied to a magnetic disk apparatus.

First, an example of the overall configuration of the magnetic disk drive will be described with reference to FIG. Magnetic disk drive 10
Is a storage device that receives and stores information from the higher-level device 19, or that outputs corresponding information to the higher-level device 19 in response to a request to submit information. The configuration is such that an interface circuit 18 for inputting and outputting information to and from a host machine 19, and information input through the interface circuit 18 are transferred to the magnetic recording medium 11.
And a demodulation circuit 8 for performing a demodulation operation for converting a code reproduced from the magnetic recording medium 11 into information that can be understood by the host machine 19. Further, the code recorded on the magnetic recording medium 11 is subjected to recording correction or the like by the recording circuit 7 and
(RW-IC) to convert to a current waveform signal (NRZI) for recording. The recording current waveform signal is supplied to the MR composite head 34.

The MR composite head 34 is used for the magnetic recording medium 11.
And a magneto-resistive head (reproducing MR head 38) for reproducing the magnetization information of the magnetic recording medium 11 using the magneto-resistive effect. I have. The above-described recording current waveform signal is applied to the magnetic recording medium 11 by the recording induction type head 37.
Is recorded in the form of magnetization reversal.

The information is reproduced by the reproducing MR head 38 in the MR composite head 34 and the recording / reproducing circuit 33 is used.
Performs signal amplification. Then, the waveform shaping and discrimination are performed in the reproduction circuit 13, and the signs “1” and “0” are obtained. The digital code resulting from the discrimination is converted into information in the modulation / demodulation circuit 8.

One or a plurality of magnetic recording media 11 for storing information are incorporated, and a motor 20 for rotating the spindle 20a through a spindle 20a in which the magnetic recording media 11 are stacked in a coaxial and parallel posture.
It is supported by. At least one MR composite head 34 is arranged on each surface of the magnetic recording medium 11.

In order to write information at a certain track position of the magnetic recording medium 11, a plurality of MR composite heads 34 are mechanically supported in the gap of the stack of the magnetic recording medium 11 via the arm 14a, and are further moved to the target track position. Actuator 14 for feeding composite head 34 and voice coil motor 15 for driving actuator 14
(VCM), and a servo system is configured by the positioning control 16 for taking in servo information by the MR compound head 34 and performing control for moving to a predetermined radial position.

The above-mentioned components constituting the magnetic disk drive 10 are controlled under the control of the control unit 17.

In the case of this embodiment, as exemplified in FIG. 1, a transmission line 35 composed of two lead lines L1 and L2 is provided between the MR compound head 12 and the recording / reproducing circuit 9.
(FPC (1)). The transmission line 35 (FPC (1)) has, for example, a structure in which two lead wires L1 and L2 are formed by a conductive pattern inside a flexible insulating resin.
In the case of the present embodiment, the transmission line 35 has a plurality of MRs.
Each of the composite heads 34 is associated with a corresponding actuator 14
Also functions as a support member for supporting the arm 14a.

In the case of this embodiment, as shown in FIG. 1, the recording / reproducing circuit 33 (RW-IC) includes a first stage resistance change detecting circuit 30 (R-IC) on the reproducing side and a main amplifying circuit on the reproducing side. And a reproduction signal selection circuit 31 (head selection circuit) and a recording-side current waveform conversion circuit 32 (W-IC). The recording / reproducing circuit 33 includes a reproduction signal selection circuit 31, a current waveform conversion circuit 32 (W-IC), and a transmission line 35 (FPC (FPC)) including two lead lines L1 and L2 to the MR compound head 34. 1)) and a switch control section 36A (SW) for controlling a switch for selecting whether to transmit a recording signal or to receive a reproduction signal.
Control circuit).

The MR composite head 34 includes a recording inductive head 37 for recording and a reproducing MR head 38 for reproduction, and further, a recording signal is sent as a signal on a transmission line 35 (FPC (1)). Switch control circuit 39 (SW control) for controlling the head connected to the transmission path, the switch unit 40 for actually connecting the head, and the resistance change of the MR head 38 for reproduction. Resistance change detection circuit 30 on the reproduction side for converting
(R-IC).

Next, one embodiment of a method of manufacturing the MR composite head 34 of this embodiment will be described with reference to FIG.

In a conventional manufacturing method, an MR head and an inductive head are formed in a laminated structure on a wafer using a substrate having a slider length corresponding to the thickness of the wafer, and then the slider is cut out. Processing is generally performed.

In the case of this embodiment, prior to forming the reproducing MR head 38 on the wafer in the conventional manufacturing method,
A switch section 40 and a switch control circuit 39 are formed, on which a resistance change detection circuit 30 (R-IC), a terminal 37a of the recording induction type head 37, a switch control circuit 39,
An input terminal 40a for the switch section 40 is formed. Thereafter, a reproduction MR head 38 and a recording induction type head 37 are formed and cut out as a slider. Further, the sliding surface of each slider is subjected to, for example, negative pressure slider processing and polishing in which grooves, projections, and the like are formed in parallel to the running direction relative to the magnetic recording medium 11. Then, a protective film is formed on the sliding surface to complete the process.

Next, the current waveform conversion circuit 32 (W-
An embodiment of the output stage of IC) will be described with reference to FIGS.

The recording signal 43 having undergone the recording timing correction in the recording circuit 7 is converted into a current waveform conversion circuit 32 (WI
C) to convert the recording signal 43 into recording data 49. In the output stage, the recording data 49 is input as a differential signal to the bases of the transistors Q71 and Q72. The base of the transistor Q73 is connected to the emitter of the transistor Q71.
Is connected to the base of transistor Q74.
The transistors Q73 and Q74 are connected to the current source I
WG4 is a current switch for the current Iw. Further, the emitter of transistor Q71 is connected to the base of transistor Q75 via level shift circuit 65, and the emitter of transistor Q72 is connected to the base of transistor Q76 via level shift circuit 66. Transistors Q75 and Q76 are current switches for current Iw of current source IWG2. Here, the current source IWG
4 flows the same current Iw from the current source IWG2 via the current copy circuit 50.

For convenience of explanation, the P side of the recording data 49 is "
It is assumed that the high level and the N side are at a low level, in which case the emitter of the transistor Q71 is Q
This is a higher level than the 72 emitters. Therefore, the transistors Q74 and Q75 of the two current switch circuits connected to the transistors Q71 and Q72 are activated.

The recording inductive head 37 is connected between the collectors of the transistors Q73 and Q74. Since the transistor Q75 is in the active state based on the assumption of the current input level, a current Iw flows through the recording inductive head 37 in the direction from the transistor Q74 to the transistor Q75. In addition, recording data 4
When the input level of No. 9 is inverted, from the above level relationship,
The recording current of the recording induction type head 37 is reversed.

Next, an embodiment of a method of connecting the resistance change detection circuit 30 (R-IC) on the MR composite head 34 to the input stage of the reproduction signal selection circuit 31 will be described with reference to FIG.

In the configuration of this circuit system, the reproduction signal selection circuit 3
The voltage V1 is applied to the base of the transistor Q83 in the transistor 1. Thus, the emitter voltage of the transistor Q83 becomes (V1-Vbe [Q83]). On the other hand, the voltage V
Give 2. Thus, the emitter voltage of the transistor Q84 becomes (V2 + Vbe [Q84]). Here, a relationship between (V1−V2)> V is established between the voltages V1 and V2. The potential difference V is the sum of the base-emitter voltage of the transistor described below and the bias voltage applied to the reproducing MR head 38.

The emitter of the transistor Q83 has an MR
First stage resistance change detection circuit 30 on the reproduction side of composite head 34
The collector and the base of the transistor (R-IC) Q81 are connected. A bias resistor 51 is connected between the base of the transistor Q81 and the base of Q82. A reproducing MR head 38 is connected between the emitters of the transistors Q81 and Q82. The base and collector of transistor Q82 are connected. Further, the collector of transistor Q82 is connected to the emitter of Q84. Transistor Q83
The collector of the transistor Q84 is connected to the resistor 52.
Is connected to a resistor 53.

The operation of this circuit system will be described below.

The output terminals 5 of the resistance change detection circuit 30 (R-IC) in the first stage on the reproduction side are formed by the transistors Q83 and Q84.
4 is applied with a voltage (V1-Vbe [Q83]), and the other output terminal 55 is applied with (V2 + Vbe [Q84]). When the sense current of the reproducing MR head 38 flows as Is, the resistance change detection circuit 30 (R-I
The current Io of the output terminals 54 and 55 of C) can be expressed by the following equation.

Io = Is + (V1-V2-2Vbe) / R where Vbe: voltage between the base and the emitter of the transistor Vbe = Vbe (Q83) = Vbe (Q84) R: bias resistor 51 Further, the sense current Is is represented by the following equation. be able to.

Is = (V1-V2-4Vbe) / Rmr where Vbe: voltage between the base and the emitter of the transistor Vbe = Vbe (Q83) = Vbe (Q84) = Vbe (Q81) = Vbe (Q82) Rmr: MR head for reproduction From the above equation, the sense current Is is determined by the transistors Q83 and Q8.
4 is a function of the base potential difference. Therefore, the sense current can be optimized by adjusting (V1-V2).

When the reproducing MR head 38 detects a magnetic field from the magnetic recording medium 11, the resistance of the reproducing MR head 38 changes by δR. However, transistors Q81 and Q8
2 does not change, so that Q81 and Q82
The emitter current, ie, the collector current of
Only change.

Δi = −δR (V1-V2-4Vbe) /
{(Rmr + δR) × Rmr} Therefore, the transistors Q83 and Q84 convert the signal current δi into the signal voltage δv by the resistors 52 and 53 connected to the collector as shown in the following equation.

Δv = δi × R Next, an example of the overall operation of this embodiment will be described with reference to FIGS.

First, there are recording and reproducing operations. The recording / reproduction control signal 41 may be used as a mode signal for distinguishing the two. In FIG. 6, as an example, the recording mode is set to correspond to the recording mode when the recording / reproducing control signal 41 is at "high" level, and the reproducing mode is set to correspond to the "low" level.
In this embodiment, the switch control unit 36A of the switch circuit 36 of the recording / reproducing circuit 33 is operated by the recording / reproducing control signal 41.
Control. The switch in the switch circuit 36 is connected to the recording inductive head 37 or the reproducing MR head 38 by the switch control unit 36A.

Now, consider the case where the connection is made to the recording side (A1-A2 terminals). At this time, since the recording information has been output from the W-IC 32, a waveform as shown in the recording column of the A1-A2 row in FIG. 6 is output. At this time, since the switch is on the recording side, the transmission line 35 (FPC
(1)) C1-C of each of the two lead wires L1 and L2
The waveform shown in FIG. 6 appears at the two terminals.

On the other hand, consider the case where the connection is made to the reproduction side (terminals B1-B2). At this time, as described with reference to FIG. 5, a potential difference is applied between the lead L1 and the lead L2 of the transmission line 35 (FPC (1)). Therefore, B1 in FIG.
A potential difference is generated between the terminals as in the reproduction column of the -B2 row. By switching the switch for recording and reproduction as described above, the two lead lines L1 and L2 of the transmission line 35 (FPC (1)) are connected to the time line as shown in the column of the line C1-C2 in FIG. By sharing, it can be commonly used as a signal transmission path for recording and reproduction.

Next, an embodiment of the switch control circuit 39 and the switch section 40 in the MR compound head 34 will be described with reference to FIGS.

In FIG. 7, the collector and base of transistor Q91 are connected to one lead L1 of transmission line 35.
And the emitter is connected to the other lead L2 via an integrating circuit 70 including a resistor 56 and a capacitor 58. The transistor Q92 has a collector connected to the lead wire L1 side via a load resistor 57, an emitter connected to the lead wire L2 side, and a base connected between the resistor 56 and the capacitor 58 forming the integrating circuit 70. I have. A Schmitt trigger inverter 59 is connected to the collector of the transistor Q92, and the switch control circuit 3
The switch unit 40 is driven as the output of the switch 9.

In the case of this embodiment, the following states are used as SW control signals for switching the switch section 40 in the MR compound head 34. That is, at the time of reproduction, the lead line L1
Note that there is a potential difference between the two lines L2 and L2, and that no DC voltage is generated between the two lines during recording. However, when a rectangular current waveform is applied due to the inductance of the recording induction type head 37, a flyback voltage waveform 62 as shown in the recording section of FIG. 8 appears. Therefore, as shown in FIG. 7, the switch control circuit 39 is provided with an integrating circuit 70 (consisting of the resistor 56 and the capacitor 58) so as not to respond to the impulsive flyback voltage waveform 62. Further, the transistor Q91 is for shutting off the recording current waveform so as not to be affected when the recording current waveform has an opposite phase. Therefore, since the DC voltage is applied in a stepwise manner during reproduction, the voltage exceeds the threshold level after the time constant of the integration circuit. At that time, the switch unit 40 can be switched.

The switching of the switch section 40 is performed as follows. A switch 60 of a B contact type (normally connected state and shut off when a signal is input) is used on the recording induction type head 37 side. On the reproduction MR head 38 side, a switch 61 of an A contact type (normally in a cutoff state and connected when a signal is input) is used. Thus, when a voltage longer than the time constant of the integrating circuit is applied to the switch control unit 36A, a switch switching signal is output, and the two lead lines L1, L2 are connected to the recording induction type head 37 and the reproduction MR head 38. Switches.

However, by using this method, a state in which the switch section 40 does not switch during the time constant of the integrating circuit 70 is created. Therefore, when the recording mode is switched to the reproducing mode, as shown in FIG. (Area) occurs. Therefore, it is desirable to provide a reproduction buffer area and a recording buffer area as the format of the magnetic recording medium 11.

As described above, according to the magnetic recording / reproducing apparatus of this embodiment, the connection between the MR composite head 34 and the recording / reproducing circuit 33 is established by the two first and second lead lines L1 of the transmission line 35. , L2,
The external force applied to the MR composite head 34 due to the rigidity of the transmission line 35 can be reduced, and the variation in the attitude of the slider that causes the MR composite head 34 to fly with respect to the magnetic recording medium 11 is reduced. The flying height of the composite head 34 can be further reduced. Thereby, the recording density of the magnetic recording medium 11 can be improved.

The first stage resistance change detection circuit 30 on the reproduction signal side is connected to the reproduction MR head 38 in the MR composite head 34.
And a first and second lead wire L between the two.
1 and L2, the band is not limited by the first and second lead lines L1 and L2. In particular, the effect that the reproduction data can be transferred at high speed can be obtained. Can be

The first and second lead wires L1, L
2 via a transmission line 35 constituted by
Since the composite head 34 is configured to be supported by the arm 14a of the actuator 14, extra components such as a leaf spring can be omitted, and the configuration can be simplified and the cost can be reduced.

[0058]

According to the magnetic recording / reproducing apparatus of the present invention, the rigidity of the support structure for supporting the composite magnetic head on the actuator can be reduced, and the floating gap of the composite magnetic head with respect to the magnetic recording medium can be further reduced. Can be obtained.

Further, the effect that the band limitation in the transmission line serving as the information transmission path between the composite magnetic head and the recording / reproducing circuit is relaxed or eliminated, thereby realizing higher-speed data transfer can be obtained. Can be

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating an example of a configuration of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of a method of manufacturing an MR composite head constituting a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 4 is a circuit diagram illustrating an example of a configuration of a current waveform conversion circuit included in the magnetic recording / reproducing apparatus according to one embodiment of the present invention.

FIG. 5 is a circuit diagram showing an example of a configuration of a reproduction signal selection circuit and a resistance change detection circuit that constitute the magnetic recording and reproduction apparatus according to one embodiment of the present invention.

FIG. 6 is a diagram showing an example of the operation of the magnetic recording / reproducing apparatus according to one embodiment of the present invention.

FIG. 7 is a circuit diagram showing an example of a circuit configuration of an MR composite head constituting a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 8 is a diagram showing an example of the operation of the magnetic recording / reproducing apparatus according to one embodiment of the present invention.

FIG. 9 is a block diagram showing an example of a configuration of a conventional magnetic recording / reproducing apparatus.

FIG. 10 is a block diagram illustrating an example of a configuration of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

7: recording circuit, 8: modulation / demodulation circuit, 9: recording / reproducing circuit, 10: magnetic disk drive, 11 ...
Magnetic recording medium, 12 ... MR combined head, 13 ...
Reproduction circuit, 14: Actuator, 14a: Arm, 15: Voice coil motor, 16: Positioning control, 17: Control unit, 18: Interface circuit, 19: Host machine , 20 ... motor, 20a
... Spindle, 30 ... Resistance change detection circuit, 31
... Reproduction signal selection circuit, 32 ... Current waveform conversion circuit, 33 ... Recording / reproduction circuit, 34 ... MR composite head (composite magnetic head), 35 ... Transmission line, L1 ...
Lead wire (first transmission line), L2 ... lead wire (second transmission line)
, 36 ... switch circuit (switching means), 36A ... switch control section (switching means),
37: recording induction type head, 37a: terminal, 3
8 ... MR head for reproduction, 39 ... Switch control circuit (switching means), 40 ... Switch section (switching means), 40a ... Input terminal, 41 ... Recording / reproduction control signal, 41A .. a head selection signal, 42... A reproduction signal, 43... A recording signal, 44.
..Transmission line, 46 ... recording current source, 47 ... MR sense current source, 47A ... RW-IC power supply, 48 ...
RW-IC power supply 49 recording data (input) 50
... Current copy circuit, 51 ... Bias resistor, 52
... Resistance, 53 ... Resistance, 54 ... Output terminal, 5
5 output terminal, 56 resistance, 57 load resistance, 58 capacitor, 59 Schmitt trigger inverter, 60 switch (B contact specification),
61 ... switch (A contact specification), 62 ... flyback voltage waveform, 65, 66 ... level shift circuit,
70: integrating circuit, IWG1 to IWG4: current source, Q71 to Q76: transistor, Q81 to Q8
4: Transistor, Q91, Q92: Transistor

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akihiko Hirano 2880 Kozu, Kozuhara-shi, Kanagawa Pref.Hitachi, Ltd. Storage System Division (72) Inventor Seiichi Mita 2880 Kofu, Kozuhara-shi, Kanagawa Pref. In the business division (56) References JP-A-59-110027 (JP, A) JP-A-1-92902 (JP, A) JP-A-63-213103 (JP, A) JP-A-5-211415 (JP, A A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 5/02

Claims (3)

(57) [Claims] A composite magnetic head in which a magnetic recording medium, a recording magnetic head for recording information on the magnetic recording medium, and a reproducing magnetic head for reproducing the information from the magnetic recording medium are integrated; An actuator to which the composite magnetic head is fixed and which performs a positioning operation of the composite magnetic head with respect to the magnetic recording medium; a recording / reproducing circuit provided independently of the composite magnetic head on the actuator side; Two first and second transmission lines that are arranged along and connect the composite magnetic head to the recording / reproducing circuit, and the first and second transmission lines are used for the recording magnetic head and the reproducing magnetic head. A magnetic recording / reproducing apparatus, comprising: switching means for switching connection. 2. The recording magnetic head and the reproducing magnetic head each comprise an inductive head for recording and a reproducing MR head using a magnetoresistive element, and the recording / reproducing circuit includes at least a magnetic recording medium. A current waveform conversion circuit that converts the information to be written into a current waveform of a recording signal and provides the current waveform to the inductive head for recording;
A resistance change detection circuit for obtaining a reproduction signal from the reproducing MR head as a change in a bias current applied to the magnetoresistive effect element, applying a recording signal to the recording magnetic head, and reproducing from the reproducing magnetic head. Sampling is performed by superimposing the information on currents flowing through the first and second transmission lines, and the switching means is provided on the actuator side, and the first and second transmission lines are provided. To give a specific DC potential difference to
And the specific DC potential difference provided from the first switch control circuit to the first and second transmission lines is provided, and the first and second switch control circuits are provided in the composite magnetic head. And a second switch control circuit for switching which of the recording magnetic head and the reproducing magnetic head is connected to the transmission line. The switching means is configured to connect the first and second transmission lines to each other. A third transmission line provided in parallel, a third switch control circuit provided on the actuator side and outputting a switching signal to the third transmission line, and a third switch control circuit provided on the composite magnetic head; From the third switch control circuit to the third
And a fourth switch control circuit for detecting which of the recording magnetic head and the reproducing magnetic head is connected to the first and second transmission lines by detecting the switching signal output to the transmission line. 2. The magnetic recording / reproducing apparatus according to claim 1, further comprising at least one of the following second configurations. 3. The composite magnetic head according to claim 1, wherein a resistance change detection circuit for obtaining a reproduction signal from the reproduction MR head as a change in a bias current applied to the magnetoresistive element is arranged on the composite magnetic head. 3. The magnetic recording and reproducing apparatus according to 2.