JP2005078773A - Magnetic head drive circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head drive circuit in which high speed modulation operation of a magnetic field generated by a magnetic head in accordance with a recording signal is realized and noise due to a magnetic field generated by the magnetic head is lightened. <P>SOLUTION: When a switch 8 provided in parallel to a magnetic head 1 is made an ON state in a servo area provided at an magneto-optical disk, one part of current flowing to the magnetic head 1 from switches 2A, 2B is made to flow to a load 7 and the switch 8. In the same way, one part of current flowing to the magnetic head 1 from auxiliary current supply means 3A, 3B is made to flow to the load 7 and the switch 8. Therefore, a current flowing in the magnetic head 1 in the servo area is reduced more than that of a normal state. When a current of the magnetic head 1 becomes small and a direction of current flowing in the magnetic head 1 is switched, voltage generated at ends of the magnetic heads becomes smaller than that at the time of recording operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic head drive circuit suitable for application to a magneto-optical disk apparatus that performs magnetic field modulation recording using a magnetic head and a light beam.

  In recent years, a magneto-optical disk is widely known as a high-density recording medium for information. In a magneto-optical disk, a recording / reproducing track on which information is recorded and reproduced is composed of a plurality of magnetic films, and the recording / reproducing track is provided concentrically or spirally.

  A method of reproducing the magneto-optical disk will be described with reference to the schematic diagram of the magneto-optical disk shown in FIG. The magneto-optical disk 100 is attached to a disk rotation drive mechanism (not shown) and rotates at a predetermined rotational speed. The semiconductor laser 101 irradiates the magneto-optical disk 100 with light having a predetermined output.

  The light emitted from the semiconductor laser 101 is condensed by an objective lens 103 provided in the pickup 102, and an arbitrary one of the magneto-optical disk 100 is provided by a focus actuator and a tracking actuator (not shown) provided in the pickup 102. Focused on the position.

  The light condensed on the magneto-optical disk 100 is deflected and reflected by the magneto-optical effect due to the magnetization direction of the magneto-optical disk 100. Light deflected and reflected by the magneto-optical disk 100 is guided to photoelectric conversion elements 105A and 105B through a pickup 102 and a PBS (Polarizing Beam Splitter) 104, converted into a reproduction signal corresponding to the deflection direction, and a differential amplifier 106. The reproduction signal 107 corresponding to the information recorded on the magneto-optical disk 100 is output.

  Next, a recording method of the magneto-optical disk will be described with reference to FIG. When recording is performed on the magneto-optical disk 100, a relatively large output light is emitted from the semiconductor laser 101 and condensed on the magneto-optical disk 100 as compared with the reproduction.

  When a large output light is collected on the magneto-optical disk 100, a local heating action works. When the temperature of the magneto-optical disk 100 heated by light exceeds the Curie temperature, the holding power is suddenly reduced, and the recorded magnetization characteristic (direction) is lost. At this time, when a magnetic field corresponding to the recording information is applied to the magneto-optical disk 100 with reduced holding power using the magnetic head 108, the magnetization direction of the magneto-optical disk 100 can be switched in the same direction as the applied magnetic field. That is, new information can be recorded on the magneto-optical disk 100.

  FIG. 8 shows a magnetic head drive circuit that drives the magnetic head 108 in accordance with the recording signal. The constant current source 110 controls the current flowing through the magnetic head 108 and is set to a value corresponding to the characteristics of the magneto-optical disk 100 and the magnetic head 108.

  FETs or the like are used for the SWs 111 </ b> A to 111 </ b> D and constitute a bridge circuit that drives the magnetic head 108. In the figure, SW111A and SW111D are turned on when current flows in the direction A, and SW111B and SW111C are turned on when current flows in the direction B. When the current flowing through the magnetic head 108 is switched in the A / B direction, the direction of the generated magnetic field is switched, and the magnetic field applied to the magneto-optical disk 100 is switched.

  Further, when reproducing the magneto-optical disk, the magnetic field by the magnetic head 108 is not necessary, so that the SWs 111A to 111D are all turned off.

  FIG. 9 shows another magnetic head driving circuit for driving the magnetic head 108. The coil 120A is connected to the midpoint of the SW111A / SW111C / magnetic head 108, and the coil 120B is connected to the midpoint of the SW111B / SW111D / magnetic head 108.

  When a current flows in the direction A in the figure, SW111A and SW111D are turned on. At this time, a current also flows from the coil 120A to the magnetic head 108 and the SW 111D, and compensates for a current change by a bridge circuit constituted by the SW 111A to SW 111D.

  Further, when a current is passed in the direction B in the figure, SW111B and SW111C are turned on. At this time, a current also flows from the coil 120B to the magnetic head 108 and the SW 111C, and compensates for a current change by a bridge circuit composed of the SW 111A to SW 111D.

  It is known that the magnetic head drive circuit operating in this way can switch the current flowing through the magnetic head 108 at a higher speed than the magnetic head drive circuit described with reference to FIG. 8 (for example, Patent Document 1). reference).

  Further, when reproducing the magneto-optical disk, the magnetic field by the magnetic head 108 is not necessary, so that the SWs 111A to 111D are all turned off.

As described above, when information is recorded on the magneto-optical disk 100, the magnetic head 108 is driven according to the recorded information to generate a magnetic field according to the recorded information.
JP-A-5-342508 JP 2000-331388 A

  However, the current flowing through the magnetic head 108 during recording operation is as large as about 100 to 200 mA, and large noise is generated by switching the current at high speed.

  As a method of reducing the noise, the magnetic head driving circuit for driving the magnetic head 108 is disposed on the suspension to which the magnetic head 108 is attached, so that the wiring between the magnetic head driving circuit and the magnetic head 108 is shortened, and the driving current depends on the driving current. There is one that reduces noise (for example, see Patent Document 2).

  However, since the suspension part to which the magnetic head 108 is attached moves according to the recording position of the magneto-optical disk 100, providing the magnetic head drive circuit in the suspension part makes the operating part heavy. Therefore, it is not suitable for moving the recording position of the magneto-optical disk 100 at high speed. In addition, since the circuit is installed in the moving part, a space for the moving part is required in addition to the actual circuit volume, and it is difficult to reduce the size of the apparatus.

  As shown in FIG. 10, there is a magneto-optical disk 100 on which information is recorded / reproduced, which uses a sample servo system. In the drawing, 130 is a data area where information is recorded, and 131 is a servo area for stably condensing light on the magneto-optical disk 100.

  As shown in FIG. 11, the servo area is provided with a pair of wobble pits 133A and 133B that are shifted from each other by a predetermined amount with respect to the data recording track 132, a clock pit 134 that serves as a sampling reference, and an address mark 135. It has been.

  The operation of the sample servo system will be briefly described. The clock pits 134 are provided on the magneto-optical disk 100 at equal intervals and at the same position as adjacent tracks. Therefore, when light is focus-controlled on the magneto-optical disk 100, the clock pits 134 can be detected at predetermined intervals. By detecting the clock pit 134, the sampling timing of the servo area 131 is determined.

  When the sampling timing is determined, the wobble pits 133A and 133B and the address mark 135 provided in the servo area 131 are sampled. At this time, the light on the magneto-optical disk 100 varies with respect to the track because tracking control is not performed.

  In this state, when the light moves in the position shown in FIG. 11A, if the wobble pits 133A and 133B are sampled, the reproduction signal from the wobble pit 133A is detected larger than the reproduction signal from the wobble pit 133B. It is detected that the track is shifted from the track center of the magneto-optical disk 100. Similarly, when the light moves to the position indicated by C, the reproduction signal from the wobble pit 133A is detected to be smaller than the reproduction signal from the wobble pit 133B, so that it deviates from the track center of the magneto-optical disk 100. Is detected.

  Tracking control for positioning the light focused on the magneto-optical disk 100 at the center of the track drives a tracking actuator (not shown) so that the reproduction signal levels from the wobble pits 133A and 133B are equal. Is done.

  In the magneto-optical disk 100 using the sample servo system, it is necessary to correctly reproduce the servo area 131 while information is recorded on the magneto-optical disk 100.

  As described above, when information is recorded on the magneto-optical disk 100, the magnetic head 108 is driven according to the recorded information to generate a magnetic field according to the recorded information.

  However, the current flowing through the magnetic head 108 during recording operation is as large as about 100 to 200 mA, and large noise is generated by switching the current at high speed. For this reason, noise due to the magnetic field generated by the magnetic head 108 is mixed in reproduction signals such as the wobble pits 133A and 133B and the clock pit 134 provided in the servo area 131, and stable and accurate reproduction becomes difficult. If the servo area 131 is not reproduced correctly, there is a problem that light cannot be correctly controlled on the magneto-optical disk 100.

  Further, when the servo area 131 is reproduced, the current flowing through the magnetic head 108 is driven so as to be fixed in the direction A shown in FIG. 9, thereby preventing noise from being mixed due to a magnetic field generated by the magnetic head 108. Is possible.

  However, when the current flowing through the magnetic head is fixed, the current flowing through the coil 120A constituting the pair of auxiliary current supply means is relatively smaller than the current flowing through the coil 120B due to the influence of the insertion impedance of the magnetic head. For this reason, since the supply current of the coil 120A becomes smaller than the supply current of the coil 120B at the moment of switching from the servo area 131 to the data area, a DC fluctuation occurs in the magnetic field generated by the magnetic head 108, and a sufficient recording magnetic field is generated. There is a problem that cannot be applied.

  Accordingly, the present invention provides a magnetic head drive circuit that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk, and realizes a high-speed modulation operation according to a recording signal for the magnetic field generated by the magnetic head. An object of the present invention is to provide a magnetic head driving circuit that reduces noise caused by a generated magnetic field.

  In order to solve the above problems, the present invention provides a current switching means capable of switching the direction of a current flowing through a magnetic head in a drive circuit for a magnetic head that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk. A first auxiliary current applying means for flowing into the magnetic head from a certain direction; a second auxiliary current applying means for flowing into the magnetic head from the other; a switch means and a load connected in series with the magnetic head in parallel And when the data magnetic recording requires a recording magnetic field by the magnetic head, the switch means is turned off, and when the magnetic head does not require a recording magnetic field, the switch means is turned on. It is characterized by that.

  Further, in a magnetic head drive circuit that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk, a current switching means capable of switching a direction of a current flowing through the magnetic head, and a first current flowing into the magnetic head from a certain direction. The first auxiliary current applying means, the second auxiliary current applying means flowing into the magnetic head from the other, and the current from the first auxiliary current applying means can be supplied to a load different from that of the magnetic head. First switching means and second switching means capable of flowing a current from the second auxiliary current applying means to a load different from the magnetic head, and a recording magnetic field is required by the magnetic head. If not, the direction of the current flowing through the magnetic head is fixed in one direction by the current switching means or is stopped, and the first or second switch means One of them is in the ON state.

  With the above configuration, the magnetic field generated by the magnetic head can be modulated at high speed according to the recording signal, and noise caused by the magnetic field generated from the magnetic head can be reduced.

  In the recording operation using the magnetic head for the magneto-optical disk, the present invention allows the current to flow to the magnetic head by flowing the current flowing through the magnetic head to a switch and a load provided in parallel with the magnetic head when reproducing the servo area. The current that flows is reduced. This reduces the magnetic field and noise generated by the magnetic head when the servo area is played back, and enables wobble pits, clock pits, and address pits provided in the servo area to be played back stably and without error. It is.

  In addition, by keeping the current supplied to the auxiliary current supply means constant in the data area and the servo area, it is possible to keep the energy stored in the auxiliary current supply means constant, and the servo area is switched to the data area. Even at the moment, the current flowing through the magnetic head can be stably switched at high speed without impairing the function of the auxiliary current supply means.

  Also in the servo area, by making it possible to supply the same current to the pair of auxiliary current supply means, it is possible to prevent DC fluctuation of the magnetic field generated by the magnetic head.

  Furthermore, in the recording operation using a magnetic head for a magneto-optical disk, the noise generated by the magnetic head when reproducing the servo area is reduced by interrupting the current flowing through the magnetic head when reproducing the servo area. The wobble pit, clock pit, and address pit provided in the servo area can be stably reproduced without error.

  Also in the servo area, the current equal to that during the recording operation can be supplied to the pair of auxiliary current supply means, so that the current flowing through the magnetic head at the start of recording again can be switched stably and at high speed. is there.

  As described above, by reducing the noise generated by the magnetic head, information recorded on the magneto-optical disk can be reproduced stably and accurately.

  Next, embodiments of the present invention will be described with reference to the drawings.

  An embodiment of the magnetic head drive circuit according to the present invention will be described below with reference to a block diagram in FIG. 1 and a timing chart in FIG.

  In FIG. 1, reference numeral 1 denotes a magnetic head for applying an external magnetic field corresponding to recorded information to a magneto-optical disk.

  2A to 2D are switches for switching the direction of current flowing through the magnetic head 1. A bridge circuit is configured by two pairs of switches 2A to 2D, and semiconductors such as transistors and FETs are applied to the switches 2A to 2D, respectively.

  Reference numerals 3A and 3B denote auxiliary current supply means for supplying current to the magnetic head 1 from a certain direction. In this embodiment, the magnetic head 1 is composed of a coil having an inductance sufficiently larger than that of the magnetic head 1.

  4A to 4D are control signals for turning on / off the two pairs of switches 2A to 2D using signals recorded on the magneto-optical disk. When the control signal 4A / 4D is turned ON and the control signal 4B / 4C is turned OFF, a current in the direction indicated by A in the figure flows through the magnetic head 1.

  Further, when the control signal 4A / 4D is turned OFF and the control signal 4B / 4C is turned ON, a current in the direction indicated by B in the figure flows through the magnetic head 1. By switching the direction of the current flowing through the magnetic head 1, the magnetic head 1 applies a magnetic field in a predetermined direction to the magneto-optical disk.

  Reference numeral 5A / 5B denotes a current limiting resistor that determines a current value supplied to the magnetic head 1 from the auxiliary current supply means 3A / 3B. As an alternative to the current limiting resistor 5A / 5B, the current of the auxiliary current supply means 3A / 3B may be determined by adjusting in advance the power supply voltage VDD to which the auxiliary current supply means 3A / 3B is connected. As another means, auxiliary current supply means may be connected to a constant current source, and the current value of the constant current source may be adjusted in advance.

  6A / 6B is a current limiting resistor that determines a current value to be supplied to the magnetic head 1 by a bridge circuit including two pairs of switches 2A to 2D. As an alternative to the current limiting resistors 6A / 6B, the currents of the bridge circuits 2A to 2D may be determined by adjusting the power supply voltage VCC to which the bridge circuits 2A to 2D are connected in advance. As another means, the bridge circuits 2A to 2D may be connected to a constant current source, and the current value of the constant current source may be adjusted in advance.

  Reference numeral 7 denotes a load provided in parallel to the magnetic head 1 and is composed of, for example, a resistor. A switch 8 is also provided in parallel with the magnetic head 1 and in series with the load 7. The current flows from the switches 2A and 2B to the magnetic head 1 and from the auxiliary current supply means 3A / 3B to the magnetic head 1. A current can be selectively passed through the load 7.

  Hereinafter, the operation of the present invention will be described in detail.

  When a recording operation to the magneto-optical disk is started by a CPU (not shown) or the like, the two pairs of switches 2A to 2D are ON / OFF controlled by control signals 4A to 4D.

  As an example, if 4A / 4D is ON and 4B / 4C is OFF, the switches 2A / 2D corresponding to these control signals are ON, and 2B / 2C is OFF. At this time, the magnetic head current flows in the direction of A in the figure from the power supply voltage VCC to which the bridge circuit is connected in the order of the current limiting resistor 6A, the switch 2A, the magnetic head 1, and the switch 2D.

  Further, the magnetic head current is also supplied in the direction A in the figure from the power supply voltage VDD, the current limiting resistor 5A, and the auxiliary current supply means 3A. At this time, the current flowing through the power supply voltage VDD, the current limiting resistor 5B, and the auxiliary current supply means 3B flows into the switch 2D without flowing into the magnetic head 1.

  Next, when 4A / 4D is turned OFF and 4B / 4C is turned ON, the switches 2A / 2D corresponding to these control signals are turned OFF and 2B / 2C are turned ON. At the time of switching, the magnetic head 1 is inductive, and therefore operates so as to continue to flow a current in the direction of current that has flowed up to that point, in this case, the direction of A in the figure.

  At the same time, since the auxiliary current supply means 3B provided at one end of the magnetic head 1 is also an inductance, it operates to continue the current that has flown until then, but the switch 2D that has been turned on until then is turned off. Therefore, a very high voltage is generated at the connection point of the auxiliary current supply means 3B, the switch 2D and the magnetic head 1.

  The high voltage acts as a force that reverses the current direction of the magnetic head 1 and the auxiliary current supply means 3B. However, since the inductance of the magnetic head 1 is sufficiently smaller than the inductance of the auxiliary current supply means 3B, the actual operation is performed. For example, the current direction of the magnetic head 1 is merely reversed from the direction A to the direction B in the drawing.

  When the current of the magnetic head 1 is reversed, the magnetic head current continues in the direction of B in the figure from the power supply voltage VCC connected to the bridge circuit in the order of the current limiting resistor 6B, the switch 2B, the magnetic head 1, and the switch 2C. Flowing.

  Further, the magnetic head current is continuously supplied from the power supply voltage VDD, the current limiting resistor 5B, and the auxiliary current supply means 3B in the direction B in the figure. At this time, the current flowing through the power supply voltage VDD, the current limiting resistor 5A, and the auxiliary current supply means 3A flows into the switch 2C without flowing into the magnetic head 1.

  As described above, the magnetic head drive circuit in this embodiment switches the current flowing through the magnetic head 1 at high speed by using a coil having a sufficiently larger inductance than the magnetic head 1 for the auxiliary current supply means 3A / 3B. It is possible to switch the magnetic field applied to the magneto-optical disk.

  At the same time as generating a magnetic field according to the recording information, light from a semiconductor laser or the like is condensed on the magneto-optical disk, and a recording operation is executed by the application of the magnetic field and the joint action of the semiconductor laser.

  Next, when the recording position reaches a servo area provided on the magneto-optical disk during the recording operation, the control signals 4A to 4D are switched to pseudo recording signals. At the same time, the switch 8 provided in parallel with the magnetic head 1 is turned on.

  When the switch 8 is turned on, a part of the current flowing from the switches 2 A and 2 B to the magnetic head 1 flows to the load 7 and the switch 8. Similarly, a part of the current flowing from the auxiliary current supply means 3 </ b> A and 3 </ b> B to the magnetic head 1 flows to the load 7 and the switch 8.

  For this reason, in the servo area, the current flowing through the magnetic head 1 is reduced from the steady state. When the current of the magnetic head 1 is reduced, when the direction of the current flowing through the magnetic head 1 is switched, the voltage generated at the end of the magnetic head 1 is smaller than that during the recording operation, and the current flowing through the magnetic head 1 is reduced. Due to the synergistic effect, the magnetic field and noise generated by the magnetic head 1 can be sufficiently suppressed.

  With the magnetic field and noise generated by the magnetic head 1 being sufficiently suppressed, wobble pits, clock pits, and address marks recorded in the servo area can be reproduced without error by a reproduction signal processing circuit (not shown). To do.

  Next, when the servo area is reached again from the servo area, the switch 8 is turned off, and the control signals 4A to 4D are again controlled by the recording signal and the recording operation is continued.

  Next, another embodiment of the magnetic head drive circuit will be described with reference to FIG. In FIG. 3, those having the same numbers as those in FIG. 1 perform similar functional operations, and will not be described again.

  9A is a switch that can selectively flow the current from the auxiliary current supply unit 3A, or a switch and a load, and 9B is a switch that can selectively flow the current from the auxiliary current supply unit 3B. Or a switch and a load.

  Since the operation of the present embodiment is substantially the same as that of the first embodiment, detailed description thereof will be omitted, and only portions different from the first embodiment will be described with reference to a timing chart shown in FIG.

  When the recording position reaches a servo area provided on the magneto-optical disk during the recording operation, the control signals 4A to 4D are switched to pseudo recording signals for fixing the current flowing through the magnetic head 1 in one direction. For example, when the control signals 4B and 4C are turned on and the switches 2B and 2C are turned on, the current flowing through the magnetic head 1 is fixed in the B direction.

  At the same time, the switch 9B capable of selectively flowing the current from the auxiliary current supply unit 3B is turned ON, and the current from the auxiliary current supply unit 3B flows into the amount flowing through the magnetic head 1 and the amount flowing through the switch 9B. Branch off.

  At this time, the switch 9A that can selectively flow the current from the auxiliary current supply unit 3A is OFF, and the current from the auxiliary current supply unit 3A flows only to the switch 2C without flowing to the magnetic head 1. Is. Further, the current flowing through the switch 9B is adjusted by the load constituting the switch 9B so that the current flowing through the auxiliary current supply unit 3A is equal to the current flowing through the auxiliary current supply unit 3B.

  On the contrary, the direction of the current flowing through the magnetic head 1 may be fixed in the direction A in the figure. For this reason, in the servo area, the current flowing through the magnetic head 1 is fixed in one direction.

  When the current flowing through the magnetic head 1 is fixed, the wobble pits and clock pits recorded in the servo area and further the address marks are reproduced with the noise generated by the magnetic head 1 being sufficiently suppressed. (Not shown) enables reproduction without error.

  At the same time, the current flowing through the pair of auxiliary current supply means 3A and 3B can be kept the same. Thereby, simultaneously with the start of recording again, the current supplied from the auxiliary current supply means to the magnetic head 1 is constant regardless of the current direction, so that a stable recording magnetic field can be generated.

  Further, another operation of the present embodiment will be described with reference to a timing chart shown in FIG.

  When the recording position reaches the servo area provided on the magneto-optical disk during the recording operation, the control signals 4A to 4D are all switched to the OFF state in order to cut off the current flowing through the magnetic head 1.

  At the same time, the switch 9A that can selectively flow the current from the auxiliary current supply means 3A and the switch 9B that can selectively flow the current from the auxiliary current supply means 3B are turned on to supply the auxiliary current. The current from the means 3A and 3B flows to the switches 9A and 9B without flowing to the magnetic head 1. At this time, the current flowing through the auxiliary current supply means 3A and 3B is adjusted by the load constituting the switches 9A and 9B so as to be equal to the current flowing through the magnetic head 1 during the recording operation.

  Furthermore, the switches 9A and 9B can be replaced by the switches 2C and 2D constituting the bridge circuit, which will be described with reference to a timing chart in FIG.

  When the recording position reaches the servo area provided on the magneto-optical disk during the recording operation, the control signals 4A and 4B are switched to the OFF state in order to cut off the current flowing through the magnetic head 1.

  At the same time, in order to turn on the switch 2C that can selectively flow the current from the auxiliary current supply means 3A and the switch 2D that can selectively flow the current from the auxiliary current supply means 3B, 4C and 4D are switched to the ON state, and the current from the auxiliary current supply means 3A and 3B flows to the switches 2C and 2D without flowing to the magnetic head 1. At this time, the current flowing through the auxiliary current supply means 3A and 3B is substantially equal to the current flowing through the magnetic head 1 during the recording operation.

  As described above, since the current flowing through the magnetic head 1 is interrupted in the servo area, wobble pits, clock pits, and even address marks recorded in the servo area can be reproduced without error without noise. It is what.

  Further, the current flowing through the pair of auxiliary current supply means 3A and 3B can be kept equal to that during the recording operation. Thereby, simultaneously with the start of recording again, the current supplied from the auxiliary current supply means to the magnetic head 1 can be stably supplied to generate a stable recording magnetic field.

1 is a block diagram of Embodiment 1 of a magnetic head drive circuit of the present invention. FIG. 2 is a timing chart of the first embodiment of the magnetic head driving circuit of the present invention. FIG. 6 is a block diagram of a magnetic head drive circuit according to a second embodiment of the present invention. 6 is a timing chart of Embodiment 2 of the magnetic head driving circuit of the present invention. 12 is another timing chart of the magnetic head drive circuit according to the second embodiment of the present invention. 12 is another timing chart of the magnetic head drive circuit according to the second embodiment of the present invention. It is the schematic which shows the recording / reproducing method of the conventional magneto-optical disc. It is a block diagram of a conventional magnetic head drive circuit. It is a block diagram of another conventional magnetic head drive circuit. It is an explanatory view of a sample servo type magneto-optical disk. It is explanatory drawing of each recording area of the magneto-optical disk of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic head 2A-2D Switch 3A, 3B Auxiliary current supply means 4A-4D Control signal 5A, 5B Current limiting resistor 6A, 6B Current limiting resistor 7 Load 8 Switch 9 Switch (load)

Claims (4)

In a drive circuit for a magnetic head that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk,
Current switching means capable of switching the direction of current flowing through the magnetic head, first auxiliary current applying means flowing into the magnetic head from a certain direction, and second auxiliary current applying means flowing into the magnetic head from the other side And switch means and load means connected in series with the magnetic head in parallel,
When a recording magnetic field is required by the magnetic head during data recording, the switch means is turned off, and when a recording magnetic field is not required by the magnetic head, the switch means is turned on. Magnetic head drive circuit. In a drive circuit for a magnetic head that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk,
Current switching means capable of switching the direction of current flowing through the magnetic head, first auxiliary current applying means flowing into the magnetic head from a certain direction, and second auxiliary current applying means flowing into the magnetic head from the other side A first switch means capable of flowing a current from the first auxiliary current applying means to a load different from the magnetic head, and a current from the second auxiliary current applying means to the magnetic head. Comprises second switch means capable of flowing to different loads,
When the magnetic field is not required by the magnetic head, the direction of the current flowing through the magnetic head is fixed in one direction by the current switching means, and one of the first or second switch means is turned on. A magnetic head driving circuit. In a drive circuit for a magnetic head that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk,
Current switching means capable of switching the direction of current flowing through the magnetic head, first auxiliary current applying means flowing into the magnetic head from a certain direction, and second auxiliary current applying means flowing into the magnetic head from the other side A first switch means capable of flowing a current from the first auxiliary current applying means to a load different from the magnetic head, and a current from the second auxiliary current applying means to the magnetic head. Comprises second switch means capable of flowing to different loads,
When no recording magnetic field is required by the magnetic head, the current flowing through the magnetic head is stopped by the current switching means, and the first and second switch means are turned on. Magnetic head drive circuit. In a drive circuit for a magnetic head that generates a magnetic field for performing magnetic field modulation recording on a magneto-optical disk,
Current switching means comprising two to four switch means capable of switching the direction of current flowing through the magnetic head, first auxiliary current application means flowing into the magnetic head from a certain direction, and the magnetic head from the other side Means for applying a second auxiliary current to flow in,
When the magnetic head does not require a recording magnetic field, the one-to-two switch means provided on the power supply side of the current switching means is turned off, and the pair provided on the ground side of the current switching means A magnetic head drive circuit characterized in that two switch means are turned on.

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