JP2014068530A - Disk drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device which makes it possible to supply necessary driving power to a motor during emergency operation while suppressing the enlargement of a circuit area, and a disk drive device using the motor control device.SOLUTION: During retraction operation, a short-circuit mode and a rectifying mode are alternately repeated. In the short-circuit mode, each terminal (U, V and W) of a spindle motor M1 is short-circuited to a terminal ICOM. In the rectifying mode, back electromotive force of the spindle motor M1 is rectified and output to power supply lines (ISO3V and VGND) while input of power from the power supply lines (ISO3V and VGND) to the spindle motor M1 is blocked.

Description

  The present invention relates to a disk drive device such as a hard disk drive device having an emergency head retracting function and a motor control device used for controlling the motor.

  2. Description of the Related Art Generally, a hard disk drive device has a spindle motor (SPM) that rotates a disk, a head that records and reproduces data, an arm that has a head attached to a tip, and a voice coil motor that moves the arm. VCM). When data is recorded / reproduced, the head is moved to a desired position on the disk by driving the voice coil motor.

  The head and the disk are kept at a minute distance by utilizing the air flow generated near the surface of the rotating disk. For this reason, a hard disk drive device generally mounted on a mobile device has a function of preventing a collision between the two. For example, when an abnormality such as a power supply voltage, an environmental temperature, or a disk rotation speed is detected, an operation (retract) for drawing the head into a safety area called a lamp is executed.

  The ramp includes an ascending first inclined portion, a horizontal portion, and a descending second inclined portion from the side close to the disk. During retraction, the arm is moved by the voice coil motor so that the arm climbs over the first slope and stays in the parking area ahead of the second slope. Since it is necessary to perform retraction even after the power is shut off, as a power source for the voice coil motor, for example, a voltage of a capacitor charged in advance for retraction or a back electromotive force (back electromotive force) of a spindle motor rotating by inertia A voltage obtained by rectifying BEMF) is used.

US Pat. No. 7,301,722

  By the way, in the conventional hard disk drive device, the control method of the voice coil motor from the start time to the end time of the retraction operation is switched according to a preset timer value. In this case, the type of power source used for driving the voice coil motor (capacitor voltage / BEMF rectified voltage) is also automatically switched at a preset time.

  However, since the capacitor voltage decreases due to discharge, when switching the power source of the voice coil motor according to the set value of the timer, the capacitor voltage may decrease to near zero volts before the switching depending on the conditions. If it does so, the torque of a voice coil motor will fall temporarily and the force which pulls an arm to the lamp side will become weak. At this time, if the arm moves to the disk side, the arm may not be able to be pulled into the lamp.

  Therefore, in the conventional hard disk drive device, it is necessary to sufficiently increase the capacitance of the capacitor in order to suppress the decrease in the capacitor voltage, and there is a disadvantage that the circuit area is large and the component cost is high.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a motor control device capable of supplying necessary drive power to a motor during an emergency operation while suppressing an increase in circuit area, and a disk drive device using the motor control device. It is to provide.

  According to a first aspect of the present invention, a first motor for rotating a disk-shaped recording medium and a second motor for moving a head for accessing information on the disk-shaped recording medium are provided. The present invention relates to a motor control device that performs control based on electric power supplied to the motor. The motor control device includes: a first motor driving unit including a plurality of transistors that connect the first power supply line and the second power supply line to a plurality of input terminals of the first motor; and the head in a safety region. In the emergency operation to be evacuated, the back electromotive force generated at the plurality of input terminals of the first motor is compared with the voltage of the first power supply line and the voltage of the second power supply line, and according to the comparison result, The first power supply line and the second power supply line are blocked by preventing input of power from the first power supply line and the second power supply line to the first motor, and rectifying the counter electromotive force generated by the first motor. And a first motor control unit that controls each transistor of the first motor driving unit.

  Preferably, the first motor control unit controls each transistor of the first motor drive unit so as to short-circuit all terminals of the first motor to the second power supply line during the emergency operation. According to the voltage comparison result, the power input from the first power line and the second power line to the first motor is blocked, and the counter electromotive force generated by the first motor is rectified. The rectification mode for controlling each transistor of the first motor driving unit so as to output to the first power supply line and the second power supply line may be alternately repeated.

  Preferably, the first motor control unit alternately switches the short-circuit mode and the rectification mode when a power supply voltage generated between the first power supply line and the second power supply line is lower than a predetermined threshold value. You can repeat it.

  Preferably, the first motor driving unit includes a plurality of first transistors that connect the plurality of input terminals of the first motor and the first power supply line, the plurality of input terminals of the first motor, and the A plurality of second transistors connected to the second power supply line may be included. The first motor control unit is a plurality of first transistor drive circuits that output drive signals for the plurality of first transistors, and compares voltages across the first transistors to be driven in the rectification mode. A plurality of first transistors that output a drive signal for controlling the conduction state of the first transistor to be driven according to the result, and that output a drive signal for making the first transistor to be driven non-conductive in the short-circuit mode. A driving circuit and a plurality of second transistor driving circuits that output driving signals for the plurality of second transistors, and according to a result of comparing voltages across the second transistors to be driven in the rectification mode; A drive signal for controlling the conduction state of the second transistor to be driven is output, and in the short circuit mode, the drive target It may include a plurality of second transistor drive circuit for outputting a driving signal to a non-conductive two transistors.

  Preferably, the motor control device outputs a drive signal group generated so as to supply power from the first power supply line and the second power supply line to the first motor during the normal operation. And the plurality of first transistors and the plurality of first transistors and the plurality of second transistor drive circuits generated by the first transistor drive circuits and the plurality of second transistor drive circuits during the emergency operation. A signal selection circuit for inputting to the plurality of second transistors may be provided.

  Preferably, the motor control device is driven with a polarity for accelerating or decelerating the head based on the detection unit for detecting the speed of the head and the power supply voltages of the first power supply line and the second power supply line. A second motor driving unit that generates a voltage and applies the generated driving voltage to the second motor, and according to a detection result of the detection unit so that the head approaches a predetermined speed during the emergency operation. And a second motor control unit for controlling the polarity and output timing of the drive voltage.

  Preferably, the detection unit may detect a counter electromotive force generated by the second motor during a period in which the second motor driving unit does not apply the driving voltage to the second motor.

  Preferably, the first motor driving unit includes a plurality of first transistors that connect the plurality of input terminals of the first motor and the first power supply line, the plurality of input terminals of the first motor, and the A plurality of second transistors connected to the second power supply line may be included. The first motor control unit is a plurality of first transistor drive circuits that output drive signals for the plurality of first transistors, and the first motor control unit corresponds to a result of comparing voltages across the first transistors to be driven. A plurality of first transistor drive circuits for outputting a drive signal for controlling a conduction state of a first transistor to be driven; and a plurality of second transistor drive circuits for outputting a drive signal for the plurality of second transistors. And a plurality of second transistor drive circuits that output a drive signal for controlling a conduction state of the second transistor to be driven according to a result of comparing the voltages at both ends of the target second transistor.

  Preferably, in the emergency operation, the motor control device connects the plurality of input terminals of the first motor and a common terminal to which the plurality of coils of the first motor are commonly connected to the second power supply line. There may be provided a resistance circuit including a plurality of resistance elements.

  A disk drive device according to a second aspect of the present invention includes a first motor that rotates a disk-shaped recording medium, a second motor that moves a head for accessing information on the disk-shaped recording medium, and the first motor A motor control device according to an aspect.

  According to a third aspect of the present invention, the second motor that operates the head with respect to the disk-shaped medium is driven using the back electromotive force of the first motor that is a three-phase DC motor that rotates the disk-shaped medium. The present invention relates to a control circuit that controls a retracting operation of a head. The control circuit includes a first motor driving unit and a first motor control unit. The first motor drive unit includes a first transistor connected between a first terminal of the first motor and a first voltage supply line, the first terminal and a second voltage supply line. A second transistor connected between the second motor, a third transistor connected between the second terminal of the first motor and the first voltage supply line, and the second terminal. A fourth transistor connected between the second voltage supply line and a fifth transistor connected between a third terminal of the first motor and the first voltage supply line; And a sixth transistor connected between the third terminal and the second voltage supply line. The first motor control unit compares the voltage of the first terminal with the voltage of the first voltage supply line in the retract mode for retracting the head, and compares the voltage of the first voltage supply line according to the comparison result. A first transistor driving circuit for controlling a conduction state of one transistor, a voltage of the first terminal and a voltage of the second voltage supply line, and the second transistor according to the comparison result A second transistor driving circuit for controlling a conduction state of the second transistor, and comparing the voltage of the second terminal with the voltage of the first voltage supply line, and according to the comparison result, the conduction state of the third transistor A third transistor driving circuit for controlling the voltage, and the voltage of the second terminal and the voltage of the second voltage supply line are compared, and the conduction state of the fourth transistor is controlled according to the comparison result. 4th transition And a fifth transistor drive circuit that compares the voltage of the third terminal and the voltage of the first voltage supply line and controls the conduction state of the fifth transistor according to the comparison result. And a sixth transistor drive circuit that compares the voltage of the third terminal and the voltage of the second voltage supply line and controls the conduction state of the sixth transistor according to the comparison result. . A voltage is generated between the first voltage supply line and the second voltage supply line under the control of the first motor control unit.

  Preferably, the control circuit is connected to the first, second and third terminals of the first motor, a common terminal of the first motor, and the first or second voltage supply line. It may further include a resistance circuit. In the save mode, the first, second and third terminals and the common terminal are connected to the first or second voltage supply line via the resistor circuit, and the first to second terminals are connected. 6 is controlled by the first to sixth transistor drive circuits of the first motor control unit so that a voltage is generated between the first voltage supply line and the second voltage supply line. The generated commutation mode may be repeated.

  Preferably, the control circuit may further include a capacitor connected between the first voltage supply line and the second voltage supply line, and a voltage detection circuit for detecting the voltage of the capacitor. . In the save mode, when the voltage detection circuit detects that the voltage of the capacitor is equal to or lower than a predetermined value, the first motor control unit controls the conduction state of the first to sixth transistors to A voltage may be generated between the first voltage supply line and the second voltage supply line.

  According to the present invention, it is possible to supply necessary driving power to a motor during an emergency operation while suppressing an increase in circuit area.

It is a figure which shows an example of a structure of the disk drive device which concerns on embodiment of this invention. FIG. 2 is a diagram showing an example of a circuit configuration of a portion related to driving and control of a spindle motor in the disk drive device shown in FIG. 1. FIG. 2 is a diagram showing an example of a circuit configuration of a portion related to driving and control of a voice coil motor in the disk drive device shown in FIG. 1. FIG. 2 is a diagram showing a main part of a circuit related to driving of a voice coil motor and a spindle motor in the disk drive device shown in FIG. 1. It is a figure which illustrates the change of the voltage of the capacitor for the drive electric power supply at the time of a retraction operation | movement, and the voltage of a power supply line. It is a figure for demonstrating the case where rectification | straightening of the counter electromotive force of a spindle motor is not performed until fixed time passes. It is a figure which shows the example of the simulation waveform of the voltage of the capacitor for the drive electric power supply in a 1st rectification | straightening method, the voltage of a power supply line, and the terminal voltage of a spindle motor. It is a figure which shows the example of the simulation waveform of the voltage of the capacitor for the drive electric power supply in the 2nd rectification | straightening method, the voltage of a power supply line, and the terminal voltage of a spindle motor.

FIG. 1 is a diagram showing an example of the configuration of a disk drive device according to an embodiment of the present invention.
1 includes a spindle motor M1, a voice coil motor M2, motor drive units 10 and 30, a retract damping resistor unit 12, transistor drive units 20, 22, 40, and 42, and a signal selection circuit. 24, 44, retract control unit 50, clock generation circuit 51, transistor drive circuits 52, 53, analog-digital conversion circuit 54, charge pump circuit 61, regulator circuits 62, 63, clamp circuit 64, , Switches SW1 and SW2, transistors Tr1 and Tr2, capacitors C10 to C12, a diode D1, and a resistor RG.

The spindle motor M1 is an example of a first motor in the present invention.
The voice coil motor M2 is an example of a second motor in the present invention.
The motor drive unit 10 is an example of a first motor drive unit in the present invention.
The circuit including the transistor drive unit 20 and the retract control unit 50 is an example of a first motor control unit in the present invention.
The signal selection circuit 24 is an example of a signal selection circuit in the present invention.
The analog-digital conversion circuit 54 is an example of a detection unit in the present invention.
The motor drive unit 30 is an example of a second motor drive unit in the present invention.
The circuit including the transistor drive unit 40 and the retract control unit 50 is an example of a second motor control unit in the present invention.
The retract damping resistance unit is an example of a resistance circuit in the present invention.

  First, in the disk drive device shown in FIG. 1, a circuit related to the drive and control of the spindle motor M1 will be described with reference to FIG.

The spindle motor M1 is a motor that rotates a disk-shaped recording medium such as a magnetic disk, and is, for example, a three-phase drive type DC motor.
For example, as shown in FIG. 2, the spindle motor M1 has three coils LU, LV, and LW. One ends of the coils LU, LV, and LW are connected to the common terminal P1. The other end of the coil LU is connected to the terminal U, the other end of the coil LV is connected to the terminal V, and the other end of the coil LW is connected to the terminal W.

  The motor drive unit 10 drives the spindle motor M1 based on the power supplied from the power supply lines (ISO3V, VGND). The spindle motor M1 is directly driven by a voltage between the power supply line ISO3V and the power supply line ICOM connected to the power supply line VGND via the resistor RG.

  The motor drive unit 10 includes transistors Tr11 to Tr16 such as n-type MOSFETs as shown in FIG. The transistors Tr11 to Tr16 control a current path between the terminals U, V, and W and the power supply line ISO3V or the terminal ICOM in accordance with a gate drive signal input through a signal selection circuit 24 described later. The terminal ICOM is short-circuited to the ground line VGND via a current detection resistor RG having a very small resistance value.

The transistor Tr11 is provided in a path connecting the terminal U and the power supply line ISO3V. The transistor Tr12 is provided in a path connecting the terminal U and the terminal ICOM. The transistor Tr13 is provided in a path connecting the terminal V and the power supply line ISO3V. The transistor Tr14 is provided in a path connecting the terminal V and the terminal ICOM. The transistor Tr15 is provided in a path connecting the terminal W and the power supply line ISO3V. The transistor Tr16 is provided in a path connecting the terminal W and the terminal ICOM.
The transistors Tr11, Tr13, Tr15 are examples of the first transistor in the present invention, and the transistors Tr12, Tr14, Tr16 are examples of the second transistor in the present invention.

The transistor drive unit 20 outputs a drive signal to be applied to each gate of the transistors Tr11 to Tr16 according to the control of the retract control unit 50 during the retract operation for retracting the head to the safe area.
For example, the transistor drive unit 20 rectifies the counter electromotive force of the spindle motor M1, and controls the transistors Tr11 to Tr16 so as to output the rectified voltage to the power supply line (ISO3V, VGND (or ICOM)) (rectification mode). ) And a mode in which all input terminals (U, V, W) of the spindle motor M1 are short-circuited to the terminal ICOM (short-circuit mode) are switched according to the control signal of the retract control unit 50.

When the transistor drive unit 20 is set to the rectification mode, a voltage obtained by rectifying the counter electromotive force of the spindle motor M1 is output to the power supply line (ISO3V, VGND).
On the other hand, when the transistor drive unit 20 is set to the short circuit mode, a current in which the back electromotive force is short-circuited by the coil resistance of the coil flows through each coil (LU, LV, LW) of the spindle motor M1. When the short-circuit mode is canceled and the rectification mode is set, a surge voltage corresponding to the current flowing in each coil is generated, and the surge voltage is rectified and output to the power supply line (ISO3V, VGND). A voltage higher than the time is output to the power supply lines (ISO3V, VGND).

The transistor drive unit 20 includes gate drive circuits 201 to 206 as shown in FIG.
The gate drive circuit 201 outputs a drive signal applied to the gate of the transistor Tr11. The gate drive circuit 202 outputs a drive signal applied to the gate of the transistor Tr12. The gate drive circuit 203 outputs a drive signal applied to the gate of the transistor Tr13. The gate drive circuit 204 outputs a drive signal applied to the gate of the transistor Tr14. The gate drive circuit 205 outputs a drive signal applied to the gate of the transistor Tr15. The gate drive circuit 206 outputs a drive signal applied to the gate of the transistor Tr16.

In the rectification mode, the gate drive circuits 201 to 206 compare the counter electromotive force generated at the terminals U, V, and W of the spindle motor M1 with the voltage of the power supply line ISO3V or the voltage of the terminal ICOM. The gate drive circuits 201 to 206 rectify the electromotive force generated by the spindle motor M1 while blocking the input of power from the power supply lines (ISO3V, VGND) to the spindle motor M1 according to the voltage comparison result. A drive signal for linearly controlling the conduction / non-conduction state of the transistors Tr11 to Tr16 is outputted so as to be outputted to the power supply lines (ISO3V, VGND).
That is, the gate drive circuits 201, 203, and 205 compare the voltages at both ends of the transistors to be driven (Tr11, Tr13, Tr15), and the voltage at the terminal (U, V, W) of the spindle motor M1 is the power supply line ISO3V. When the voltage is higher than the voltage, a drive signal for controlling the conduction state of the transistor is output according to the voltage difference. When the voltage is opposite, a drive signal for turning the transistor off is output.
The gate drive circuits 202, 204, and 206 compare the voltages at both ends of the transistors to be driven (Tr12, Tr14, and Tr16), and the voltage at the terminals (U, V, W) of the spindle motor M1 is the voltage at the terminal ICOM. When the voltage is lower, a drive signal for controlling the conduction state of the transistor is output according to the voltage difference. When the voltage is lower, a drive signal for turning the transistor off is output.

  As described above, in the rectification mode, the circuit configured by each pair of the transistors Tr11 to Tr16 and the gate drive circuits 201 to 206 functions as a rectification circuit in which the voltage value (resistance value) is controlled.

  On the other hand, in the short circuit mode, the gate drive circuits 201, 203, and 205 output drive signals that turn off the transistors to be driven (Tr11, Tr13, Tr15). Further, the gate drive circuits 202, 204, and 206 output drive signals that turn on the transistors to be driven (Tr12, Tr14, Tr16). As a result, the three terminals (U, V, W) of the spindle motor M1 are connected to the terminal ICOM.

  The gate drive circuits 201 to 206 function as, for example, a regulation amplifier that outputs a gate control signal corresponding to a comparison result of input signals (voltage difference of comparison voltages) in the rectification mode.

  The transistor drive unit 22 outputs drive signals for the transistors Tr11 to Tr16 in accordance with a control signal from a control unit (not shown) during normal operation. When the transistors Tr11 to Tr16 are turned on / off according to the drive signal of the transistor drive unit 22, power is supplied from the power supply lines (ISO3V, VGND) to the spindle motor M1, and the spindle motor M1 rotates.

The signal selection circuit 24 inputs drive signals S11 to S16 generated by the transistor drive unit 22 to the transistors Tr11 to Tr16 of the motor drive unit 10 during normal operation, and the gate of the transistor drive unit 20 during retract operation. The drive signals generated by the drive circuits 201 to 206 are input to the transistors Tr11 to Tr16.
The signal selection circuit 24 includes switches SW11 to SW16, for example, as shown in FIG. The switch SW11 inputs the drive signal of the gate drive circuit 201 or the drive signal S11 of the transistor drive unit 22 to the gate of the transistor Tr11. The switch SW12 inputs the drive signal of the gate drive circuit 202 or the drive signal S12 of the transistor drive unit 22 to the gate of the transistor Tr12. The switch SW13 inputs the drive signal of the transistor drive circuit 203 or the drive signal S13 of the transistor drive unit 22 to the gate of the transistor Tr13. The switch SW14 inputs the drive signal of the gate drive circuit 204 or the drive signal S14 of the transistor drive unit 22 to the gate of the transistor Tr14. The switch SW15 inputs the drive signal of the gate drive circuit 205 or the drive signal S15 of the transistor drive unit 22 to the gate of the transistor Tr15. The switch SW16 inputs the drive signal of the gate drive circuit 205 or the drive signal S16 of the transistor drive unit 22 to the gate of the transistor Tr16.

  The retract damping resistor unit 12 forms a current path for suppressing a spike voltage generated when the back electromotive force of the spindle motor M1 is rectified in the retract operation. That is, the retract damping resistor unit 12 forms a resistor circuit that connects the terminals U, V, and W of the coils LU, LV, and LW and the common terminal P1 during the retract operation, so that the transistors Tr11 to Tr16 are turned from on to off. The spike voltage generated in the coils LU, LV, and LW when switching is suppressed.

For example, as shown in FIG. 2, the retract damping resistor 12 includes resistors R1, R2, and R3 having one terminal connected to a common node, and a resistor connected in series between the common node and the terminal ICOM. R4 and R5.
The other terminal of the resistor R1 is connected to the terminal U through the switch circuit SW3. The other terminal of the resistor R2 is connected to the terminal V via the switch SW3. The other terminal of the resistor R3 is connected to the terminal W through the switch SW3. A connection node between the resistors R4 and R5 is connected to the common terminal P1 through the switch SW3.

The switch SW3 includes a plurality of switches that are turned on in response to a control signal from the control unit 50 during the retraction operation. When each switch of the switch SW3 is turned on, a path of current flowing from the terminals U, V, W of the spindle motor M1 to the common terminal P1 via the resistors R1 to R4 is formed. This current path reduces the spike voltage generated in each coil LU, LV, LW when the connection between each coil LU, LV, LW and the power supply line ISO3V is switched from on to off in accordance with the rectification operation. Current is drawn from the terminals U, V, W to the common terminal P1.
For example, when a current flows from the coil LU to the power supply line ISO3V through the transistor Tr11 in the on state, when the voltage at the terminal U decreases and the transistor Tr11 is in the off state, the terminal U has a counter electromotive force of the coil LU. A spike voltage is generated due to. At this time, the spike voltage is suppressed by the current flowing through the path of the terminal U, the switch SW3, the resistor R1, the resistor R4, the switch SW3, and the terminal P1. Similarly to the case of the terminal U, spike voltages generated at the other terminals V and W are also suppressed by the retract damping resistance unit 34.

  Next, in the disk drive device shown in FIG. 1, circuits related to the drive and control of the voice coil motor M2 will be described with reference to FIG.

  The voice coil motor M2 advances and retracts an arm on which a read / write head for a disk-shaped recording medium is mounted. The voice coil motor M2 operates according to the voltage applied to the terminals VCA and VCB.

  The motor drive unit 30 drives the voice coil motor M2 based on the power supplied to the power supply lines (ISO3V, VGND).

  The motor drive unit 30 includes transistors Tr21 to Tr24 such as n-type MOSFETs as shown in FIG. 3, for example. The transistors Tr21 to Tr24 connect the terminals VCA and VCB to the power supply line ISO3V or the ground line VGND according to a gate drive signal input through a signal selection circuit 44 described later.

  The transistor Tr21 is provided in a path connecting the terminal VCA and the power supply line ISO3V. The transistor Tr22 is provided in a path connecting the terminal VCA and the ground line VGND. The transistor Tr23 is provided in a path connecting the terminal VCB and the power supply line ISO3V. The transistor Tr24 is provided in a path connecting the terminal VCB and the ground line VGND.

The transistor drive unit 40 outputs drive signals to be applied to the gates of the transistors Tr21 to Tr24 according to the control of the retract control unit 50 during the retraction operation. When the transistors Tr21 to Tr24 are turned on / off according to the drive signal of the transistor drive unit 40, power is supplied from the power lines (ISO3V, VGND) to the voice coil motor M2, and the voice coil motor M2 moves the arm in the retracting direction. .
For example, as illustrated in FIG. 3, the transistor driving unit 40 includes gate driving circuits 401 to 404. The gate drive circuit 401 outputs a drive signal applied to the gate of the transistor Tr21. The gate drive circuit 402 outputs a drive signal applied to the gate of the transistor Tr22. The gate drive circuit 403 outputs a drive signal applied to the gate of the transistor Tr23. The gate drive circuit 404 outputs a drive signal applied to the gate of the transistor Tr24.

  The transistor drive unit 42 outputs drive signals for the transistors T21 to Tr24 in accordance with a control signal from a control unit (not shown) during normal operation. When the transistors Tr21 to Tr24 are turned on / off according to the drive signal of the transistor drive unit 42, power is supplied from the power lines (ISO3V, VGND) to the voice coil motor M2, and the voice coil motor M2 moves the arm forward and backward.

The signal selection circuit 44 inputs the drive signals S21 to S24 generated by the transistor drive unit 42 to the transistors Tr21 to Tr24 of the motor drive unit 30 during the normal operation, and the gate of the transistor drive unit 40 during the retract operation. The drive signals generated by the drive circuits 401 to 404 are input to the transistors Tr21 to Tr24.
The signal selection circuit 44 includes switches SW21 to SW24, for example, as shown in FIG. The switch SW21 inputs the drive signal of the gate drive circuit 401 or the drive signal S21 of the transistor drive unit 42 to the gate of the transistor Tr21. The switch SW22 inputs the drive signal of the gate drive circuit 402 or the drive signal S22 of the transistor drive unit 42 to the gate of the transistor Tr22. The switch SW23 inputs the drive signal of the gate drive circuit 403 or the drive signal S23 of the transistor drive unit 42 to the gate of the transistor Tr23. The switch SW24 inputs the drive signal of the gate drive circuit 404 or the drive signal S24 of the transistor drive unit 42 to the gate of the transistor Tr24.

  The analog-digital conversion circuit 54 inputs the voltage between the terminal VCA and the terminal VCB during the period in which the supply of the drive voltage from the power supply line (ISO3V, VGND) to the voice coil motor M2 is stopped, and samples and holds the voltage. The voltage is converted into a digital value and output to the retract control unit 50. The switch SW2 connects the terminal VCB and the input terminal of the analog-digital conversion circuit 54.

The analog-digital conversion circuit 54 inputs back electromotive force generated in the voice coil motor M2 when the transistors Tr21, Tr23, Tr24 are off, the transistor Tr22 is on, and the switch SW2 is on, and converts them into digital values. To do. This counter electromotive force has a magnitude corresponding to the arm driving speed by the voice coil motor M2.
Here, the operations of the transistors Tr21 to Tr24 are controlled by the retract controller 50, and the switch SW2 is also controlled to be turned on / off by a control signal from the retract controller 50. As will be described later, the transistors Tr21 to Tr24 are retracted so that the arm speed falls within a predetermined range while repeatedly supplying the drive voltage to the voice coil motor M2 and measuring the back electromotive force by the analog-digital conversion circuit 54. It is controlled by the control unit 50.

  Next, returning to FIG. 1, the power supply system and control system circuits in the disk drive device according to the present embodiment will be described.

  The transistor Tr1 connects a power supply line P3P3V to which a voltage (eg, 3.3 volts) from an external power supply (not shown) is applied to the internal power supply line ISO3V. The transistor drive circuit 52 turns on the transistor Tr1 during normal operation and turns off the transistor Tr1 during retract operation according to the control signal of the retract control unit 50. As a result, the internal power supply line ISO3V is connected to the power supply line P3P3V during normal operation, and is disconnected from the power supply line P3P3V during retraction.

  The anode of diode D1 is connected to power supply line P3P3V, and its cathode is connected to power supply line ISO3V. As a result, when the external power supply is not stopped during the retraction operation, power can be supplied from the power supply line P3P3V to the power supply line ISO3 via the diode D1.

  The capacitor C10 is connected between the power supply line ISO3V and the ground line VGND, and holds the power supply voltage supplied to the motor (M1, M2) and the like during the retraction operation.

  The clamp circuit 64 is connected between the power supply line ISO3V and the ground line VGND, and clamps the power supply voltage so as not to exceed a predetermined upper limit value.

  The charge pump circuit 16 boosts the voltage of the power supply line P3P3V connected to the external power supply during normal operation. For example, the charge pump circuit 16 boosts the voltage of 3.3 volts of the power supply line P3P3V to 8 volts. The capacitor C11 is connected between the terminal V8 and the ground line VGND, and receives the voltage boosted by the charge pump circuit 16.

  The switch SW1 is provided between the output of the charge pump circuit 16 and the terminal V8, and is on / off controlled by the retract control unit 50. That is, the switch SW1 is turned on during normal operation and turned off during retraction.

The regulator circuit 62 generates a voltage of about 6 volts based on the output voltage of the charge pump circuit 61 during the normal operation in which the switch SW1 is turned on. On the other hand, the regulator circuit 62 is turned off during the retraction operation in which the switch SW1 is turned off, and the terminals V8 and V6 are electrically disconnected.
The capacitor C12 is connected between the terminal V6 and the ground line VGND, and receives a voltage of 6 volts generated in the regulator circuit 62.

  The voltage of 6 volts at the terminal V6 is used for circuit driving (for example, driving of the transistors of the motor driving units 10 and 30) during the retraction operation.

  The regulator circuit 63 generates a power supply voltage and a reference voltage for a circuit used during the retraction operation. For example, the regulator circuit 63 includes a power circuit for an analog circuit, a power circuit for a digital circuit, a band gap circuit that generates a reference voltage, and the like. The regulator circuit 63 is configured to operate with lower power consumption than a power supply circuit used during normal operation.

The transistor Tr2 is connected between the terminal V8 and the power supply line ISO3V. The transistor drive circuit 53 applies a predetermined voltage Vg to the gate of the transistor Tr2 during the retraction operation according to the control of the retract control unit 50.
When the voltage Vg is applied to the gate of the transistor Tr2, the transistor Tr2 becomes conductive, and a charging current flows from the capacitor C11 of the terminal V8 to the capacitor C10 of the power supply line ISO3V. When the difference between the voltage of the power supply line ISO3V and the output voltage Vg of the transistor drive circuit 53 becomes smaller than the threshold voltage Vt of the transistor Tr2 due to the charging of the capacitor C10, the transistor Tr2 is turned off and charging is stopped. Thus, when the voltage of the capacitor C11 is sufficiently higher than the voltage of the power supply line ISO3V, the power supply line ISO3V is maintained at a predetermined voltage Vm (= Vg−Vt).

  The retraction control unit 50 controls each circuit of the disk drive device so that a retraction operation is performed when an abnormality such as a power supply voltage, an environmental temperature, or a rotation speed of the spindle motor 30 is detected.

When starting the retraction operation, the retraction control unit 50 sets the transistor Tr1 to off to disconnect the internal power supply line ISO3V from the power supply line P3P3V, and sets the switch SW1 to off to connect the capacitor C11 to the charge pump circuit 61. Disconnect from output. The retract control unit 50 controls the signal selection circuit 24 to input the drive signal of the transistor drive unit 20 to the motor drive unit 10 and controls the signal selection circuit 44 to transfer the drive signal of the transistor drive unit 40 to the motor. Input to the drive unit 30.
Then, the retract control unit 50 controls the transistor driving unit 40 to supply a driving voltage to the voice coil motor M2, and moves the arm in the retracting direction. At this time, the retract control unit 50 acquires the measured value of the back electromotive force as needed by the analog-digital conversion circuit 54, and controls the polarity of the drive voltage and the application timing (duty) according to the measured value. The arm speed is controlled to be within a predetermined range.
When the voice coil motor M2 is driven, the power supply voltage of the power supply line ISO3V is lowered. At this time, the retract control unit 50 controls the transistor drive circuit 53 so that a predetermined voltage Vg is applied to the gate of the transistor Tr2, and the capacitor By charging capacitor C10 with the charge of C11, a decrease in power supply voltage is suppressed.
Further, the retract control unit 50 controls the transistor drive unit 20 so that the counter electromotive force of the spindle motor M1 that rotates by inertia is rectified and output to the power supply lines (ISO3V, VGND). In this case, the retract control unit 50 alternately increases the back electromotive force of the spindle motor M1 and outputs it to the power supply line ISO3V by alternately repeating the rectification mode and the short-circuit mode.

  Here, the disk drive device according to the present embodiment having the above-described configuration will be described focusing on the operation at the time of retraction.

In normal operation, the transistor Tr1 is turned on, and the voltage (3.3V) from the external power supply is supplied to the internal power supply line ISO3V via the power supply line P3P3V. At this time, the switch SW1 is turned on, and the charge pump circuit 61 charges the capacitor C11 to 8 volts.
In normal operation, the drive signal of the transistor drive unit 22 is input to the motor drive unit 10 via the signal selection circuit 24, and the drive signal of the transistor drive unit 42 is input to the motor drive unit 30 via the signal selection circuit 44. Is done. As a result, the transistors (Tr11 to Tr16, Tr21 to Tr24) of the motor drive units 10 and 20 are on / off controlled by a control unit (not shown), and the rotation of the spindle motor M1 and the forward / backward movement of the voice coil motor M2 are controlled. .

  When an abnormality is detected in the rotation speed, power supply voltage, etc. of the spindle motor M1 during this normal operation, the retracting operation is started. The transistor Tr1 is turned off under the control of the retract control unit 50. As a result, since the power supply line P3P3V connected to the external power supply is cut off from the internal power supply line ISO3V, for example, even when the voltage of the external power supply is reduced, no current flows from the power supply line ISO3V to the power supply line P3P3V. At this time, since the switch SW1 is turned off, the charge of the capacitor C11 is prevented from being discharged to the power supply line P3P3V via the charge pump circuit 61.

  When the switch SW1 is turned off, the regulator circuit 62 stops operating, and the terminal V8 and the terminal V6 are disconnected. The regulator circuit 63 generates a power supply voltage for each circuit (retract control unit 50, clock generation circuit, etc.) involved in the retraction operation based on the output voltage of the capacitor C12.

During the retraction operation, the signal selection circuit 24 selects the drive signal for the transistor drive unit 20 and inputs it to the motor drive unit 10. Thus, the conduction state of each transistor (Tr11 to Tr16) of the motor driving unit 10 that drives the spindle motor M1 is controlled by the retract control unit 50.
At this time, the signal selection circuit 44 selects the drive signal of the transistor drive unit 42 and inputs it to the motor drive unit 30. Thereby, each transistor (Tr21-Tr24) of the motor drive part 30 which drives the voice coil motor M2 is ON / OFF-controlled by the retract control part 50.

  When retraction is started, first, the low-side transistors Tr22 and Tr24 of the motor drive unit 30 are turned on and the high-side transistors Tr21 and Tr23 are turned off in order to zero the current flowing through the voice coil motor M2. Thus, the input terminals (VCA, VCB) of the voice coil motor M2 are short-circuited to the ground line VGND. In addition, the movement of the head can be controlled by applying a brake to the voice coil motor M2.

Next, a drive voltage is applied to the voice coil motor M2 so as to move the arm in the retracting direction.
For example, it is assumed that the polarity at which the voltage of the terminal VCB is higher than the voltage of the terminal VCA is “positive”, the opposite polarity is “negative”, and the arm moves in the retracting direction by applying a positive driving voltage. . In this case, in order to move the arm in the retracting direction, the transistors Tr23 and Tr22 are turned on and the transistors Tr21 and Tr24 are turned off. As a result, the terminal VCB is connected to the power supply line ISO3V, and the terminal VCA is connected to the ground line VGND.

  After a positive voltage is applied to the voice coil motor M2 for a certain time, the back electromotive force generated between the terminals VCA and VCB is detected in the analog-digital conversion circuit 54. That is, the transistors Tr21, Tr23, Tr24 are turned off, and the supply of the drive voltage to the voice coil motor M2 is stopped. Further, the transistor Tr22 is turned on, and the terminal VCA is connected to the ground line VGND. In this state, the switch SW2 is turned on, and the back electromotive force generated between the terminal VCA and the terminal VCB is input to the analog-digital conversion circuit 54. In the analog-digital conversion circuit 54, the voltages at the terminals VCA and VCB are sampled, and the digital conversion result is input to the retract control unit 50.

The retract control unit 50 adjusts the polarity of the driving voltage of the voice coil motor M2 and the timing of application thereof so that the arm speed is within a certain range based on the digital value input from the analog-digital conversion circuit 54. Is done.
For example, if the digital value indicates that the arm speed has not reached a certain range, a positive drive voltage is input to the voice coil motor M2 for a certain period of time in order to further accelerate the arm. . In this case, similarly to the above, the transistors Tr23 and Tr22 are turned on, and the transistors Tr21 and Tr24 are turned off. On the other hand, when the digital value indicates that the arm speed exceeds a certain range, a negative drive voltage is input to the voice coil motor M2 for a certain period of time in order to decelerate the arm. In this case, the transistors Tr21 and Tr24 are turned on, and the transistors Tr22 and Tr23 are turned off. When the digital value indicates that the speed of the arm is within a certain range, the state where the supply of the drive voltage is stopped is maintained, and the measurement of the back electromotive force by the analog-digital conversion circuit 54 is repeated.

  By the way, when the voice coil motor M2 is driven as described above, the charge of the capacitor C10 is discharged by the power consumption, and the power supply voltage of the power supply line ISO3V is lowered. Therefore, during the retraction operation, as shown in FIG. 4, the voltage of 8 volts of the capacitor C11 is used for charging the capacitor C10. That is, under the control of the retract control unit 50, the predetermined voltage Vg is supplied from the transistor drive circuit 53 to the gate of the transistor Tr2, and the transistor Tr2 is turned on. Since the charge of the capacitor C11 flows to the capacitor C10 through the transistor Tr2, the power supply voltage of the power supply line ISO3V is a constant voltage Vm that is lower than the output voltage Vg of the transistor drive circuit 53 by the threshold voltage Vt. Maintained.

  However, if the charge of the capacitor C11 continues to decrease due to the discharge, the voltage Vm defined by the output voltage Vg of the transistor drive circuit 53 and the threshold voltage Vt cannot be maintained. Therefore, in the disk drive device according to the present embodiment, the back electromotive force of the spindle motor M1 is rectified as shown in FIG. A rectifying operation for outputting to the power supply lines (ISO3V, VGND) is performed.

  The drive driving apparatus according to the present embodiment can rectify the back electromotive force by, for example, two methods.

  In the first rectification method, the transistor driver 20 always operates in the rectification mode. In this case, the terminal having the highest voltage among the three terminals (U, V, W) of the spindle motor M1 and the voltage higher than the power supply line ISO3V is connected to the power supply line ISO3V. Further, the terminal having the lowest voltage among the three terminals (U, V, W) and having a voltage lower than that of the terminal ICOM is connected to the terminal ICOM.

  On the other hand, in the second rectification method, the transistor driver 20 operates alternately in the short-circuit mode and the rectification mode. In the short circuit mode, the three terminals (U, V, W) of the spindle motor M1 are short-circuited to the ground line VGND. Thereby, the current according to the back electromotive force accompanying rotation and the conducting wire resistance of each coil flows through the three coils (LU, LV, LW). When the short-circuit mode is canceled and the mode is changed to the rectification mode, the magnetic energy stored in each coil is output as a surge voltage to the power supply line (ISO3V, VGND). Generated.

  In the drive driving apparatus according to the present embodiment, the transistor driving unit 20 is controlled so as to enable rectification by the above-described rectification method from the beginning of the retract operation, for example. In the initial stage of the retraction operation, the voltage of the power supply line ISO3V is maintained by the current of the capacitor C11, and the voltage of the power supply line ISO3V is higher than the three terminals U, V, and W of the spindle motor M1, so Is not done. At this time, no power is input from the power supply line ISO3V to the spindle motor M1. As the capacitor C11 is discharged, the voltage of the power supply line ISO3V decreases, and when the voltage of the power supply line ISO3V becomes lower than the three terminals U, V, and W of the spindle motor M1, the back electromotive force rectification operation is automatically started. The

  FIG. 5 is a diagram exemplifying changes in the voltage (V8) of the capacitor C11 and the voltage of the power supply line ISO3V during the retraction operation. The shaded portion in the figure indicates the voltage obtained by rectifying the counter electromotive force of the spindle motor M1.

When the voltage (V8) of the capacitor C11 decreases due to discharge and becomes lower than “Vm + Vt” at time t1, the voltage of the power supply line ISO3V decreases in conjunction with the voltage of the capacitor C11.
At time t2, when the voltage of the power supply line ISO3V becomes lower than the voltages of the terminals U, V, and W of the spindle motor M1, the motor drive unit 10 is configured so that the counter electromotive force of the spindle motor M1 is rectified and output to the power supply line ISO3V. The conduction state of each transistor is controlled. Thereby, the voltage drop of power supply line ISO3V interlocked with the voltage drop of capacitor C11 is suppressed. The voice coil motor M2 is driven stably based on the counter electromotive force of the spindle motor M1.

On the other hand, FIG. 6 is a diagram for explaining a case where the back electromotive force of the spindle motor M1 is not rectified until a certain time has elapsed. This corresponds to the conventional method of switching the power supply method to the voice coil motor according to a predetermined timer value.
In the example of FIG. 6, since the back electromotive force of the spindle motor M1 is not rectified until a predetermined time t3 is reached, the voltage of the power supply line ISO3V has dropped to zero volts before that. If the power supply line ISO3V becomes zero volts and the driving power is not supplied to the voice coil motor M2, the torque of the voice coil motor M2 decreases, so that the arm may return to the disk side due to impact or the like. In the drive device according to the present embodiment, the rectification of the back electromotive force is not started based on the timer value as shown in FIG. 6, but automatically according to the voltage drop of the power supply line ISO3V as shown in FIG. Thus, the back electromotive force rectification is started. Therefore, the problem due to the torque reduction of the voice coil motor M2 as described above is avoided.

  Next, an example of the voltage waveform of each node obtained by simulation in each case of the first rectification method and the second rectification method described above will be shown.

FIG. 7 is a diagram illustrating an example of simulation waveforms of the voltage (V8) of the capacitor C11, the voltage of the power supply line ISO3V, and the terminal voltage (U, V, W) of the spindle motor M1 in the first rectification method.
In the example of FIG. 7, the rectification operation starts around 3 [msec], and the pace of the voltage drop of the power supply line ISO3V is moderated.

  In FIG. 7, a period Tdet in which the voltage of the power supply line ISO3V and the voltage (V8) of the capacitor C11 are substantially equal appears repeatedly, but this is reversed by stopping the supply of the drive voltage to the voice coil motor M2. Corresponds to the period during which electromotive force is measured. During this period, almost no current flows through the voice coil motor M2, so the voltage drop of the transistor Tr2 is small.

On the other hand, FIG. 8 is a diagram showing examples of simulation waveforms of the voltage (V8) of the capacitor C11, the voltage of the power supply line ISO3V, and the terminal voltage (U, V, W) of the spindle motor M1 in the second rectification method. is there.
The terminal voltage (U, V, W) due to the counter electromotive force is about 1.4 volts at the peak, but the terminal voltage (U, V, W) at the time of transition from the short-circuit mode to the rectification mode rises to around 3 volts. To do. As a result, in the second rectification method, the voltage of the power supply line ISO3V is increased to around 3V.

  As described above, according to the present embodiment, during the retraction operation, the back electromotive force of the spindle motor M1 is rectified by blocking the input of power from the power supply line ISO3V to the spindle motor M1, and the power supply line (ISO3V , VGND (or ICOM)), the transistors (Tr11 to Tr16) of the motor driving unit 10 are controlled. Thereby, when the voltage of the power supply line (ISO3V, VGND) becomes lower than the rectified voltage of the counter electromotive force, the rectified voltage is automatically output to the power supply line (ISO3V, VGND). As in the conventional device for switching the power supply, the voltage of the power supply lines (ISO3V, VGND) temporarily decreases, and the problem that the drive power cannot be supplied to the voice coil motor M2 can be avoided.

  Further, according to the present embodiment, each terminal (U, V, W) of the spindle motor M1 is short-circuited to the terminal ICOM, and the power to the spindle motor M1 from the power supply line (ISO3V, VGND (or ICOM)) is reduced. The rectification mode in which the back electromotive force of the spindle motor M1 is rectified and output to the power supply lines (ISO3V, VGND) while the input is blocked is alternately repeated. This makes it possible to output a higher voltage to the power supply lines (ISO3V, VGND) than when the back electromotive force of the pindle motor M1 is directly rectified.

Generally, in a hard disk drive device, the back electromotive force of a spindle motor tends to decrease as the disk size decreases. When the back electromotive force is small, the rectified voltage is also small, so that it is difficult to supply a voltage sufficient for the retraction operation to the voice coil motor. In this case, in the conventional apparatus, it is necessary to drive the voice coil motor by the charging voltage of the capacitor, and it is necessary to increase the capacity of the capacitor in order to obtain a sufficient driving time.
According to the present embodiment, a voltage larger than the back electromotive force of the spindle motor can be generated by alternately repeating the short-circuit mode and the commutation mode, so that even when the back electromotive force of the spindle motor is small, the increase in the capacity of the capacitor is suppressed. Can do.

  In addition, according to the present embodiment, since the voltage drop rate of the power supply line ISO3V is relatively reduced by generating a voltage larger than the back electromotive force of the spindle motor M1, the voice coil motor is used for a long time. M2 can be driven. As a result, it is possible to lengthen the time for driving the voice coil motor M2 so as to keep the head in the safe area, and therefore it is possible to effectively prevent the head from rebounding from the safe area.

  Furthermore, according to the present embodiment, the voice coil motor M2 is controlled so that the arm speed falls within a predetermined range in the retracting operation, so that the motor driving is performed as compared with a method in which a constant voltage is continuously applied to the voice coil motor. Electric power can be reduced. Thereby, the capacity | capacitance of the capacitor (C11) which supplies drive electric power to a voice coil motor in retract operation | movement can be suppressed.

  As mentioned above, although several embodiment of this invention was described, this invention is not limited only to embodiment mentioned above, Various modifications are included.

For example, in another embodiment of the present invention, the first rectification method and the second rectification method described above may be switched in accordance with the voltage of the power supply line (ISO3V, VGND (or ICOM)). For example, the retract control unit 50 monitors the voltage of the power supply line (ISO3V, VGND (or ICOM)) with the voltage detection circuit, and when the voltage becomes lower than a predetermined threshold, the second rectification described above. Rectification by a method may be performed.
Thereby, in the first half of the retract, the charge of the capacitor C11 is mainly used for driving the voice coil motor M2, and when the voltage of the capacitor C11 is lowered to a certain level, the back electromotive force of the spindle motor M1 is changed to that of the voice coil motor M2. Used for driving.

  In another embodiment of the present invention, the application time of the drive voltage input to the voice coil motor M2 may be changed according to the digital value of the analog-digital conversion circuit 54. That is, as the error with respect to the standard value of the arm speed is larger, the application time of the drive voltage may be longer.

M1 ... spindle motor,
M2 ... Voice coil motor,
10, 30 ... motor drive unit,
12 ... Retract damping resistor,
20, 22, 40, 42 ... transistor driver,
201-206, 401-404 ... gate drive circuit,
24, 44 ... signal selection circuit,
50: Retract control unit,
51. Clock generation circuit,
52, 53 ... transistor drive circuit,
54. Analog-digital conversion circuit,
61 ... Charge pump circuit,
62, 63 ... regulator circuit,
64 ... clamp circuit,
SW1 to SW3, SW11 to SW16, SW21 to SW24, switches,
Tr1, Tr2 ... transistors,
C10 to C12 capacitors,
D1 ... diode,
R1-R5, RG ... resistance,
LU, LV, LW ... Coil

Claims (1)

A first motor for rotating the disk-shaped recording medium and a second motor for moving the head for accessing information on the disk-shaped recording medium are controlled based on the power supplied to the first power line and the second power line. A motor control device,
A first motor drive unit including a plurality of transistors connecting the first power supply line and the second power supply line and a plurality of input terminals of the first motor;
In an emergency operation of retracting the head to a safe area, the back electromotive force generated at the plurality of input terminals of the first motor is compared with the voltage of the first power supply line and the voltage of the second power supply line, and the comparison Depending on the result, the power input from the first power line and the second power line to the first motor is blocked and the counter electromotive force generated by the first motor is rectified to rectify the first power line. And a first motor control unit that controls each transistor of the first motor driving unit to output to the second power line,
A motor control device.