JP2008172854A - Disk apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly determine whether a spindle motor is failed by a short circuit in a disk apparatus. <P>SOLUTION: The disk apparatus 1 includes: the spindle motor 3 for rotating a disk 2; a calculation means 12 for calculating a discrimination value from an input voltage and an output voltage of the spindle motor 3; and a failure determination section 10 for determining whether the spindle motor 3 is failed or not based on the discrimination value. While the discrimination value is compared with a threshold value 500 times, the failure determination section 10 determines that the spindle motor 3 is failed when a state that three consecutive discrimination values are lower than the threshold value occurs 10 times. The failure determination section 10 correctly determines a failure in the spindle motor 3 without an effect of an unexpected change in the input voltage and the output voltage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a disk device including a DC motor that rotates a disk.

  In a disk device that records and reproduces an image or the like by rotating a disk such as a CD, CD-R, or DVD using a DC motor such as a spindle motor, dust is generated due to wear of the brush in the DC motor, The commutator in the DC motor may be short-circuited by the generated dust. When the commutator is short-circuited, the rotation of the spindle stops, so that the rotation of the disk stops. When the rotation of the disk is stopped, the control unit that controls the disk device increases the output current of the drive IC that drives the DC motor in order to increase the rotation speed of the spindle. The drive IC generates heat as the output current increases. The drive IC may malfunction due to heat generation and cause a large current to flow through the actuator. Further, when the rotation of the disk is stopped, the control unit cannot grasp the accurate operation of the actuator. Therefore, the control unit forcibly operates the drive IC to rotate the disk. At this time, a large current flows from the drive IC to the actuator, which may burn the cover of the actuator.

  Therefore, in Patent Document 1, it is determined whether or not to execute a short circuit detection process for detecting a short circuit of the drive circuit unit based on the voltage of the power supply unit that supplies drive power to the apparatus and the voltage of the drive circuit unit that drives the motor. Techniques for determining are disclosed. Further, in Patent Document 2, it is determined whether or not this voltage follows the pulse signal in a device that applies a voltage to the motor by turning the pulse signal on or off, and the voltage follows the pulse signal. Means for determining that a short circuit has occurred in the motor when the non-operating state continues for a predetermined time is disclosed.

However, in the technique disclosed in Patent Document 1, even when a short circuit detection process for detecting a short circuit of the drive circuit unit is executed, a failure due to a short circuit of the spindle motor that causes a large current to flow through the drive IC is detected. It could not be detected. Moreover, in the technique shown in Patent Document 2, in order to determine whether or not a short circuit is made based on the fact that the abnormal state of the voltage continues for a predetermined time, the state in which the motor is always short-circuited is detected. However, a part of the motor is short-circuited, and a state in which a short-circuited state and a non-short-circuited state are alternately generated by rotating the motor could not be detected.
JP-A-11-341323 JP 2001-298888 A

  The present invention has been made to solve the above problems, and in a disk device having a spindle motor for rotating a disk, it is possible to accurately determine whether or not the spindle motor has failed due to a short circuit, It is another object of the present invention to prevent the spindle motor from being driven when the spindle motor has failed due to a short circuit.

  In order to achieve the above object, a first aspect of the present invention provides a DC motor for rotating a disk, a drive unit for supplying an offset voltage to the DC motor via two voltage supply lines, and supply of the offset voltage to the drive unit. In a disk device comprising a control unit for instructing data and a reproduction unit for reading data recorded on the disk and performing reproduction processing based on the data, the DC motor is connected to two voltage supply lines, and the DC motor is A detector that detects the input voltage and the output voltage of the drive unit at least three times during a pause from when the playback unit stops reading data from the disk to when it resumes, and an input A failure determination unit that determines whether or not the DC motor has failed based on the voltage and the output voltage, and the failure determination unit receives the input voltage every time the input voltage and the output voltage are detected. And a calculation unit that calculates a ratio between the output voltage and the output voltage as a discriminant value, and the failure determination unit performs a comparison process that compares the discriminant value with a predetermined threshold value, and the comparison process is repeated at least 500 times. In the meantime, when the state where the discriminant value is continuously smaller than the threshold value occurs at least 10 times at least 10 times, it is determined that the DC motor has failed, and the control unit determines that the DC motor has failed by the failure determination unit. The drive unit is controlled so as not to drive the DC motor in response to the determination that the DC motor is present.

  According to a second aspect of the present invention, there is provided a DC motor for rotating a disk, a drive unit for supplying an offset voltage to the DC motor via two voltage supply lines, and a control unit for instructing the drive unit to supply the offset voltage. And a playback unit that reads data recorded on the disk and performs playback processing based on the data, and is connected to two voltage supply lines, and a DC motor rotates the disk A detector that continuously detects the input voltage and output voltage of the drive unit at the pause from when the playback unit stops reading data from the disk to when it resumes, and the input voltage and output voltage A failure determination unit that determines whether or not the DC motor has failed, and the failure determination unit determines whether or not the DC motor has failed based on the input voltage and the output voltage The control unit, in response to the determination that the DC motor by the failure determination unit is faulty, in which so as to control the driving unit so as not to drive the DC motor.

  The invention according to claim 3 is the disk device according to claim 2, wherein the failure determination unit further includes calculation means for calculating a ratio between the input voltage and the output voltage as a discriminant value every time the input voltage and the output voltage are detected. The failure determination unit compares the discriminant value with a predetermined threshold value, and the DC motor fails when the discriminant value is continuously smaller than the threshold value a predetermined number of times. It is determined that it is.

  According to the first aspect of the present invention, when the DC motor is rotating the disk and the playback unit pauses after reading data from the disk is stopped and restarted, the calculation unit outputs the input voltage and the output. Each time a voltage is detected, the ratio of the output voltage and the input voltage is calculated as a discriminant value, and the failure determination unit compares the discriminant value with a predetermined threshold value 500 times while the discriminant value is 3 It is determined that the DC motor has failed when 10 consecutive occurrences that are smaller than the threshold value occur 10 times. As a result, the failure determination unit is accurate without being affected by sudden changes in the input voltage or output voltage that occur when the disk is scratched or when the disk is rotating while being shaken by an eccentric component. It is possible to determine whether or not the DC motor has failed.

  According to the invention of claim 2, when the disk device is paused, the failure determination unit determines whether or not the DC motor has failed based on the input voltage and the output voltage, and the control unit determines whether the DC determination is performed by the failure determination unit. In response to determining that the motor has failed, the drive unit is controlled so as not to drive the DC motor. Thereby, the failure determination part can determine correctly whether the DC motor has failed. In addition, when it is determined that the DC motor has failed, the control unit controls the driving unit so as not to drive the DC motor. This prevents a large current from flowing through the actuator by causing a current to flow through the DC motor in which the drive unit is faulty, so that it is possible to prevent the cover of the actuator from burning.

  According to the invention of claim 3, the failure determination unit compares the discriminant value, which is the ratio between the input voltage and the output voltage, with a predetermined threshold value, and the discriminant value is continuously determined from the threshold value a predetermined number of times. When the state that becomes smaller occurs at least twice, it is determined that the DC motor has failed. Thereby, in addition to the effect of the invention described in claim 2, the failure determination unit can accurately determine whether or not the DC motor has failed according to the type and state of the disk device or the DC motor. .

  Hereinafter, a disk device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a disk device according to the present embodiment. The disk device 1 is connected between a spindle motor 3 (DC motor) that rotates the disk 2, a drive IC 4 (drive unit) that drives the spindle motor 3, and the spindle motor 3 and the drive IC 4. A differential operational amplifier 5 (detector) that detects an input voltage and an output voltage, a reproducing unit 6 that performs a reproducing process on the disk 2, and a control unit 7 that controls the entire disk device 1 are provided. The reproducing unit 6 includes a pickup unit 8 that reads information from the disk 2 and a signal processing unit 9 that performs decoding processing on the information read by the pickup unit 8.

  The control unit 7 is driven according to the determination of the failure determination unit 10 and a failure determination unit 10 that determines whether the spindle motor 3 has failed based on the input voltage and the output voltage output from the differential operational amplifier 5. And an IC control unit 11 for controlling the IC 4. The failure determination unit 10 includes a calculation unit 12 that calculates a ratio between an input voltage and an output voltage as a discrimination value. The signal processing unit 9 includes a memory 9 a that temporarily stores data read from the disk 2 by the pickup unit 8. Here, the disk 2 is, for example, a CD or a DVD.

  The IC control unit 11 notifies the drive IC 4 of the reference voltage VREF, which is a reference voltage, based on a signal representing the rotation state of the disk 2 received from the pickup unit 8 and further drives the spindle motor 3. Is instructed to supply an offset voltage Vf representing a deviation from the reference voltage. The drive IC 4 includes a terminal O1 and a terminal O2. The terminal O1 is connected to the brush B1 of the spindle motor 3 via the voltage supply line SP +, and the terminal O2 is connected to the brush B2 of the spindle motor 3 via the voltage supply line SP-. The drive IC 4 sets the voltages of the terminal O1 and the terminal O2 based on the reference voltage VREF and the offset voltage Vf instructed from the IC control unit 11. The non-inverting input terminal 5a of the differential operational amplifier 5 is connected to the voltage supply line SP +, and the inverting input terminal 5b is connected to the voltage supply line SP-. The differential operational amplifier 5 detects the voltage at the non-inverting input terminal 5 a as the input voltage of the spindle motor 3 and the voltage at the inverting input terminal 5 b as the output voltage of the spindle motor 3. The differential operational amplifier 5 outputs the detected input voltage and output voltage to the failure determination unit 10.

  When receiving the input voltage and the output voltage, the failure determination unit 10 causes the calculation unit 12 to calculate a determination value used to determine whether or not the spindle motor 3 has failed from the input voltage and the output voltage. Here, the discriminant value is calculated by dividing a value obtained by multiplying the output voltage by 1000 by the input voltage. The failure determination unit 10 determines whether or not the spindle motor 3 has failed based on the determination value. The failure determination unit 10 holds a predetermined threshold regarding the determination value as a reference for determining whether or not the spindle motor 3 has failed. The failure determination unit 10 determines that the spindle motor 3 has failed due to a short circuit when the determination value calculated by the calculation means 12 continuously exceeds the threshold value, and indicates that the spindle motor 3 has failed. The failure signal shown is transmitted to the IC control unit 11. When receiving the failure signal from the failure determination unit 10, the IC control unit 11 instructs the drive IC 4 not to drive the spindle motor 3. As a result, the failed spindle motor 3 is not driven, so that a large current is prevented from flowing through the drive IC 4 and the actuator cover is prevented from burning.

  FIG. 2 shows a schematic configuration of the spindle motor 3 in the present embodiment. The spindle motor 3 is a DC motor, and includes a brush B1 that is a positive terminal, a brush B2 that is a negative terminal, commutators C1 to C3, and coils L1 to L3. The brush B1 is connected to the voltage supply line SP +, and the brush B2 is connected to the voltage supply line SP-. The drive IC 4 supplies a direct current voltage to the brush B1 and the brush B2 via the voltage supply line SP + and the voltage supply line SP-, so that a direct current is a part of the commutators C1 to C3 and a part of the coils L1 to L3. Between the brush B1 and the brush B2. Thereby, the spindle motor 3 rotates.

  If the brushes B1 and B2 are worn by the rotation of the spindle motor 3, dust on the brushes B1 and B2 is generated. When the dust enters between the commutators C1 to C3, the brush B1 and the brush B2 are short-circuited. When the brush B1 and the brush B2 are short-circuited, the difference between the input voltage and the output voltage output from the differential operational amplifier 5 to the failure determination unit 10 is a value close to zero. Here, among the three gaps existing between the commutators C1 to C3, a state in which any two gaps are short-circuited is referred to as a complete short. Further, a state in which only one of the three gaps existing between the commutators C1 to C3 is short-circuited is referred to as a partial short. When the spindle motor 3 is completely short-circuited, the brush B1 and the brush B2 are always short-circuited, so that the commutators C1 to C3 do not rotate. On the other hand, when the commutator C1 to the commutator C3 rotate when the spindle motor 3 is partially shorted, a state where the brush B1 and the brush B2 are short-circuited and a state where the brush B2 is not short-circuited alternately appear. Become.

  Here, the discrimination value in the present embodiment will be described. FIG. 3 shows changes in the discrimination value according to the present embodiment. 3A shows a change in the discriminant value of the spindle motor 3 that is not short-circuited, and FIG. 3B shows a change in the discriminant value of the spindle motor 3 that is partially short-circuited. 3A and 3B, a graph showing a change in the discriminant value is a discriminant value change graph, the vertical axis shows the discriminant value, and the horizontal axis shows the number of times the discriminant value is calculated. In FIG. 3A, the discriminant value is a value from about 50 to about 68. On the other hand, in FIG. 3B, the discriminant value shows a value between about 57 and about 63 several times, then shows a value smaller than about 33 several times, and again a value between about 56 mV and about 68 mV. Is repeated several times, and the change indicating a value smaller than about 33 is repeated several times. When the discriminant value is smaller than about 33, the brush B1 and the brush B2 are short-circuited. On the other hand, when the discriminant value is larger than about 33, the brush B1 and the brush B2 are not short-circuited.

  The failure determination unit 10 uses the characteristics of the determination values of the failed spindle motor 3 and the non-failed spindle motor 3 shown in FIGS. Thus, it is possible to accurately determine whether or not the spindle motor 3 has failed based on whether or not it is smaller than the threshold value. The input voltage or the output voltage may suddenly change when the disk is scratched or when the disk rotates while being shaken by an eccentric component. Therefore, the failure determination unit 10 does not immediately determine that the spindle motor 3 has failed even when the determination value is continuously smaller than the threshold value three times, and determines the determination value as the threshold value. If the state in which the discriminant value is continuously smaller than the threshold value three times continuously occurs 10 times during the comparison of 500 times, the spindle motor 3 is determined to have failed. Thereby, the failure determination unit 10 can accurately determine the failure of the spindle motor 3 even when the input voltage and the output voltage change suddenly. Here, the threshold value is desirably “33”, for example.

  FIG. 4 shows a failure determination process flow of the spindle motor 3 according to the present embodiment. When the reproduction unit 6 starts the reproduction process, the failure determination unit 10 performs initialization to set the variable m, the variable i, the variable N, and the variable P to 0 (S101). Here, the variable m is used to count the number of times that the differential operational amplifier 5 detects the input voltage and the output voltage, and the variable i determines that the discriminant value becomes smaller than the threshold value three times in succession. Used for The variable N is used to determine whether or not the state in which the determination value is continuously three times smaller than the threshold value has occurred 10 times, and the variable P has a size between the determination value and the threshold value of 500. Used to determine whether or not the comparison has been made.

  When the failure determination unit 10 performs initialization, the control unit 7 determines whether or not a pause command is output from the signal processing unit 9 (S102). Here, the pause command is a command for stopping the pickup unit 8 from reading data from the disk 2. The speed at which the signal processing unit 9 performs the decoding process is slower than the speed at which the pickup unit 8 reads data from the disk 2. Therefore, the signal processing unit 9 temporarily stores the data read by the pickup unit 8 in the memory 9a. When the memory 9a is full, the pickup unit 8 reads the data from the disk 2 to the control unit 7. Outputs a pause command to stop. As a result, the pickup unit 8 stops reading data from the disk 2 until there is free space in the memory 9a.

  In step S102, when the pause command is output from the signal processing unit 9 (Yes in S102), the differential operational amplifier 5 detects the input voltage of the spindle motor 3 and outputs it to the failure determination unit 10 (S103). The output voltage of the spindle motor 3 is detected and output to the failure determination unit 10 (S104). When the input voltage and the output voltage are output to the failure determination unit 10, the calculation unit 12 calculates a discrimination value from the input voltage and the output voltage (S105). Here, since the output voltage is a voltage after passing through the differential operational amplifier 5, it is not an output voltage of only the spindle motor 3. Therefore, the calculation means 12 calculates the discriminant value by dividing the value obtained by multiplying the output voltage by 1000 by the input voltage in consideration of the output voltage passing through the differential operational amplifier 5.

  The failure determination unit 10 adds 1 to the variable P used to determine whether the determination value and the threshold value are compared 500 times (S106), and the differential operational amplifier 5 detects the input voltage and the output voltage. 1 is added to the variable m used to count the number of times (S107). Next, the failure determination unit 10 compares the discriminant value with a predetermined threshold value (S108). When the determination value is not smaller than the threshold value (No in S108), the failure determination unit 10 sets the variable i to 0 (S109), and proceeds to Step S112. On the other hand, when the determination value is smaller than the threshold value in step S108 (Yes in S108), the failure determination unit 10 determines whether or not the variable i is 3 (S110). In step S110, when the variable i is not 3 (No in S110), the failure determination unit 10 adds 1 to the variable i (S110). As a result, the failure determination unit 10 can increase the variable i until the determination value is continuously smaller than the threshold value three times.

  Next, the control unit 7 stops the operations of the failure determination unit 10 and the differential operational amplifier 5 for 1 ms (S112). The differential operational amplifier 5 in the present embodiment continuously detects the input voltage and the output voltage while the spindle motor 3 hardly rotates. Therefore, the control unit 7 stops the operations of the failure determination unit 10 and the differential operational amplifier 5 for 1 ms in order to cause the differential operational amplifier 5 to detect the input voltage and the output voltage in various rotation states of the spindle motor 3. The failure determination unit 10 determines whether or not the variable m is 21 (S113). When the variable m is not 21 (No in S113), since the differential operational amplifier 5 has not detected the input voltage and the output voltage 20 times, the process returns to Step S103, and the differential operational amplifier 5 detects the input voltage (S103). .

  On the other hand, in step S113, when the variable m is 21 (Yes in S113), the differential operational amplifier 5 detects the input voltage and the output voltage 20 times, so the failure determination unit 10 sets the variable m to 0 (S114). Next, the control unit 7 determines whether or not a release signal for releasing the pause command is output from the signal processing unit 9 (S115). When the release signal is not output (No in S115), the control unit 7 waits for the release signal to be output. On the other hand, when the release signal is output (Yes in S115), since the failure determination unit 10 does not determine that the spindle motor 3 has failed, the control unit 7 causes the reproduction unit 6 to continue the reproduction process ( S116). The failure determination unit 10 determines whether or not the variable P is 500 (S117). When the variable P is not 500 (No in S117), the process returns to step S102, and the control unit 7 determines whether or not a pause command is output from the signal processing unit 9 (S102). On the other hand, when the variable P is 500 in step S117 (Yes in S117), the failure determination unit 10 compares the discriminant value with the threshold value 500 times, so the process returns to step S101 to return the variable m, the variable i, Initialization is performed to set the variables N and P to 0 (S101).

  In step S110, when the variable i is 3 (Yes in S110), the determination value is continuously smaller than the threshold value three times. Therefore, the failure determination unit 10 sets the variable i to 0 (S118), and the determination value is continuous. Then, 1 is added to the variable N for counting that the state becomes smaller than the threshold value three times (S119). The failure determination unit 10 determines that the spindle motor 3 has failed if the state in which the discriminant value is continuously smaller than the threshold value three times occurs before the variable P reaches 500. Therefore, the failure determination unit 10 determines whether or not the variable N is 10 (S120). When the variable N is not 10 (No in S120), the failure determination unit 10 does not determine that the spindle motor 3 has failed, so the control unit 7 causes the reproduction unit 6 to continue the reproduction process (S116). On the other hand, when the variable N is 10 in step S120, the failure determination unit 10 determines that the spindle motor 3 has failed (Yes in S120). If it is determined that the spindle motor 3 has failed, the IC control unit 11 instructs the drive IC 4 not to drive the spindle motor 3, and the control unit 7 causes the reproduction unit 6 to stop the reproduction process (S121). ), The spindle motor 3 failure determination process is terminated.

As described above, in the present embodiment, the failure determination unit 10 generates a state in which the determination value is continuously smaller than the threshold value 10 times 10 times while comparing the determination value and the threshold value 500 times. At this time, it is determined that the spindle motor 3 has failed. As a result, the failure determination unit 10 can accurately determine whether or not the spindle motor 3 has failed. Further, when it is determined that the spindle motor 3 has failed, the control unit 7 causes the reproducing unit 6 to stop the reproduction process. Since the flow of a large current is avoided, the actuator cover can be prevented from burning.

In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible, for example,
The failure determination unit 10 is not configured to determine whether or not the spindle motor 3 has failed during the comparison between the determination value and the threshold value 500 times, but the determination value and the threshold value 300 times. During the comparison, it may be configured to determine whether or not the spindle motor 3 has failed. Further, the differential operational amplifier 5 may not be configured to detect the input voltage and the output voltage 20 times during the pause, but may be configured to detect the input voltage and the output voltage 20 times or more.

1 is a configuration diagram showing an outline of a disk device according to an embodiment of the present invention. The block diagram which shows the outline of the spindle motor which concerns on this embodiment. The figure which shows the change of the discriminant value which concerns on this embodiment. 7 is a failure determination process flowchart according to the present embodiment.

Explanation of symbols

1 disk device 2 disk 3 spindle motor (DC motor)
4 Drive IC (Driver)
5 Differential operational amplifier (detector)
6 Regeneration Unit 7 Control Unit 10 Failure Determination Unit 12 Calculation Means Vf Offset Voltage SP + Voltage Supply Line SP− Voltage Supply Line

Claims (3)

A DC motor that rotates the disk;
A drive unit for supplying an offset voltage to the DC motor via two voltage supply lines;
A control unit that instructs the drive unit to supply the offset voltage;
In a disk device comprising: a reproduction unit that reads data recorded on the disk and performs reproduction processing based on the data;
In a state where the DC motor is rotating the disk, connected to the two voltage supply lines, and the playback unit pauses reading data from the disk and restarts it. A detector that detects an input voltage and an output voltage of the drive unit at least three times;
A failure determination unit that determines whether or not the DC motor has failed based on the input voltage and the output voltage;
The failure determination unit
A calculation means for calculating a ratio between the input voltage and the output voltage as a discriminant value each time the input voltage and the output voltage are detected;
The failure determination unit performs a comparison process for comparing the magnitude of the discrimination value with a predetermined threshold value, and the discrimination value is continuously repeated at least 3 times while the comparison process is repeated at least 500 times. When the state smaller than the threshold occurs at least 10 times, it is determined that the DC motor has failed,
The disk device according to claim 1, wherein the controller controls the drive unit so as not to drive the DC motor in response to the failure determination unit determining that the DC motor has failed. A DC motor that rotates the disk;
A drive unit for supplying an offset voltage to the DC motor via two voltage supply lines;
A control unit that instructs the drive unit to supply the offset voltage;
In a disk device comprising: a reproduction unit that reads data recorded on the disk and performs reproduction processing based on the data;
In a state where the DC motor is rotating the disk, connected to the two voltage supply lines, and the playback unit pauses reading data from the disk and restarts it. A detector that continuously detects an input voltage and an output voltage of the drive unit;
A failure determination unit that determines whether or not the DC motor has failed based on the input voltage and the output voltage;
The failure determination unit
Determining whether the DC motor is faulty based on the input voltage and the output voltage;
The disk device according to claim 1, wherein the controller controls the drive unit so as not to drive the DC motor in response to the failure determination unit determining that the DC motor has failed. The failure determination unit
A calculation means for calculating a ratio between the input voltage and the output voltage as a discriminant value each time the input voltage and the output voltage are detected;
The failure determination unit compares the magnitude of the discriminant value with a predetermined threshold value, and when the discriminant value is continuously smaller than the threshold value by a predetermined number of times, the DC motor The disk device according to claim 2, wherein the disk device is determined to have failed.

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