DISK DRIVE

• US 20100302670A1
• Filed: 03/10/2010
• Published: 12/02/2010
• Est. Priority Date: 05/31/2009
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Yamashita, Masaki, Ota, Chisako, Wasa, Nobuhiko
• Granted Patent: US 8,497,641 B2
• Time in Patent Office: Days
• US Class Current: 360/55
• CPC Class Codes: G11B 19/20 Driving; Starting; Stopping; Control thereof
• CPC Class Codes: G11B 21/12 Raising and lowering; Back-spacing or forward-spacing along track; Returning to starting position otherwise than during transducing operation
• CPC Class Codes: H02P 6/34 Modelling or simulation for control purposes

Abstract

To provide a disk drive capable of inhibiting the occurrence of acoustic noise caused by a voltage pulse when the head is retracted using a speed control method using voltage obtained by rectifying a back electromotive force after the power source has been cut off from the rotation of a spindle motor. Retraction control circuit is used to control the on and off modes of transistors in accordance with the speed of VCM. The voltage across VCM becomes a voltage that can be regulated with VCM voltage control circuit. At this time, voltage is supplied to the terminals based on the voltage of ISO5V that is the rectified voltage of the back electromotive force of the spindle motor and the pulsating voltage is synchronized and produced at both terminals. As a result, the potential difference across VCM is such that the pulsating voltage is negated and acoustic noise is inhibited.

Claims

1. A disk drive used to generate a drive voltage for a second motor used to move a head when the head is used to read or record information on a disk-shaped recording medium based on a rectified voltage with a rectified back electromotive force generated by a first motor used to turn the abovementioned disk-shaped recording medium, the invention characterized as a disk drive provided with

a detection device used to detect the abovementioned head,

a motor drive means used to apply positive polarity or negative polarity to the abovementioned second motor in accordance with input control signals and to adjust the abovementioned drive voltage so that it is constant without relying on a pulsating current component of the abovementioned rectified voltage, and

a control means used to output the abovementioned control signals used to control the abovementioned drive voltage in accordance with the above-mentioned detection means so that the abovementioned head is provided with a prescribed speed.

2. The disk drive described in claim 1 wherein the abovementioned control means is used to adjust the abovementioned polarity and output timing of the abovementioned drive voltage in accordance with the output results of the abovementioned detection means so that the abovementioned head is provided with a prescribed speed.

3. The disk drive described in claim 2 wherein the abovementioned motor drive means makes adjustments so that the drive voltage approaches the reference voltage set in accordance with the abovementioned control signals,

and the abovementioned control means is used to further output the abovementioned control signals used to set the abovementioned reference voltage in accordance with the detection results of the abovementioned detection means.

4. The disk drive described in claim 3, provided with a first voltage supply line and a second voltage supply line, used to supply the abovementioned rectified voltage, wherein the abovementioned motor drive means is provided with

a first drive voltage supply means that is used when the abovementioned drive voltage having positive polarity is applied to the abovementioned second motor, and when a first input node of the abovementioned second motor is connected to the abovementioned first voltage supply line and the abovementioned negative polarity drive voltage is applied to the abovementioned second motor, connects the input node of the abovementioned second motor to the abovementioned first voltage supply line, and with a

second drive voltage supply means used to adjust the voltage occurring between the abovementioned first input node and the abovementioned second voltage supply line so that said drive voltage approaches the abovementioned reference voltage when the abovementioned drive voltage having positive polarity is applied to the above-mentioned second motor and to adjust the voltage occurring between the abovementioned second input node and the abovementioned second voltage supply line so that said drive voltage approaches the abovementioned reference voltage and the above-mentioned drive voltage having negative polarity is applied to the abovementioned second motor.

5. The disk drive described in claims 1 wherein the abovementioned motor drive means is used to detect the back electromotive force generated by the abovementioned second motor while the abovementioned motor drive means is not applying the abovementioned drive voltage to the abovementioned second motor.

6. The disk drive described in claim 4 also having a rectifying circuit that is used to output the abovementioned rectified voltage obtained by rectifying the back electromotive force generated by using a poliphase coil comprising the above-mentioned first motor between the first voltage supply line and the abovementioned second voltage supply line when the abovementioned head is retracted.

7. The disk drive described in claim 6 wherein the abovementioned first drive voltage supply means is provided with a first transistor placed between the abovementioned first voltage supply line and the abovementioned first input node, and

a second transistor placed between the abovementioned first voltage supply line and the abovementioned second input node,

wherein the abovementioned second drive voltage supply means is provided with

a third transistor placed between the abovementioned first input node and the abovementioned second voltage supply line,

a fourth transistor placed between the abovementioned second input node and the abovementioned second voltage supply line and

a transistor control means used to control a transistor selected in accordance with the abovementioned polarity from between the abovementioned third transistor and the abovementioned fourth transistor so that the potential difference between the abovementioned first input node and the abovementioned second input node approaches the abovementioned reference voltage.

8. The disk drive described in claim 7 wherein in an unloading operation, the abovementioned first and fourth transistors are turned off, the abovementioned second transistor is turned on and the abovementioned transistor control means selects and controls the abovementioned third transistor, and

in a loading operation, the abovementioned first transistor is turned on, the abovementioned second and third transistors are turned off, and the above-mentioned transistor control means selects and controls the abovementioned fourth transistor.

9. The disk drive described in any of claims 7 wherein the above-mentioned motor drive means controls the abovementioned drive voltage so that the abovementioned drive voltage gradually rises and falls.

10. A motor control device used to supply the back electromotive force of a first motor between a first power source line and a second power source line, and supply electric power from said first power source line and second power source line to a second motor, thereby driving said second motor, the invention characterized as a motor control device comprising

a first rectifying circuit comprising a first transistor connected between a first terminal of the abovementioned first motor and the abovementioned first power source line and a first operational amplifier used to control the on and off modes for the abovementioned first transistor in accordance with the potential difference between the first terminal of the abovementioned first motor and the abovementioned first power source line,

a motor drive circuit comprising a seventh transistor used to connect the abovementioned first power source line and one terminal of the abovementioned second motor, an eighth transistor used to connect the abovementioned second power source line and the other terminal of the abovementioned second motor, and a drive control circuit used to control the voltage applied to a control terminal of the above-mentioned eighth transistor to control the drive voltage applied to the abovementioned second motor, and

a voltage control circuit used to detect the back electromotive force present between said second motor terminals when the abovementioned second motor is in a non-drive mode,

the abovementioned drive control circuit drives the abovementioned second motor in response to the voltage between the abovementioned second motor terminals detected by the abovementioned voltage control circuit.

11. The motor control device described in claim 10 that comprises a resistance circuit including a resistance element connected between a common terminal of the abovementioned first motor and the abovementioned second power source line.

12. The motor control device described in claim 10 wherein the abovementioned motor drive circuit comprises a ninth transistor used to connect the abovementioned first power source line and the other terminal of the above-mentioned second motor and a tenth transistor used to connect the abovementioned second power source line and one terminal of the abovementioned second motor, and when a current flows along the path of the abovementioned first power source line, the above-mentioned seventh transistor, the abovementioned second motor, the abovementioned eighth transistor and the abovementioned second power source line, the abovementioned drive control circuit controls the voltage of the control terminal of the abovementioned eighth transistor, and

when a current flows along the path of the abovementioned first power source line, the abovementioned ninth transistor, the abovementioned second motor, the abovementioned tenth transistor and the abovementioned second power source line, the abovementioned drive control circuit controls the voltage of the control terminal of the abovementioned tenth transistor.

13. The motor control device described in claim 12 comprising

a second rectifying circuit comprising a second operational amplifier used to control the on and off modes for the abovementioned second transistor in accordance with the differential voltage between the second transistor connected between the first terminal of the abovementioned first motor and the abovementioned second power source line and the first terminal of the abovementioned first motor and the abovementioned second power source line,

a third rectifying circuit comprising a third operational amplifier used to control the on and off modes for the abovementioned third transistor in accordance with the differential voltage between the third transistor connected between the second terminal of the abovementioned first motor and the aforementioned first power source and the second terminal of the abovementioned first motor and the abovementioned first power source line,

a fourth rectifying circuit comprising a fourth operational amplifier used to control the on and off modes of the abovementioned fourth transistor in accordance with the differential voltage between the fourth transistor connected between the second terminal of the abovementioned first motor and the abovementioned second power source line and the second terminal of the abovementioned first motor and the abovementioned second power source line,

a fifth rectifying circuit comprising a fifth operational amplifier used to control the on and off modes of the abovementioned fifth transistor in accordance with the differential voltage between the fifth transistor connected between the third terminal of the abovementioned first motor and the abovementioned first power source line and the third terminal of the abovementioned first motor and the abovementioned first power source line and

a sixth rectifying circuit comprising a sixth operational amplifier used to control the on and off modes for the abovementioned sixth transistor in accordance with the differential voltage between the sixth transistor connected between the third terminal of the abovementioned first motor and the abovementioned second power source line and the third terminal of the abovementioned first motor and the abovementioned second power source line,

wherein the abovementioned first motor is a three-phase DC motor, and the abovementioned second motor is a voice coil motor.

14. The motor control device described in any of claims 13 wherein the abovementioned motor drive circuit is used to control the rise and fall of the drive voltage applied to the abovementioned second motor so that they are gradual.