KR100365619B1 - Method for starting spindle motor of disk driver - Google Patents

Abstract

PURPOSE: A method for starting a spindle motor of a disk driver is provided to use an open loop type motor ramp for a disk driver that operates a sensorless motor to control the initial operation of the motor. CONSTITUTION: A method for starting a motor of a disk driver that stores a ramp profile of a spindle motor includes a step(311) of initializing a profile table for motor ramp-up in a starting mode, a step of supplying starting current to the motor to initialize a rotator(313), a step of generating an appropriate frequency using an internal clock generation source to output the frequency to the motor and waiting for a predetermined period of time(315,317), and a step of performing a motor ramping operation using the initial profile(319). The method further includes a step of performing a normal rotation operation when spin-up of the motor is normal(323), and a step of changing the motor ramp profile when spin-up of the motor is abnormal and then repeating the motor ramping operation(325).

Description

How to Start Spindle Motor of Disk Driver

The present invention relates to a method of driving a spindle motor of a disk driver, and more particularly, to a method of initially driving a sensorless motor.

In general, a disk driver includes a spindle motor for rotating the disk and a head actuator for reading and writing data on the rotating disk. In addition, the function of controlling the driving of the head and the spindle motor is performed by a servo controller.

The block structure of the disk driver as described above may be configured as shown in FIG. FIG. 1 shows a block configuration of a hard disc driver (HDD).

FIG. 1 is a block diagram of a typical HDD, and includes four magnetic heads 12 each having two magnetic disks 10 correspondingly installed on each side of the disks 10, respectively. It will be shown an example provided with. With reference to FIG. 1, a conventional disc recording apparatus useful for understanding the present invention will be described. The disks 10 are rotated by a spindle motor 38.

The heads 12 are located on the corresponding one of the disks 10, and the disks 10 from the E-block assembly 14 coupled with the rotary voice coil actuator 32. It is installed to correspond to each of the support arms extending to the side. The preamplifier 16 preamplifies the signal picked up by one of the heads 12 when reading, and applies the analog read signal to the read / write channel circuit 18 and writes. Encoded write data applied from the read / write channel circuit 18 is recorded on the disc through a corresponding one of the heads 12 at the time. At this time, the preamplifier 16 includes switching means for selecting one of the heads 12 under the control of the disk data controller (DDC) 24 controlled by the microcontroller 26. An example of such a preamplifier is the read / write device SSI 32R2026R, an integrated circuit (IC) manufactured and marketed by silicon systems. The read / write channel circuit 18 detects and decodes a data pulse from a read signal applied from the preamplifier 16 to generate read data RDATA, and decodes the write data WDATA applied from the DDC 24 to decode the preamplifier. Is applied to (16). The read / write channel circuit 18 also demodulates the head position information which is a part of the servo information recorded on the disk to generate a position error signal (PES). An example of such a read / write channel circuit is a read channel SSI 32P4742 / 4742A / 4746 / 4746A having 1,7ENDEC, 4-burst Servo, ICs manufactured and sold by Silicon Systems. The PES generated from the read / write channel circuit 18 is applied to the analog-to-digital converter (ADC) 20 and the read data RDATA is applied to the track information detector 22 and the DDC 24. The ADC 20 converts the PES into a digital step value corresponding to its level and provides it to the microcontroller 26. The track information detector 22 detects a track number, etc., in which the current head is located, from the read data RDATA and provides it to the microcontroller 26. The DDC 24 is controlled by the microcontroller 26 and writes data received from the host computer through the read / write channel circuit 18 and the preamplifier 16 onto the disc or reads data from the host. Send to a computer. The DDC 24 also interfaces the communication between the host computer and the microcontroller 26. The microcontroller 26 controls the DDC 24 in response to read or write commands received from the host computer and controls track search and track following. At this time, the microcontroller 26 controls the track search and track following as described above by using the track number applied from the track information detector 22 and the PES value applied from the ADC 20. The digital-to-analog converter (DAC) 28 converts a control value for position control of the heads 12 generated from the microcontroller 26 into an analog signal. The servo driver 30 generates a driving current for driving the actuator 32 by a signal applied from the DAC 28 and applies it to the voice coil of the actuator 32. The actuator 32 is the servo driver 30. The heads 12 are moved on the disks 10 in correspondence with the direction and level of the driving current applied from the same. The motor controller 34 controls the spindle motor driver 36 according to a control value for controlling the rotation of the disks 10 generated from the microcontroller 26. The spindle motor driver 36 drives the spindle motor 38 to rotate the disks 10 under the control of the motor controller 34.

In the hard disk driver as shown in FIG. 1, the spindle motor driver has an initial driving circuit as shown in FIG. "HA13481A" manufactured and sold by Hitachi, Inc. has a circuit for minimizing reverse rotation of the spindle motor as shown in FIG. In order to drive a sensorless motor having the configuration as shown in FIG. 2, the minimum BEMF necessary for the commutation of the motor should be generated.

As described above, the minimum BPMF potential required for the rotation of the spindle motor is generated. When power is applied to the spindle motor driving circuit as shown in FIG. 2, the voltage of the STMON node is set to the low logic state by the capacitor C1. At this time, the output of the voltage controlled oscillator (VCO) 21 has a high frequency, and the high frequency causes the current to flow in the motor coil 25 so that the spindle motor rotates. After some time has elapsed (20-30 msec), when the voltage of the STMON node rises, the output frequency of the voltage controlled oscillator 21 transitions to low logic. The spindle motor rotates when the low frequency causes the spindle motor to fall below a self starting frequency.

The start-up method of the spindle motor as described above affects the head / disk at the time of starting the motor, for two reasons as follows. First, the head-to-disk damage due to the motor reverse rotation (clockwise direction) to detect BEMF required for the rotation of the motor. That is, even if the current position of the head is a parking area, even if there is no movement or movement of the head, there is a head damage due to the rotational movement of the disk, so even if the reverse rotation is minimized, the influence is affected. Secondly, the motor oscillation mode, which is applied as a way to solve sticktion that is likely to occur in high temperature and humidity environment (65 ℃, 80%), can solve the problem of stiction to some extent. However, there can be a significant degree of dedemaye between heads / disks.

As described above, driving a sensorless motor is more difficult than driving a brush motor. In order to detect the BEMF needed for the motor's rotation, the motor must be rotated to the minimum to generate the BEMF signal. However, the BEMF cannot be detected when the sensorless motor is initially driven. Therefore, a method for determining when to control the rotation should be introduced.

Accordingly, an object of the present invention is to provide a method for controlling initial driving of a motor by using an open loop motor ramping in a disk driver for driving a sensorless motor.

Another object of the present invention is to configure and store a motor ramp profile for initial driving of a motor using an internal clock in a disk driver, and to control the driving of the motor using the motor ramp profile during initial motor driving. In providing.

In order to achieve the above object of the present invention, a motor initial driving method of a disk driver for storing a ramping profile of a spindle motor includes an initialization process of supplying an initial current to the motor and performing an initial drive mode during initial driving, and the initialization process. Performing a motor ramping operation using the initial profile set after the execution, performing a normal rotation operation when the spin up of the motor is normal after ramping the motor, and performing an abnormal rotation of the motor after the motor ramping. After changing the lamp profile is characterized in that the motor ramping operation is performed repeatedly.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same parts in the figures represent the same reference signs wherever possible.

The block configuration of the disk driver for carrying out the present invention is the same as that in FIG. 1, and the reference numerals are the same.

First, as a new method for driving a motor, open-loop motor ramping works by first creating and registering a motor ramp profile for initial driving using an internal clock. The motor lamp profile as described above is configured by the following process.

Initially, the initializing state is performed by a microprocessor. At this time, if the commutator state is initialized to a specific value, there is an advantage that the rotor can be positioned.

When the first current flows into the motor, the motor moves forward and backward by one commutatoin angle in a given stator area and is aligned.

Secondly, the Startup Methods should accelerate the motor in an open loop with minimal RPM to detect BEMF. At this time, the commutation sequence is performed by the microprocessor based on a startup profile. This open loop method must be flexible whenever the motor or load conditions change. And two to three revolutions (revolution) is enough to drive the motor.

For example, in a 12-pole motor, the commutator sequence is 72 (12 x 2 x 3), but more open loop commutation sequencing steps must be constructed.

Third, Computing a startup profile is performed as follows.

The distance △ traveled for each rotation is calculated as in the following formula (1).

(where Nρ = motor pole, Nφ = number of phase)

Angular accenleration α under no friction is given by Equation 2 below.

(where Kt = torque const, Jθ = inertia)

In order to find the angular velocity at time t, integrating the angular acceleration W from T = 0 to t is given by the following equation (3).

In order to find the absolute value of the rotor position, the angular velocity is integrated from T = 0 to t as shown in the following formula (4).

Each moving distance can be calculated as follows.

θi = i × V

(i = each commutation sequence step range)

The instantaneous velocity at time t = ti can be calculated by the following equation (6).

The motor ramp profile can be implemented using the equations (1) to (6) above.

After implementing the motor ramp profile as described above, the off-loop motor driving method is driven in the same manner as in FIG. First, the microcontroller 26 initializes the profile table for the motor ramp-up in the initial driving mode in step 311. In step 313, the initial current is supplied to the motor to initialize the rotor in the stator area. Thereafter, the microcontroller 26 generates an appropriate frequency from the internal clock source in step 315 and outputs it to the spindle motor driver. In order to satisfy the above three initialization conditions, the microcontroller 26 performs a delay operation for a time set in step 317.

Thereafter, the microcontroller 26 performs a motor ramping operation with a start up profile set in step 319. Thereafter, the microcontroller 26 checks whether the spindle motor spins up in step 321. If the spin up is normal, the microcontroller 26 proceeds to step 323. In this case, since the spin up of the spindle motor is normally performed in step 323, the constant speed mode by the BEMF is performed until another interrupt signal such as brake and preset is generated.

However, if the spin up operation of the motor is abnormal in step 321, the motor profile is changed in step 325, and then the process returns to step 315 to repeat the above process and retry the initial driving of the motor.

That is, if the spin up of the motor is not performed normally, the time of the motor ramp profile is too small, and the profile is modified and retried in a flexible condition.

As described above, when the sensorless motor is initially driven, the motor ramping profile is created, and then the motor is ramped in the open loop method, so that the initial driving of the motor can be efficiently performed in the disk driver.

1 is a block diagram showing a block configuration of a disk driver.

2 is a diagram showing the configuration of a conventional spindle motor drive unit in FIG.

3 is a flowchart illustrating a process of initially driving a spindle motor in a disk driver according to the present invention.

Claims (2)

In the motor initial drive method of the disk driver for storing the ramping profile of the spindle motor, Initial driving the motor by using an initial motor ramp profile set at initial driving, Performing a normal rotation operation when the spin up of the motor is normal after the ramping; And repeating the motor ramping operation after changing the motor ramp profile when the spin up of the motor is abnormal after the ramping. In the motor initial drive method of the disk driver for storing the ramping profile of the spindle motor, Initializing the profile table for the motor ramp-up in the initial driving mode; Initializing the rotor in the stator area by supplying an initial driving current to the motor; Generating a proper frequency by an internal clock source and outputting the motor to the motor and waiting for a set time; Performing a motor ramping operation using the initial profile set after the waiting process; Performing a normal rotation operation when the spin up of the motor is normal after the motor ramping; And repeating the motor ramping operation after changing the motor ramp profile when the spin up of the motor is abnormal after the ramping of the motor.