Method for controlling the spindle motor speed of an audio/video disk player

A method for controlling speed of a spindle motor within a disk player is provided. The spindle motor drives a disk thereon and the disk player includes a control circuit. The method comprises the steps of: (1) set speed of the spindle motor to operate at a Nominal speed; (2) test if disk data access operation has not occurred for a predetermined amount of time; (3) if result of step 2 is YES, set the spindle motor running at a speed which is between zero and the Nominal speed.

TECHNICAL FIELD OF INVENTION 
The invention relates to an optical information reproduction apparatus and, 
in particular, power saving method of the optical information reproduction 
apparatus. 
BACKGROUND OF INVENTION 
Optical disk player such as digital audio-video disc player or information 
disc apparatus is basic component of the state-of-art multi-medium 
computer system. 
The prior art control systems for the information disk apparatus known to 
the inventors of this invention includes the U.S. Pat. Nos. 4,485,337, 
4,783,774, 5,289,097, 5,246,1019 and 5,345,3101. 
The U.S. Pat. No. 4,485,337 discloses a servo data driven motor speed 
control. The disclosure uses the servo data present on all disk drives to 
provide an indication of rotational velocity. The circuit ordinary 
associated with the disk drive's servo system is utilized by the 
disclosure to recover the sync pulses present in each frame of servo data. 
The invention then couples the recovered sync pulses into the speed 
control circuit. The speed control circuit compares the frequency of the 
recovered sync pulses with the frequency of a reference oscillator. The 
result of the comparison is used to adjust the selection of a 
predetermined number of duty cycles of power application to the disk 
motor. The period of the duty cycle is determined by the frequency of the 
sync pulses. 
The U.S. Pat. No. 4,783,774 discloses a control system for driving an 
optical information reproducing apparatus at a relatively low power 
consumption and a high power conversion efficiency. The disclosure employs 
a circuit for producing a response control signal and a drive circuit for 
applying the turntable motor or the pickup transfer motor with a power 
supply voltage which is changeable in response to the response control 
signal. 
The U.S. Pat. No. 5,289,097 discloses a spindle control method and 
apparatus for disk drive. Responsive to detecting a start-up or an idle 
operation mode, a pulse width modulation mode control is applied to drive 
current to the spindle motor. Responsive to detecting one of the 
predetermined critical operations, a linear mode control is applied to 
drive current to the spindle motor. A small percentage of the overall file 
power-on time is spent performing critical file operations so that 
substantial power saving are achieved by the PWM mode control. The error 
rate reduction that results by operating in the linear mode during 
critical file operation is also advantageous. 
The U.S. Pat. No. 5,246,1019 discloses a drive motor controller for low 
power disk drive. The disclosure uses a switching regulator type DC/DC 
power converter to control spindle motor speed. In the switching 
regulator, a switching transistor is located near the ground side of the 
circuit so that a low resistance n-channel power MOSFET switching 
transistor is employed. 
The U.S. Pat. No. 5,345,3101 discloses a disk drive with several reduced 
power modes. The disclosure employs a control system which allows the disk 
drive to automatically enter and operate in reduced power modes when the 
drive is not actively reading or writing data in response to commands from 
the host computer. The power savings in these modes are achieved by 
selectively disabling certain electrical components of the disk drive. 
These electrical components include spindle controller, actuator 
controller and servo controller circuitry, which control operation of 
spindle motor, actuator motor, and read/write head positioning 
respectively. The controller circuits are in turn under the control of a 
drive microcontroller which is programmed to control entry and exit from 
the reduced power modes. 
SUMMARY OF THE INVENTION 
While the prior art control systems provide generally effective operation 
to meet the respective object of the invention, it is desirable to provide 
a method for controlling the spindle motor speed of the audio-video disk 
player such that a reduced power consumption thereof is achieved. 
The first step is to set speed of the spindle motor to operate at a Nominal 
speed. The second step is to test if disk data access operation has not 
occurred for a predetermined amount of time. The third step is to set the 
spindle motor running at a speed which is between zero and the Nominal 
speed, if result of step 2 is YES.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, the mechanical and electrical components of a typical 
disk drive system includes a head/disk assembly (HDA) having therein an 
actuator 11, which preferably includes a radial coil, a focus coil and an 
actuator motor, which positions the pickup head 12 to different radial 
positions relative to the surface of disk 13. HDA also includes read 
preamplifier circuitry 18 for amplifying the data and servo information 
from the disk surface. The device 18 also contains a read buffer for 
supplying read data from the particular track selected for reading. The 
digital signal processor (DSP) 19 receives analog read data from circuitry 
18 in the IDA. As well known in the arts, DSP 19 includes a read channel 
analog filter which supplies the analog signal to a pulse detector (not 
shown). The output of pulse detector is supplied to a data separator (not 
shown) as raw digital read data. The disk drive circuitry components, i.e. 
19, 15, interface with a microcontroller 10 through a bus 102 which 
carries address, control and data information, as is well known in the 
art. The disk drive control circuit further includes a servo controller 
section 15 for detecting and processing servo information from disk 13 
relating to servo bursts, sync pulses and track ID number indicating the 
radial position of pickup head 12 relative to the disk surface. Servo 
controller section 15 connects to microcontroller 10 through bus 102 and 
operates to control the flow of information relating to servo read timing 
and control. Servo controller section 15 preferably includes servo 
controller, analog-to-digital to-digital (A/D) converter circuitry and 
digital-to-analog (D/A) circuitry. The analog output 151 from servo 
controller section 15 is supplied as an input to the actuator driver 
circuitry 90. Circuitry 90 includes power amplifier control circuitry 
which supplies an actuator drive signal to a power amplifier which in turn 
supplies control current to actuator 11 in HDA. The system shown also 
includes spindle motor control driver circuitry 14 for controlling the 
spindle drive motor 16 in HDA for rotating audio-video disk 13. The disk 
drive also includes a host interface 17 which operates to provide control 
and information paths between a host computer, through a bus 171 and the 
bus 102, and the associated elements shown. A buffer memory 93 is provided 
to accommodate differences in data transfer rate between the host 
interface 17 and host computer and that between the host interface 17 and 
drive. In other words, the buffer memory temporarily stores the 
video-audio information read from the disk 13. The DSP 19 also provides a 
feedback signal 191 into a digital motor speed control circuit 91 which 
compares the feedback signal 191 with a signal 101 from microcontroller 
10. The result of comparison provides an indication of whether the motor 
is spinning too fast or too slow at the present time with regard to data 
transfer rate. The result of the comparison are used to control the motor 
driver 14, which provides power to the spindle motor 16. The device 92 is 
Digital/Analog converter and the output of the device 94 is audio signal. 
The flow chart of FIG. 2 discloses the steps of the invention. Step 20 is 
the initialization. In step 21, the motor 16 is set to spin at Nominal 
speed of the audio-video player. In step 22, test if the disk data access 
operation has not occurred for a period of time .DELTA.T1. If yes in step 
22, in step 23, the motor 16 is set to spin at one half of the Nominal 
speed to save power consumption. If No in step 22, go back to step 21. In 
step 24, test if the disk data access operation has not occurred for a 
period of time .DELTA.T2. If yes in step 24, in step 25, the motor 16 is 
set to spin at one third of the Nominal speed to further save power 
consumption. If No in step 24, go back to step 23. In step 26, test if the 
disk data access operation has not occurred for a period of time 
.DELTA.T3. If yes in step 26, in step 27, the motor 16 is caused to stop 
totally to save power consumption entirely. If No in step 26, go back to 
step 25. 
Shown in the steps of FIG. 3 are the steps involved when the motor 16 is 
operated at speed other than the Nominal speed. In the step 30, the motor 
16 is operated at speed other than the Nominal speed. Step 31 tests if 
disk data access operation is occurred. If it is yes in step 31, go to 
initialization step 20 in FIG. 1. If it is no in step 31, go back to step 
30. 
It is to be noted, all steps shown are performed within the microcontroller 
10 in a manner well known in the art and, when step 23, 25 or 27 is 
performed, the microcontroller 10 sends a signal to speed control circuit 
91 via signal line 101. The speed control circuit 91 then instructs the 
motor driver to slow down the r.p.m. of the spindle motor 16 such that the 
corresponding spin speed is resulted.