Device for reducing power consumption of optical drive and method for the same

Abstract

A device and method for reducing power consumption of an optical drive are proposed. The present invention samples a carrier control signal and then compares the samples of the signals with predetermined threshold signals. According to the comparison result, the present invention increases or decreases an output signal index. The variation of the output signal index is used to control phases of diphase excitation control signals so as to control the rotation direction of a motor or make it stop. The present invention need not output the diphase excitation control signals continuously. It only needs to output a predetermined number of the diphase excitation control signals after the output signal index is increased or decreased. Hence, the present invention reduces the time for outputting the control signals and greatly reduces the power consumption of the optical drive thereby.

1 . A device for reducing power consumption of an optical drive, comprising: 
 a signal controller for receiving a central error signal and producing a carrier control signal;    a signal processor for sampling the carrier control signal to produce a first output signal;    a comparator for receiving the first output signal of the signal processor and comparing the output signal with a positive threshold signal and a negative threshold signal to produce a second output signal; and    a waveform generator for receiving the second output signal of the comparator and producing a periodic signal, the periodic signal being formed by sampling a segment of the carrier control signal, wherein a location of the segment is adjustable.    
   
   
       2 . The device as claimed in  claim 1 , wherein the signal controller further comprises a track-following error controller and a carrier controller, the track-following error controller receives a track-following error signal and produce a track-following control signal, and the carrier controller receives the central error signal and the track-following control signal and output one of them as the carrier control signal.  
   
   
       3 . The device as claimed in  claim 2 , wherein before the track-following control signal is sent to the carrier controller, the track-following control signal is diminished by an amplifier to avoid signal overflow caused by the carrier controller.  
   
   
       4 . The device as claimed in  claim 3 , wherein after the track-following control signal is passed through the carrier controller, the track-following control signal is amplified by another amplifier.  
   
   
       5 . The device as claimed in  claim 2 , wherein the carrier controller includes a first low-pass filter and a second low-pass filter.  
   
   
       6 . The device as claimed in  claim 5 , wherein the first low-pass filter has a high sample frequency and the second low-pass filter has a low sample frequency.  
   
   
       7 . The device as claimed in  claim 1 , wherein the signal processor samples the carrier control signal to output a sampled carrier control signal.  
   
   
       8 . The device as claimed in  claim 1 , wherein the second output signal sent from the comparator is an output signal index.  
   
   
       9 . The device as claimed in  claim 8 , wherein the comparator adds one to the output signal index if the sampled carrier control signal is larger than the positive threshold signal, the comparator subtracts one from the output signal index if the sampled carrier control signal is smaller than the negative threshold signal, and the comparator maintains the output signal index if the sampled carrier control signal is located between the positive threshold signal and the negative threshold signal.  
   
   
       10 . The device as claimed in  claim 8 , wherein the waveform generator outputs a predetermined number of periodic diphase excitation control signals having equal time spacing according to the output signal index sent from the comparator.  
   
   
       11 . The device as claimed in  claim 10 , wherein phases of the diphase excitation control signals are changed as the output signal index is changed.  
   
   
       12 . The device as claimed in  claim 10 , wherein, after receiving the output signal index produced by the comparator, the waveform generator samples the carrier control signal and then outputs a predetermined number of impulse signals to form the diphase excitation control signals.  
   
   
       13 . The device as claimed in  claim 10 , wherein the waveform generator employs a group of gain signals to adjust positive edges of the diphase excitation control signals.  
   
   
       14 . The device as claimed in  claim 10 , wherein the waveform generator employs two groups of gain signals to adjust positive edges and negative edges of the diphase excitation control signals, respectively.  
   
   
       15 . The device as claimed in  claim 10 , further comprising: 
 a power actuator for receiving the diphase excitation control signal and outputting two groups of motor control signals according to the diphase excitation control signal.    
   
   
       16 . The device as claimed in  claim 15 , further comprising: 
 a carrier motor for receiving the two groups of the motor control signals so as to move a pickup head to a correct optical track.    
   
   
       17 . The device as claimed in  claim 16 , wherein the two groups of the motor control signals are two groups of complementary signals.  
   
   
       18 . A method for reducing power consumption of an optical drive, comprising: 
 inputting a carrier control signal to a signal processor;    sampling the carrier control signal to obtain a sampled carrier control signal by using the signal processor;    inputting the sampled carrier control signal to a comparator and comparing the sampled carrier control signal with a positive threshold signal and a negative threshold signal by using the comparator;    producing an output signal index according to a comparison result provided by the comparator; and    outputting a predetermined number of diphase excitation control signals having equal time spacing according to the output signal index by using a waveform generator.    
   
   
       19 . The method as claimed in  claim 18 , further comprising: 
 selecting either a central error, signal or a track-following control signal as the carrier control signal by using a carrier controller.    
   
   
       20 . The method as claimed in  claim 18 , wherein phases of the diphase excitation control signals are changed as the output signal index is changed.  
   
   
       21 . The method as claimed in  claim 18 , wherein the signal processor samples the carrier control signal according to a predetermined sample frequency.  
   
   
       22 . The method as claimed in  claim 18 , further comprising: 
 adding one to the output signal index if the sampled carrier control signal is larger than the positive threshold signal.    
   
   
       23 . The method as claimed in  claim 22 , wherein the waveform generator sends the diphase excitation control signals to a power actuator to make the power actuator produce two groups of motor control signals so as to make a carrier motor rotate forward.  
   
   
       24 . The method as claimed in  claim 23 , wherein after finishing sending the diphase excitation control signals to the power actuator, the waveform generator stops sending the diphase excitation control signals and the power actuator keeps outputting the two groups of the motor control signals to make the carrier motor rotate forward according the diphase excitation control signals received last.  
   
   
       25 . The method as claimed in  claim 18 , further comprising: 
 subtracting one from the output signal index if the sampled carrier control signal is smaller than the negative threshold signal.    
   
   
       26 . The method as claimed in  claim 25 , wherein the waveform generator sends the diphase excitation control signals to a power actuator to make the power actuator produce two groups of motor control signals so as to make a carrier motor rotate backward.  
   
   
       27 . The method as claimed in  claim 26 , wherein, after finishing sending the diphase excitation control signals to the power actuator, the waveform generator stops sending the diphase excitation control signals and the power actuator keeps outputting the two groups of the motor control signals to make the carrier motor rotate backward according the diphase excitation control signals received last.  
   
   
       28 . The method as claimed in  claim 18 , further comprising: 
 maintaining the output signal index if the sampled carrier control signal is located between the positive and negative threshold signals.    
   
   
       29 . The method as claimed in  claim 28 , wherein the waveform generator stops outputting the diphase excitation control signals to a power actuator to make the power actuator stop outputting motor control signals to a carrier motor so as to stop the motor.  
   
   
       30 . The method as claimed in  claim 18 , wherein the waveform generator employs a group of gain signals to adjust positive edges of the diphase excitation control signals.  
   
   
       31 . The method as claimed in  claim 18 , wherein the waveform generator employs two groups of gain signals to adjust positive edges and negative edges of the diphase excitation control signals, respectively.