Abstract:
A control system controlling the tilt actuator and the tray motor of a optical disk drive includes a control device including a control unit generating control signals and a selection unit outputting a selection signal. A signal amplifier coupled to the control unit amplifies signals from the control unit. A de-multiplexer has an input node coupled to the signal amplifier and a control node coupled to the selection unit. A tilt actuator coupled to the first node of the de-multiplexer controlling the tilt angle of a pick-up head and a tray motor coupled to the second node of the de-multiplexer.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention provides a control system for controlling an optical disc drive. More particularly, the present invention provides a combined servo controller for controlling a pick-up head and a tray motor of an optical disc drive. 
         [0003]    2. Description of the Prior Art 
         [0004]    The control of an optical disc drive comprises spindle control, sledge motor control, pick-up head actuator control, and tray motor control. The pick-up head actuator control further comprises a focus control, a radial control, and a tilt control. Generally, the signal of the tilt control is close to that of the tray motor control. Thus, the tilt control and the tray motor control are usually combined in a main controller. In this way, the main controller can control the pick-up head actuator and the tray motor with different auxiliary controllers respectively. 
         [0005]    Please refer to  FIG. 1 .  FIG. 1  is a diagram illustrating a conventional control system  180  controlling the tilt actuator of the pick-up head and the tray motor. As shown in  FIG. 1 , the control system  180  comprises controller  100 , a first amplifier  115 , a second amplifier  120 , a tilt actuator  125  of the pick-up head, and a tray motor  130 . The controller  100  comprises a first control unit  105  and a second control unit  110 . 
         [0006]    Please refer to  FIG. 2  with  FIG. 1  together.  FIG. 2  is a flowchart illustrating the conventional control system  180  controlling the tilt actuator of the pick-up head and tray motor. The steps are described as follows. 
         [0007]    Step  200 : Start. 
         [0008]    Step  202 : Controller  100  transmits a first control signal to the first control unit  105  and a second control signal to the second control unit  110 . 
         [0009]    Step  204 A: The first control unit  105  transmits a third control signal to the first amplifier  115  according to the first control signal. 
         [0010]    Step  204 B: The second control unit  110  transmits a fourth control signal to the second amplifier  120  according to the second control signal. 
         [0011]    Step  206 A: The first amplifier  115  amplifies the third control signal, and transmits the amplified third control signal to the tilt actuator  125  of the pick-up head. 
         [0012]    Step  206 B: The second amplifier  120  amplifies the fourth control signal, and transmits the amplified fourth control signal to the tray motor  130 . 
         [0013]    Step  208 A: The tilt actuator  125  generates a reaction according to the amplified third control signal. 
         [0014]    Step  208 B: The tray motor  130  generates a reaction according to the amplified fourth control signal. 
         [0015]    Step  210 : End. 
         [0016]    The drawback of the conventional control system  180  is that the control system  180  uses 2 control units and 2 amplifiers to respectively control the tilt actuator of the pick-up head and the tray motor. That is, the conventional control system  180  uses more hardware components to operate. However, the tilt actuator of the pick-up head and the tray motor do not operate at the same time. Therefore, when the control unit of the tilt actuator is operating, the control unit of the tray motor idles, and vice versa. 
       SUMMARY OF THE INVENTION 
       [0017]    The present invention provides a control system for controlling a tilt actuator and a tray motor of an optical disc drive comprising a control device having a control unit for generating a control signal and a selection unit for outputting a selection signal. A signal amplifier is coupled to the control unit for amplifying the control signal from the control unit. A de-multiplexer comprises a first output end, a second output end, and an input end that is coupled to the signal amplifier. A control end of the de-multiplexer is coupled to the selection unit for receiving the selection signal. A tilt actuator is coupled to the first output end of the de-multiplexer for controlling a tilt angle of a pick-up head and a tray motor is coupled to the second output end of the de-multiplexer. 
         [0018]    The present invention further provides a control system for controlling a pick-up head actuator and a tray motor of an optical disc drive. The control system includes a control device comprising a first control unit for generating a first control signal, a second control unit for generating a second control signal, and a selection unit for outputting a selection signal. A signal amplifier is coupled to the first control unit and the second control unit for amplifying the first control signal of the first control unit and the second control signal of the second control unit. A de-multiplexer comprises a first output end, a second output end, and an input end that is coupled to the signal amplifier. A control end of the de-multiplexer is coupled to the selection unit for receiving the selection signal. A pick-up head actuator is coupled to the first output end of the de-multiplexer for controlling a pick-up head and a tray motor is coupled to the second output end of the de-multiplexer. 
         [0019]    The present invention further provides a control method for controlling a tilt actuator and a tray motor of an optical disc drive. The method includes a control device that transmits a first control signal to a control unit and a second control signal to a selection unit. The control unit transmits a third control signal to an amplifier according to the first control signal. The selection unit transmits a selection signal to a de-multiplexer according to the second control signal. The amplifier amplifies the third control signal, and transmits the amplified third control signal to the de-multiplexer. The de-multiplexer transmits the amplified third control signal to the tilt actuator or the tray motor according to the selection signal. The tilt actuator or the tray motor generating a reaction according to the amplified third control signal transmitted from the de-multiplexer. 
         [0020]    The present invention further provides a control method for controlling a pick-up head actuator and a tray motor of an optical disc drive. The method comprises a control device selectively transmitting a first control signal to a first control unit or a second control signal to a second control unit. The first control unit transmits a third control signal according to the first control signal or the second control unit transmits a fourth control signal to an amplifier according to the second control signal. The amplifier amplifies the third control signal or the fourth control signal and transmits the amplified third control signal or the amplified fourth control signal to a de-multiplexer. The control device transmits a fifth control signal to a selection unit. The selection unit transmits a selection signal to the de-multiplexer according to the fifth control signal. The de-multiplexer transmits the amplified third control signal to the pick-up head actuator or the amplified fourth control signal to the tray motor according to the emitting selection signal from the selection unit. It is the pick-up head actuator or the tray motor to generate a reaction is according to the amplified signal coming from the first unit or the second unit. 
         [0021]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a diagram illustrating a conventional control system controlling the tilt actuator and the tray motor. 
           [0023]      FIG. 2  is a flowchart illustrating the conventional control system controlling the tilt actuator and tray motor. 
           [0024]      FIG. 3  is a diagram illustrating a control system of a first embodiment of the present invention. 
           [0025]      FIG. 4  is a flowchart illustrating the control system of the first embodiment of the present invention. 
           [0026]      FIG. 5  is a diagram illustrating a control system of a second embodiment of the present invention. 
           [0027]      FIG. 6  is a flowchart illustrating the control system of the second embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Please refer to  FIG. 3 .  FIG. 3  is a diagram illustrating a control system  380  of a first embodiment of the present invention. The control system  380  comprises a control device  300 , an amplifier  310 , a de-multiplexer  315 , a tilt actuator  320 , and a tray motor  325 . The control device  300  comprises a control unit  305  and a selection unit  330 . The control device  300  transmits a first control signal to the control unit  305  and a second control signal to the selection unit  330 . The control unit  305  transmits a third control signal to the amplifier  310  according to the first control signal. The selection unit  330  transmits a selection signal to the de-multiplexer  315  according to the second control signal. The amplifier  310  amplifies the third control signal and transmits the amplified third signal to the de-multiplexer  315 . The de-multiplexer  315  transmits the amplified third signal to the tilt actuator  320  or the tray motor  325  according to the selection signal. The tilt actuator  320  or the tray motor  325  then generates a reaction. 
         [0029]    Please refer to  FIG. 4 .  FIG. 4  is a flowchart illustrating the control system  380  of the first embodiment of the present invention controlling the tilt actuator of the pick-up head and tray motor. The steps are described as follows. 
         [0030]    Step  400 : Start. 
         [0031]    Step  402 : The control device  300  transmits a first control signal to the control unit  305  and a second control signal to the selection unit  330 . 
         [0032]    Step  404 : The control unit  305  transmits a third control signal to the amplifier  310  according to the first control signal. 
         [0033]    Step  406 : The amplifier  310  amplifies the third control signal, and transmits the amplified third control signal to the de-multiplexer  315 . 
         [0034]    Step  408 : The selection unit  330  transmits a selection signal to the de-multiplexer  315  to control the output end of the de-multiplexer  315  coupled to the tilt actuator  320  or the tray motor  325  according to the second control signal. 
         [0035]    Step  410 : The de-multiplexer  315  transmits the amplified third control signal to the tilt actuator  320  or the tray motor  325  according to the step  408 . 
         [0036]    Step  412 : The tilt actuator  320  or the tray motor  325  generates a reaction according to the amplified third control signal. 
         [0037]    Step  414 : End. 
         [0038]    To achieve the above steps, the signal to control the tilt actuator and the signal to control the tray motor have to be arranged in the same format. In this way, the tilt actuator and the tray motor can be controlled by one control signal such as the third control signal described above. Thus, the 2 control units of the conventional control system  180  can be reduced to one control unit  305 , and the 2 amplifiers of the conventional control system  180  can be reduced to one amplifier  310 . 
         [0039]    Please refer to  FIG. 5 .  FIG. 5  is a diagram illustrating a control system  580  of a second embodiment of the present invention. The control system  580  comprises a control device  500 , an amplifier  520 , a de-multiplexer  525 , a tilt actuator  530 , and a tray motor  535 . The control device  500  comprises a first control unit  505 , a second control unit  510 , and a selection unit  515 . The control device  500  generates a first control signal to the first control unit  505  or a second control signal to the second control unit  510 , and generates a third control signal to the selection unit  515 . The first control unit  505  transmits a fourth control signal to the amplifier  520  according to the first control signal. The second control unit  510  transmits a fifth control signal to the amplifier  520  according to the second control signal. The selection unit  515  transmits a selection signal to the de-multiplexer  525  according to the third control signal. The amplifier  520  amplifies the fourth control signal or the fifth control signal and then transmits the signals to the de-multiplexer  525 . The de-multiplexer  525  transmits the fourth control signal to the tilt actuator  530  or the fifth control signal to the tray motor  535 . 
         [0040]    Please refer to  FIG. 6 .  FIG. 6  is a flowchart illustrating the control system  580  of the second embodiment of the present invention controlling the tilt actuator of the pick-up head and tray motor. The steps are described as follows. 
         [0041]    Step  600 : Start. 
         [0042]    Step  602 : The control device  500  transmits a first control signal to the first control unit  505  or transmits a second control signal to the second control unit  510 , and transmits a third control signal to the selection unit  515 . 
         [0043]    Step  604 : The first control unit  505  transmits a fourth control signal to the amplifier  520  or the second control unit  510  transmits a fifth control signal to the amplifier  520 . 
         [0044]    Step  606 : The amplifier  520  amplifies the fourth control signal or the fifth control signal and transmits the amplified fourth control signal or the amplified fifth control signal to the de-multiplexer  525 . 
         [0045]    Step  608 : The selection unit  515  transmits a selection signal to the de-multiplexer  525  according to the third control signal. 
         [0046]    Step  610 : The de-multiplexer  525  transmits the amplified fourth control signal to the tilt actuator  530  or the amplified fifth control signal to the tray motor  530  according to the selection signal. 
         [0047]    Step  612 : The tilt actuator  530  or the tray motor generates a reaction. 
         [0048]    Step  614 : End. 
         [0049]    In the second embodiment of the present invention, the format of the control signal of the tilt actuator  530  and that of the tray motor  535  can be different since the tilt actuator  530  and the tray motor  535  belong to different control units. Besides, in this embodiment, compared with the conventional control system, an amplifier is reduced. 
         [0050]    Additionally, when the first control unit  505  is transmitting the fourth control signal to control the tilt actuator  530 , and the control device  500  is about to transmit a second control signal to the second control unit  510 , the control device  500  waits until the first control unit  505  finishes transmitting and the tilt actuator  530  finishes the corresponding reaction. Then the control device  500  transmits the second control signal to the second control unit  510 , and vice versa. Or, one of the first control unit  505  and the second control unit  510  has a higher priority. For example, when the first control unit  505  is transmitting the fourth control signal to control the tilt actuator  530 , and the control device  500  is about to transmit the second control signal to the second control unit  510  to control the tray motor  535 , the first control unit  505  pauses transmitting the fourth control signal, that is, the tilt actuator  530  pauses generating the reaction, to allow the second control unit  510  to transmit the fifth control signal and the tray motor  530  to generate a reaction. This design described above avoids the interference between the two control units. 
         [0051]    In the control system  580  of the second embodiment of the present invention, the first control unit  505  and the second control unit  510  can respectively control the tilt actuator  530  and the tray motor  535 . However, the tilt actuator  530  can be replaced with a radial actuator or a focus actuator. For example, if the tilt actuator  530  is replaced with the radial actuator, the 2 control units  505  and  510  are used for respectively controlling the radial actuator and the tray motor. If the tilt actuator  530  is replaced with the focus actuator, the 2 control units  505  and  510  are used for respectively controlling the focus actuator and the tray motor. 
         [0052]    The embodiments of the present invention both increase the efficiency of an optical disc drive and reduce the hardware components of the optical disc drive. 
         [0053]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.