Abstract:
A monitor for controlling power-on and power-off of a host computer includes a switch device, a monitoring device and a transmission device. The host computer has a processing device. The switch device is used for changing a status thereof in response to an external force applied thereto. The monitoring device is electrically connected to the switch device for monitoring the change of the status of the switch device, and determines if a power management event is activated by the change of the status of the switch status. The transmission device is electrically connected to the monitoring device, and transmits a power management signal to the host computer according to the determination that the change of the status of the switching device activates a power management event, such that the processing device performs a startup power-on or a power-off operation on the host computer.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a monitor, and more particularly to a monitor for controlling power-on and power-off of a host computer. The present invention also relates to a control method of powering on and powering off the host computer by such monitor.  
       BACKGROUND OF THE INVENTION  
       [0002]     A power management system is widely used to save power consumption in a personal computer system. Advanced Configuration and Power Management Interface (ACPI), which was published by Intel, Microsoft and Toshiba in Dec. 22, 1996, is a specification defining standard interfaces for hardware configuration and power management of a power-saving system. According to the ACPI specification, the function of power management is integrated into the operation system to increase the efficiency of power management and the processing speed of the computer system.  
         [0003]     According to the ACPI specification, the power management of the computer system is classified into six modes including S 0  (a normal mode), S 1 ˜S 4  (suspended modes) and S 5  (a power off mode) from low to high. Each of these different suspended modes S 1 ˜S 4  allows for different level of power saving and usage. A computer system in the S 1  mode simply shuts down the hard drives and the monitor, but leaves everything else running normally. S 2  mode offers slightly greater power saving than the S 1  mode. A computer system in the S 2  mode not only shuts down the monitor and hard drives, but also interrupts power to be supplied to the CPU and its cache. A computer system in the S 3  mode shuts down almost everything except for the RAM and the power management controller. The S 3  mode is also referred as a “suspend to RAM” mode to listen for a wake-up action. When the computer system comes into the S 3  mode, the ACPI allows the RAM to store the last operation of the computer system. When the computer system is turned back on from the S 3  mode, the computer system is quickly restored to the last operation based on the data stored in the RAM without normal booting. S 4  mode is known as a hibernation mode in which the entire computer system is stopped and all of the system modes and contexts are stored to disk selected by the BIOS. The S 4  mode is also referred as a “suspend to disk” mode.  
         [0004]     On the other hand, the computer system principally comprises a host computer, a monitor and other peripheral devices. The monitor may be a cathode array tube (CRT) monitor or a liquid crystal display (LCD). Recently, the LCD monitors are becoming popular. The host computer transmits video signals to the monitor via signal lines. The peripheral devices are also electrically connected to the host computer. Generally, the host computer and the monitor are distant from each other. For example, the monitor is placed on a table, whereas the host computer is placed under the table. As such, when the host computer is to be started, the user needs to bend down to press the power button, which is not user-friendly. The common human-machine interfaces for the computer system include the monitor, the mouse, the keyboard, and the front panel of the host computer (which is used to turn on/off the host computer, draw out/insert disks or swap IEEE 1394 interface and USB devices, etc). However, among these the human-machine interfaces, the monitor, the mouse and the keyboard are frequently manipulated by a computer user when a computer system is used.  
         [0005]     U.S. Patent Application Publication 2003/0107566, which is published in Jun. 12, 2003, describes the use of an external USB device such as a keyboard or a mouse to control the turning on/off state of the host computer. This technology provides a monitor having a USB hub in connection with external USB devices. In addition, a digital video interactive (DVI) cable is employed to connect the monitor with the power output port, the graphic card and the USB port of the host computer so as to transmit video signals from the host computer to the monitor for display. In the S 3  mode of the power management system of the host computer, by operating the input/output device, for example, a USB keyboard or a mouse connected to the USB hub of the monitor, a USB controller inside the monitor will transmit a wake-up signal to the host computer via the USB cable to wake up the host computer from the power saving mode to the normal mode.  
         [0006]     According to the above technology, the host computer can be woken up by employing a keyboard or a mouse. However, the external device should be connected to a monitor having a USB hub. Since the ordinary LCD monitor has no USB hub to connect the external USB device, this LCD monitor should be specifically designed. For example, an internal USB hub is provided in the LCD monitor as a connection medium of the external device. The fabrication cost of this LCD monitor having an internal USB hub is relatively high. After a triggering signal is asserted from the external device, the USB controller in the monitor will transmit a wake-up signal to the host computer to wake up the host computer from the suspended mode when the USB controller detects an input signal from the input/output device via the USB hub. However, such means of waking up the host computer by signal transmissions from the USB device to the LCD monitor and then from the LCD monitor to the host computer is inefficient. Furthermore, two power supply apparatuses are required by the LCD monitor to generate driving power for the USB controller and the USB hub, which is not cost effective.  
       SUMMARY OF THE INVENTION  
       [0007]     It is an object of the present invention to provide a monitor and a method for controlling power-on and power-off of a host computer so as to reduce fabricating cost and increase efficiency of signal transmission.  
         [0008]     In accordance with a first aspect of the present invention, there is provided a monitor for controlling power-on and power-off of a host computer. The host computer has a processing device. The monitor comprises a switch device, a monitoring device and a transmission device. The switch device is used for changing a status thereof in response to an external force applied thereto. The monitoring device is electrically connected to the switch device for monitoring a change of the status of the switch device, and determines if a power management event is activated by the change of the status of the switch device. The transmission device is electrically connected to the monitoring device, and transmits a power management signal to the host computer according to the determination that the change of the status of the switch status activates a power management event, such that the processing device performs a power-on or a power-off operation on the host computer.  
         [0009]     In accordance with a second aspect of the present invention, there is provided a computer system. The computer system comprises a host computer and a monitor. The host computer has a processing device. The monitor comprises a switch device, a monitoring device and a transmission device. The switch device is used for changing a status thereof in response to an external force applied thereto. The monitoring device is electrically connected to the switch device for monitoring a change of the status of the switch device, and determines if a power management event is activated by the change of the status of the switch device. The transmission device is electrically connected to the monitoring device, and transmits a power management signal to the host computer according to the determination that the change of the status of the switch device activates a power management event, such that the processing device performs a power-on or a power-off operation on the host computer.  
         [0010]     In accordance with a third aspect of the present invention, there is provided a method for controlling power-on and power-off of a host computer. Firstly, a monitor having a switch device is provided. Then, a status of the switch device is changed in response to an external force applied thereto. Then, if the status of the switch device is changed by means of successively pressing the switch device twice, a power management event is activated and detected accordingly. Afterward, a power management signal is transmitted to the host computer according to the determination that the change of the status of the switch device activates a power management event, so as to perform a power-on or a power-off operation on the host computer.  
         [0011]     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of a computer system according to an embodiment of the present invention;  
         [0013]      FIG. 2  is a block diagram illustrating the connection of the LCD monitor and the host computer;  
         [0014]      FIG. 3  is a flowchart illustrating a method for controlling the power-off of the host computer by proceeding to the sleeping procedure; and  
         [0015]      FIG. 4  is a flowchart illustrating a method for controlling the power-on of the host computer by proceeding to the wake-up procedure. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     Referring to  FIG. 1 , a computer system according to an embodiment of the present invention is shown. The computer system  1  comprises a host computer  10  and a LCD monitor  20 . The host computer  10  comprises a plurality of hardware components such as a graphic card  11 . The LCD monitor  20  comprises a switch device  27  such as a multistage electronic/mechanic switch. A digital video interactive (DVI) cable  50  and a USB cable are employed to connect the LCD monitor  20  and the host computer  10 , respectively. The DVI cable  50  comprises a video connector  28  connected to the graphic card  11  of the host computer  1 , and the USB cable comprises a USB connector  26  connected to a USB port  12  of the host computer  1 .  
         [0017]     Referring to  FIG. 2 , a block diagram illustrating the connection of the LCD monitor and the host computer is shown. The LCD monitor  20  comprises a switch device  27 , a monitoring device  22 , a transmission device  23 , a control chip module  24  and a LCD panel  25 . The host computer  10  comprises a graphic card  11 , a USB port  12 , a USB controller  13 , a basic input/output system (BIOS)  14 , a central processing unit (CPU)  15  and an operating system directed power management (OSPM)  16 .  
         [0018]     If the switch device  27  is successively pressed twice, a power management event is generated in response to the change of the status of the switch device  27 . According to the change of the status of the switch device  27 , the monitoring device  22  determines if a power management event is activated. If the power management event is associated with the power management of the host computer  10 , the transmission device  23  will transmit a power management signal to the host computer  10 .  
         [0019]     The transmission device  23  comprises a USB client driver  231  and a USB controller  232 . When the power management event is activated, the USB client driver  231  will be downloaded into the USB controller  232  to drive the USB controller  232 . As such, the USB controller  232  and host computer  10  can communicate signals with each other. Furthermore, the LCD monitor  20  can not only receive but also transmit signals. Via the USB connector  26  as shown in  FIG. 1 , the power management signal is transmitted from the LCD monitor  20  to the USB port  12  of the host computer  10  accordingly.  
         [0020]     The control chip module  24  comprises a transition minimized differential signaling (TMDS) part  241 , a micro-controller  242  and a scaler  243 . In the LCD monitor  20 , a compressed digital video signal is transmitted from the host computer  10  to the TMDS part  241  via the DVI cable  50 . Then, the TMDS part  241  decompresses the transmitted digital video signal, and transmits horizontal/vertical synchronous signals HVS to the micro-controller  242  and the scaler  243 , and transmits RGB signals to the scaler  243 . Thereafter, the micro controller  242  determines the resolution of the LCD panel  24  on the basis of the horizontal/vertical synchronous signal HVS, and transmits a control signal to the scaler  243 , thereby adjusting the RGB signals according to the determined resolution. The adjusted RGB signals are then transmitted to the LCD panel  25  for display.  
         [0021]     The method for controlling power of the host computer by using the LCD monitor of the present invention will be described in more detail as follows.  
         [0022]     After the power management signal is received from the USB port  12 , the USB controller  13  of the host computer  10  transmits this power management signal to the BIOS  14 . In response to the power management signal, the BIOS  14  performs a power-on or a power-off operation associated with the host computer  10 .  
         [0023]     The ACPI specification defines six power modes from low to high, i.e. S 0  (a working mode), S 1 ˜S 4  (suspended modes), and S 5  (a power off mode). Each of these different suspended modes S 1 ˜S 4  allows for different level of power saving and usage. In this embodiment, the power modes used therein are similar to those described in the background of the invention, and are not to be redundantly described herein. In addition, the power management signal can be a wake-up signal or a sleeping signal.  
         [0024]     Please refer to  FIG. 2 , again. When the host computer  10  is in any one of the modes S 1 ˜S 5  and the LCD monitor  20  is in a standby mode, if the switch device  27  of the LCD monitor  20  is successively pressed twice, a wake-up signal will be transmitted to the host computer  10  via the USB connection between the LCD monitor  20  and the host computer  10 . After the wake-up signal is received by the USB controller  13 , the BIOS  14  will enable the CPU  15  to execute a power-on operation for the host computer  10 . That is, the host computer  10  returns to a working mode. During the startup operation, the LCD monitor  20  also returns from the power saving modes to the working mode in response to the wake-up signal transmitted from the host computer  10 .  
         [0025]     When the host computer  10  and the LCD monitor  20  are both operated in the working mode, if the switch device  27  of the LCD monitor  20  is pressed once, the LCD monitor  20  will be turned off. If the switch device  27  of the LCD monitor  20  is successively pressed twice, a sleeping signal will be transmitted to the host computer  10  via the USB connection between the LCD monitor  20  and the host computer  10 . After the sleeping signal is received by the USB controller  13 , the BIOS  14  will determine which one of the power saving modes S 1 ˜S 5  is to be entered and allow a corresponding component to execute the sleeping procedures. The sleeping procedures can be performed as follows. For example, when any one of the S 1 ˜S 3  power modes is to be entered, the sleeping procedure is performed by the BIOS  14 . When the S 4  power mode is to be entered, the sleeping procedure is performed by the BIOS  14  or the OSPM  16  as required. However, when the S 5  power mode is to be entered, the sleeping procedure is performed by the BIOS  14 . After the host computer  10  enters the suspend mode, the LCD monitor  20  will enter the power saving mode.  
         [0026]     Referring to  FIG. 3 , a flowchart illustrating a method for controlling power-off of the host computer by proceeding to the sleeping procedure is shown. Firstly, the change of the status of the switch device  27  is monitored by the monitoring device  22  (step A 1 ). Then, the switch device  27  is successively pressed twice to change the status of the switch device  27 . According to the change of the status of the switch device  27 , the monitoring device  22  determines if a sleeping signal is activated. If a sleeping signal is activated, it will be transmitted to the host computer  10  (step A 2 ). According to the contents carried by the sleeping signal, the host computer  10  is operating in one of the suspended modes S 1 ˜S 5  (step A 3 ). According to the determined suspended mode, the host computer  10  executes the corresponding sleeping procedure (step A 4 ).  
         [0027]     Referring to  FIG. 4 , a flowchart illustrating a method for controlling power-on of the host computer by proceeding to the wake-up procedure is shown. Firstly, the switching status of the switch device  27  is monitored by the monitoring device  22  (step B 1 ). Then, the switch device  27  is successively pressed twice to change the switching status. According to the change of the status of the switch status, the monitoring device  22  determines if a wake-up signal is activated. If a wake-up signal is activated, it will be transmitted to the host computer  10  (step B 2 ). In response to the wake-up signal, it is determined which one of the power saving modes S 1 ˜S 5  is the host computer  10  (B 3 ). According to the power saving mode, the related components are subsequently driven and enabled (step B 4 ). Then, the wake-up procedure is performed such that the host computer  10  is operated in the normal mode (step B 5 ).  
         [0028]     From the above description, the monitor and the method of controlling power-on and power-off of a host computer by such monitor according to the present invention are capable of effectively controlling the power of the host computer. In addition, for enhancing user&#39;s convenience, the power management modes are controlled by activating the switch device. Since the LCD monitor does not require the USB hub according to the present invention, the fabrication cost is effectively reduced. Moreover, the power management signals can be directly transmitted to the host computer via USB connection so as to provide an efficient signal transmission.  
         [0029]     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.