Abstract:
A power saving electronic apparatus includes a processing unit; a power management unit for selectively turning on or off a power supplied to the processing unit; and a control unit connected to the processing unit and the power management unit. The control unit is provided for telling the processing unit to prepare for a power saving mode when a power saving command is created, and for controlling the power management unit to turn off the power supplied to the processing unit when the processing unit is ready for the power saving mode. Related power saving methods is also provided.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to electronic apparatuses and, more particularly, to a power saving electronic apparatus and a power saving method.  
       DESCRIPTION OF RELATED ART  
       [0002]     Electronic apparatus, such as disc players, portable computers, desktop computers, serving as information processing terminals, become widely used. In order to reduce power consumption of such electronic apparatus, various power saving modes, including a sleep mode and a standby mode, are developed.  
         [0003]     Referring to  FIG. 7 , a traditional electronic apparatus  1 , such as a disc player, a portable computer, and a desktop computer, includes an input terminal  10 , a processing unit  12 , a power management unit  14 , and a display unit  16 . The processing unit  12 , such as a servo and decode circuit of a disc player, or a central processing unit (CPU) of a computer, is provided for performing main tasks of the electronic apparatus  1 . The power management unit  14  is provided for controlling powers supplied to the processing unit  12  and to the display unit  16 . When a user wants to temporarily discontinue execution of the electronic apparatus  1  and inputs a sleep command via the input terminal  10 , the processing unit  10  interrupts a current program and generates a pulse signal to be sent to the power management unit  14 . After receiving the pulse signal from the processing unit  10 , the power management unit  14  turns off powers supplied to some particular components such as the display unit  14 .  
         [0004]     However, in the above mentioned conventional power saving modes, the processing unit  12  still has a low power consumption after the power management unit  14  has turned off powers supplied to some particular components.  
         [0005]     Therefore, an power saving apparatus which has a lower power consumption is desired.  
       SUMMARY OF INVENTION  
       [0006]     A power saving electronic apparatus includes a processing unit; a power management unit for selectively turning on or off a power supplied to the processing unit; and a control unit connected to the processing unit and the power management unit. The control unit is provided for telling the processing unit to prepare for a power saving mode when a power saving command is created, and for controlling the power management unit to turn off the power supplied to the processing unit when the processing unit is ready for the power saving mode.  
         [0007]     A power saving method includes the steps of: telling a processing unit to prepare for a power saving mode when a power saving command is created; waiting until the processing unit is ready for the power saving mode; and controlling a power management unit to turn off a power supplied to the processing unit when the processing unit is ready for the power saving mode.  
         [0008]     A power saving method includes the steps of: informing a processing unit of preparation for a power saving mode when a power saving command is created; performing in the processing unit the preparation of ready to the power saving mode; and turning off power supplied to the processing unit when the processing unit is ready for the power saving mode.  
         [0009]     Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a block diagram of a power saving electronic apparatus in accordance with a preferred embodiment, the power saving electronic apparatus including a controlling unit;  
         [0011]      FIG. 2  is a schematic diagram of an internal circuit of the power saving electronic apparatus of  FIG. 1 ;  
         [0012]      FIG. 3  is a block diagram of the controlling unit of the power saving electronic apparatus of  FIG. 1 ;  
         [0013]      FIG. 4  is a flow chart illustrating a working procedure of the control unit in accordance with a preferred embodiment;  
         [0014]      FIG. 5  is a flow chart illustrating a power saving procedure of a power saving method in accordance with a preferred embodiment;  
         [0015]      FIG. 6  is a flow chart illustrating a restoring procedure of the power saving method of  FIG. 5 ; and  
         [0016]      FIG. 7  is a block diagram of a traditional electronic apparatus.  
     
    
     DETAILED DESCRIPTION  
       [0017]     Referring to  FIG. 1 , a block diagram of a power saving electronic apparatus  3  in accordance with a preferred embodiment is illustrated. The power saving electronic apparatus  3  can be a disc player, or a computer, and the processing unit  34  can be a servo and decode circuit, or a CPU, accordingly. The power saving electronic apparatus  3  includes an input terminal  30 , a control unit  32 , a processing unit  34 , a power management unit  36 , and a display terminal  38 . The input terminal  30 , such as, a mouse, a keyboard, or a remote controller, is used for inputting commands. The control unit  32  is a micro control unit (MCU), and is provided for notifying the processing unit  34  to prepare for a power saving mode based on input signals from the input terminal  30 . The control unit  32  is also provided for generating controlling signals to control operations of the power management  36  when the processing unit  34  is ready for the power saving mode. The power management unit  36  is provided for controlling powers supplied to the processing unit  34  and the display terminal  38  according to the controlling signals generated by the control unit  32 . When the power saving electronic apparatus  3  is ready to go into the power saving mode, the power management unit  36  turns off the powers supplied to the processing unit  34  and the display terminal  38 . When the power saving electronic apparatus  3  is in a normal working mode, the power management unit  36  turns on the powers supplied to the processing unit  34  and the display terminal  38 .  
         [0018]     Referring to  FIG. 2 , an internal circuit of the power saving electronic apparatus  3  is illustrated. The control unit  32  connects to the processing unit  34  via a first wire A and a second wire B. The first wire A is provided for transmitting an interrupt signal, which tells the processing unit  34  to prepare for the power saving mode. The first wire A employs a serial communicating protocol, such as an inter-integrated circuit (I 2 C), a serial peripheral interface (SPI), and a data communication interface system provided in another copending application, which is named as “DATA TRANSMISSION INTERFACE SYSTEM AND METHOD FOR ELECTRONIC COMPONENT”, and filed by the same applicant as this application. The second wire B is provided for transmitting status information of the processing unit  34 . For example, when being ready for the power saving mode, the processing unit  34  switches the second wire B from a high level state to a low level state, so as to notify the control unit  32  that the processing unit  34  is ready for the power saving mode. In other alternative embodiments, the second wire B also can employ one of the above-mentioned communication protocols. The control unit  32  is connected to the power management unit  36  via a third wire C, a fourth wire D, and a fifth wire E. The third wire C, the fourth wire D, and the fifth wire E are provided for transmitting the controlling signals from the control unit  32  to the power management unit  36 . The controlling signals are represented by switching signals of the third wire C, the fourth wire D, and the fifth wire E. For example, the control unit  32  controls the third wire C, the fourth wire D, and the fifth wire E to switch from a low level state to a high level state, which tells the power management unit to turn off the powers supplied to the processing unit  34  and the display terminal  38 . That is, when the third wire C, the fourth wire D, and the fifth wire E are in the low level state, the power management unit  36  turns on the powers supplied to processing unit  34  and the display terminal  38 . On the contrary, when the third wire C, the fourth wire D, and the fifth wire E are switched to the high level state, the power management unit  36  turns off the powers supplied to the processing unit  34  and the display terminal  38 .  
         [0019]     Referring to  FIG. 3 , a block diagram of the controlling unit  32  is illustrated. The controlling unit  32  includes an analyzing module  320 , a communicating module  322 , and a controlling module  324 . The analyzing module  320  is provided for receiving an input signal from the input terminal  30 , and determining whether the input signal is a power saving command. If the input signal is a power saving command, the analyzing module  320  notifies the communicating module  322  of the power saving command. If the input signal is not a power saving command, the analyzing module  320  notifies the communicating module  322  that the input signal is not a power saving command. The communicating module  322  is provided for communicating with the processing unit  34 . When the input signal is a power saving command, the communicating module  322  generates the interrupt signal to tell the processing unit  34  to prepare for the power saving mode. When the input signal is not a power saving command, the communicating module  322  generates the interrupt signal to the processing unit  34  to tell the processing unit  34  to perform programs corresponding to the input signal. The controlling module  324  is provided for generating the control signals to the power management unit  36  to turn off the powers supplied to the processing unit  34  and the display terminal  38 , when receiving the status information indicating that the processing unit  34  is ready for the power saving mode.  
         [0020]     Referring to  FIG. 4 , a flow chart of a working procedure of the control unit in accordance with a preferred embodiment is illustrated. Firstly, in step  50 , the control unit  32  waits for an input signal from the input terminal  30 . In step  52 , the control unit  32  detects whether an input signal is received. If an input signal is received, the analyzing module  320  analyzes the received input signal and determines whether the input signal is a power saving command (step  54 ). If the input signal is not the power saving command, the communicating module  322  generates an interrupt signal telling the processing unit  34  to perform other programs corresponding to the input signal (step  56 ). If the input signal is the power saving command, the communicating module  322  generates an interrupt signal telling the processing unit  34  to prepare for the power saving mode (step  58 ). Then, the communicating module  322  waits for status information indicating the processing unit  34  is ready for the power saving mode (step  510 ). The communicating module  322  detects the state of the second wire B and determines whether the processing unit  34  is ready for the power saving mode (step  512 ). If the communicating module  322  receives status information indicating the processing unit  34  is ready for the power saving mode, the controlling module  324  generates controlling signals and sends the controlling signals to the power management unit  36  (step  514 ).  
         [0021]     Referring to  FIG. 5 , a flow chart of a power saving procedure of a power saving method in accordance with a preferred embodiment is illustrated. Firstly, in step  60 , the control unit  32  receives an input signal from the input terminal  30 . Then, the control unit  32  generates an interrupt signal based on the input signal and sends the interrupt signal to the processing unit  34 , telling the processing unit  34  to prepare for the power saving mode (step  62 ). The processing unit  34  prepares for the power saving mode. The processing unit  34  stores information on current working status of the processing unit  34  into a memory device (not shown). After finishing storing information on the current working status, the processing unit  34  feeds back status information to the control unit  32  to notify the control unit  32  that the processing unit  34  is ready for the power saving mode (step  66 ). Upon receiving the status information indicating the processing unit  34  is ready, the control unit  32  generates controlling signals to the power management unit  36  (step  68 ). Finally, the power management unit  36  turns off the powers supplied to the processing unit  34  and the display terminal  38 .  
         [0022]     Referring to  FIG. 6 , a flow chart of a restoring procedure of the power saving method of  FIG. 5  is illustrated. Firstly, in step  70 , the control unit  32  receives an input signal from the input terminal  30 . Then, the control unit  32  generating controlling signals to the power management unit  36  (step  72 ). Upon receiving the controlling signals, the power management unit  36  turns on the powers supplied to the processing unit  34  and the display terminal  38  (step  74 ). Finally, the processing unit  34  reads information on the stored working status from the memory device (step  76 ). Hence, the power saving electronic apparatus  3  is restored to the same working status as that before the power saving procedure.  
         [0023]     The embodiments described herein are merely illustrative of the principles of the present invention. Other arrangements and advantages may be devised by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, the present invention should be deemed not to be limited to the above detailed description, but rather by the spirit and scope of the claims that follow, and their equivalents.