Abstract:
A method for achieving power management for a PDA. The PDA includes a CPU for processing data, a microprocessor for supervising power condition of the PDA, and a display module for displaying data and information. The method includes: (a) using the microprocessor and the CPU to switch the PDA from OFF mode to SHUTDOWN mode wherein when the PDA is in OFF mode, the CPU, the microprocessor, and the display are all off, and when the PDA is in SHUTDOWN mode, the CPU and the display module are off while the microprocessor is on; (b) after step (a), switching the PDA from SHUTDOWN mode to ON mode wherein when the PDA is in ON mode, the CPU, the microprocessor, and the display module are on; (c) after step (b), switching the PDA among SHUTDOWN mode, STANDBY mode, and SCREEN TOGGLE mode.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a method for managing a power system of a PDA, and more particularly, to a method for switching the PDA among SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode to manage the power system of the PDA.  
           [0003]    2. Description of the Prior Art  
           [0004]    Nowadays, low-polluting electric power applications are advocated and many electric appliances use electric power to operate. A reduction in the volume and the weight of electric appliances makes the appliances more convenient and portable. A PDA (Personal Digital Assistant) is a portable and popular device and can allow users to manage their schedules and to store data. Compared with a desktop or a notebook, it is more convenient for users who have to deal with computer data mobilely like sales and on-line production managers. Like other portable electric appliances, a battery is the main power supply source in the PDA, but the volume of the battery is limited in a PDA. A power control system can alert users to the exhaustion of the volume of the battery and allow users to control the consumption of the volume of the battery. For instance, users can store data, change another battery, or recharge the PDA using an external power supply before the exhaustion of the battery so that data is not lost or so that damage does not occur in the PDA due to over-discharging. In view of the above, an effective and perfect power control system is emphasized in modern industry.  
           [0005]    To reduce the power consumption of a PDA in the present power control system, the power supply of the electric component can be cut or reduced when the system is in an idling state. The power control system in the PDA is capable of detecting whether input buttons, display devices, and other components are switched on. If the power control system does not detect any activity during a certain period, the power supply of the main system will be shut down temporarily. However, in the prior art, the power management of the PDA is usually mainly controlled by the CPU, and the feasibility of using the microprocessor to control the power management of the PDA is neglected. Therefore, besides consuming a lot of system resources, the prior art method is dangerous because the large power consumption of using the CPU to control the power management of the whole system could result in over-discharging. In addition, the most power-consuming part of the PDA is the display panel. The prior art usually neglects to consider the power consumption of the display panel when utilizing the power management of the PDA so that the danger of over-discharging still exists. To solve the above-mentioned problems, first, not only can the technology of the prior art pertaining to the power control system of the microprocessor be utilized, but also the microprocessor can be used to supervise the whole power control system in the PDA. Besides, the display panel and other related peripherals should be taken into consideration of the power management of the PDA.  
         SUMMARY OF INVENTION  
         [0006]    It is therefore a primary objective of the claimed invention to provide a method for achieving power management for a PDA system to solve the above-mentioned problems of the prior art.  
           [0007]    According to the claimed invention, a method for achieving power management of a PDA is provided. The PDA comprises a CPU for processing data; a microprocessor for supervising the power system of the PDA; and a display module for displaying the data. The method comprises (a)switching the PDA from OFF mode to SHUTDOWN mode, wherein when the PDA is in OFF mode, the CPU, the microprocessor, and the display are all off, and when the PDA is in SHUTDOWN mode, the CPU and the display module are off while the microprocessor is on; (b) after step (a), switching the PDA from SHUTDOWN mode to ON mode, wherein when the PDA is in ON mode, the CPU, the microprocessor, and the display module are all on; (c) after step (b), switching the PDA between ON mode and SCREEN TOGGLE mode, wherein when the PDA is in SCREEN TOGGLE mode, the CPU and the microprocessor are on while the display module is off; and (d) after step (b), switching the PDA between ON mode and STANDBY mode, wherein when the PDA is in STANDBY mode, the CPU is idle, the microprocessor sleeps, and the display module is off, and an operating current of the CPU when the CPU is idle is smaller than the operating current when the CPU is on, and an operating current of the microprocessor when the microprocessor sleeps is smaller than the operating current when the microprocessor is on.  
           [0008]    According to the claimed invention, a PDA capable of managing power of the PDA comprises a power operating system comprising a slide switch for switching the PDA from OFF mode to SHUTDOWN mode; a power button for switching the PDA among SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode; and a screen-toggle key for switching the PDA from ON mode to SCREEN TOGGLE mode; a CPU for processing data; a microprocessor for supervising the power operating system; and a display module for displaying the data; wherein when the slide switch is turned on, the PDA is switched from OFF mode to SHUTDOWN mode, wherein when the PDA is in OFF mode, the CPU, the microprocessor, and the display are all off, and when the PDA is in SHUTDOWN mode, the CPU and the display module are off while the microprocessor is on; when the power button is pressed, the PDA is switched from SHUTDOWN mode to ON mode, wherein when the PDA is in ON mode, the CPU, the microprocessor, and the display module are all on; when the screen-toggle key is pressed, the PDA is switched from ON mode to SCREEN TOGGLE mode, wherein when the PDA is in SCREEN TOGGLE mode, the CPU and the microprocessor are on while the display module is off; when the power button is pressed during the PDA being in SCREEN TOGGLE mode, the PDA is switched from SCREEN TOGGLE mode to ON mode; when the PDA is in ON mode with the power button pressed, the PDA is switched from ON mode to STANDBY mode, wherein when the PDA is in STANDBY mode, the CPU is idle, the microprocessor sleeps, and the display module is off; when the power button is pressed repeatedly, the PDA is switched between ON mode and STANDBY mode; an operating current of the CPU when the CPU is idle is smaller than the operating current when the CPU is on, and an operating current of the microprocessor when the microprocessor sleeps is smaller than the operating current when the microprocessor is on.  
           [0009]    It is an advantage of the claimed invention that instead of the CPU, the microprocessor is used to supervise and manage a power managing system of the PDA for reducing the power consumption and avoiding over-discharging damage to the PDA.  
           [0010]    It is an advantage of the claimed invention that a display panel and other related peripherals are all taken into consideration of the power management of the PDA.  
           [0011]    It is an advantage of the claimed invention that when the remaining power volume of the PDA is less than a critical voltage, the microprocessor is capable of switching the CPU from being on to being idle, or preventing the CPU from switching from being idle to being on when the CPU is idle, for avoiding the over-discharging damage to a battery. In addition, when the remaining power volume of the PDA detected by the gas gauge is less than a cut-off voltage, the PDA is switched from SCREEN TOGGLE mode or STANDBY mode to SHUTDOWN mode.  
           [0012]    These and other objectives and advantages 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 DRAWINGS  
       [0013]    [0013]FIG. 1 is a functional block diagram of an embodiment of a PDA.  
         [0014]    [0014]FIG. 2 is a state flowchart of the PDA as shown in FIG. 1 in different modes according to the present invention.  
         [0015]    [0015]FIG. 3 is a flowchart of the different voltage values of the PDA as shown in FIG. 1 in different modes according to the present invention.  
         [0016]    [0016]FIG. 4 is a functional block diagram of another embodiment of a PDA.  
         [0017]    [0017]FIG. 5 is a state flowchart of the PDA as shown in FIG. 4 in different modes according to the present invention.  
         [0018]    [0018]FIG. 6 is a flowchart of the different voltage values of the PDA as shown in FIG. 4 in different modes according to the present invention.  
         [0019]    [0019]FIG. 7 is a list showing all the conditions in various modes in the embodiment as shown in FIG. 4. 
     
    
     DETAILED DESCRIPTION  
       [0020]    Please refer to FIG. 1, which is a functional block diagram of an embodiment of a PDA  10  of the present invention. The PDA  10  comprises a CPU  14 , a microprocessor  12 , a display module  16 , and a power operating system  18 . The present embodiment does not include peripherals of the PDA  10  for emphasizing a basic structure of the PDA  10  regarding power management. The user can make use of the power operating system  18  to switch the PDA  10  among various modes. The power operating system  18  comprises a slide switch  20 , a power button  22 , and a screen-toggle key  24 . The display module  16  comprises a display panel  26  and a front light  28 . The display panel  26  can be an LCD panel or an LTPS LCD panel. In addition, inside the PDA  10 , the microprocessor  12  is electrically connected to the power operating system  18  and the CPU  14  of the PDA  10  for controlling the related power system of the PDA  10 . The CPU  14  is also electrically connected to the power operating system  18 , the microprocessor  12 , and the display module  16  of the PDA  10  mainly for controlling the power conditions of the display module  16 .  
         [0021]    The user can switch the PDA  10  among various modes by pressing the slide switch  20 , the power button  22 , and the screen-toggle key  24  of the power operating system  18 . Please refer to FIG. 2, which a state flowchart of the PDA  10  in different modes according to the present invention. When the user turns on the slide switch  20 , the PDA  10  will be switched by the microprocessor  12  from OFF mode to SHUTDOWN mode. When the PDA  10  is in OFF mode, the CPU  14 , the microprocessor  12 , and the display module  16  are all off, and when the PDA  10  is in SHUTDOWN mode, the CPU  14  is off, the microprocessor  12  is on, and the display module  16  is off. After that, when the user presses the power button  22  or the screen-toggle key  24 , the PDA  10  will be switched among SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode. As shown in FIG. 2, when the PDA  10  is in SHUTDOWN mode, once the user presses the power button  22 , the microprocessor  12  will switch the PDA  10  from SHUTDOWN mode to ON mode. In ON mode, the CPU  14 , the microprocessor  12 , and the display module  16  are on. Moreover, when the PDA  10  is in ON mode, the user can press the screen-toggle key  24  to utilize the CPU  14  to switch the PDA between ON mode and SCREEN TOGGLE mode; when the PDA  10  is in SCREEN TOGGLE mode, the user can press the screen-toggle key  24  and the power button  22  to switch the PDA  10  back to ON mode. When the PDA  10  is in SCREEN TOGGLE mode, the CPU  14  and the microprocessor  12  are on, and the display module  16  is off. When PDA  10  is in ON mode, the user can press the power button  22  to utilize the microprocessor  12  to switch the PDA  10  between ON mode and STANDBY mode. When PDA  10  is in STANDBY mode, the CPU  14  is idle, the microprocessor  12  sleeps, and the display module  16  is off. From the above-mentioned description, OFF mode, SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode are those various modes for describing different power statuses of the PDA  10 . Please notice that most of the modes are mainly controlled and supervised by the microprocessor  12 , and only those modes related to the display module  16  are mainly controlled by the CPU  14 .  
         [0022]    Please continue referring to FIG. 2. When the PDA  10  is in OFF mode, that is, the CPU  14 , the microprocessor  12 , and the display module  16  are off. The display panel  26  and the front light  28  of the display module  16  are off so that no operating current is consumed. When the user turns on the slide switch  20 , the PDA  10  is switched to SHUTDOWN mode, the CPU  14  and the display module  16  are still off while the microprocessor  12  is turned into being on. That is, the microprocessor  12  can operate based on a stable supplied voltage and consume a stable current. The microprocessor  12  consumes less power than the CPU  14  does. Generally, due to that the full operating current of the microprocessor  12  is around several mA, the PDA  10  only consumes little power in SHUTDOWN mode. If the user wants to perform the whole functions of the PDA  10 , the user can press the power button  22  to utilize the microprocessor  12  to switch the PDA  10  from SHUTDOWN mode to ON mode. Then the CPU  14  and the microprocessor  12  are on. Regarding the display module  16 , the display panel  26  is on while the front light  28  will be switched between being off and being on. In brief, the CPU  14 , the display panel  26 , and the microprocessor  12  can respectively fully operate based on a stable supplied voltage. Generally, the full operating current of the CPU  14  is around about one hundred mA to several hundreds mA during maximum operation, which is much higher than the full operating current of the microprocessor  12 . Actually, the full operating current of the display panel  26  is the main power-consuming source of the PDA  10 . When the PDA  10  is in ON mode, if the user does not input any signal into the PDA  10  during a predetermined period of time, the front light  28  will automatically turn off. When PDA  10  is in SCREEN TOGGLE mode, the display panel  26  and front light  28  are off without any power consumption. When PDA  10  is in STANDBY mode, the display panel  26  and front light  28  are also off. Please notice that when the CPU  14  is idle, the operating current of the CPU  14  is much less than the full operating current of the CPU  14 . When the microprocessor  12  sleeps, the microprocessor  12  operates at a clock with a period T and is on during half of the period T and is off during another half of the period T. Therefore, the appropriate period value, which is less than the period value the user spends turning on buttons, can allow the microprocessor  12  to detect any operation from the user during half of the period T in which the microprocessor  12  is on for awakening the microprocessor  12  and the PDA  10  again.  
         [0023]    Please notice, all the designs, including SCREEN TOGGLE mode, automatic switch of the front light  28  from being on to being off, of the present embodiment significantly reduce the power consumption by effectively managing the display panel  26  and the front light  28 . In addition, when the microprocessor  12  sleeps, the operating current of the microprocessor  12  will decrease to several μA which is much less than the value of the full operating current of the microprocessor  12 . In preliminary summary, the PDA  10  can save a lot of power from the display panel  26 , the front light  28 , the microprocessor  12 , and CPU  14  to greatly increase the operating time of the PDA  10 .  
         [0024]    Please refer to FIG. 3, which is a flowchart of the different voltage values of the PDA  10  in different modes according to the present invention. When the remaining power volume of the PDA  10  is less than a critical voltage, if the CPU  14  is on, the microprocessor  12  will switch the CPU  14  to being idle (the PDA  10  is switched to STANDBY mode), if the CPU  14  is idle, the microprocessor  12  will prevent the CPU  14  from being switched to being on for avoiding over-discharging effect to permanently damage the PDA  10 . When the remaining power volume of the PDA  10  is less than a cut-off voltage and the PDA  10  is in STANDBY mode, the PDA  10  will switched from STANDBY mode to SHUTDOWN mode and then the CPU  14  is off. At this moment, only the microprocessor  12  takes charges of supervising the power conditions of the PDA  10 . When the remaining power volume of the PDA  10  is less than a cut-off voltage and the PDA  10  is in SCREEN TOGGLE mode, the PDA  10  will be switched from SCREEN TOGGLE mode to SHUTDOWN mode for avoiding over-discharging damage to the PDA  10 .  
         [0025]    Please refer to FIG. 4, which is a functional block diagram of another embodiment of a PDA  30  of the present invention. The PDA  30  comprises a CPU  34 , a microprocessor  32 , a display module  36 , a power operating system  38 , an LED panel  50 , and a plurality of peripherals  52 . The present embodiment includes the peripherals  52  of the PDA  30  for detailing the power managing system of the present invention. The power operating system  38  comprises a slide switch  40 , a power button  42 , and a screen-toggle key  44 . As with the previous embodiment, the PDA  30  can still be switched among various modes by the power operating system  38 .  
         [0026]    Please continue referring to FIG. 4. The display module  36  comprises a display panel  46  and a front light  48 . The display panel  46  can be an LCD panel or an LTPS LCD panel. The power operating system  38  further comprises a gas gauge  54  for detecting a remaining power volume of the PDA  30 . The peripherals  52  include a memory  56 , a power supply port  58 , and a plurality of input keys  60 . The memory  56  is used for storing data, the power supply port  58  is used for providing external power supply, and the input keys  60  are used for the user to input signals into the PDA  30 . The input keys  60  include at least a hot key  62 . In addition, the microprocessor  32  is electrically connected to the power operating system  38 , the CPU  34 , the peripherals  52 , and the LED panel  50  of the PDA  30 , and the CPU  34  is electrically connected to the power operating system  38 , the microprocessor  32 , and the display module  36  of the PDA  30  mainly for controlling the display module  36 .  
         [0027]    The user can press the slide switch  40 , the power button  42 , and the screen-toggle key  44  of the power operating system  38  to switch the PDA  30  among various modes. Please refer to FIG. 5, which is a state flowchart of the PDA  30  in different modes according to the present invention. When the user turns on the slide switch  40 , the PDA  30  will be switched from OFF mode to SHUTDOWN mode. When the PDA  30  is in OFF mode, the CPU  34 , the microprocessor  32 , the display panel  46  and the front light  48  of the display module  36 , and the memory  56  are off while the input keys  60  sleep and the power supply port  58  is on. When the PDA  30  is in SHUTDOWN mode, the CPU  34 , the memory  56 , the display module  36 , and the input keys  60  are off while the microprocessor  32  is on. As with the previous embodiment, the PDA  30  consumes little power in SHUTDOWN mode. After that, when the user presses the power button  42  or the screen-toggle key  44 , the PDA  30  will be switched among SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode. The detailed operations are described in FIG. 5. When the PDA  30  is in SHUTDOWN mode, if the user presses the power button  42 , the microprocessor  32  will switch the PDA  30  from SHUTDOWN mode to ON mode so that the CPU  34 , the microprocessor  32 , the display panel  46 , the memory  56 , and the power supply port  58  are on. However, at this moment, the front light  48  will be switched between being off and being on, and the input keys  60  will be switched between sleeping and being on. That is, if the user does not make use of the PDA  30  for a predetermined period of time, the front light  48  will automatically turn off, and the input keys  60  will be automatically switched from being on to sleeping. All the above-mentioned designs are for saving power. When PDA  30  is in ON mode, the user can press the screen-toggle key  44  to utilize the CPU  34  to switch the PDA  30  between ON mode and SCREEN TOGGLE mode. When the PDA  30  is in SCREEN TOGGLE mode, the user can press the screen-toggle key  44 , the power button  42 , or the hot key  62  to return the PDA  30  to ON mode. When PDA  30  is in SCREEN TOGGLE mode, the CPU  34 , the microprocessor  32 , the memory  56 , and the power supply port  58  are on while the input keys  60  sleep and the display module  36  is off. In addition, when the PDA  30  is in ON mode, the user can press the power button  42  to utilize the microprocessor  32  to switch the PDA  30  between ON mode and STANDBY mode. When PDA  30  is in STANDBY mode, the CPU  34  is idle, the microprocessor  32  sleeps, the display module  36  is off, the memory  56  is in a low-power status, the input keys  60  sleeps, and the power supply port  58  is on. Please notice that, as with the previous embodiment, when the microprocessor  32  sleeps, the microprocessor  32  operates at a clock with a period T and is in ON mode during half of the period T and is in OFF mode during another half of the period T. Therefore, the appropriate period value, which is less than the period value users spend turning on buttons, can allow the microprocessor  32  to detect any operation of users during half of the period T (in which the microprocessor  32  is on) for awakening the microprocessor  32  and the PDA  30  again. Please notice that most of the modes are mainly controlled and supervised by the microprocessor  32 , and only those modes related to the display module  16  are mainly controlled by the CPU  34 .  
         [0028]    Please notice, as with the previous embodiment, all the designs, including SCREEN TOGGLE mode, automatic switch of the front light  48  from being on to being off, of the present embodiment significantly reduce the power consumption by effectively managing the display panel  46  and the front light  48 . In preliminary summary, the PDA  30  can save the a lot of power from the display panel  46 , the front light  48 , peripherals  52 , the microprocessor  32 , and CPU  34  to greatly increase the operating time of the PDA  30 .  
         [0029]    Please refer to FIG. 6, which is a flowchart of the different voltage values of the PDA  30  in different modes according to the present invention. When the remaining power volume of the PDA  30  detected by the gas gauge  54  is lower than a threshold voltage, the microprocessor  32  is capable of transmitting a message to the LED panel  40  so as to produce a flash of light on the LED panel  50 . When the remaining power volume of the PDA  30  is less than a critical voltage, if the CPU  34  is on, the microprocessor  32  will switch the CPU  34  to being idle (the PDA  30  is switched to STANDBY mode), if the CPU  34  is idle, the microprocessor  32  will prevent the CPU  34  from being switched to being on for avoiding over-discharging effect to permanently damage the PDA  30 . When the remaining power volume of the PDA  30  is less than a cut-off voltage and the PDA  30  is in STANDBY mode, the PDA  30  will be switched from STANDBY mode to SHUTDOWN mode and then the CPU  34  is off. At this moment, only the microprocessor  32  takes charges of supervising the power conditions of the PDA  30 . When the remaining power volume of the PDA  30  is less than a cut-off voltage and the PDA  30  is in SCREEN TOGGLE mode, the PDA  30  will be switched from SCREEN TOGGLE mode to SHUTDOWN mode for avoiding over-discharging damage to the PDA  30 .  
         [0030]    Please refer to FIG. 7, which lists all the conditions in various modes in the embodiment as shown in FIG. 4. Please notice that the power supply port  58  as shown in FIG. 4 is divided into DC_VCC and 3.3/5.5V in FIG. 7 according different functions.  
         [0031]    In contrast to the prior art, the present invention provides a method for achieving the whole power management of a PDA. A display panel and other related peripherals are all taken into consideration of the power management of the PDA. In addition, according to the present invention, the PDA can be switched among SHUTDOWN mode, ON mode, SCREEN TOGGLE mode, and STANDBY mode for effectively saving power.  
         [0032]    Those skilled in the art will readily observe that numerous modifications and alterations of the 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.