Patent Publication Number: US-2012043926-A1

Title: Power Management Device, Power Management Method and Portable Electronic Device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a power management device, power management method and portable electronic device, and more particularly, to a power management device, power management method and portable electronic device capable of reducing power consumption timely and avoiding system failures. 
     2. Description of the Prior Art 
     Due to the variation of business models and the advancement of technology, manufacturers of consumer electronic products usually develop products with different functionalities or prices to meet different needs. Take computer systems for example, some aim for high performance, such as spectacular audio/video experiences, unparalleled computing speed, etc., while others appeal to day-to-day routines, such as word processing and web browsing, with low prices. In such a situation, the more product lines are, the more difficult the stocking management is. 
     For example, a laptop with power consumption set to 90 watts in a basic input/output system (BIOS) thereof, yet equipped with a 65-watt power supply, may result from a wrongly configured BIOS or an assembling mistake. In such a situation, when a customer uses the laptop to perform heavy computing power tasks, such as playing video games or performing imaging processing, the system may consume more than 65 watts because the BIOS configuration is set to 90 watts. When the power consumption of the system surpasses the maximum power that the power supply can provide, i.e. 65 watts, the power supply will issue an error alert which suspends the system and requires a reboot procedure. In other words, when the BIOS is not properly configured or the system equips with a wrong make of power supply, the power supply cannot match the system, such that the laptop suspends and requires a reboot procedure upon performing the heavy computing power tasks. A flaw with this magnitude compromises convenience of the customer, and discredits the manufacturers. 
     Therefore, in order to increase the flexibility on the stocking management, it is necessary to develop a redress scheme for improving the shortcomings of the prior art. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary objective of the present invention to provide power management device, power management method using the same and portable device using the same. 
     An embodiment of the invention discloses a power management device for a portable electronic device, which comprises a sensing unit, coupled between a power supply and a system circuit of the portable electronic device, for sensing a current outputted from the power supply to the system circuit, to generate a sensing signal; and a control unit, coupled between the sensing unit and a charger module of the portable electronic device, for indicating the charger module to stop charging when the sensing signal indicates that the current outputted from the power supply to the system circuit is greater than a predetermined value. 
     An embodiment of the invention further discloses a portable electronic device, which comprises a rechargeable battery, for storing electric energy; a charger module, for charging the rechargeable battery; a power supply, for converting an alternating-current (AC) power source to a direct-current (DC) power source; a system circuit, driven by the electric energy stored in the rechargeable battery or the DC power source outputted from the power supply; and a power management device comprising a sensing unit, coupled between the power supply and the system circuit, for sensing current of the DC power source outputted from the power supply to the system circuit, to generate a sensing signal; and a control unit, coupled between the sensing unit and the charger module, for indicating the charger module to stop charging the rechargeable battery when the sensing signal indicates that the current outputted from the power supply to the system circuit is greater than a predetermined value. 
     An embodiment of the invention further discloses a method of power management for a portable electronic device, which comprises steps of sensing current outputted from a power supply of the portable electronic device to a system circuit of the portable electronic device, to generate a sensing signal; and indicating a charger module of the portable electronic device to stop charging when the sensing signal indicates that the current outputted from the power supply to the system circuit is greater than a predetermined value. 
     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 
         FIG. 1  is a schematic diagram of a portable electronic device according to an embodiment of the invention. 
         FIG. 2  is a schematic diagram of a control unit shown in  FIG. 1  according to an embodiment of the invention. 
         FIG. 3  is a schematic diagram of a power management procedure according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , which illustrates a schematic diagram of a portable electronic device  10  according to an embodiment of the invention. The portable electronic device  10  can be a laptop, an electronic reader, a smart phone, a mobile phone, a portable audio/video player, etc., and has a power management redress scheme to increase flexibility on management. The portable electronic device  10  includes a rechargeable battery  100 , a charger module  102 , a power supply  104 , a system circuit  106  and a power management device  108 . The power supply  104  converts an alternating-current (AC) power source to a direct-current (DC) power source, to provide energy for the charger module  102  and the system circuit  106  to function. The charger module  102  charges rechargeable battery  100 , to store electric energy. The system circuit  106  is driven by the electric energy stored in the rechargeable battery  100  or the DC power source outputted from the power supply  104 , and is utilized for fulfilling functionalities of the portable electronic device  10 . The power management device  108  includes a sensing module  110  and a control unit  112  to provide a power management redress scheme. The sensing module  110  is coupled between the power supply  104  and the system circuit  106 , and is utilized for sensing a direct current outputted from the power supply  104  to the system circuit  106 , to generate a sensing signal V_SEN. The control unit  112  is coupled between the sensing module  110  and the charger module  102 , and is utilized for indicating the charger module  102  to stop charging the rechargeable battery  100  when the sensing signal V_SEN indicates that the current outputted from the power supply to the system circuit surpasses a default value. In other words, when the system circuit  106  operates with high power consumption, if the current outputted from the power supply  104  to the system circuit  106  surpasses the default value, the power management device  108  outputs a control signal V_CTR indicating the charger module  102  to stop charging the rechargeable battery  100 , so as to reduce the power consumption and prevent the power supply  104  from overloading. 
     In short, if the power supply  104  does not match power specification of the system circuit  106 , e.g. the power consumption of the system circuit  106  is configured to 90 watts but a maximum power that the power supply  104  can provide is 65 watts, the power management device  108  is applicable for the power management redress scheme. Namely, when the current outputted from the power supply  104  to the system circuit  106  surpasses the maximum power, the power management device  108  stops the charger module  102  from charging, to reduce the system power consumption, prevent the power supply  104  from overloading, and ensure the system functions properly. Certainly, if the current outputted from the power supply  104  to the system circuit  106  returns within a normal range, the power management device  108  reinstates the charger module  102  to charge. 
     Note that,  FIG. 1  illustrates a composition of the portable electronic device  10  with functional blocks, when in practice, details and operations should be properly adjusted according to required applications. Take a laptop for example, main components of the system circuit  106  can be a central processing unit (CPU), a mother board, memories, a hard drive, etc., which are driven by the power supply  104  when the power supply  104  is working, and driven by the rechargeable battery  100  when the power supply  104  is not working. However, how to drive the system circuit  106  and the details and operations of the system circuit  106  are utilized for narrating the concept of the invention, devisers should coordinate with the required applications. 
     On the other hand, the invention is utilized for timely stopping the charger module  102  from charging, to reduce power consumption. However, except for stopping the charger module  102  from charging to reduce power consumption, the power consumption of the system circuit  106  can be reduced by reducing CPU speed, luminance and refreshing rate of a monitor, volume of a speaker, output rate of a video card, etc. In such a situation, the control unit  112  should take an extra route to control the system circuit  106 , which should be readily known by those skilled in the art. Namely, stopping the charger module  102  from charging is merely one embodiment of the invention, and other skills utilized for reducing the power consumption of the system circuit  106  are equally applicable for the invention, not limited thereto. 
     In addition, the power management device  108  is utilized for sensing the current outputted from the power supply  104 , so as to determine whether to stop the charger module  102  from charging or reducing CPU speed in other embodiments. Thus, the sensing module  110  is not limited to any formations, as long as it is capable of sensing the current outputted from the power supply  104  and outputting the corresponding sensing signal V_SEN. The sensing signal V_SEN is not limited to any formations either, but depends on the formations of the sensing module  110 , which can be a value obtained by analog to digital conversion, or simply an analog signal. Similarly, the control unit  112  is not limited to any formations, as long as being capable of determining whether the power supply  104  approaches overloading according to the sensing signal V_SEN, so as to timely control or indicate the charger module  102  to stop charging. For example, please refer to  FIG. 2 , which illustrates a schematic diagram of the control unit  112  shown in  FIG. 1  according to an embodiment of the invention. In  FIG. 2 , the control unit  112  comprises a divider circuit  200  and a comparator  202 . The divider circuit  200  comprises resistors R 1 , R 2 , and serves as a reference signal generator for dividing a voltage VC, to generate a reference signal V_REF. The reference signal V_REF is corresponding to an overloading or near-overloading current of the power supply  104 , and the comparator  202  compares the reference signal V_REF and the sensing signal V_SEN. The corresponding comparison result signal is the control signal V_CTR outputted to the charger module  102 . 
       FIG. 2  is an example taking the sensing signal V_SEN as a voltage form. Note that, the presumption herein is that the comparison of the reference signal V_REF and the sensing signal V_SEN can fully reflect whether the power supply  104  approaches overloading. For example, if the sensing signal V_SEN of the power supply  104  when overloading is a 4-volts voltage signal, the reference signal V_REF should be devised as a voltage signal which is equal to or slightly smaller than 4 volts. Besides, if the sensing signal V_SEN is a digitalized value, the control unit  112  should include a value comparator. However, the control unit  112  is utilized for accurately determining whether the power supply  104  approaches overloading, to control or indicate the charger module  102  to timely stop charging; thus, other frameworks and signal generation schemes of the control unit  112  are not limited to particular specifications. For example, the control unit  112  can be integrated into the charger module  102 , or further outputs the control signal VCTR via a keyboard controller, micro processors, etc. 
     Therefore, the power management device  108  provides a proper redress scheme, to increase the flexibility on management. For example, if a laptop adopts the structure of the portable electronic device  10  and includes the power management device  108 , when BIOS is not properly configured or a make of an equipped power supply is wrong, e.g. power consumption is configured to 90 watts in the BIOS, while the laptop is equipped with a 65-watt power supply, with the help of the power management device  108 , the power management device  108  can control or indicate to stop charging when the system power consumption approaches the maximum power that the power supply can provide, i.e. 65 watts, to reduce the power consumption, and avoid overloading. In comparison, in the same condition, the prior art without the power management device  108  requires rebooting due to the power supply overloading, causing the system crashing. 
     As can be seen from the above, the invention provides an extra redress scheme, to increase the flexibility on management, and to elevate product competitivity. 
     On the other hand, the operations of the power management device  108  can be further generalized as a power management procedure  30 , as shown in  FIG. 3 , including the following steps: 
     Step  300 : Start. 
     Step  302 : The sensing module  110  senses the current outputted from the power supply  104  to the system circuit  106 , to generate the sensing signal V_SEN. 
     Step  304 : The control unit  112  indicates the charger module  102  to stop charging the rechargeable battery  100  when the sensing signal V_SEN indicates that the current outputted from the power supply  104  to the system circuit  106  surpasses a default value. 
     Step  306 : End. 
     Detailed description of power management procedure  30  can be referred to the above, and is not narrated hereinafter for simplicity. 
     To sum up, the invention provides a redress scheme for a portable electronic device, to increase the flexibility on management when power supply approaches overloading, so as to timely stop charging, to reduce power consumption, hence preventing the system from crashing. 
     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.