Abstract:
The present invention relates to a power management method for portable computers with a wireless device and detects the electric power source of a portable computer through a power source detection circuit during the operation of portable computer. In addition, any one of the following is dynamically changed: the supporting rate of the connection interface between a wireless device and the portable computer, the data rate between the AP (Access Point) and the wireless device. Moreover, the invention provides a plurality of input methods for triggering the power saving modes of the portable computer to achieve the object of reducing power consumption.

Description:
BACKGROUND  
       [0001]     The present invention relates to a method of managing power consumption of a portable computer, and more particularly to a method of managing power consumption of a portable computer connected to a wireless device with a connection interface for a wireless communication system. The portable computer with a battery can include a PDA mobile phone, smart phone notebook PC, and the like.  
         [0002]     To attain better working efficiency in current portable computers, the operating speed and capability of a mobile CPU, which is used particularly for portable computers, has been enhanced. Therefore, the power consumption of mobile CPUs for the portable computers has increased relatively, resulting in greater heat. Hence, both Intel and Microsoft have provided excellent electronic power management for mobile CPUs of portable computers, such as Advanced Configuration and Power Interface (ACPI) and Speed step. ACPI has defined five states from C0 to C4, the higher states have better electric power management efficiency. However, mobile. CPUs of portable computers still have some drawbacks, e.g., the newly promoted mobile CPU speed of portable computers on the market always lags behind desktop CPUs by at least three to six months, and the price is also higher than desktop PCs.  
         [0003]     The issue of power saving is important for a portable computer which needs a battery as a power source. If the system power consumption can be reduced, battery life-time (working time) can be extended.  
         [0004]     US patent publication No. 2004/0078606 is a prior art which provides a power management method for portable computers in order to dynamically tune up voltage and frequency of a portable computer, and maintains normal operation of the portable computer. The components for adjustment are the External Clock and voltage of CPU, frequency of memory, or frequency and performance of the Video Graphics Array (VGA) card or the frequency of memory.  
         [0005]     The apparatus of the related art, however, can not further improve power saving for a portable computer connected to a wireless device in a wireless communication system. The power consumption required by the data transmission of the transmitter and the receiver of the wireless device in the communication system is large. This situation can occur for a PDA mobile phone, smart phone, notebook PC with a wireless device, and the like.  
         [0006]     To solve the described problem, the present invention provides a power management method for a wireless communication system which includes an AP and a portable computer connected to a wireless device.  
       SUMMARY  
       [0007]     The present invention provides an apparatus and method for a one-button power-saving WLAN system with an USB interface triggered by a one-button switch.  
         [0008]     The present invention provides an apparatus and method of reducing power consumption of a portable computer applied in a wireless communication system, the wireless communication system includes an AP and a wireless device connected to a host computer with a USB interface by adjusting the USB supporting rate and data rate between AP and the wireless device.  
         [0009]     The present invention relates to a power management method for portable computers with a wireless device and detects the power source of the portable computer through a power source detection circuit during operation, and dynamically changes any one of the following: the supporting rate of the connection interface between a wireless device and the portable computer; the data rate between the AP (Access Point) and the wireless device. Moreover, the invention provides a plurality of input methods to trigger the power saving mode of a portable computer for achieving reduced power consumption. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0010]     The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0011]      FIG. 1  is a function block diagram of a portable computer according to the first embodiment of the invention.  
         [0012]      FIG. 2  is a flowchart showing the steps of a power management method of the first embodiment applied to the portable computer in  FIG. 1 .  
         [0013]      FIG. 3  is a function block diagram of a portable computer includes a wireless device according to the second embodiment of the invention.  
         [0014]      FIG. 4  is a flowchart showing the detailed steps of step A of  FIG. 2 .  
         [0015]      FIG. 5  is a table related to the standards for an 802.11a/b/g, and USB interface in the present invention. 
     
    
     DESCRIPTION  
       [0016]     Finalized in 2001, USB 2.0 is a complete overhaul to the Universal Serial Bus input/output bus protocol which achieves substantial gain over USB 1.1 standard did. As an aside, USB mice and keyboards require only 1.5 Mbits/s to function.  
         [0017]     USB 1.1 allowed a maximum transfer rate of 12 Mbits/second. The USB 2.0 specification incorporates three speeds: Hi-Speed, Full-Speed and Low-Speed. Low Speed USB mode is 1.5 Mbits/second, Full Speed USB mode is 12 Mbits/second, and Hi-Speed USB mode is up to 480 Mbits/second.  
       FIRST PREFERRED EMBODIMENT (ONE-SWITCH POWER-SAVING FUNCTION)  
       [0018]      FIG. 1  is a function block diagram of a portable computer according to the first embodiment of the invention. The portable computer  120 , such as a notebook computer, communicates with an access point (AP)  130  through a wireless device  110 .  
         [0019]     The wireless device  110  connects to the portable computer  120  via USB interface  170 . The wireless device  110 , such as 802.11a, 802.11b or 802.11g wireless device, includes an RF section  112 , a MAC (Medium Access Control) section  116  and a baseband section  114 , communicating with the AP  130  using a data rate. The portable computer  120  includes managing controller  140  which comprises an USB interface mode controller  142  for changing USB interface mode according to detaching and re-attaching operation and a data rate controller  144  for adjusting data transmission rate between the wireless device  110  and the AP  130 , a power source detector  126 , a power unit  125  and a one-button switch  150  connected to a GPIO (General Purpose Input Output)  120 , and the GPIO  120  connected to a processor  122 .  
         [0020]     The power unit  125  comprises a battery  128  and power supply  160  which receives and converts an external AC source, respectively powering the portable computer  120 .  
         [0021]     In this embodiment, when the switch  150  is activated or pushed, a power-saving event will be triggered. The power source detector  126  is used to recognize that the portable computer  120  is powered by the battery  128  or the power supply  160  and to detect the power level of the power unit  125 .  
         [0022]      FIG. 2  is a flowchart showing the steps of a power management method of the first embodiment applied to the portable computer  120  in  FIG. 1 .  
         [0023]     At step S 300 , the wireless device  110  is plugged into the portable computer  120  through the USB interface  170 .  
         [0024]     At step S 305 , it is detected if a power-saving event is trigged (when pushing the switch  150 ) or a power-saving signal is input from the input device (such as the keyboard of the portable computer  120 ). When the power-saving event or the power-saving signal is detected, step S 310  is carried out otherwise step S 305  is repeated.  
         [0025]     At step S 310 , if the portable computer  120  is powered by the battery  128  based on the detection of the power source detector  126 , then step S 340  is carried out otherwise step S 320  is carried out.  
         [0026]     At step S 320 , if the power level of the power supply  160  is low power, then step S 340  is carried out otherwise step S 330  is carried out.  
         [0027]     At step S 330 , if the power-saving signal instructs to reduce the data rate between the AP  130  and the wireless device  110  through the control of the data rate controller  144 , then step S 360  is carried out to reduce the data rate between AP and the wireless device, otherwise step A is performed. In this embodiment step A does nothing, i.e., at step S 360 , the power consumption of the portable computer  120  is reduced by reducing the data rate.  
         [0028]     At step S 340 , the USB interface mode is changed by performing a detaching and re-attaching operation through the control of the USB interface mode controller  142  and the USB supporting rate is set to full speed. In this embodiment, if the default USB interface mode is USB 2.0, it can be changed to be USB 1.1 interface mode in response to the power-saving event. Another implementation or option as described below, if the default USB interface mode is USB 2.0 with supporting rate up to 480 Mbps (H mode), the supporting rate is reduced to a second supporting rate such as 1.2 Mbps (F mode) or 1.5 Mbps (L mode) in response to the power-saving event; if the default USB interface mode is USB 1.1 with a supporting rate of up to 12 Mbps (F mode), the supporting rate is reduced to a second supporting rate such as 1.5 Mbps (L mode) in response to the power-saving event. After step S 340  is performed, step S 330  is subsequently performed.  
         [0029]     In the other words, the present invention provides a power management method for managing power consumption of a portable computer having a battery and communicating with an access point (AP) through a wireless device connected to the portable computer via a USB interface. The USB interface at least has a first and second mode respectively with a first and second supporting rate less than the first supporting rate. The AP communicates with the wireless device with a first data rate. The portable computer works under a first clock frequency and a first reference voltage, wherein the portable computer includes a first circuit which is in standby or suspends its function in the power-saving mode, and the wireless device includes a second circuit which is in standby or suspends its function in power-saving mode, the method comprises the steps of:  
         [0030]     (a) inputting a power-saving signal through an input device, such as keyboard of the portable computer;  
         [0031]     (b) detaching and re-attaching the wireless device to the portable computer to change the USB interface mode from the first supporting rate to the second supporting rate, wherein the second supporting rate is less than the first supporting rate;  
         [0032]     (c) decrease the first data rate to a second data rate between the AP and the wireless device, wherein the second date rate is less than the first data rate.  
         [0033]     The power saving function is triggered when:  
         [0034]     A. The user determines the time to enforce the system to execute the power-saving function which is triggered by pushing a button, i.e., the power-saving signal is generated via a switch coupled to a GPIO to trigger the power-saving function.  
         [0000]     B. The system itself determines when to execute a power-saving function, as following.  
         [0000]    
       
         
           
              a. The power source is changed from AC to battery, i.e., the AC plug of the portable computer is detached.  
              b. Low power indication for system power is detected. It can be implemented by a system event received by the portable computer, then notify the USB device, USB interface mode controller and data rate controller, to execute the power-saving function.  
           
         
       
     
         [0037]     C. The USB interface only needs a bandwidth of 12 Mbps (i.e. USB Full Speed) for transmission.  
         [0038]     For example, the maximum data rate is 54 Mbps for an 802.11a/g wireless device, the portable computer can reduce the USB supporting rate from 480 Mbps to 12 Mbps to reduce the power consumption of the USB interface.  
         [0039]     For example, when the data rate of WLAN is less than a threshold, i.e., the bottleneck is the data rate, the portable computer can reduce the data rate of the wireless device to reduce the power consumption of the wireless device.  
         [0040]     U.S. Pat. No. 6,765,416B2, entitled “Device for recognizing power source and associated method”, disclosed a device for recognizing a power source by voltage-dividing circuits can be applied in the circuit of power source detector  126  in  FIG. 1 . The power source detector  126  is used to detect that the current power source is external AC power supply  160  or the battery  128 . If the power source is battery or detected to be low power, the portable computer will reduce the USB supporting rate or reduce the data rate between the wireless device and the AP to reduce the power consumption.  
       SECOND PREFERRED EMBODIMENT  
       [0041]      FIG. 3  is a function block diagram of a portable computer including a wireless device according to the second embodiment of the invention. The portable computer  320 , such as a notebook computer, communicates with an access point (AP)  330  through a wireless device  310  which can be provided inside the portable computer  320  or simply serving as an external device.  
         [0042]     The wireless device  310  connects to the portable computer  320  via a connection interface  370  such as a USB interface. The wireless device  310 , such as 802.11a, 802.11b or 802.11g wireless device, includes an RF section  312 , a MAC (Medium Access Control) section  316  and a baseband section  314 , communicating with the AP  330  using a data rate. The portable computer  320  includes managing controller  340  which comprises an connection interface mode controller  342  (such as a USB controller) for changing the connection interface mode according to detaching and re-attaching operation of the connection interface  370 , a data rate controller  344  for adjusting the data transmission rate between the wireless device  310  and the AP  330 , a power unit  325  and a power-saving input device  350  which includes a power source detector  326  and an input device  352  and is connected to a processor  322 .  
         [0043]     The power unit  325  comprises a battery  328  and power supply  360  which receives and converts an external AC source, respectively powering the portable computer  320 .  
         [0044]     The power source detector  326  is used to recognize that the portable computer  320  is powered by the battery  328  or the power supply  360  and to detect the power level of the power unit  325 .  
         [0045]     In this embodiment, through the power-saving input device  350 , a power-saving event can be triggered and the USB controller is notified to response to the power-saving event. The managing controller  340  further includes a clock generator  348 , a reference voltage generator  346  and a block turn-off device  349 . The connection interface  370  can be an USB interface, a RS232 interface or other interface.  
         [0046]     The main steps of the power management method for a portable computer  320  according to a second embodiment of the invention is similar to those disclosed according to the flow chart of  FIG. 2 , and are not described here for brevity, except for the step A.  
         [0047]      FIG. 4  is a flowchart showing detailed steps in step A of  FIG. 2 . The step A includes the following steps:  
         [0048]     At step S 400 , start the process.  
         [0049]     At step S 410 , if the power-saving signal or the power-saving event indicates the portable computer  320  needs to reduce the (operation) clock frequency, then step S 440  is performed to reduce the clock frequency, otherwise step S 420  is performed. Step S 440  reduces the system power consumption of the portable computer  320  by reducing the clock frequency.  
         [0050]     At step S 420 , if the power-saving signal or the power-saving event indicates the portable computer  320  needs to reduce the reference voltage, then step S 450  is performed to reduce the reference voltage to a lower reference voltage, otherwise step S 430  is performed. Step S 450  reduces the system power consumption by reducing the reference voltage.  
         [0051]     At step S 430 , if the power-saving signal or the power-saving event indicates the portable computer  320  needs to turn off the un-used circuit or block, then step S 460  is performed to turn off un-used circuit, otherwise step S 310  in  FIG. 2  is performed. Step S 460  reduces the system power consumption by turning-off the un-used circuit.  
         [0052]     In the other words, the present invention provides a power management method for managing power consumption of a portable computer having a battery and communicating with an access point (AP) through a wireless device connected to the portable computer via a USB interface. The USB interface at least has a first and second mode respectively with a first and second supporting rate less than the first supporting rate. The AP communicates with the wireless device with a first data rate. The portable computer works under a first clock frequency and a first reference voltage, wherein the portable computer includes a first circuit which is standby or suspends its function under power-saving mode, and the wireless device includes a second circuit which is standby or suspends its function under power-saving mode, the method comprises the steps of: (a) inputting a power-saving signal through an input device, such as a keyboard or button of the portable computer;  
         [0053]     (b) detaching and re-attaching the wireless device to the portable computer from the first supporting rate to the second supporting rate; wherein, taking the USB interface as an example, the first USB supporting rate equals 480 Mbps (High speed) if the first USB mode is USB 2.0 standard, and wherein the first USB supporting rate equals 12 Mbps (Full speed) if the first USB mode is USB 1.1 standard.  
         [0054]     (c) decreasing the first data rate to a second data rate between the AP and the wireless device, wherein the second date rate is less than the first data rate; wherein the second supporting rate is one selected from 480 Mbps, 12 Mbps and 1.5 Mbps, the second data rate is one selected from 54, 48, 36, 24, 18, 12, 9 and 6 Mbps for 802.11a standard, the second data rate is one selected from 11, 5.5, 2 and 1 Mbps for 802.11b standard, and the second data rate is one selected from 54, 48, 36, 24, 18, 12, 11, 9, 6, 5.5, 2 and 1 Mbps for 802.11g standard.  
         [0055]     (d) reducing the first clock frequency of the portable computer to a second clock frequency, the second clock frequency is lower than the second clock frequency.  
         [0056]     (e) reducing the first reference voltage to a second reference voltage, the second reference voltage is less than the first reference voltage.  
         [0057]     (f) turning off the first circuit of the portable computer.  
         [0058]     For the convenience in understanding the adjustment of the data rate in the present invention, the related data list for 802.11a/b/g and USB interface is shown in  FIG. 5 .  
         [0059]     As for the detailed implementation of the function blocks of the clock generator  348 , the reference voltage generator  346 , and power source detection means  326  of the  FIG. 3  can be seen in the related arts, and is not described here.  
         [0060]     US application number US2005/0138444A1, titled as “Frequency voltage mechanism for microprocessor power management”, discloses a power management technique which adjusts the clock frequency and the voltage of the microprocessor.  
         [0061]     The input device  352  of  FIG. 3  of the present invention can include a remote controller coupled to a wireless receiver, or the like.  
         [0062]     U.S. Pat. No. 6,072,334, entitled “signal converter with a dynamically adjustable reference voltage and chipset including the same”, discloses a method of reducing power consumption of the chipset by adjusting reference voltage.  
         [0063]     U.S. Pat. No. 6,034,508, entitled “Battery life extending power-switching device for all-time operational system”, discloses a switching method and apparatus of switching power sources from a battery or an external power source to an all-time circuit by means of a power source detection circuit to detect the power sources.  
         [0064]     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. Those who are skilled in this technology can still make various alterations and modifications without departing from the scope and spirit of this invention. Therefore, the scope of the present invention shall be defined and protected by the following claims and their equivalents.