Patent Publication Number: US-2011057605-A1

Title: Power Supply System with Power Saving Function and Power Supply Method Thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 098130175 filed in Taiwan, Republic of China on Sep. 8, 2009, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a power supply system and, more particularly, to a power supply system with a power saving function and a power supply method thereof. 
     2. Description of the Related Art 
     At present, a portable electronic device (such as a notebook computer, a portable personal computer, and a handheld computer and so on) usually equips with a power adapter. A notebook computer is taken for example. The power adapter can be connected with commercial power for supplying power for the computer system and charging a battery of the notebook computer. 
     Usually, the higher a voltage of the power adapter outputs, the lower the system efficiency is. To satisfy charging needs, the conventional power adapter outputs a high fixed voltage (such as 19V). When the battery is fully charged, the power adapter may always output the high voltage, thereby reducing conversion efficiency of the system. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention provides a power supply system with a power saving function and a power supply method thereof to improve the prior art. 
     This invention provides a power supply system with a power saving function for a rechargeable battery. The power supply system includes a power adapter and a portable electronic device body. The power adapter has a control pin. The portable electronic device body includes a connector, a charging unit, and an embedded controller. The connector is used for connecting the rechargeable battery. The charging unit is coupled with the connector and the power adapter. The embedded controller is coupled with the control pin, the connector, and the charging unit. The embedded controller is used for detecting a capacity state of the rechargeable battery and whether the rechargeable battery is connected with the connector to determine whether the rechargeable battery needs to be charged. When the rechargeable battery does not need to be charged, the embedded controller controls the power adapter to output a first voltage to the portable electronic device body via the control pin. When the rechargeable battery needs to be charged, the embedded controller controls the power adapter to output a second voltage to the portable electronic device body via the control pin and controls the charging unit to use the second voltage to charge the rechargeable battery. The first voltage is lower than the second voltage. 
     This invention also provides a power supply method with a power saving function for a rechargeable battery. The power supply method includes the following steps. An embedded controller is used to detect a capacity state of the rechargeable battery and whether the rechargeable battery is connected with the connector to determine whether the rechargeable battery needs to be charged. When the rechargeable battery does not need to be charged, the embedded controller controls the power adapter to output a first voltage via the control pin. When the rechargeable battery needs to be charged, the embedded controller controls the power adapter to output a second voltage via the control pin and controls the charging unit to use the second voltage to charge the rechargeable battery. The first voltage is lower than the second voltage. 
     According to the power supply system in the invention, the power adapter additionally has a control pin and the embedded controller is used to detect the capacity state of the rechargeable battery and whether the rechargeable battery is connected with the connector to determine whether the rechargeable battery needs to be charged. In addition, according to different states of the rechargeable battery, the power supply system outputs different voltages to the computer system. When the rechargeable battery needs to be charged, the high voltage is outputted. When the rechargeable battery does not need to be charged (the battery is not connected or is fully charged), the lower voltage is outputted. Thereby, the energy conversion efficiency of the power system of the portable electronic device can be improved, and the structure is simple and is easy to be realized. 
     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a functional block diagram showing a power supply system according to one preferred embodiment of the invention. 
         FIG. 2  is a flowchart showing a power supply method according to one preferred embodiment of the invention. 
         FIG. 3  is a functional block diagram showing a power supply system according to another preferred embodiment of the invention. 
         FIG. 4  is a flowchart showing a power supply method according to another preferred embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a functional block diagram showing a power supply system according to one preferred embodiment of the invention. In the embodiment, a power supply system  1  is for a rechargeable battery  30 . For example, the power supply system  1  can control the rechargeable battery  30  to be charged or discharged. 
     In the embodiment, the rechargeable battery  30  may be a lithium battery. However, the invention is not limited thereto. In other embodiments, the rechargeable battery  30  may be a nickel-cadmium battery or a nickel-metal hydride battery. 
     In the embodiment, the rechargeable battery  30  includes six pins for connecting the power supply system  1 . A first pin is a positive electrode, a second pin is a pin for detecting whether the battery is connected, a third pin is a data pin for transmitting battery parameters, a fourth pin is an empty pin, and a fifth pin is a ground pin. 
     In the embodiment, the rechargeable battery  30  can include a battery management chip (such as a Gauge IC). The battery management chip includes a series of registers for storing parameters such as battery capacity, temperature, battery identification codes, battery states, charging states, discharging times and so on. The parameters gradually changes in a using process of the rechargeable battery  30 . In the embodiment, the parameters of the rechargeable battery  30  can be transmitted to the power supply system  1  via the data pin to perform corresponding charging or discharging operation. 
     In the embodiment, the power supply system  1  includes a power adapter  10  and a portable electronic device body  20 . The portable electronic device body  20  can use working power provided by the power adapter  10  or the rechargeable battery  30  to perform different operation. 
     In the embodiment, the portable electronic device body  20  may be a notebook computer body. However, the invention is not limited thereto. In other embodiments, the portable electronic device body  20  may be a mobile phone body. 
     In the embodiment, the portable electronic device body  20  includes a connector  202 , an embedded controller  203 , a charging unit  204 , and a discharging unit  205 . The connector  202  is used for connecting the rechargeable battery  30  and can receive the parameters of the rechargeable battery  30 . The embedded controller  203  is coupled with the connector  202 , the charging unit  204 , and the discharging unit  205 . The charging unit  204  and the discharging unit  205  are also coupled with the connector  202 . 
     In the embodiment, in a charging state, the charging unit  204  converts the working power (such as the working power from the power adapter  10 ) to charging power of the rechargeable battery  30  thus to charge the rechargeable battery  30 . 
     In the embodiment, in a discharging state, the discharging unit  205  can convert output power of the rechargeable battery  30  to the power needed by operation of different functional units in the portable electronic device body  20 . 
     In the embodiment, the embedded controller  203  can detect a state of the connector  202 . For example, the embedded controller  203  can determine whether the rechargeable battery  30  is connected by detecting whether the connector  202  is connected with the second pin of the rechargeable battery  30 . In addition, the embedded controller  203  can detect whether the power adapter  10  is connected with the portable electronic device body  20 . 
     In the embodiment, the embedded controller  203  can receive the state parameters of the rechargeable battery  30  from the connector  202 , and the state parameters may include whether the rechargeable battery  30  needs to be charged at present and the present capacity. 
     In the embodiment, when the rechargeable battery  30  does not need to be charged, the embedded controller  203  can output a first state control signal. In detail, there are two conditions that the rechargeable battery  30  does not need to be charged. The first condition is that the embedded controller  203  detects that the rechargeable battery  30  is not connected with the connector  202 . The second condition is that the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  does not need to be charged at that moment. In this condition, usually the capacity of the rechargeable battery  30  is greater than a predetermined value. For example, the capacity may be greater than 95% of full capacity of the rechargeable battery  30 . The predetermined value can be set when the rechargeable battery  30  leaves the factory according to needs, and it can also be set by users via software. However, the invention is not limited thereto. 
     In the embodiment, the first state control signal may be a low level control signal. In other embodiments, it may also be a high level control signal. However, the invention is not limited thereto. 
     In another aspect, in the embodiment, when the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  needs to be charged, the embedded controller  203  can output a second state control signal. At that moment, the capacity of the rechargeable battery  30  is usually lower than the predetermined value. However, the invention is not limited thereto. 
     In the embodiment, whether the rechargeable battery  30  needs to be charged is determined according to whether the rechargeable battery  30  is connected with the connector  202  and whether the capacity of the rechargeable battery  30  is greater than a predetermined value. That is, in this embodiment, the determination whether the rechargeable battery  30  needs to be charged does not depend on whether the portable electronic device body  20  is started up. 
     In the embodiment, the embedded controller  203  determines whether the rechargeable battery  30  needs to be charged, and the operation of the embedded controller  203  does not depend on start-up of the portable electronic device body  20 . Therefore, even if the portable electronic device body  20  is in a shutdown state, once the embedded controller  203  determines that the rechargeable battery  30  needs to be charged, the embedded controller  203  can still output the second state control signal. 
     In the embodiment, the second state control signal may correspondingly be a high level control signal. In other embodiments, it may correspondingly be a low level control signal. However, the invention is not limited thereto. 
     In the embodiment, when the embedded controller  203  detects that the power adapter  10  is connected with the portable electronic device body  20 , and the rechargeable battery  30  needs to be charged, the embedded controller  203  can control the charging unit  204  to charge the rechargeable battery  30  until the rechargeable battery  30  is fully charged. 
     When the embedded controller  203  detects that the power adapter  10  is not connected with the portable electronic device body  20 , the embedded controller  203  can control the discharging unit  205  to discharge the rechargeable battery  30 . 
     In the embodiment, the power adapter  10  has a control pin  1011  coupled with the embedded controller  203 . The power adapter  10  includes a control unit  101  and an output unit  102 . The control unit  101  is coupled with the output unit  102  and the control pin  1011 , respectively. 
     In the embodiment, the control pin  1011  receives the first state or second state control signal outputted from the embedded controller  203  and transmits the control signal to the control unit  101 . The control unit  101  controls the output unit  102  to output a corresponding voltage to the portable electronic device body  20  according to the control signal. 
     In the embodiment, when the rechargeable battery  30  does not need to be charged, the embedded controller  203  outputs the first state control signal, the control pin  1011  outputs the received first state control signal to the control unit  101 . The control unit  101  can output a first voltage, such as a voltage of 12V, to the portable electronic device body  20  according to the first state control signal. 
     When the rechargeable battery  30  needs to be charged, the embedded controller  203  outputs the second state control signal, the control pin  1011  outputs the received second state control signal to the control unit  101 . The control unit  101  can output a second voltage, such as a voltage of 19V, to the portable electronic device body  20  according to the second state control signal. When the portable electronic device body  20  normally operates, the embedded controller  203  can further control the charging unit  204  to use the second voltage to charge the rechargeable battery  30 . In the embodiment, the first voltage is lower than the second voltage. 
     In the embodiment, when the rechargeable battery  30  needs to be charged and the portable electronic device body  20  is in the shutdown state, the control unit  101  can still output the second voltage, such as a voltage of 19V, to the portable electronic device body  20  according to the second state control signal outputted from the embedded controller  203 . Thereby, the embedded controller  203  can still control the charging unit  204  to use the second voltage to charge the rechargeable battery  30 . That is, in the embodiment, no matter whether the portable electronic device body  20  is started up, the charge for the rechargeable battery  30  is performed by the charging unit  204 . 
     Usually, a battery needs a higher voltage during charge to allow current to flow into the battery. Meanwhile, the current also needs to be accurately controlled within a predetermined value to ensure safety of the battery. Therefore, in a charging process, the charging voltage needs to increase with the increase of the voltage of the battery thus to prevent too much current from wholly entering into the battery in a short time to cause execution of an over-current protection function of the battery or explosion of the battery due to over-heat. 
     Compared with the power adapter  10 , the charging unit  204  usually has a current limit function, while the power adapter  10  usually only has an over-current protection function (greater than charging current). Therefore, in the shutdown state, in the embodiment, the charging unit  204  still can be used to charge the rechargeable battery  30  to prevent the power adapter  10  from directly charging the rechargeable battery  30  thus to protect the rechargeable battery  30 . 
       FIG. 2  is a flowchart showing a power supply method according to one preferred embodiment of the invention. Please refer to  FIG. 1  and  FIG. 2  together. 
     In step S 210 , an embedded controller  203  is used to detect a capacity state of the rechargeable battery  30  and whether the rechargeable battery  30  is connected with a connector thus to determine whether the rechargeable battery needs to be charged. 
     In detail, the embedded controller  203  determines whether the rechargeable battery  30  is connected by detecting whether the connector  202  is connected with the second pin of the rechargeable battery  30 . In addition, the embedded controller  203  can further detect whether the power adapter  10  is connected with the portable electronic device body  20 . The embedded controller  203  can receive the state parameter of the rechargeable battery  30  in the battery management chip via the third pin connected with the connector  202 , and the state parameter may include whether the rechargeable battery  30  needs to be charged at present and the present battery capacity. 
     In step S 220 , when the rechargeable battery  30  does not need to be charged, the embedded controller  203  outputs a first state control signal. 
     In detail, there are two conditions that the rechargeable battery  30  does no need to be charged. The first condition is that the embedded controller  203  detects that the rechargeable battery  30  is not connected with the connector  202 . The second condition is that the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  does not need to be charged. In the condition, usually the capacity of the rechargeable battery  30  is greater than a predetermined value. For example, the capacity may be greater than 95% of full capacity of the rechargeable battery  30 . However, the invention is not limited thereto. 
     In the embodiment, the first state control signal can be a low level control signal. In other embodiments, the first state control signal may also be a high level control signal. However, the invention is not limited thereto. 
     In step S 230 , the power adapter  10  outputs a first voltage according to the first state control signal. 
     In detail, the control pin  1011  of the power adapter  10  receives the first state control signal and transmits the first state control signal to the control unit  101 . The control unit  101  controls the output unit  102  to output the first voltage according to the first state control signal and supplies power for the portable electronic device body  20  via an output positive electrode  1021  and an output negative electrode  1022 . The first voltage can be 12V, and it can be used as a working voltage of the portable electronic device body  20  to maintain normal operation. However, the invention is not limited thereto. 
     In step S 240 , when the rechargeable battery  30  needs to be charged, the embedded controller  203  outputs the second state control signal. 
     In detail, when the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  needs to be charged, the embedded controller  203  can output the second state control signal. At that moment, the capacity of the rechargeable battery  30  is usually lower than the predetermined value. However, the invention is not limited thereto. 
     In the embodiment, the second state control signal can correspondingly be a high level control signal. In other embodiments, the second state control signal may correspondingly be a low level control signal. However, the invention is not limited thereto. 
     In step S 250 , the power adapter  10  outputs a second voltage according to the second state control signal. 
     In detail, the power adapter  10  receives the second state control signal via the control pin  1011  and transmits the second state control signal to the control unit  101 . The control unit  101  controls the output unit  102  to output the second voltage to the portable electronic device body  20  via the output positive electrode  1021  and the output negative electrode  1022  according to the second state control signal. In the embodiment, the second voltage can be 19V. However, the invention is not limited thereto. 
     In step S 260 , the embedded controller  203  controls the charging unit  204  to use the second voltage to charge the rechargeable battery  30 . 
     In the embodiment, in one aspect, the second voltage is used as a working voltage of the portable electronic device body  20  to maintain the normal operation. In another aspect, the charging unit  204  is controlled by the embedded controller  203  to convert the second voltage to the charging voltage of the rechargeable battery  30  to charge the rechargeable battery  30 . 
     In the above method, the power adapter  10  is connected with the portable electronic device body  20 . In addition, when the embedded controller  203  detects that the power adapter  10  is not connected with the portable electronic device body  20 , the embedded controller  203  controls the discharging unit  205  to supply power for the rechargeable battery  30  to provide the working voltage for the portable electronic device body  20  to maintain the normal operation. 
       FIG. 3  is a functional block diagram showing a power supply system according to another preferred embodiment of the invention. The difference between a power supply system  2  in  FIG. 3  and the power supply system  1  in  FIG. 1  is that in this embodiment a portable electronic device body  20  further includes a switch circuit  201  coupled with an embedded controller  203  and a control pin  1011 . Other modules and the relation therebetween are the same as that in the power supply system  1 . Therefore, they are not described for a concise purpose. 
     In the embodiment, when a rechargeable battery  30  does not need to be charged, the embedded controller  203  controls the switch circuit  201  to be in a first state. That is, when the embedded controller  203  detects that the rechargeable battery  30  is not connected with the connector  202  or a received state parameter of the rechargeable battery  30  indicates that the rechargeable battery  30  does not need to be charged at that moment, the embedded controller  203  controls the switch circuit  201  to be in the first state. 
     In the embodiment, the first state can be that the switch circuit is opened. In other embodiments, the first state may be that the switch circuit is closed. However, the invention is not limited thereto. 
     In the embodiment, when the control pin  1011  of the power adapter  10  detects that the switch circuit  201  is in the first state, the embedded controller  203  and the control pin  1011  are not connected, and the control pin  1011  fails to receive any signal from the embedded controller  203 . Therefore, the control unit  101  also cannot receive any signal from the control pin  1011 . In this condition, the control unit  101  can control the output unit  102  to output a first voltage and supplies power for the portable electronic device body  20  via an output positive electrode  1021  and an output negative electrode  1022 . 
     In other embodiments, when the first state is that the switch circuit is closed, the embedded controller  203  and the control pin  1011  is connected with each other, and the control pin  1011  can correspondingly transmit a signal from the embedded controller  203  to the control unit  101 . The control unit  101  can control the output unit  102  to output the first voltage according to the signal. However, the invention is not limited thereto. 
     In another aspect, in the embodiment, when the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  needs to be charged, the embedded controller  203  controls the switch circuit  201  to be in a second state. At that moment, the capacity of the rechargeable battery  30  is usually lower than a predetermined value, such as lower than 95% of full capacity of the rechargeable battery  30 . However, the invention is not limited thereto. 
     The same as the above embodiment, in this embodiment, the determination whether the rechargeable battery  30  needs to be charged does not depend on whether the portable electronic device body  20  is started up. In the embodiment, even if the portable electronic device body  20  is in a shutdown state, once the embedded controller  203  determines that the rechargeable battery  30  needs to be charged, the embedded controller  203  can still control the switch circuit  201  to be in the second state. 
     In the embodiment, the second state can be that the switch circuit is closed. In other embodiments, the second state may be that the switch circuit is opened. However, the invention is not limited thereto. 
     In the embodiment, when the control pin  1011  of the power adapter  10  detects that the switch circuit  201  is in the second state, the embedded controller  203  and the control pin  1011  is connected with each other, and the control pin  1011  can receive signals from the embedded controller  203 . At that moment, the control pin  1011  transmits the signals from the embedded controller  203  to the control unit  101 . Thereby, the control unit  101  controls the output unit  102  to output a second voltage to the portable electronic device body  20  via the output positive electrode  1021  and the output negative electrode  1022 . The second voltage can maintain the normal operation of the portable electronic device body  20  and can also be used for charging the rechargeable battery  30 . 
     In the embodiment, when the rechargeable battery  30  needs to be charged and the portable electronic device body  20  is in a shutdown state, the second voltage can be mainly used to charge the rechargeable battery  30 . However, the invention is not limited thereto. 
     In other embodiments, when the second state is that the switch circuit is opened, the embedded controller  203  and the control pin  1011  is not connected with each other, and the control pin  1011  fails to receive any signal from the embedded controller  203 . Therefore, the signal fails to be transmitted to the control unit  101 . At that moment, the control unit  101  can control the output unit  102  to output the second voltage. However, the invention is not limited thereto. 
       FIG. 4  is a flowchart showing a power supply method according to another preferred embodiment of the invention. Please refer to  FIG. 3  and  FIG. 4  together. 
     In step S 410 , the embedded controller  203  is used to detect a capacity state of the rechargeable battery  30  and whether the rechargeable battery  30  is connected with the connector  202  to determine whether the rechargeable battery needs to be charged. The step is the same as the step  210  in  FIG. 2 . Therefore, it is not described for a concise purpose. 
     In step S 420 , when the rechargeable battery  30  does not needs to be charged, the embedded controller  203  controls the switch circuit  201  to be in the first state. 
     In the embodiment, when the embedded controller  203  detects that the rechargeable battery  30  is not connected with the connector  202  or the received state parameter of the rechargeable battery  30  indicates that the rechargeable battery  30  does not need to be charged at that moment, the embedded controller  203  controls the switch circuit  201  to be in the first state. 
     In the embodiment, the first state can be that the switch circuit is opened. In other embodiment, the first state may be that the switch circuit is closed. However, the invention is not limited thereto. 
     In step S 430 , the power adapter  10  output a first voltage according to the first state. 
     In detail, in the embodiment, the embedded controller  203  controls the state of the switch circuit  201  according to the detected capacity state of the rechargeable battery  30  and whether the rechargeable battery  30  is connected with the connector  202 . When the switch circuit  201  is in the first state, that is, the switch circuit is opened, the control unit  101  fails to receives any signal from the control pin  1011 , thus controlling the output unit  102  to output the first voltage to supply power for the portable electronic device body  20 . 
     In step S 440 , when the rechargeable battery  30  needs to be charged, the embedded controller  203  controls the switch circuit  201  to be in the second state. 
     In the embodiment, when the state parameter of the rechargeable battery  30  received by the embedded controller  203  indicates that the rechargeable battery  30  needs to be charged, the embedded controller  203  controls the switch circuit  201  to be in the second state. At that moment, the capacity of the rechargeable battery  30  is usually lower than a predetermined value. However, the invention is not limited thereto. 
     In the embodiment, the second state can be that the switch circuit is closed. In other embodiments, the second state may be that the switch circuit is opened. However, the invention is not limited thereto. 
     In step S 450 , the power adapter  10  outputs a second voltage according to the second state. 
     In detail, when the switch circuit  201  is in the second state, that is, the switch circuit is closed, the control pin  1011  transmits the signal from the embedded controller  203  to the control unit  101 . Thereby, the control unit  101  controls the output unit  102  to output the second voltage to the portable electronic device body  20 . The second voltage is greater than the first voltage. 
     In step S 460 , the embedded controller  203  controls the charging unit  204  to use the second voltage to charge the rechargeable battery  30 . 
     In the embodiment, in one aspect, the second voltage is used as a working voltage for the portable electronic device body  20  to maintain the normal operation. In another aspect, the charging unit  204  is controlled by the embedded controller  203  to convert the second voltage to a charging voltage of the rechargeable battery  30  to charge the rechargeable battery  30 . 
     During the above method, the power adapter  10  is connected with the portable electronic device body  20 . In addition, when the embedded controller  203  detects that the power adapter  10  is not connected with the portable electronic device body  20 , the embedded controller  203  controls the discharging unit  205  to discharge the rechargeable battery  30  thus to provide the working voltage for the portable electronic device body  20  to maintain the normal operation thereof. 
     To sum up, according to the power supply system in the invention, the power adapter additionally has a control pin, and the embedded controller is used to detect the capacity state of the rechargeable battery and whether the rechargeable battery is connected with the connector thus to determine whether the rechargeable battery needs to be charged. According to the different states of the rechargeable battery, different voltages can be outputted and supplied to the computer system. When the rechargeable battery needs to be charged, the second voltage (that is, the higher voltage) is outputted. When the rechargeable battery does not need to be charged (the battery is not connected or is fully charged), the first voltage (that is, the lower voltage) is outputted. Thereby, power conversion efficiency of the portable electronic device can be improved, and the structure is simple and is easy to be realized. 
     Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope of the invention. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope and spirit of the invention. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.