Patent Publication Number: US-2005140337-A1

Title: Charging apparatus

Description:
FIELD OF THE INVENTION  
      The present invention is related to a charging apparatus, and more particularly to a charging apparatus for use with an electronic apparatus.  
     BACKGROUND OF THE INVENTION  
      With the incessant progress of the wireless communication technology, a mobile phone has been widely used by people as a necessary communication tool in daily life. The advent of mobile phone greatly facilitates the interactions between modern people. People can use a mobile phone to exchange information and transmit messages. Moreover, people can use a mobile phone to connect to the Internet, browse the web pages on the Internet, send/receive e-mail, and upload/download data or files.  
      In addition, traditional complicated circuit design has been successfully incorporated into a mobile IC component because of the advancement of IC manufacturing technique. Thus the size of a mobile phone has been scaled down as thin and small, and the portability of a mobile phone has been significantly improved. Although the high portability of a mobile phone can accommodate plenty of conveniences, a mobile phone has to count on an internal battery to supply sufficient electric power to sustain its operation. Therefore, a charging apparatus adapted to charge a mobile phone when the battery of the mobile phone is low has been put in a significant position.  
       FIG. 1  shows a mobile phone being connected to a charging apparatus according to the prior art. As shown in  FIG. 1 , if it is desired to charge the mobile phone, a charging apparatus  11  and an AC power source  10  have to be connected together, so that the mobile phone  12  is charged by the AC power source  10  through the contact with the charger  11 . When the charger  11  is plugged into an outlet, it will receive an input AC power therefrom. The received AC power will be converted into a DC voltage of 5.6 volts by an AC/DC converter embedded within the charger  11  (not shown), so that the mobile phone  12  can be charged with advantage.  
      The conventional charging apparatus can actually perform a fast charging operation to a mobile phone. However, if the battery capacity of a mobile phone is low and there is no available external power source, the charging apparatus cannot bring itself into play to charge the mobile phone. Therefore, how to obviate the problem encountered by the prior art charging apparatus, that is, how to enable the charging apparatus to charge the mobile phone in the absence of an available external power source, has become a major task to be pursued by the invention.  
     SUMMARY OF THE INVENTION  
      A major object of the present invention is to provide a charging apparatus that can obviate the disadvantages encountered by the prior art that the charging apparatus cannot charge an electronic device in the absence of an available external power source.  
      To this end, a broader aspect to be encompassed by a preferred embodiment of the present invention is directed to a charging apparatus for charging an electronic device electrically connected therewith, wherein the electronic device can generate a control signal to switch the conducting paths within the charging apparatus for charging the electronic device therethrough. The charging apparatus includes: an input terminal for receiving a first type of electric power; an output terminal for coupling to the electronic device; a transducer electrically connected to the input terminal for converting the first type of electric power into a second type of electric power; an energy storage element electrically connected between the transducer and the output terminal for storing the second type of electric power and/or providing the stored second type of electric power for the output terminal to charge the electronic device; and a relay circuit electrically connected to the transducer, the energy storage element and the output terminal, wherein the relay circuit is configured to provide either a first conducting path connected to the output terminal or a second conducting path connected to the energy storage element. The relay circuit can materialize the first conducting path and lead the power required to charge the electronic device through the first conducting path in response to the control signal. In this manner, when the input terminal receives a first type of electric power, the transducer can convert the first type of electric power into a second type of electric power, which is to be transferred to the output terminal through the first conducting path to charge the electronic device. Otherwise, when the input terminal does not receive a first type of electric power, the energy which is conserved in the form of a second type of electric power in the energy storage element is transferred to the output terminal through the second conducting path to charge the electronic device.  
      In accordance with the present invention, the electronic device is a portable electronic device, for example, a mobile phone, a digital audio recorder, or a personal digital assistant.  
      In accordance with the present invention, the transducer is an AC/DC converter.  
      In accordance with the present invention, the first type of electric power is an AC power, and the second type of electric power is a DC power.  
      In accordance with the present invention, the energy storage element includes a rechargeable battery which is electrically connected to the relay circuit and is used to store the second type of electric power, and a boost circuit which is electrically connected to the rechargeable battery and the output terminal and is used to step up the voltage level of the second type of electric power to a level being sufficient to drive the electronic device.  
      In accordance with the present invention, the energy storage element further includes a battery indicator which is electrically connected to the rechargeable battery for indicating the remaining capacity of the rechargeable battery.  
      Another broader aspect to be encompassed by a preferred embodiment of the present invention is made by the provision of a charging apparatus for charging an electronic device connected therewith, wherein the electronic device can generate a control signal to switch the conducting paths within the charging device for charging the electronic device therethrough. The charging apparatus includes: an input terminal for receiving a first type of electric power; an output terminal for coupling to the electronic device; a transducer electrically connected to the input terminal for converting the first type of electric power into a second type of electric power; an energy storage element electrically connected between the transducer and the output terminal for storing the second type of electric power; and a relay circuit electrically connected to the transducer, the energy storage element, and the output terminal, wherein the relay circuit is configured to provide either a first conducting path being connected to the output terminal or a second conducting path being connected to the energy storage element, and is able to materialize the first conducting path in response to the control signal and materialize the second conducting path in the absence of the control signal. In this way, the second type of electric power produced by the transducer can be leaded to the output terminal to charge the electronic device through the first conducting path, or can be leaded to charge the energy storage element through the second conducting path.  
      Now the foregoing and other features and advantages of the present invention will be best understood through the following descriptions with reference to the accompanying drawings, wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a plan view showing a prior art charging apparatus being connected to a mobile phone;  
       FIG. 2  is a plan view showing a charging apparatus being connected to an electronic device according to a preferred embodiment of the present invention;  
       FIG. 3  is a plan view showing a charging apparatus being configured to charge the electronic device according to a preferred embodiment of the present invention; and  
       FIG. 4  is plan view showing a charging apparatus being configured to charge the internal energy storage element according to a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The present invention provides a charging apparatus which utilizes a relay circuit to switch the power source of the charging apparatus either from an AC power source or from an internal rechargeable battery, and thereby eliminate the drawbacks encountered by the prior art that the charging apparatus is inoperable to charge the mobile phone in the absence of an available external power source.  
       FIG. 2  shows a circuit block diagram of an electronic device being connected to a charging apparatus according to a preferred embodiment of the present invention. As shown in  FIG. 2 , the main function of the charging apparatus  20  is to charge the electronic device  29  with electricity. When the electronic device  29  is electrically connected to the charging apparatus  20 , a control signal will be generated within the charging apparatus  20 . The charging apparatus  20  basically includes an input terminal  21 , an output terminal  24 , a transducer, a relay circuit  23 , and an energy storage element  25 .  
      The input terminal  21  is used to receive a first type of electric power transmitted from an outlet, and the output terminal  24  is used to couple to the electronic device  29 . The transducer is preferably implemented by an AC/DC converter  22 , and is used to convert the first type of electric power into a second type of electric power. In the present embodiment, the first type of electric power is directed to an AC power, and the second type of electric power is directed to a DC power.  
      The core components of the energy storage element  25  include a rechargeable battery  251 , a boost circuit  252 , and a battery indicator  253 . The rechargeable battery  251  is used to store the DC power outputted from the AC/DC converter  22 , or discharge the DC power stored therein to the boost circuit  252  when the input terminal  21  does not receive an AC power. The boost circuit  252  can step up the voltage level of the DC power obtained from the rechargeable battery  251  to a level tailored to drive the electronic device  29 , and then output the boosted DC power to the output terminal  24  to charge the electronic device  29 . In addition, the battery indicator  253  is provided and electrically connected to the rechargeable battery  251 , a green LED  254  and a red LED  255 , and is used to monitor the remaining capacity of the rechargeable battery  251 . If the battery capacity of the rechargeable battery  251  is full, the message indicating the full battery capacity condition will be given by the green LED  254 . Otherwise, the red LED  255  will send an alarm message to indicate that the battery capacity of the rechargeable battery  251  is low.  
      The relay circuit  23  is configured to provide either a first conducting path  231  connected to the input terminal  24  or a second conducting path  232  connected to the rechargeable battery  251 , and is electrically connected to the AC/DC converter  22 , the rechargeable battery  251  and the output terminal  24 . The main purpose of the relay circuit  23  is to materialize the first conducting path  231  in response to the control signal. When the input terminal  21  receives an input AC power, the relay circuit  23  materializes the first conducting path  231  and charges the electronic device  29  by leading the DC power produced by the AC/DC converter  22  through the first conducting path  231  to the output terminal  24 . In the absence of the control signal, the relay circuit  23  materializes the second conducting path  232  and charges the rechargeable battery  251  through the second conducting path  232  when the input terminal  21  receives an input AC power.  
      In the present embodiment, the operation of the charging apparatus can be accomplished in compliance with the following modes:  
      1. Referring to  FIG. 3 , a plan view illustrating the configuration for charging the electronic device by a charging apparatus according to the present invention is indicated. When the charging apparatus  20  is electrically connected with the electronic device  29  and an input AC power is received by the input terminal  21 , as shown in  FIG. 3 , the relay circuit  23  materializes a first conducting path  231  in response to the control signal generated by the electronic device  29 . Therefore, the input AC power is converted into a DC power by the AC/DC converter  22 , and then the converted DC power is transferred to the output terminal  24  through the first conducting path  231  to charge the electronic device  29 .  
      2. Referring to  FIG. 3  again, when the charging apparatus  20  is electrically connected with the electronic device  29  but the input terminal  21  is not coupled to an input AC power, as shown in  FIG. 3 , the DC power stored in the rechargeable battery  251  is transferred to the boost circuit  252 , and the boost circuit  252  starts stepping up the voltage level of the DC power until the voltage level of the DC power is up to a level being sufficient to drive the electronic device  29 . The boosted DC power outputted from the boost circuit  252  is then transferred to the output terminal  24  to charge the electronic device  29 .  
      3. Referring to  FIG. 4 , a plan view illustrating the configuration for charging the internal energy storage element of a charging apparatus according to the present invention is indicated. As shown in  FIG. 4 , when the charging apparatus  20  is not coupled to the electronic device  29  and the input terminal  21  is coupled to an input AC power, the relay circuit  23  materializes a second conducting path  232  in the absence of the control signal. Therefore, the AC power is converted into a DC power by the AC/DC converter  22 , and then the rechargeable battery  251  is charged by the converted DC power through the second conducting path  232 .  
      4. Referring to  FIG. 4  again, when the charging apparatus  20  is not coupled to the electronic device  20  and the input terminal  21  is not coupled to an input AC power, the charging device  20  will be working in an idle state.  
      In the present embodiment, the electronic device  29  is selected as a type of portable electronic device, which includes but is not limited to, a mobile phone, a digital audio recorder, and a personal digital assistant.  
      While the present invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the present invention need not be restricted to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. Therefore, the above description and illustration should not be taken as limiting the scope of the present invention which is defined by the appended claims.