Abstract:
A wireless charging apparatus includes a transmitter, and first receiver, and a second receiver. The transmitter wirelessly transmits first power from a charger. The first receiver amplifies first current corresponding to the first power to second current. The second receiver wirelessly receives second power corresponding to the second current. The second power charges a battery of an electronic device, and the first and second receivers are coupled to the electronic device.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Korean Patent Application No. 10-2015-0002636, filed on Jan. 8, 2015, and entitled, “Wireless Charging Apparatus,” is incorporated by reference herein in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    One or more embodiments herein relate to a wireless charging apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    Wireless charging refers to wirelessly charging the battery of an electronic product, e.g., a portable electronic device. Wireless charging is performed by placing the battery, or device, on a charger (e.g., a charging pad) without establishing a physical connection to a separate charging adapter or power cable. Wireless charging has also been referred to as non-contact charging. 
         [0006]    One type of wireless charging is performed in an electromagnetically inductive manner in one-to-one correspondence between the primary coil of the device and the secondary coil of the charger. However, wireless charging may be especially difficult for some types of devices and/or under some conditions. For example, mobile phones designed for use in a mountainous areas or for military purposes may have battery covers with a thickness that exceeds a wireless charging range. In these and other situations, wireless charging may be difficult to perform. 
       SUMMARY 
       [0007]    In accordance with one or more embodiments, a wireless charging apparatus includes a transmitter to wirelessly transmit first power from a charger; a first receiver to amplify first current corresponding to the first power to second current; and a second receiver to wirelessly receive second power corresponding to the second current, wherein the second power is to charge a battery of an electronic device and wherein the first and second receivers are coupled to the electronic device. The second receiver may be inside a cover of the electronic device, and the first receiver may be coupled to an outer surface of the cover. The transmitter may include a transmission coil to transmit the first power to the first receiver. 
         [0008]    The first receiver may include an input circuit to induce the first current based on the first power; an amplifier electrically connected to the input circuit to amplify the first current to the second current, where the second current may be greater than the first current; and an output circuit to transmit the second power to the second receiver based on the second current. 
         [0009]    The input circuit may include an input coil to the first current based on electromagnetic induction with the transmission coil; and one or more capacitors electrically connected to the input coil, wherein the one or more capacitors are to perform a frequency-matching operation between the input coil and transmission coil. 
         [0010]    The amplifier may include a first coil electrically connected to the input circuit; and a second coil facing the first coil, wherein the second coil has a number of turns greater than first coil and is electrically connected to the output circuit. The number of turns of the second coil may be twice a number of turns of the first coil. 
         [0011]    The output circuit may include an output coil to induce the second power to be received by the second receiver; and one or more output capacitors to store the second power corresponding to the second current, the one or more capacitors electrically connected to the output coil. 
         [0012]    The second receiver may include a reception coil to receive the second power transmitted from the first receiver. The second receiver may be electrically connected to the battery to charge the battery based on the second power. 
         [0013]    In accordance with one or more other embodiments, an apparatus includes an input circuit to wirelessly receive first power from a charger; an amplifier to amplify the first power to a second power; and an output circuit to wirelessly transmit the second power to a receiver of a device, wherein an amplification factor of the amplifier is based on a predetermined distance between the charger and the receiver of the electronic device and wherein the second power has a level sufficient to charge a battery of the device. 
         [0014]    The predetermined distance between the charger and the second receiver may be less than a distance between the charger and the second receiver. The predetermined distance between the charger and the second receiver may be equal to a distance between the charger and the second receiver. The predetermined distance may correspond to an effective wireless charging range. The effective wireless charging range may be greater than a wireless charging range between the charger and the receiver of the device when the charger and receiver are coupled without the amplifier. 
         [0015]    The second power may have a level sufficient to charge a battery of the device at a predetermined rate. The level of the second power predetermined distance between the charger and the second receiver may be less than a distance between the charger and the second receiver may be based on the following equation: 
         [0000]    
       
      
       P=P 
       second level 
       −P 
       D  
      
     
         [0000]    where P second level  is the second power, D is a distance between the apparatus and the receiver of the electronic device, P D  is the attenuation of power that occurs in distance D, and P is power for charging the battery of the electronic device at the predetermined rate. The apparatus may be electromagnetically coupled to each of the charger and device receiver. 
         [0016]    In accordance with one or more other embodiments, an electronic device includes a first receiver to wirelessly receive first power from a charger; an amplifier to amplify the first power to a second power; an output circuit to wirelessly transmit the second power; and a second receiver to receive the second power, wherein an amplification factor of the amplifier is based on a predetermined distance between the charger and the second receiver and wherein the second power has a level sufficient to charge a battery of a device at a predetermined rate. 
         [0017]    The predetermined distance between the charger and the second receiver may be less than a distance between the charger and the second receiver. The predetermined distance may correspond to an effective wireless charging range. The effective wireless charging range may be greater than a wireless charging range between the charger and the first receiver when the charger and first receiver are coupled without the amplifier. 
         [0018]    The charger maybe electromagnetically coupled to the first receiver, and the output circuit be electromagnetically coupled to the second receiver. A cover of the device may be between the output circuit and the second receiver. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
           [0020]      FIG. 1  illustrates an embodiment of a wireless charging apparatus; 
           [0021]      FIG. 2  illustrates a more detailed embodiment of the apparatus in  FIG. 1 ; and 
           [0022]      FIG. 3  illustrates a circuit embodiment of the wireless charging apparatus. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Example embodiments are described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. Like reference numerals refer to like elements throughout. 
         [0024]    In accordance with one or more embodiments described herein, a battery to be charged may include, for example, a rechargeable secondary battery (e.g., a lithium ion battery, a lithium polymer battery, or a lithium ion polymer battery), a small-sized battery (e.g., for use in smart phones, cellular phones, notebook computers, or digital cameras), and/or a large-sized battery for use in electric vehicles, hybrid vehicles, electric bicycles, or electric motorcycles. 
         [0025]      FIGS. 1 to 3  illustrate embodiments of a wireless charging apparatus  100  which includes a transmission unit  110 , a first reception unit  120 , and a second reception unit  130 . The transmission unit  110  transmits power for charging a battery B of an electronic device  20 . The first reception unit  120  amplifies first current for the power transmitted from the transmission unit  110  and transmits the amplified current to the second reception unit  130 . The second reception unit  130  charges a battery B based on the current induced by the first reception unit  120 . The wireless charging apparatus  100  may perform wireless charging when the electronic device  20  incorporating the battery B is placed within range of a wireless charger  10 . Thus, the battery B may be charged without establishing a mechanical or physical connection between the electronic device  20  and a charger using, for example, a power cable. 
         [0026]    The transmission unit  110  may be mounted in the wireless charger  10  for supplying charging power to the battery B. The first reception unit  120  and the second reception unit  130  may be mounted in the electronic device  20  incorporating the battery B. The electronic device  20  may include a main body  21  in which the battery B is mounted and a cover  22  covering one surface of the main body  21  to protect the battery B from external surroundings. The first reception unit  120  may be mounted on an outer surface of the cover  22  and the second reception unit  130  may be mounted on the battery B. For example, the second reception unit  130  may be positioned inside the cover  22  and the first reception unit  120  may be positioned outside the cover  22 . 
         [0027]    The transmission unit  110  may include a transmission coil L 1  electrically connected to a power supply V of the wireless charger  10 . The transmission unit  10  transmits first power from the power supply V to the first reception unit  120 . 
         [0028]    The first reception unit  120  includes an input unit  121 , an amplification unit  122 , and an output unit  123 . The input unit  121  receives the first power transmitted from the transmission unit  110  as an input. The amplification unit  122  amplifies first current induced by electromagnetic induction between the transmission coil L 1  of the transmission unit  110  and the input coil L 2  of the input unit  121 . The amplified current is transmitted to the second reception unit  130  through an output coil L 3  of output unit  123 . 
         [0029]    The input unit  121  includes the input coil L 2  and one or more capacitors. The input coil L 2  performs electromagnetic induction with respect to the transmission coil L 1  when the input coil L 2  comes within range of the transmission coil L 1 . The one or more capacitors performs a frequency-matching operation between the reception coil L 2  and the transmission coil L 1 . For example, when the electronic device  20  comes near (e.g., within wireless range of) the transmission unit  110  of the wireless charger  10 , the reception coil L 2  of the input unit  121  applies first current generated based on the electromagnetic induction to the amplification unit  122 . 
         [0030]    As illustrated in  FIG. 3 , the one or more capacitors may include a first input capacitor C 1  connected in parallel to the reception coil L 2 , a second input capacitor C 2  electrically connected to a first electrode of the first input capacitor C 1 , and a third input capacitor C 3  electrically connected to a second electrode of the first input capacitor C 1 . 
         [0031]    In another embodiment, the input unit  121  may include only one capacitor (e.g., the first input capacitor C 1 ) for performing frequency-matching between the reception coil L 2  and the transmission coil L 1 . Frequency-matching with the transmission unit  110  may be achieved by, for example, adjusting the capacitance value of the first input capacitor C 1 . In an embodiment where the input unit  121  includes a plurality of input capacitors, frequency-matching may be more easily performed than in the case where the only one capacitor is used in the input unit  121  for performing frequency matching. In any case, the first current induced by the matched frequency between the transmission unit  110  and the input unit  121  may flow through the input unit  121 . 
         [0032]    The amplification unit  122  includes a first coil La and a second coil Lb. The first coil La is electrically connected to the input unit  121  and applies the first current as an input. The second coil Lb is electrically connected to the output unit  123 , faces the first coil La, and amplifies the current applied to the first coil La. The first coil La may be connected in parallel to the reception coil L 2  and the first input capacitor C 1 . 
         [0033]    The first coil La may have a first electrode electrically connected to the second input capacitor C 2  and a second electrode electrically connected to the third input capacitor C 3 . The second input capacitor C 2  is electrically connected between the first electrode of the reception coil L 2  and the first electrode of the first coil La. The third input capacitor C 3  is electrically connected between the second electrode of the reception coil L 2  and the second electrode of the first coil La. 
         [0034]    The number of turns of the first coil La may be less than the number of turns of the second coil Lb. Since the number of turns of the second coil Lb is greater than the number of turns of the first coil La, the second current induced to the second coil Lb is greater than the first current applied to the first coil La. The number of turns of the second coil Lb may be, for example, twice the number of turns of the first coil La, and the second current induced through the second coil Lb and applied to the output unit  123  may be twice the first current. The number of turns in the first and second coils may correspond to a different ratio in another embodiment. 
         [0035]    The output unit  123  includes an output coil L 3 , a fourth capacitor C 4 , and a fifth capacitor C 5 . The output coil L 3  is connected in parallel to the second coil Lb of the amplification unit  122 . The fourth capacitor C 4  electrically connects the first electrode of the second coil Lb and the first electrode of the output coil L 3 . The fifth capacitor C 5  electrically connects the second electrode of the second coil Lb and the second electrode of the output coil L 3 . The fourth capacitor C 4  and the fifth capacitor C 5  may store a voltage for the second current applied through the second coil Lb. The output unit  123  transmits the second current amplified by the amplification unit  122  to the second reception unit  130  through the output coil L 3 . 
         [0036]    Since the first reception unit  120  amplifies the first current applied through the input coil L 2  and applies the amplified current to the output unit  123 , the amplified second current may be easily transmitted to the second reception unit  130  positioned inside the cover  22 , even when the cover of the electronic device  20  has an increased thickness that otherwise would adversely affect or prevent wireless charging. Thus, wireless charging of the battery B of the electronic device  20  may be reliably performed using the first reception unit  120 . 
         [0037]    In one embodiment, the first reception unit  120  is mounted on an outer surface of the cover  22  of the electronic device  20 . As a result, the distance between the first reception unit  120  and the transmission unit  110  may be reduced, thereby easily achieving electromagnetic induction between the transmission unit  110  and the first reception unit  120 . In another embodiment, the first reception unit  120  may mounted on an inner surface of the cover  22 . 
         [0038]    The output coil L 3  of the output unit  123  may face a reception coil L 4  of the second reception unit  130 . In this case, the battery B may be charged by second power for the second current induced by electromagnetic induction between the output coil L 3  and the reception coil L 4 . The second reception unit  130  may be electrically connected to the battery B. 
         [0039]    By way of summary and review, one type of wireless charging is performed in an electromagnetically inductive manner in one-to-one correspondence between the primary coil of an electronic device and the secondary coil of the charger. However, wireless charging may be especially difficult for some types of devices and/or under some conditions. For example, mobile phones designed for use in a mountainous areas or for military purposes may have battery covers with a thickness that exceeds a wireless charging range. In these situations, wireless charging may be difficult to perform. 
         [0040]    In accordance with one or more of the aforementioned embodiments, the wireless charging apparatus  100  includes a first reception unit  120  and a second reception unit  130 . The first reception unit is mounted on the outer surface of the cover  22  and in the main body  21  of the electronic device  20 . The second reception unit  130  is mounted on the battery B positioned inside the cover  22  of the electronic device  20 . Therefore, first current of power transmitted from the transmission unit  110  is amplified in the first reception unit  120 . The amplified current is then transmitted to the second reception unit  130 . 
         [0041]    Thus, the wireless charging range is effectively increased. As a result, wireless battery charging may be reliably performed even when, for example, the distance between the battery B and the wireless charger exceeds the wireless charging range of the charger taken alone, e.g., if the first reception unit  120  were not present. In another embodiment, the first reception unit  120  and the second reception unit  130  may be mounted inside the cover  22  of the electronic device, or both of these reception units  120  and  130  may be mounted outside of the cover  22 . 
         [0042]    Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as set forth in the following claims.