Patent Publication Number: US-11652356-B2

Title: Portable device communicating with charger and method of operating the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2020-0105535, filed on Aug. 21, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     The inventive concepts relate to a portable device including a battery, and more particularly, to a portable device communicating with a battery and a method of operating the portable device. 
     Portable devices including batteries have been broadly used. Portable devices may have structures in which batteries thereof are replaced when the batteries run out, or may include rechargeable batteries. Rechargeable batteries included in portable devices may be charged from power provided by chargers connected to the portable devices. Portable devices including such rechargeable batteries may communicate with chargers for purposes of quick charging, battery protection, overheating prevention, high-efficiency charging, and/or the like, and thus, more efficient and/or more accurate communication between the portable devices and the chargers may be advantageous. 
     SUMMARY 
     The inventive concepts provide a portable device more efficiently and/or more accurately communicating with a charger and a method of operating the portable device. 
     According to an aspect of the inventive concepts, there is provided a portable device including: a modem configured to perform power line communication with a charger external to the portable device; and a charging circuit configured to, from first power provided by the charger, charge a battery and supply power to an electrical load, wherein the charging circuit is further configured to cut off the supply of the first power to the electrical load and supply second power from the battery to the electrical load, during a first period including a period in which the power line communication occurs. 
     According to another aspect of the inventive concepts, there is provided a portable device including: a first terminal and a second terminal, each contacting a charger external to the portable device; a modem configured to perform power line communication with the charger via the first terminal and/or the second terminal; a charging circuit connected to the first terminal, the second terminal, a battery, and an electrical load, wherein the charging circuit includes: a first switch connected between the first terminal and the electrical load; a second switch connected between the electrical load and the battery; and a switch controller configured to turn off the first switch and turn on the second switch, during a first period including a period in which the power line communication occurs. 
     According to yet another aspect of the inventive concepts, there is provided a method of operating a portable device for performing power line communication with a charger external thereto, the method including: during a first period including a period in which the power line communication occurs, cutting off supply of first power, which is provided by the charger, to an electrical load and supplying second power from a battery to the electrical load; and, when the first period is terminated, from the first power, charging the battery and supplying power to the electrical load. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments of the inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG.  1    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  2    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIGS.  3 A and  3 B  are timing diagrams illustrating examples of packets, according to example embodiments of the inventive concepts; 
         FIG.  4    illustrates an example of noise generated by a portable device, according to example embodiments of the inventive concepts; 
         FIG.  5    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  6    is a timing diagram illustrating an example of an operation of a portable device, according to example embodiments of the inventive concepts; 
         FIG.  7    illustrates an example of power line communication performed by a portable device, according to example embodiments of the inventive concepts; 
         FIG.  8    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  9    is a timing diagram illustrating an example of an operation of a portable device, according to example embodiments of the inventive concepts; 
         FIG.  10    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  11    illustrates an example of noise generated by a portable device, according to example embodiments of the inventive concepts; 
         FIGS.  12 A and  12 B  are timing diagrams illustrating examples of operations of portable devices, according to example embodiments of the inventive concepts; 
         FIG.  13    is a flowchart illustrating a method of operating a portable device, according to example embodiments of the inventive concepts; 
         FIGS.  14 A and  14 B  are flowcharts illustrating examples of methods of operating portable devices, according to example embodiments of the inventive concepts; 
         FIGS.  15 A and  15 B  are flowcharts illustrating examples of methods of operating portable devices, according to example embodiments of the inventive concepts; 
         FIG.  16    is a flowchart illustrating a method of operating a portable device, according to example embodiments of the inventive concepts; 
         FIG.  17    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  18    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; 
         FIG.  19    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts; and 
         FIG.  20    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a block diagram illustrating a portable device  100  according to example embodiments of the inventive concepts. For example, the block diagram of  FIG.  1    illustrates the portable device  100 , a charger  200  connected to the portable device  100 , and/or a power source  300  connected to the charger  200 . 
     The charger (or charging device)  200  may provide power to the portable device  100 , based on power provided by the power source  300 . In some example embodiments, the power source  300  may provide an AC voltage, and the charger  200  may provide, to the portable device  100 , a DC voltage generated from the AC voltage. In some example embodiments, the power source  300  may provide, to the charger  200 , a first DC voltage generated from an AC voltage, and the charger  200  may provide, to the portable device  100 , a second DC voltage generated from the first DC voltage. In some example embodiments, as described below with reference to  FIG.  17   , the charger  200 , which may also be a portable device, may include a rechargeable battery, and the rechargeable battery of the battery  200  may be charged from power provided by the power source  300 . 
     As shown in  FIG.  1   , the charger  200  may include a modem  220 , a power management integrated circuit (PMIC)  240 , and/or a processor  260  and may include a first terminal T 21  and a second terminal T 22 , which are respectively connected to a first terminal T 11  and a second terminal T 12  of the portable device  100 . The first terminal T 21  and the second terminal T 22  of the charger  200  may be electrically connected to the first terminal T 11  and the second terminal T 12  of the portable device  100  via cables, respectively, or may be directly connected to the first terminal T 11  and the second terminal T 12  of the portable device  100 , respectively. Herein, it is assumed that the first terminal T 21  of the charger  200  and the first terminal T 11  of the portable device  100  have higher electric potentials than the second terminal T 22  of the charger  200  and the second terminal T 12  of the portable device  100 . 
     The modem  220  may be connected to the first terminal T 21  and the second terminal T 22  of the charger  200  and may perform power line communication (PLC) with the portable device  100  via the first terminal T 21  and/or the second terminal T 22 . For example, the modem  220  may transmit a packet, which is generated by encoding and modulating data provided by the processor  260 , to the portable device  100  and may provide data, which is generated by decoding and demodulating the packet received from the portable device  100 , to the processor  260 . 
     The PMIC  240  may generate power, which is supplied to the portable device  100 , from power provided by the power source  300 . For example, the PMIC  240  may include at least one regulator for generating DC voltages, at least one sensor for sensing currents and/or voltages, at least one power switch for selectively cutting off currents and/or voltages, and at least one passive element such as a capacitor and/or a diode. In addition, in some example embodiments, when the charger  200  receives an AC voltage from the power source  300 , the PMIC  240  may include a converter for generating a DC voltage from the AC voltage. Power, which the charger  200  provides to the portable device  100  by using the PMIC  240 , may be referred to as first power. 
     The processor  260  may communicate with the portable device  100  via the modem  220  and may control the PMIC  240 . For example, the processor  260  may identify information, a state, or the like of the portable device  100 , based on data received from the portable device  100  via the modem  220 , and may transmit data including information, a state, or the like of the charger  200  to the portable device  100  via the modem  220 . For example, the processor  260  may control the PMIC  240 , based on the information and/or the state of the portable device  100 , and thus, the first power provided to the portable device  100  may be controlled. In some example embodiments, the processor  260  may include a logic circuit including a state machine and may include at least one core executing a series of instructions. 
     The portable device  100  may include a battery  180  and may be any device independently operable based on power provided by the battery  180 . For example, the portable device  100  may include a computing device such as a laptop computer, a tablet personal computer (PC), or a mobile phone, an input/output device such as a wireless keyboard, a wireless mouse, or a wireless speaker, a wearable device such as smart glasses, a smart watch, a smart band, or wireless earphones, and a transport device such as an electric vehicle, an electric bicycle, or an electric kickboard. The battery  180  included in the portable device  100  may include a rechargeable battery. As shown in  FIG.  1   , the portable device  100  may be connected to the charger  200  and may charge the battery  180  from the power provided by the charger  200 , that is, the first power. The rechargeable battery may be simply referred to as a battery. As shown in  FIG.  1   , the portable device  100  may include a modem  120 , a charging circuit  140 , and/or an electrical load  160 , in addition to the battery  180 , and may include the first terminal T 11  and the second terminal T 12 , which are respectively connected to the first terminal T 21  and the second terminal T 22  of the charger  200 . 
     The modem  120  may be connected to the first terminal T 11  and the second terminal T 12  of the portable device  100  and may perform power line communication with the charger  200 , that is, the modem  220  of the charger  200 , via the first terminal T 11  and/or the second terminal T 12 . For example, the modem  120  may transmit a packet, which is generated by encoding and modulating data provided by a processor  164  of the electrical load  160 , to the charger  200  and may provide data, which is generated by decoding and demodulating the packet received from the charger  200 , to the processor  164 . An example of the modem  120  will be described below with reference to  FIG.  2   . 
     The charging circuit  140  may charge the battery  180  from the first power provided by the charger  200  and may provide power to the electrical load  160 . In addition, the charging circuit  140  may provide power, which is provided by the battery  180 , to the electrical load  160 . The power, which the battery  180  provides to the electrical load  160 , may be referred to as second power. For example, the charging circuit  140  may charge the battery  180  by supplying at least a portion of the first power to the battery  180  and may cut off the supply of the first power to the battery  180  when the charging of the battery  180  is completed. In addition, when the portable device  100  is disconnected from the charger  200 , the charging circuit  140  may supply the second power to the electrical load  160 , and when the battery  180  is overdischarged, the portable device  100  may cut off the supply of the second power to the electrical load  160 . Examples of the charging circuit  140  will be described below with reference to  FIG.  5    and the like. 
     The electrical load  160  may perform an operation for a function provided by the portable device  100 , based on power supplied by the charging circuit  140 . For example, as shown in  FIG.  1   , the electrical load  160  may include a transceiver  162 , the processor  164 , and/or a memory  166 , and the transceiver  162 , the processor  164 , and the memory  166  may be operated based on the power supplied by the charging circuit  140 , that is, at least a portion of the first power and/or the second power. In some example embodiments, the modem  120  may also be operated based on the power supplied by the charging circuit  140  and may be referred to as an electrical load. The electrical load may be referred to as a load or a load circuit. 
     The transceiver  162  may be connected to an antenna and may perform wireless communication with a host device (for example,  40  of  FIG.  17   ) and/or another portable device. For example, the transceiver  162  may perform mobile communication such as long term evolution (LTE) and 5 th  generation new radio (5G NR) of the 3 rd  generation partnership project (3GPP), may perform communication based on a wireless personal area network (PAN) such as Bluetooth, Li-Fi, Wireless USB, or Zigbee, may perform communication based on a wireless local area network (LAN) such as Wi-Fi, or may perform near-field communication (NFC). The transceiver  162  may consume relatively high power, and in particular, may consume high power during transmission of signals via the antenna. Accordingly, while wireless communication is performed by the transceiver  162  in a state in which the portable device  100  is connected to the charger  200 , a current I N1  flowing from the first terminal T 11  to the charging circuit  140 , at a first node connected to the first terminal T 11 , may increase. Although it is assumed that the portable device  100  includes, as the electrical load  160 , the transceiver  162  for wireless communication, it should be noted that the portable device  100  may include any electrical load performing an operation for a function provided by the portable device  100 . 
     The processor  164  may communicate with the charger  200  via the modem  120  and may control other components of the portable device  100 . For example, the processor  164  may identify the information, the state, or the like of the charger  200 , based on data received from the charger  200  via the modem  120 , and may transmit data including the information, the state, or the like of the portable device  100  to the charger  200  via the modem  120 . In addition, the processor  164  may transmit data to another device via the transceiver  162  and may receive data, which is transmitted by the other device, via the transceiver  162 . In some example embodiments, the processor  164  may include a logic circuit including a state machine and may include at least one core executing a series of instructions. 
     The memory  166  may store instructions (or software) executed by the processor  164 , may store data transmitted or received via the modem  120 , and may store data transmitted or received via the transceiver  162 . In some example embodiments, the memory  166  may include a volatile memory device such as dynamic random access memory (DRAM) or static random access memory (SRAM), or a non-volatile memory device such as flash memory or resistive random access memory (RRAM). 
     As described below with reference to  FIGS.  4  and  11   , noise may be generated due to various causes, and power line communication between the portable device  100  and the charger  200  may be affected by the noise. For example, the modem  120  of the portable device  100  and/or the modem  220  of the charger  200  may misidentify the noise as a signal transmitted by a counterpart, and a signal transmitted to the counterpart by the modem  120  and/or the modem  220  may be distorted by the noise. As described below with reference to figures, the portable device  100  may allow communication with the charger  200  to be free from noise, and thus, the communication between the portable device  100  and the charger  200  may be more efficiently and/or more accurately performed. In addition, due to the more efficient and/or more accurate communication between the portable device  100  and the charger  200 , desirable functions, for example, quick charging, battery protection, overheating prevention, high-efficiency charging, and/or the like, of the portable device  100  may be readily achieved. Further, due to the more efficient and/or more accurate power line communication, the portable device  100  may be simply connected to the charger  200 , and the portable device  100  and/or the charger  200  may have a simple structure. 
       FIG.  2    is a block diagram illustrating a portable device  100 ′ according to example embodiments of the inventive concepts. Similarly to the portable device  100  of  FIG.  1   , the portable device  100 ′ of  FIG.  2    may include a modem  120 ′ and may include, as electrical loads, a transceiver  162 ′, a processor  164 ′, a memory  166 ′, and/or a bus  168 ′. The modem  120 ′, the transceiver  162 ′, the processor  164 ′, and the memory  166 ′ may communicate with each other via the bus  168 ′. In the following descriptions regarding  FIG.  2   , repeated descriptions given with reference to  FIG.  1    are omitted. 
     The modem  120 ′ may be connected to the first terminal T 11  and the second terminal T 12 . In addition, the modem  120 ′ may be connected to the bus  168 ′ and may generate a packet from data provided via the bus  168 ′ and transmit the packet via the first terminal T 11  and/or the second terminal T 12  or may generate data from a packet received via the first terminal T 11  and/or the second terminal T 12  and transmit the data to the bus  168 ′. As shown in  FIG.  2   , the modem  120 ′ may include an analog front-end circuit AFE, an encoder  122 , a modulator  124 , a demodulator  126 , and/or a decoder  128 , and the encoder  122 , the modulator  124 , the demodulator  126 , and the decoder  128  may be collectively referred to as a digital circuit DIG. 
     The encoder  122  may receive data from the processor  164 ′ or the memory  166 ′ via the bus  168 ′. The encoder  122  may encode data according to a format shared with the charger  200  and may provide the encoded data to the modulator  124 . In some example embodiments, the encoder  122  may further encode a header in addition to data. The modulator  124  may modulate the encoded data according to a modulation method shared with the charger  200  and may provide a modulated signal to the analog front-end circuit AFE. The analog front-end circuit AFE may output a signal to the first terminal T 11  and/or the second terminal T 12 , based on the modulated signal. For example, the analog front-end circuit AFE may output a signal based on current modulation. 
     The analog front-end circuit AFE may provide the modulated signal, which is received via the first terminal T 11  and/or the second terminal T 12 , to the demodulator  126 . For example, the analog front-end circuit AFE may provide a signal, which is received based on voltage modulation, to the demodulator  126 . The demodulator  126  may demodulate the modulated signal according to the modulation method shared with the charger  200  and may provide the demodulated signal to the decoder  128 . The decoder  128  may decode the demodulated signal according to the format shared with the charger  200  and may transmit decoded data to the processor  164 ′ or the memory  166 ′ via the bus  168 ′. In some example embodiments, the decoder  128  may further decode a header in addition to data. In addition, in some example embodiments, the decoder  128  may further output information about errors occurring during reception. 
       FIGS.  3 A and  3 B  are timing diagrams illustrating examples of packets, according to example embodiments of the inventive concepts. For example, the timing diagrams of  FIGS.  3 A  and  3 B each illustrate a voltage V N1  of a first node N 1  with the lapse of time, the voltage V N1  of the first node N 1  corresponding to a packet that refers to a unit of transmission or reception in power line communication between the portable device  100  and the charger  200  in  FIG.  1   . Hereinafter, descriptions regarding  FIGS.  3 A and  3 B  will be made with reference to  FIG.  1   , and it is assumed that the modem  120  of the portable device  100  transmits a packet. In the descriptions regarding  FIGS.  3 A and  3 B , repeated descriptions given with reference to each other are omitted. 
     Referring to  FIG.  3 A , in some example embodiments, a packet may sequentially include a preamble, a header, and/or data, in the stated order. The preamble may include a series of pulses, and a reception side may detect a frequency, a duty, and/or the like, which are used in transmission, based on the pulses included in the preamble. For example, the preamble may include the pulses which are used in the header and the data and have minimum pulse widths, the header and the data being subsequent to the preamble. The header may include information about attributes of the data that is subsequent to the header. For example, the header may indicate that a value represented by the data is version information or is a currently measured voltage of the battery  180 . In some example embodiments, the header may include a start bit and/or a parity bit. In addition, in some example embodiments, the data may include a parity bit and/or a stop bit. 
     Referring to  FIG.  3 B , in some example embodiments, a packet may sequentially include a preamble, a header, and/or data in the stated order, and the data may sequentially include a message and/or a checksum in the stated order. The checksum may be used to check the integrity of the data on a reception side, and in some example embodiments, the checksum may be between a parity bit of the data and a stop bit of the data. It will be understood that the packets shown in  FIGS.  3 A and  3 B  are merely examples, and that a packet in power line communication is not limited to the examples shown in  FIGS.  3 A and  3 B . 
       FIG.  4    illustrates an example of noise generated by a portable device, according to example embodiments of the inventive concepts. For example,  FIG.  4    illustrates examples of waveforms of a voltage V N1  and a current I N1  of the first node N 1  of  FIG.  1   . Hereinafter, descriptions regarding  FIG.  4    will be made with reference to  FIG.  1   . 
     Referring to the upper part of  FIG.  4   , the transceiver  162  may periodically communicate with a host device and/or another portable device. For example, the portable device  100  may periodically transmit or receive a signal to check whether a state of connection to the host device and/or the other portable device is maintained, to maintain synchronization with the host device and/or the other portable device, and/or to search for the host device therearound and/or the other portable device therearound. As described above with reference to  FIG.  1   , a relatively large amount of power may be consumed by wireless communication, and thus, as shown in the upper part of  FIG.  4   , on every cycle T PING  on which the wireless communication is performed, the voltage V N1  of the first node N 1  may decrease and the current I N1  of the first node N 1  may increase. 
     Referring to the lower part of  FIG.  4   , during the wireless communication, the voltage V N1  and the current I N1  of the first node N 1  may include pulses. Accordingly, the modem  120  of the portable device  100  and/or the modem  220  of the charger  200  may misidentify the pulses, generated during the wireless communication, of the voltage V N1  and the current I N1  of the first node N 1  as a packet (or a preamble) transmitted by a counterpart, and when the wireless communication occurs during the power line communication between the portable device  100  and the charger  200 , the packet may be distorted. As such, example embodiments, in which the power line communication is more accurately performed despite noise generated during the wireless communication, will be described below with reference to  FIGS.  5  to  10   . 
       FIG.  5    is a block diagram illustrating a portable device  100   a  according to example embodiments of the inventive concepts. Similar to the portable device  100  of  FIG.  1   , the portable device  100   a  of  FIG.  5    may include a modem  120   a , a charging circuit  140   a , an electrical load  160   a , and/or a battery  180   a  and may include the first terminal T 11  and the second terminal T 12 . In the following descriptions regarding  FIG.  5   , repeated descriptions given with reference to  FIG.  1    are omitted. 
     The charging circuit  140   a  may include a first switch SW 1   a , a second switch SW 2   a , and/or a switch controller  142   a . The first switch SW 1   a  may be connected between the first terminal T 11  (or the first node N 1 ) and the electrical load  160   a  and may be controlled by the switch controller  142   a . In addition, the second switch SW 2   a  may be connected between the electrical load  160   a  and the battery  180   a  and may be controlled by the switch controller  142   a . Each of the first switch SW 1   a  and the second switch SW 2   a  may have any structure capable of electrically connecting ends on both sides thereof to each other in an ON state thereof and electrically disconnecting the ends on both sides thereof from each other in an OFF state thereof. For example, each of the first switch SW 1   a  and the second switch SW 2   a  may include a power transistor, which is a field effect transistor (FET) having a gate connected to the switch controller  142   a . The switch controller  142   a  may supply the first power to the electrical load  160   a  and/or the battery  180   a  by turning on the first switch SW 1   a  and may cut off the supply of the first power by turning off the first switch SW 1   a . In addition, the switch controller  142   a  may supply the second power to the electrical load  160   a  by turning on the second switch SW 2   a  and may cut off the supply of the second power by turning off the second switch SW 2   a.    
     In some example embodiments, during a period (which may be referred to as a first period) including a period in which power line communication occurs, the charging circuit  140   a  may cut off the supply of the first power to the electrical load  160   a  and supply the second power to the electrical load  160   a . For example, the modem  120   a  may generate a first signal SIG 1  activated during the first period including a period of transmitting a packet to a charger (for example,  200  of  FIG.  1   ) through the power line communication. The switch controller  142   a  may receive the first signal SIG 1  from the modem  120   a  and may identify the first period based on the activated first signal SIG 1 . The switch controller  142   a  may turn off the first switch SW 1   a  and turn on the second switch SW 2   a , during the first period. Accordingly, the electrical load  160   a  may be operated based on the second power instead of the first power, and the first node N 1  may be free from noise caused by an operation of the electrical load  160   a.    
       FIG.  6    is a timing diagram illustrating an example of an operation of a portable device, according to example embodiments of the inventive concepts. For example, the timing diagram of  FIG.  6    illustrates an example of an operation of the portable device  100   a  of  FIG.  5   . The first signal SIG 1  in  FIG.  6    is assumed to be an active high signal, and descriptions regarding  FIG.  6    will be made with reference to  FIG.  5   . 
     At time t 61 , the first signal SIG 1  may be activated. For example, the modem  120   a  may activate the first signal SIG 1  before transmitting a packet to a charger (for example,  200  of  FIG.  1   ). In response to the activated first signal SIG 1 , the switch controller  142   a  may turn off the first switch SW 1   a  and may maintain the second switch SW 2   a  in an ON state. Accordingly, the supply of the first power may be cut off, and the second power from the battery  180   a  may be supplied to the electrical load  160   a.    
     Between time t 62  and time t 63 , transmission TX in power line communication may occur. For example, between the time t 62  and the time t 63 , the modem  120   a  may output a signal to the first terminal T 11 , based on current modulation. As shown in  FIG.  6   , between the time t 62  and the time t 63 , the first signal SIG 1  may be maintained activated and the first switch SW 1   a  may be maintained in an OFF state. Accordingly, the transmission TX may not be affected by noise that may be generated by the electrical load  160   a.    
     At time t 64 , the first signal SIG 1  may be deactivated. For example, the modem  120   a  may deactivate the first signal SIG 1  after the transmission TX is completed. In response to the deactivated first signal SIG 1 , the switch controller  142   a  may turn on the first switch SW 1   a  and may maintain the second switch SW 2   a  in an ON state. Accordingly, the first power may be supplied again to the electrical load  160   a  and the battery  180   a.    
     As shown in  FIG.  6   , a period in which the first signal SIG 1  is activated, that is, a first period P 1 , may include a period in which the transmission TX occurs, that is, a transmission period P TX . In addition, in the first period P 1 , a period before the transmission period P TX  may be referred to as a pre-transmission period P PRE , and a period after the transmission period P TX  may be referred to as a post-transmission period P POST . In some example embodiments, the pre-transmission period P PRE  and the post-transmission period P POST  may be approximately equal to each other and may be longer than a maximum length of the transmission period P TX , that is, a maximum transmission period of a packet. For example, each of the pre-transmission period P PRE , the transmission period P TX , and the post-transmission period P POST  may be approximately tens of milliseconds. 
       FIG.  7    illustrates an example of power line communication performed by a portable device, according to example embodiments of the inventive concepts. For example,  FIG.  7    illustrates waveforms of the voltage V N1  and the current I N1  of the first node N 1  of  FIG.  5   . Hereinafter, descriptions regarding  FIG.  7    will be made with reference to  FIG.  5   . 
     In periods except for the first period P 1 , similarly to the descriptions made with reference to  FIG.  4   , the current I N1  of the first node N 1  may increase on every cycle T PING . However, in the first period P 1 , a reduction in the current I N1  of the first node N 1  due to wireless communication periodically performed may not occur, and power line communication may be more accurately performed during the transmission period P TX . An increased level of the voltage V N1  of the first node N 1  and a decreased level of the current I N1  of the first node N 1 , during the first period P 1  of  FIG.  7   , may result from removal of consumption of the first power by the electrical load  160   a  during the first period P 1 . 
       FIG.  8    is a block diagram illustrating a portable device  100   b  according to example embodiments of the inventive concepts. Similarly to the portable device  100  of  FIG.  1   , the portable device  100   b  of  FIG.  8    may include a modem  120   b , a charging circuit  140   b , a transceiver  162   b  as an electrical load, and/or a battery  180   b  and may include the first terminal T 11  and the second terminal T 12 . In addition, similarly to the charging circuit  140   a  of  FIG.  5   , the charging circuit  140   b  of  FIG.  8    may include a first switch SW 1   b , a second switch SW 2   b , and a switch controller  142   b . In the following descriptions regarding  FIG.  8   , repeated descriptions given above with reference to the figures are omitted. 
     The transceiver  162   b  may generate a second signal SIG 2  activated during a period (which may be referred to as a second period) including a period in which wireless communication occurs. The switch controller  142   b  may receive the second signal SIG 2  from the transceiver  162   b  and may identify the second period based on the activated second signal SIG 2 . The switch controller  142   b  may turn off the first switch SW 1   b  and turn on the second switch SW 2   b , during the second period. Accordingly, the electrical load, that is, the transceiver  162   b , may perform the wireless communication based on the second power instead of the first power, and the first node N 1  may be free from noise caused by the wireless communication of the transceiver  162   b.    
       FIG.  9    is a timing diagram illustrating an example of an operation of a portable device, according to example embodiments of the inventive concepts. For example, the timing diagram of  FIG.  9    illustrates an example of an operation of the portable device  100   b  of  FIG.  8   . The second signal SIG 2  is assumed to be an active high signal in  FIG.  9   , and descriptions regarding  FIG.  9    will be made with reference to  FIG.  8   . 
     Between time t 91  and time t 92 , transmission or reception TX/RX in power line communication may occur. For example, between the time t 91  and the time t 92 , the modem  120   b  may output a signal to the first terminal T 11 , based on current modulation, or may receive, from the first terminal T 11 , a signal that is based on voltage modulation. As shown in  FIG.  9   , between the time t 91  and the time t 92 , wireless communication by the transceiver  160   b  may not occur, and thus, the transmission or reception TX/RX in the power line communication may be more accurately performed. 
     At time t 93 , the second signal SIG 2  may be activated. For example, the transceiver  160   b  may activate the second signal SIG 2  before transmitting (or receiving) a signal via an antenna. In response to the activated second signal SIG 2 , the switch controller  142   b  may turn off the first switch SW 1   b  and maintain the second switch SW 2   b  in an ON state. Accordingly, the supply of the first power may be cut off, and the second power from the battery  180   b  may be supplied to the transceiver  160   b.    
     At time t 94 , the transmission or reception TX/RX in the power line communication may be started, and at time t 95 , the transmission TX (or reception) by the transceiver  160   b  may be started. As shown in  FIG.  9   , the second signal SIG 2  may be maintained activated from the time t 93 , and thus, the first switch SW 1   b  may be maintained in an OFF state and the second switch SW 2   b  may be maintained in an ON state. Accordingly, the transmission TX (or reception) by the transceiver  160   b  may be performed based on the second power, and the transmission or reception TX/RX in the power line communication may not be affected by noise that may be generated due to wireless communication. Next, at the time t 95 , the transmission or reception TX/RX in the power line communication may be more accurately terminated, and at time t 96 , the transmission TX (or reception) by the transceiver  160   b  may be terminated. 
     At time t 97 , the second signal SIG 2  may be deactivated. For example, the transceiver  160   b  may deactivate the second signal SIG 2  after the transmission TX (or reception) via the antenna is completed. In response to the deactivated second signal SIG 2 , the switch controller  142   b  may turn on the first switch SW 1   b  and maintain the second switch SW 2   b  in an ON state. Accordingly, the first power may be supplied again to the transceiver  160   b  and the battery  180   b . As shown in  FIG.  9   , a period in which the second signal SIG 2  is activated, that is, a second period P 2 , may include a pre-transmission period V′ PRE , a transmission period P′ TX , and a post-transmission period P′ POST . 
       FIG.  10    is a block diagram illustrating a portable device  100   c  according to example embodiments of the inventive concepts. Similarly to the portable device  100  of  FIG.  1   , the portable device  100   c  of  FIG.  10    may include a modem  120   c , a charging circuit  140   c , an electrical load  160   c , and/or a battery  180   c  and may include the first terminal T 11  and the second terminal T 12 . In addition, the charging circuit  140   c  may include a first switch SW 1   c , a second switch SW 2   c , and/or a switch controller  142   c , and the electrical load  160   c  may include a transceiver  162   c  and/or a processor  164   c . In the following descriptions regarding  FIG.  10   , repeated descriptions given above with reference to the figures are omitted. 
     Referring to  FIG.  10   , the modem  120   c  may generate an interrupt signal INTR and may provide the interrupt signal INTR to the processor  164   c . For example, when reception in power line communication occurs, the modem  120   c  may generate the activated interrupt signal INTR. In response to the activated interrupt signal INTR, the processor  164   c  may obtain, from the modem  120   c , data received through the power line communication. The interrupt signal INTR may also be referred to as a PLC interrupt signal. 
     Similarly to the transceiver  162   b  of  FIG.  8   , the transceiver  162   c  of  FIG.  10    may generate the second signal SIG 2  activated during a period including a period in which wireless communication occurs, that is, during the second period. The processor  164   c  may receive the second signal SIG 2  and may identify the second period based on the activated second signal SIG 2 . During the second period, the processor  164   c  may ignore the activated interrupt signal INTR. Accordingly, a signal received through the power line communication in the second period may be ignored, and transmission of an acknowledgement (for example, an ACK or an NACK), in response to the reception, may not occur. Therefore, reception errors in the power line communication, which may be distorted by noise caused by the wireless communication, may be reduced or prevented. In some example embodiments, unlike the example shown in  FIG.  10   , the second signal SIG 2  may be provided to the modem  120   c  instead of the processor  164   c , and the modem  120   c  may prevent the activation of the interrupt signal INTR while the second signal SIG 2  is activated. 
       FIG.  11    illustrates an example of noise generated by a portable device, according to example embodiments of the inventive concepts. For example,  FIG.  11    illustrates examples of waveforms of the voltage V N1  and the current I N1  of the first node N 1  of  FIG.  1   . Hereinafter, descriptions regarding  FIG.  11    will be made with reference to  FIG.  1   . 
     After the portable device  100  is connected to the charger  200 , noise may be generated. For example, at a time point at which the portable device  100  is connected to the charger  200 , noise may be generated at the first node N 1 , due to: movement of electric charges, which is caused by a difference between the first power of the charger  200  and the second power of the battery  180 ; the occurrence of consumption of the first power by the electrical load  160 ; a difference between time points at which the first terminal T 11  and the second terminal T 12  of the portable device  100  are respectively brought into contact with the first terminal T 21  and the second terminal T 22  of the charger  200 ; or the like. For example, as shown in  FIG.  11   , noise may be generated in the voltage V N1  and the current I N1  of the first node N 1  directly after the portable device  100  is connected to the charger  200 , and thus, the modem  120  of the portable device  100  and/or the modem  220  of the charger  200  may misidentify the noise as a packet (or a preamble) transmitted by a counterpart, and when wireless communication occurs during the power line communication between the portable device  100  and the charger  200 , the packet may be distorted. As such, example embodiments, in which the power line communication is more accurately performed despite the noise generated during the connection between the portable device  100  and the charger  200 , will be described below with reference to  FIGS.  12 A and  12 B . 
       FIGS.  12 A and  12 B  are timing diagrams illustrating examples of operations of portable devices, according to example embodiments of the inventive concepts. For example, the timing diagrams of  FIGS.  12 A and  12 B  illustrate examples of operations of allowing power line communication between a portable device and a charger to be free from noise generated directly after the portable device is connected to the charger. In some example embodiments, the operations of  FIGS.  12 A and  12 B  may be performed by the portable device  100   c  of  FIG.  10   , and hereinafter, descriptions regarding  FIGS.  12 A and  12 B  will be made with reference to  FIG.  10   . 
     Referring to  FIG.  12 A , at time t 121 , the portable device  100   c  may be connected to a charger (for example,  200  of  FIG.  1   ), and noise may be generated as described above with reference to  FIG.  11   . The switch controller  142   c  may cut off the supply of the first power during a certain period (which may be referred to as a third period) from a time point at which the portable device  100   c  is connected to the charger. For example, as shown in  FIG.  12 A , during a third period P 3  from the time t 121  to the time t 122 , the charging circuit  140   c  may turn off the first switch SW 1   c  and turn on the second switch SW 2   c . Accordingly, noise caused by initial fluctuation of the first power may be suppressed, and the modem  120   c  may more accurately perform power line communication with the charger in the third period P 3 . 
     Referring to  FIG.  12 B , at time t 123 , the portable device  100   c  may be connected to a charger (for example,  200  of  FIG.  1   ), and noise may be generated as described above with reference to  FIG.  11   . The modem  120   c  may cut off the occurrence of an interrupt during a certain period from a time point at which the portable device  100   c  is connected to the charger. For example, as shown in  FIG.  12 B , the modem  120   c  may generate the deactivated interrupt signal INTR during the third period P 3  from the time t 123  to the time t 124 . After the third period P 3  is terminated, the activated interrupt signal INTR may be generated upon reception in power line communication at time t 125 . Accordingly, errors in the power line communication due to the initial fluctuation of the first power may be reduced or prevented. 
       FIG.  13    is a flowchart illustrating a method of operating a portable device, according to example embodiments of the inventive concepts. As shown in  FIG.  13   , the method of operating the portable device may include a plurality of operations S 11  to S 16 . In some example embodiments, the method of  FIG.  13    may be performed by the portable device  100   a  of  FIG.  5   , and hereinafter, descriptions regarding  FIG.  13    will be made with reference to  FIG.  5   . 
     In operation S 11 , it may be determined whether a first period is started. As described above with reference to  FIGS.  5  and  6   , the first period may include a period in which power line communication by the modem  120   a  occurs. For example, the modem  120   a  may generate the activated first signal SIG 1  before transmitting a packet to a charger (for example,  200  of  FIG.  1   ), and the first period may be started. As shown in  FIG.  13   , when the first period is started, operation S 12  may be subsequently performed. 
     In operation S 12 , the supply of the first power to the electrical load  160   a  and the battery  180   a  may be cut off. For example, in response to the activated first signal SIG 1 , the switch controller  142   a  may turn off the first switch SW 1   a , and the supply of the first power provided by the charger may be cut off. Accordingly, noise caused by drastic power consumption by the electrical load  160   a  during the first period may not affect the power line communication. 
     In operation S 13 , the second power may be supplied to the electrical load  160   a . For example, in response to the activated first signal SIG 1 , the switch controller  142   a  may turn on the second switch SW 2   a , and the second power provided by the battery  180   a  may be supplied to the electrical load  160   a . Accordingly, the electrical load  160   a  may be operated based on the second power even though the supply of the first power is cut off. 
     In operation S 14 , a packet may be transmitted to the charger. For example, the modem  120   a  may transmit the packet to the charger during the first period, that is, while the first signal SIG 1  is activated. The transmission of the packet may not be affected by noise caused by an operation of the electrical load  160   a , and thus, the power line communication may be more accurately performed. 
     In operation S 15 , it may be determined whether the first period is terminated. For example, after the transmission of the packet to the charger is completed, the modem  120   a  may generate the deactivated first signal SIG 1 , and the first period may be terminated. As shown in  FIG.  13   , after the first period is terminated, operation S 16  may be subsequently performed. 
     In operation S 16 , the first power may be supplied to the electrical load  160   a  and the battery  180   a . For example, in response to the deactivated first signal SIG 1 , the switch controller  142   a  may turn on the first switch SW 1   a  and the second switch SW 2   a , and thus, the first power provided by the charger may be supplied to the electrical load  160   a  and the battery  180   a.    
       FIGS.  14 A and  14 B  are flowcharts illustrating examples of methods of operating portable devices, according to example embodiments of the inventive concepts. In some example embodiments, the method of  FIG.  14 A  may be performed by the portable device  100   b  of  FIG.  8   , and the method of  FIG.  14 B  may be performed by the portable device  100   c  of  FIG.  10   . Hereinafter, descriptions regarding  FIG.  14 A  will be made with reference to  FIG.  8   , and descriptions regarding  FIG.  14 B  will be made with reference to  FIG.  10   . 
     Referring to  FIG.  14 A , the method of operating the portable device may include a plurality of operations S 21   a  to S 26   a . In operation S 21   a , it may be determined whether a second period is started. As described above with reference to  FIGS.  8  and  9   , the second period may include a period in which wireless communication by the transceiver  162   b  occurs. For example, the transceiver  162   b  may generate the activated second signal SIG 2  before transmitting a signal via the antenna, and the second period may be started. As shown in  FIG.  14 A , when the second period is started, operation S 22   a  may be subsequently performed. 
     In operation S 22   a , the supply of the first power to an electrical load and the battery  180   b  may be cut off. For example, in response to the activated second signal SIG 2 , the switch controller  142   b  may turn off the first switch SW 1   b , and the supply of the first power provided by a charger may be cut off. Accordingly, noise caused by drastic power consumption by the electrical load, for example, the transceiver  162   b , during the second period may not affect the power line communication. 
     In operation S 23   a , the second power may be supplied to the electrical load. For example, in response to the activated second signal SIG 2 , the switch controller  142   b  may turn on the second switch SW 2   b , and the second power provided by the battery  180   b  may be supplied to the electrical load, for example, the transceiver  162   b . Accordingly, the electrical load including the transceiver  162   b  may be operated based on the second power even though the supply of the first power has been cut off. 
     In operation S 24   a , the wireless communication may be performed. For example, the transceiver  162   b  may process a signal received via the antenna and may output a signal to be transmitted via the antenna. When the power line communication occurs in the second period, the power line communication may not be affected by noise caused by an operation of the transceiver  162   b , and thus, the power line communication may be more accurately performed. 
     In operation S 25   a , it may be determined whether the second period is terminated. For example, after the reception of the signal via the antenna is completed, the transceiver  162   b  may generate the deactivated second signal SIG 2 , and the second period may be terminated. As shown in  FIG.  14 A , when the second period is terminated, operation S 26   a  may be subsequently performed. 
     In operation S 26   a , the first power may be supplied to the electrical load and the battery  180   b . For example, in response to the deactivated second signal SIG 2 , the switch controller  142   b  may turn on the first switch SW 1   a  and the second switch SW 2   a , and thus, the first power provided by the charger may be supplied to the electrical load, for example, the transceiver  162   b , and to the battery  180   a.    
     Referring to  FIG.  14 B , the method of operating the portable device may include a plurality of operations S 21   b , S 22   b , S 25   b , and S 26   b . In operation S 21   b , it may be determined whether a second period is started. As described above with reference to  FIG.  10   , the second period may include a period in which wireless communication by the transceiver  162   c  occurs. For example, the transceiver  162   c  may generate the activated second signal SIG 2  before transmitting a signal via the antenna, and the second period may be started. As shown in  FIG.  14 B , when the second period is started, operation S 22   b  may be subsequently performed. 
     In operation S 22   b , a PLC interrupt may be deactivated. For example, the processor  164   c  may receive the second signal SIG 2  from the transceiver  162   c  and may receive the interrupt signal (or PLC interrupt signal) INTR from the modem  120   c . In response to the activated second signal SIG 2 , the processor  164   c  may ignore the interrupt signal INTR. Accordingly, a signal received through power line communication in the second period may be ignored, and reception errors in the power line communication, which may be distorted by noise caused by the wireless communication, may be reduced or prevented. 
     In operation S 25   b , it may be determined whether the second period is terminated. For example, after the transmission of the signal via the antenna is completed, the transceiver  162   b  may generate the deactivated second signal SIG 2 , and the second period may be terminated. As shown in  FIG.  14 B , when the second period is terminated, operation S 26   b  may be subsequently performed. 
     In operation S 26   b , the PLC interrupt may be activated. For example, in response to the deactivated second signal SIG 2 , the processor  164   c  may process the interrupt signal INTR, and when the activated interrupt signal INTR is received, the processor  164   c  may obtain data, which is received through the power line communication, from the modem  120   c.    
       FIGS.  15 A and  15 B  are flowcharts illustrating examples of methods of operating portable devices, according to example embodiments of the inventive concepts. In some example embodiments, the methods of  FIGS.  15 A and  15 B  may be performed by the portable device  100   c  of  FIG.  10   , and hereinafter, descriptions regarding  FIGS.  15 A and  15 B  will be made with reference to  FIG.  10   . 
     Referring to  FIG.  15 A , the method of operating the portable device may include a plurality of operations S 31   a  to S 35   a . In operation S 31   a , it may be determined whether a third period is started. As described above with reference to  FIGS.  12 A and  12 B , the third period may be started at a time point at which the portable device  100   c  is connected to a charger. In some example embodiments, the switch controller  142   c  may determine, by itself or based on a signal provided by another component of the portable device  100   c , whether the portable device  100   c  is connected to the charger. As shown in  FIG.  15 A , when the third period is started because the portable device  100   c  is connected to the charger, operation S 32   a  may be subsequently performed. 
     In operation S 32   a , the supply of the first power to the electrical load  160   c  and the battery  180   c  may be cut off. For example, directly after the portable device  100   c  is connected to the charger, the switch controller  142   c  may turn off the first switch SW 1   c , and the supply of the first power provided by the charger may be cut off. Accordingly, noise caused by the initial fluctuation of the first power may be suppressed, and the modem  120   c  may more accurately perform power line communication with the charger in the third period. 
     In operation S 33   a , the second power may be supplied to the electrical load  160   c . For example, the switch controller  142   c  may turn on the second switch SW 2   c , and the second power provided by the battery  180   c  may be supplied to the electrical load  160   c . Accordingly, the electrical load  160   c  may be operated based on the second power even though the supply of the first power is cut off. 
     In operation S 34   a , it may be determined whether the third period is terminated. For example, the switch controller  142   c  may determine, based on an output from a timer, whether the third period is terminated. As shown in  FIG.  15 A , when the third period is terminated, operation S 35   a  may be subsequently performed. 
     In operation S 35   a , the first power may be supplied to the electrical load  160   c  and the battery  180   c . For example, when the third period is terminated, the switch controller  142   c  may turn on the first switch SW 1   c  and the second switch SW 2   c , and thus, the first power provided by the charger may be supplied to the electrical load  160   c  and the battery  180   c.    
     Referring to  FIG.  15 B , the method of operating the portable device may include a plurality of operations S 31   b , S 32   b , S 34   b , and S 35   b . In operation S 31   b , it may be determined whether a third period is started. In some example embodiments, the modem  120   c  may determine, by itself or based on a signal provided by another component of the portable device  100   c , whether the portable device  100   c  is connected to a charger. As shown in  FIG.  15 B , when the third period is started because the portable device  100   c  is connected to the charger, operation S 32   b  may be subsequently performed. 
     In operation S 32   b , a PLC interrupt may be deactivated. For example, the modem  120   c  may not activate the interrupt signal INTR, despite voltage and/or current fluctuations occurring at the first terminal T 11  and/or the second terminal T 12 . Accordingly, errors in power line communication due to the initial fluctuation of the first power may be reduced or prevented. 
     In operation S 34   b , it may be determined whether the third period is terminated. For example, the modem  120   c  may determine, based on an output from a timer, whether the third period is terminated. As shown in  FIG.  15 B , when the third period is terminated, operation S 35   b  may be subsequently performed. 
     In operation S 35   b , the PLC interrupt may be activated. For example, when a packet is received through the power line communication upon the termination of the third period, the modem  120   c  may activate the interrupt signal INTR. 
       FIG.  16    is a flowchart illustrating a method of operating a portable device, according to example embodiments of the inventive concepts. As shown in  FIG.  16   , the method of operating the portable device may include a plurality of operations S 41  to S 43 . In some example embodiments, the method of  FIG.  16    may be performed by the portable device  100   a  of  FIG.  5   , and hereinafter, descriptions regarding  FIG.  16    will be made with reference to  FIG.  5   . 
     In the examples described above with reference to the figures, the second switch SW 2   a  connected between the electrical load  160   a  and the battery  180   a  may be maintained in an ON state by the switch controller  142   a . However, the switch controller  142   a  may cut off the supply of the second power, which is output from the battery  180   a , by turning off the second switch SW 2   a  based on a state of the battery  180   a.    
     Referring to  FIG.  16   , in operation S 41 , it may be determined whether the battery  180   a  is overdischarged. For example, the switch controller  142   a  may determine whether the battery  180   a  is overdischarged, based on an output voltage, an output current, an output quantity of electric charge, and/or the like of the battery  180   a . The battery  180   a  may be damaged or have a reduced lifespan when the battery  180   a  is maintained overdischarged, and to prevent this, the switch controller  142   a  may monitor the state of the battery  180   a . As shown in  FIG.  16   , when it is determined that the battery  180   a  is overdischarged, operation S 42  may be subsequently performed, and when it is determined that the battery  180   a  is not overdischarged, operation S 43  may be subsequently performed. 
     In operation S 42 , the second switch SW 2   a  may be turned off. For example, when the battery  180   a  is discharged, the switch controller  142   a  may cut off discharging by turning off the second switch SW 2   a . On the other hand, in operation S 43 , the second switch SW 2   a  may be turned on. For example, when the battery  180   a  is not overdischarged, the switch controller  142   a  may cause the battery  180   a  to be charged or to provide the second power to the electrical load  160   a , by turning on the second switch SW 2   a.    
     In some example embodiments, in operation S 41 , it may be determined whether the battery  180   a  is fully charged. For example, the switch controller  142   a  may determine whether the battery  180   a  is fully charged, based on the output voltage, the output current, the output quantity of electric charge, and/or the like of the battery  180   a . Charging occurring in a fully-charged state, that is, overcharging, may damage the battery  180   a  or reduce the lifespan of the battery  180   a , and to prevent this, the switch controller  142   a  may monitor the state of the battery  180   a . When it is determined that the battery  180   a  is fully charged, operation S 42  may be subsequently performed, and when it is determined that the battery  180   a  is not fully charged, operation S 43  may be subsequently performed. 
       FIG.  17    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts. For example, the block diagram of  FIG.  17    illustrates first and second earbuds  11  and  12  as a portable device and also illustrates a cradle  20  connected to the first and second earbuds  11  and  12 , a power source  30  connected to the cradle  20 , and/or a host device  40  performing wireless communication with the first and second earbuds  11  and  12 . In the following descriptions regarding  FIG.  17   , repeated descriptions given with reference to  FIG.  1    are omitted. 
     The first and second earbuds  11  and  12  may perform the wireless communication with the host device  40  and may output sound from a source signal received from the host device  40 . The host device  40  may be any device providing the source signal to the first and second earbuds  11  and  12  through the wireless communication. For example, the host device  40  may include a portable device such as a smart phone, a tablet PC, or a laptop PC, or a stationary device such as a television (TV), a multimedia player, or a desktop PC. In addition, the first and second earbuds  11  and  12  may perform the wireless communication with each other. For example, the first and second earbuds  11  and  12  may perform the wireless communication with each other for the purpose of synchronization, status delivery, or the like. Each of the first and second earbuds  11  and  12  may include a battery that is charged from power supplied by the cradle  20 , and as described above with reference to the figures, each of the first and second earbuds  11  and  12  may more efficiently and/or/or more accurately perform power line communication with the cradle  20 . Accordingly, additional terminals for communication with the cradle  20  except for a pair of terminals for charging may be omitted from the first and second earbuds  11  and  12 , and the first and second earbuds  11  and  12  and the cradle  20  may have simple structures. In particular, due to small sizes required for the first and second earbuds  11  and  12  and the cradle  20 , the simple structures of the first and second earbuds  11  and  12  and the cradle  20  may provide various advantages. 
     The cradle  20  may function as a charger of the first and second earbuds  11  and  12  and may be portable. For example, the cradle  20  may include a battery  28  and may charge the first and second earbuds  11  and  12  from power provided by the battery  28 . In addition, the cradle  20  may include a third terminal T 23  and a fourth terminal T 24  for connection to a power source  30  and may charge the battery  28  and the first and second earbuds  11  and  12  from power provided by the power source  30 . In some example embodiments, the cradle  20  may function as a case of the first and second earbuds  11  and  12 . For example, the cradle  20  may have an internal structure, to which the first and second earbuds  11  and  12  are allowed to be mounted, and may include a cover covering the first and second earbuds  11  and  12 . As shown in  FIG.  17   , the cradle  20  may include a first modem  21 , a second modem  22 , a PMIC  24 , and/or the battery  28 . 
     The PMIC  24  may generate the power, which is supplied to the first and second earbuds  11  and  12 , from the power provided by the power source  30  and/or the battery  28 . In some example embodiments, the power source  30  may provide a 5 V DC voltage based on a universal serial bus (USB) interface, and the PMIC  24  may generate, from the 5 V DC voltage, a voltage and/or a current for charging the battery  28  and a voltage and/or a current for charging the first and second earbuds  11  and  12 . The first modem  21  may perform the power line communication with the first earbud  11 , and the second modem  22  may perform the power line communication with the second earbud  12 . 
       FIG.  18    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts. Referring to  FIG.  18   , first and second portable devices  50  and  60  may respectively correspond to the portable device  100  and the charger  200  in  FIG.  1   . 
     The first portable device  50  may include a first terminal T 1 , a variable impedance circuit  51 , a controller  52 , a PLC modem  53 , a battery  54 , a PMIC  55 , and/or a wireless transceiver  56 . In some example embodiments, the variable impedance circuit  51 , the controller  52 , the PLC modem  53 , the battery  54 , the PMIC  55 , and/or the wireless transceiver  56  may be mounted on a printed circuit board. The PMIC  55  may manage power of the battery  54 . In some example embodiments, the charging circuit  140  of  FIG.  1    may be implemented as a portion of the PMIC  55 . In some example embodiments, the first portable device  50  may further include a charger and a charging integrated circuit (IC). 
     The wireless transceiver  56  may perform wireless communication with a host device  70 . For example, the wireless transceiver  56  may include a Bluetooth module and may receive data from the host device  70 . For example, non-limiting examples of the host device  70  may include a smart phone, a tablet PC, a PC, a smart TV, a mobile phone, a personal digital assistant (PDA), a laptop, a media player, a microserver, a global positioning system (GPS) device, an electronic-book (e-book) reader, a digital broadcasting terminal, a navigation system, a kiosk, an MP3 player, a digital camera, and other mobile or non-mobile computing devices. In addition, the host device  70  may include a wearable device such as a watch, glasses, a hair band, or a ring, which has a communication function and a data processing function. In some example embodiments, the wireless transceiver  56  of the first portable device  50  may provide the data, which is received from the host device  70 , to the second portable device  60  through power line communication. 
     The second portable device  60  may include a second terminal T 2 , an input terminal Tin, a variable impedance circuit  61 , a controller  62 , a PLC modem  63 , a battery  64 , and/or a PMIC  65 . In some example embodiments, the variable impedance circuit  61 , the controller  62 , the PLC modem  63 , the battery  64 , and/or the PMIC  65  may be mounted on a printed circuit board. The PMIC  65  may manage power of the battery  64 . In some example embodiments, the PMIC  65  may correspond to the PMIC  240  of  FIG.  1   . In some example embodiments, the second portable device  60  may further include a converter that converts an input voltage Vin received via the input terminal Tin. 
       FIG.  19    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts. Referring to  FIG.  19   , first and second portable devices  80  and  90  may respectively correspond to the portable device  100  and the charger  200  in  FIG.  1   . 
     The first portable device  80  may include the first terminal T 1 , an impedance circuit  85 , a control circuit  84 , a PLC module  83 , a battery  82 , and/or a charging circuit  81 . In some example embodiments, the charging circuit  81  may include a linear charger and may be implemented by a charging IC. The control circuit  84  may enable the charging circuit  81  in a charging period and may charge the battery  82  based on power received via a power line PL. In addition, the control circuit  84  may disable the charging circuit  81  in a data reception period, and the first portable device  80  may be operated based on power of the battery  82 . In some example embodiments, the battery  82  may be charged based on power received in a data transmission period. 
     The second portable device  90  may include the second terminal T 2 , the input terminal Tin, a converter  91 , a battery  92 , a PLC module  93 , a control circuit  94 , and/or an impedance circuit  95 . The converter  91  may generate a voltage Vc converted from the input voltage Vin received via the input terminal Tin or a voltage of the battery  92 . In some example embodiments, the converter  91  may include a switching regulator and may include, as a DC-DC converter, a boost converter and/or a buck converter, or a buck-boost converter. In addition, the converter  91  may charge the battery  92  based on the input voltage Vin. 
     The PLC module  83  of the first portable device  80  may include a voltage demodulator  83 _ 1  and/or a current modulator  83 _ 2  and, in some example embodiments, may further include a current source. The current modulator  83 _ 2  may perform current modulation under the control of the control circuit  84 . The current source may generate a modulated current signal (for example, a current pulse), and the current signal may be output via the first terminal T 1 . The voltage demodulator  83 _ 1  may demodulate a voltage signal received via the first terminal T 1  and may provide the demodulated signal to the control circuit  84 . 
     The PLC module  93  of the second portable device  90  may include a current demodulator  93 _ 1  and/or a voltage modulator  93 _ 2 . The control circuit  94  may control the current demodulator  93 _ 1  and the voltage modulator  93 _ 2 . The voltage modulator  93 _ 2  may generate a modulated voltage signal according to the control by the control circuit  94 , and the voltage signal may be output via the second terminal T 2 . In some example embodiments, the voltage modulator  93 _ 2  may include a linear regulator, for example, a low-dropout (LDO) regulator. The current demodulator  93 _ 1  may demodulate a current signal received via the second terminal T 2  and may provide the demodulated signal to the control circuit  94 . 
       FIG.  20    is a block diagram illustrating a portable device according to example embodiments of the inventive concepts. Referring to  FIG.  20   , an earbud  410  and a cradle  420  may respectively correspond to the portable device  100  and the charger  200  in  FIG.  1   . 
     The earbud  410  may include a control circuit  411 , a voltage demodulator  412 , and/or a current modulator  413 , and the voltage demodulator  412  may include a filter  412 _ 1  and/or an amplifier  412 _ 2 . The cradle  420  may include a control circuit  421 , an analog-to-digital converter (ADC)  422 , and/or an LDO regulator  423 , the ADC  422  may perform current demodulation, and the LDO regulator  423  may perform voltage modulation. 
     In the first portable device  410 , the filter  412 _ 1  of the voltage demodulator  412  may remove noise by cutting off a particular frequency component of a voltage signal received via the power line PL and may provide the filtered voltage signal to the amplifier  412 _ 2 . The amplifier  412 _ 2  may generate a signal having a logic high level or a logic low level by amplifying a voltage signal and thus provide the signal to the control circuit  411 . The control circuit  411  may identify information transmitted by the cradle  420 , based on a signal received from the amplifier  412 _ 2 , and to transfer information to the cradle  420 , may generate a modulated current signal, which is transmitted via the power line PL, by controlling the current modulator  413 . 
     In the cradle  420 , the ADC  422  may generate a digital signal from a current signal received via the power line PL and thus provide the digital signal to the control circuit  421 . The control circuit  421  may identify the information transmitted by the earbud  410 , based on the digital signal. In addition, the control circuit  421  may generate a modulated voltage signal, which is transmitted via the power line PL, by controlling the LDO regulator  423 . 
     One or more of the elements disclosed above may include or be implemented in processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. 
     While the inventive concepts have been particularly shown and described with reference to example embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.