ELECTRONIC DEVICE FOR CHARGING BATTERY BASED ON VOLTAGE OF INTERFACE AND METHOD FOR CONTROLLING SAME

Disclosed are an electronic device for charging a battery based on a voltage of an interface and a method for controlling the same. The electronic device for charging a battery based on a voltage of an interface, according to an embodiment, may include: an interface comprising a conductive piece, a current reference control circuit; and a charging current control circuit configured to control the magnitude of a charging current applied to the interface, based on a control signal resulting from a comparison between a charging current value applied to the interface and a first critical current value configured in the current reference control circuit, wherein the current reference control circuit is configured to, based on a voltage value applied to the interface reaching a first critical voltage value, gradually decrease the first critical current value until the voltage value applied to the interface falls below the first critical voltage value, and maintain the first critical current value based on the voltage value applied to the interface being less than the first critical voltage value.

BACKGROUND

Field

The disclosure relates to an electronic device for charging a battery based on a voltage of an interface, and a method for controlling the same.

Description of Related Art

There has been increasing use of electronic devices that are easy to carry, such as smartphones, tablet PCs, and wearable devices, and electronic devices have also been developed to be worn by users, in line with ever-increasing use of electronic devices, such that portability and user accessibility can be improved. As an example of such electronic device, an ear-wearable device (for example, earphone) can be worn on the user's ear, and such an electronic device may be driven by a chargeable/dischargeable battery.

Power may be supplied from a charging device (for example, cradle) using an interface (for example, POGO pin) provided on the housing of an electronic device (for example, ear-wearable device). If the battery voltage rises nearly to a fully-charged level, the ear-wearable device may execute charging with a predetermined voltage. For example, if the battery voltage reaches the target voltage in a constant current charging type, the charging mode may switch to a constant voltage charging type in which the current is reduced to suppress voltage increase, in order to guarantee that charging proceeds further without increasing the voltage.

A communication IC that uses a separate V_BUS may be added, or a separate element (for example, separate POGO terminal) may be added, in order to detect whether or not the battery voltage of the ear-wearable device reaches the target voltage, and to change the charging mode accordingly, but such an approach may increase the occupied area and increase the implementation cost in the case of an ear-wearable device which is aimed at compactness. In addition, if the ear-wearable device receives power through electric connection with a connection terminal (for example, POGO pin) of a charging device, there is insufficient space to allocate a separate pin. If constant-current charging and constant-voltage charging are performed based on a voltage output by a charging circuit (for example, charger of charging cradle), the output voltage of the charging circuit (for example, charger of charging cradle) reaches the target voltage before the battery voltage (for example, VCELL) reaches the target voltage, as the output voltage (for example, VCHGO) of the charging circuit is supplied to the battery. In this case, the charging current (ICELL) decreases, and such a charging type may require a long charging time. If a separate interface is allocated, or if power line communication is used, the electronic device (for example, charging cradle) may be difficult to implement, or may require an increased cost, because the separate pin for detecting the battery charging state or the additional element (for example, power line communication IC) increases the mounting space.

If a fixed voltage is applied, instead of allocating a separate interface, such that a linear charger included in an external electronic device senses the battery voltage/current, thereby charging the battery of the external electronic device through a constant-voltage/constant-current function, a relatively large difference between the interface voltage and the battery voltage may be maintained, and such a voltage difference may result in charging loss.

SUMMARY

Embodiments of the disclosure provide an electronic device capable of substantially reducing charging loss compared withFIG. 1Cwhile exhibiting a charging performance substantially identical to the charging type illustrated inFIG. 1BorFIG. 1Cwithout adding a separate interface for battery cell sensing other than conventional interfaces (for example, V_BUS terminal and GNG terminal) provided in the electronic device (for example, charging cradle) (in other words, without having to acquire battery cell voltage information by the electronic device (for example, charging cradle)).

Embodiments of the disclosure provide an electronic device capable of reducing charging loss, wherein the magnitude of charging current for charging the battery of an ear-wearable device is controlled with reference to whether or not an interface voltage (for example, POGO voltage) has reached a predesignated voltage (for example, first critical voltage), thereby reducing the difference between the charging voltage (VCHGO) and the battery cell voltage (VCELL) compared with the prior art.

Embodiments of the disclosure provide a method for controlling an electronic device, wherein a battery charging function or operation can be performed in such a manner that charging loss is substantially reduced compared with the charging type illustrated inFIG. 1Cwithout adding a separate interface for battery cell sensing other than conventional interfaces (for example, V_BUS terminal and GNG terminal) provided in the electronic device (for example, charging cradle) (in other words, without having to acquire battery cell voltage information by the electronic device (for example, charging cradle)).

Embodiments of the disclosure provide a method for controlling an electronic device capable of reducing charging loss, wherein the magnitude of charging current for charging the battery of an ear-wearable device is controlled with reference to whether or not an interface voltage (for example, POGO voltage) has reached a predesignated voltage (for example, first critical voltage), thereby reducing the difference between the charging voltage (VCHGO) and the battery cell voltage (VCELL) compared with the prior art.

An electronic device according to an example embodiment of the disclosure may include: an interface including a conductive piece, a current reference control circuit, and a charging current control circuit configured to control a magnitude of a charging current applied to the interface based on a control signal resulting from a comparison between a charging current value applied to the interface and a first critical current value of the current reference control circuit, wherein the current reference control circuit is configured to gradually decrease the first critical current value based on a voltage value applied to the interface reaching a first critical voltage value, and maintain the first critical current value based on the voltage value applied to the interface being less than the first critical voltage value.

An electronic device according to an example embodiment of the disclosure may include: an interface including a conductive piece and a power adjustment circuit, wherein the power adjustment circuit is configured to gradually increase and output a charging current value for charging a battery of an external electronic device, while the electronic device and the external electronic device contact through the interface, based on a voltage value applied to the interface reaching a first critical voltage value according to output of the charging current, charge the battery while gradually decreasing the charging current value until the voltage value applied to the interface drops below the first critical voltage value, based on the voltage value applied to the interface again reaching the first critical voltage value while the battery is charged with the gradually reduced charging current value, additionally reduce the reduced charging current value, based on the additionally reduced charging value reaching a termination current value, stop output of the charging current, and based on the additionally reduced charging value exceeding the termination current value, the battery is charged with the additionally reduced charging current value.

A method for controlling an electronic device according to an example embodiment of the disclosure may include: based on a voltage value applied to an interface of the electronic device reaching a first critical voltage value, gradually decreasing the first critical current value by a current reference control circuit of the electronic device until the voltage value applied to the interface falls below the first critical voltage value, and maintaining the first critical current value by the current reference control circuit of the electronic device based on the voltage value applied to the interface being less than the first critical voltage value, wherein the electronic device includes a charging current control circuit configured to control a magnitude of a charging current applied to the interface, based on a control signal resulting from a comparison between a charging current value applied to the interface and the first critical current value of the current reference control circuit.

Various example embodiments of the disclosure may provide an electronic device capable of performing a battery charging function or operation in such a manner that charging loss is substantially reduced without adding a separate interface for battery cell sensing other than conventional interfaces (for example, V_BUS terminal and GNG terminal) provided in the electronic device (for example, charging cradle) (in other words, without having to acquire battery cell voltage information by the electronic device (for example, charging cradle)).

Various example embodiments of the disclosure may provide an electronic device capable of reducing charging loss, wherein the magnitude of charging current for charging the battery of an ear-wearable device is controlled with reference to whether or not an interface voltage (for example, POGO voltage) has reached a predesignated voltage (for example, first critical voltage), thereby reducing the difference between the charging voltage (VCHGO) and the battery cell voltage (VCELL).

It will be apparent to those skilled in the art that advantageous effects resulting from various embodiments are not limited to the above-described advantageous effects, and various advantageous effects are incorporated in the disclosure.

DETAILED DESCRIPTION

Referring toFIG. 1A, a time interval before T1illustrated inFIG. 1Amay be a constant current charging interval, and a time interval from T1to T2may be a constant voltage charging interval. In the case in which constant current charging and constant voltage charging are performed based on a voltage that is output by a charging circuit (e.g., a charger of a charging cradle), when the output voltage (e.g., VCHGO) of the charging circuit is supplied to a battery, the output voltage of the charging circuit (e.g., the charger of the charging cradle) reaches a target voltage before a voltage (e.g., VCELL) of the battery reaches the target voltage, and thus a charging current (ICELL) is reduced. In the case of this charging method, a charging time may be long.

Referring toFIG. 1B, when a separate interface is allocated or power line communication is used, a mounting space may be increased due to additional elements such as a separate pin or power line communication IC for detecting the state of charging of a battery, and thus an electronic device (e.g., a charging cradle) is difficult to implement, or costs may be increased.

Referring toFIG. 1C, when a fixed voltage is applied without allocating a separated interface and a linear charger included in an external electronic device senses a battery voltage/current and charges a battery of the external electronic device through a constant voltage/constant current function, the difference between an interface voltage and a battery voltage may be remain relatively large, and thus this voltage difference may result in charging loss.

FIG. 2is a block diagram illustrating an example electronic device201in a network environment200according to various embodiments. Referring toFIG. 2, the electronic device201in the network environment200may communicate with an electronic device202via a first network298(e.g., a short-range wireless communication network), or at least one of an electronic device204or a server208via a second network299(e.g., a long-range wireless communication network). According to an embodiment, the electronic device201may communicate with the electronic device204via the server208. According to an embodiment, the electronic device201may include a processor220, memory230, an input module250, a sound output module255, a display module260, an audio module270, a sensor module276, an interface277, a connecting terminal278, a haptic module279, a camera module280, a power management module288, a battery289, a communication module290, a subscriber identification module (SIM)296, or an antenna module297. In various embodiments, at least one of the components (e.g., the connecting terminal278) may be omitted from the electronic device201, or one or more other components may be added in the electronic device201. In various embodiments, some of the components (e.g., the sensor module276, the camera module280, or the antenna module297) may be implemented as a single component (e.g., the display module260).

The processor220may execute, for example, software (e.g., a program240) to control at least one other component (e.g., a hardware or software component) of the electronic device201coupled with the processor220, and may perform various data processing or computation. According to an embodiment, as at least part of the data processing or computation, the processor220may store a command or data received from another component (e.g., the sensor module276or the communication module290) in volatile memory232, process the command or the data stored in the volatile memory232, and store resulting data in non-volatile memory234. According to an embodiment, the processor220may include a main processor221(e.g., a central processing unit (CPU) or an application processor (AP)), or an auxiliary processor223(e.g., a graphics processing unit (GPU), a neural processing unit (NPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor221. For example, when the electronic device201includes the main processor221and the auxiliary processor223, the auxiliary processor223may be adapted to consume less power than the main processor221, or to be specific to a specified function. The auxiliary processor223may be implemented as separate from, or as part of the main processor221.

The auxiliary processor223may control, for example, at least some of functions or states related to at least one component (e.g., the display module260, the sensor module276, or the communication module290) among the components of the electronic device201, instead of the main processor221while the main processor221is in an inactive (e.g., sleep) state, or together with the main processor221while the main processor221is in an active (e.g., executing an application) state. According to an embodiment, the auxiliary processor223(e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., the camera module280or the communication module290) functionally related to the auxiliary processor223. According to an embodiment, the auxiliary processor223(e.g., the neural processing unit) may include a hardware structure specified for artificial intelligence model processing. An artificial intelligence model may be generated by machine learning. Such learning may be performed, e.g., by the electronic device201where the artificial intelligence model is performed or via a separate server (e.g., the server208). Learning algorithms may include, but are not limited to, e.g., supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning. The artificial intelligence model may include a plurality of artificial neural network layers. The artificial neural network may be a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a restricted boltzmann machine (RBM), a deep belief network (DBN), a bidirectional recurrent deep neural network (BRDNN), deep Q-network or a combination of two or more thereof but is not limited thereto. The artificial intelligence model may, additionally or alternatively, include a software structure other than the hardware structure.

The memory230may store various data used by at least one component (e.g., the processor220or the sensor module276) of the electronic device201. The various data may include, for example, software (e.g., the program240) and input data or output data for a command related thereto. The memory230may include the volatile memory232or the non-volatile memory234.

The program240may be stored in the memory230as software, and may include, for example, an operating system (OS)242, middleware244, or an application246.

The input module250may receive a command or data to be used by another component (e.g., the processor220) of the electronic device201, from the outside (e.g., a user) of the electronic device201. The input module250may include, for example, a microphone, a mouse, a keyboard, a key (e.g., a button), or a digital pen (e.g., a stylus pen).

The sound output module255may output sound signals to the outside of the electronic device201. The sound output module255may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing record. The receiver may be used for receiving incoming calls. According to an embodiment, the receiver may be implemented as separate from, or as part of the speaker.

The display module260may visually provide information to the outside (e.g., a user) of the electronic device201. The display module260may include, for example, a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. According to an embodiment, the display module260may include a touch sensor adapted to detect a touch, or a pressure sensor adapted to measure the intensity of force incurred by the touch.

The audio module270may convert a sound into an electrical signal and vice versa. According to an embodiment, the audio module270may obtain the sound via the input module250, or output the sound via the sound output module255or an external electronic device (e.g., an electronic device202(e.g., a speaker or a headphone)) directly or wirelessly coupled with the electronic device201.

A connecting terminal278may include a connector via which the electronic device201may be physically connected with the external electronic device (e.g., the electronic device202). According to an embodiment, the connecting terminal278may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The camera module280may capture a still image or moving images. According to an embodiment, the camera module280may include one or more lenses, image sensors, image signal processors, or flashes.

The power management module288may manage power supplied to the electronic device201. According to an embodiment, the power management module288may be implemented as at least part of, for example, a power management integrated circuit (PMIC).

The battery289may supply power to at least one component of the electronic device201. According to an embodiment, the battery289may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell.

The communication module290may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device201and the external electronic device (e.g., the electronic device202, the electronic device204, or the server208) and performing communication via the established communication channel. The communication module290may include one or more communication processors that are operable independently from the processor220(e.g., the application processor (AP)) and supports a direct (e.g., wired) communication or a wireless communication. According to an embodiment, the communication module290may include a wireless communication module292(e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module294(e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device204via the first network298(e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network299(e.g., a long-range communication network, such as a legacy cellular network, a 5G network, a next-generation communication network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module292may identify or authenticate the electronic device201in a communication network, such as the first network298or the second network299, using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the subscriber identification module296.

The antenna module297may transmit or receive a signal or power to or from the outside (e.g., the external electronic device) of the electronic device201. According to an embodiment, the antenna module297may include an antenna including a radiating element including a conductive material or a conductive pattern formed in or on a substrate (e.g., a printed circuit board (PCB)). According to an embodiment, the antenna module297may include a plurality of antennas (e.g., array antennas). In such a case, at least one antenna appropriate for a communication scheme used in the communication network, such as the first network298or the second network299, may be selected, for example, by the communication module290from the plurality of antennas. The signal or the power may then be transmitted or received between the communication module290and the external electronic device via the selected at least one antenna. According to an embodiment, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as part of the antenna module297.

According to an embodiment, commands or data may be transmitted or received between the electronic device201and the external electronic device204via the server208coupled with the second network299. Each of the external electronic devices202or204may be a device of a same type as, or a different type, from the electronic device201. According to an embodiment, all or some of operations to be executed at the electronic device201may be executed at one or more of the external electronic devices202,204, or208. For example, if the electronic device201should perform a function or a service automatically, or in response to a request from a user or another device, the electronic device201, instead of, or in addition to, executing the function or the service, may request the one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device201. The electronic device201may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, mobile edge computing (MEC), or client-server computing technology may be used, for example. The electronic device201may provide ultra low-latency services using, e.g., distributed computing or mobile edge computing. In an embodiment, the external electronic device204may include an internet-of-things (IoT) device. The server208may be an intelligent server using machine learning and/or a neural network. According to an embodiment, the external electronic device204or the server208may be included in the second network299. The electronic device201may be applied to intelligent services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology or IoT-related technology.

FIG. 3Ais a diagram illustrating an example configuration of a charging system for charging a battery (e.g., a battery module326) according to various embodiments.

Referring toFIG. 3A, a charging device310according to an embodiment may include a charging circuit318(e.g., a first charger400referring toFIG. 4). The charging circuit according to an embodiment may be electrically connected to an external electronic device (e.g., an ear-wearable device320) through a pogo pin. The external electronic device (e.g., the ear-wearable device320) according to an embodiment may include a linear charger325(e.g., a second charger500referring toFIG. 5) and a battery module (e.g., including a battery)326. The charging circuit318according to an embodiment may output a charging current for charging the battery module326to the linear charger325. The linear charger325according to an embodiment may compare a current supplied to the battery module326(hereinafter, a battery current value) and a battery voltage value with a second critical current value and a second critical voltage value, respectively, and may adjust (e.g., increase), based on the result of the comparison a resistance value of a MOSFET510(refer toFIG. 5) included in the linear charger325. The charging circuit318according to an embodiment may adjust and output the magnitude of a charging current based on a voltage applied to the pogo pine, changed depending on the adjustment of the resistance value of the MOSFET510. The above-described function or operation of the disclosure will be described in greater detail below with reference toFIGS. 4 and 5.

FIGS. 3B and 3Care diagrams illustrating an example charging device310and an example ear-wearable device320according to various embodiments. According to an embodiment, the ear-wearable device320may also be referred to as an earphone, an ear piece, an ear bud, or a hearing device, or the like. Further, the charging device310according to an embodiment may be referred to as a charging cradle or a charging case, or the like.

According to an embodiment, the ear-wearable device320(e.g., the electronic device201inFIG. 2) may include a housing (or a body). For example, the housing may include a portion to be detachably mounted on a user's ear, a speaker, a battery, a wireless communication circuit, a memory, or a processor.

According to an embodiment, when being seated on the charging device310, the ear-wearable device320may perform a charging operation based on a voltage supplied from the charging device310. According to an embodiment, the ear-wearable device320may receive, through an electrical circuit, power transmitted from the charging device310, and may charge a battery based on the applied power. The ear-wearable device320may be driven by a rechargeable/dischargeable battery.

According to an embodiment, the charging device310may include a housing (or a body), and, for example, the housing may include at least one fastening groove (e.g., a fixing member) configured to receive a communication circuit, a power interface, a control circuit, a battery, and the ear-wearable device320which includes a pair of devices, including a first ear-wearable device321and a second ear-wearable device322that can be worn on both ears of the user, respectively. According to an embodiment, the charging device310may include a battery therein to charge the ear-wearable device320without being connected to a separate power supply device (not shown).

According to an embodiment, the charging device310may be connected to a power supply device to charge the ear-wearable device320regardless of whether a battery is included therein. To this end, the charging device310may include the charging circuit318for charging the ear-wearable device320.

According to an embodiment, the charging device310may process, based on state information of the ear-wearable device320, an operation of charging the ear-wearable device320. For example, the charging device310may also charge the ear-wearable device320by charging-level detection using the charging circuit318.

Referring toFIG. 3C, the charging device310may include a first mounting part312and a second mounting part313, which are configured to receive the pair of ear-wearable devices321and322. For example, the first mounting part312may have the shape of a groove in which a first ear-wearable device321is partially fitted, and likewise, the second mounting part313may have the shape of a groove in which the second ear-wearable device322is partially fitted. According to an embodiment, the first mounting part312may include at least one charging contact314. According to an embodiment, as illustrated inFIG. 3, the at least one charging contact314in the first mounting part312may include two-pin-type pogo pin, and may include, for example, a VBUS terminal and a GND terminal.

For example, when the first ear-wearable device321is mounted on the first mounting part312, at least one contact324of the first ear-wearable device321may be electrically connected to the at least one charging contact314of the first mounting part312. Likewise, the second mounting part313may include at least one charging contact315, and the at least one charging contact315may be electrically connected to at least one contact of the second ear-wearable device322.

According to an embodiment, the first ear-wearable device321and the second ear-wearable device322may use connection terminals (pads) formed in the respective housing to be provided with charging power through an electrical connection using at least one contact314or315of the charging device310. For example, as in the perspective view ofFIG. 3Billustrating the shape of the first ear-wearable device321seen in a first direction, the first ear-wearable device321may include multiple electrodes, and the multiple electrodes, which are connection terminals for being provided with charging power, may be exposed to the outer surface of the housing. Further, althoughFIG. 3Billustrates the shape of the second ear-wearable device322seen in another direction, the second ear-wearable device322may include the same multiple electrodes as the first ear-wearable device321at an opposite side to the outer surface of the housing.

According to an embodiment, the charging device310may include an outer interface (e.g., a connector)311. For example, the outer interface may be a USB-type connector or charging port. According to an embodiment, the charging device310may receive power from an external device (e.g., a power source) through the outer interface311.

According to an embodiment, the charging device310may include a battery (not shown). For example, the charging device310may receive power from the external device to charge the battery. Further, when the first ear-wearable device321and the second ear-wearable device322are mounted on the first mounting part312and the second mounting part313, respectively, a battery of each of the first ear-wearable device321and the second ear-wearable device322may be charged by the battery of the charging device310.

According to an embodiment, the charging device310may include an indicator light317for indicating the battery level of the charging device (or charging case), and may include an indicator light316for indicating the battery level of the ear-wearable devices321and322.

FIG. 4is a block diagram illustrating an example configuration of a first charger400included in the charging device310according to various embodiments. Referring toFIG. 4, the charging device310according to an embodiment may include the first charger400. The first charger400according to an embodiment may include at least one among a current reference control circuit410, a charging current control circuit420, a first comparator430, a first error amplifier440, a second error amplifier450, and a first selection circuit460. The charging device310according to an embodiment may also include a control signal generator which includes the current reference control circuit410, the first comparator430, the first error amplifier440, the second error amplifier450, and the first selection circuit460.

The current reference control circuit410according to an embodiment may determine a first critical current value based on a signal (e.g., high/low signal) received from the first comparator430. For example, when a high signal is received from the first comparator430, the current reference control circuit410according to an embodiment may decrease the first critical current value by a predesignated value (e.g., 50 mA). When a low signal is received from the first comparator430, the current reference control circuit410according to an embodiment may maintain a currently configured first critical current value. The current reference control circuit410according to an embodiment may output (or transmit) information about the first critical current value to the first error amplifier440.

The charging current control circuit420according to an embodiment may control the magnitude of charging current, which is input to the first charger400from the outside, based on a third control signal received from the first selection circuit460. The charging current control circuit420according to an embodiment may also include a current supply circuit. In this case, the charging current control circuit420according to an embodiment may be configured to output a charging current. The charging current control circuit420according to an embodiment may control a duty cycle (or a pulse width) to control the magnitude of a charging current. The third control signal according to an embodiment may include a control signal that is output from an error amplifier having a smaller error value among an amplified error (or difference) value included in a first control signal output from the first error amplifier440and an amplified error value included in a second control signal output from the second error amplifier450. The first control signal, the second control signal, and the third control signal according to an embodiment may be analog signals. The charging current control circuit420according to an embodiment may adjust, for example, the magnitude of a charging current based on a mapping table in which a correlation between an amplified error value and the magnitude of an output current is defined. When the third control signal is received, the charging current control circuit420according to an embodiment may adjust the pulse width of a charging current such that the charging current decreased by the predetermined value (e.g., 50 mA) is applied to an interface470. According to an embodiment, information about a value of the charging current having an adjusted (e.g., decreased) magnitude, may be sensed by the first error amplifier440. The first error amplifier440according to an embodiment may compare the first critical current value and the value of the charging current having an adjusted magnitude. The first error amplifier440according to an embodiment may calculate an error (in other words, a difference) between the magnitude of the charging current and the first critical current value, may amplify the same according to a gain of the first error amplifier440, and may output the same as a first signal to the first selection circuit460.

The first comparator430according to an embodiment may be configured to compare a voltage value applied to the interface470and a predetermined first critical voltage value (e.g., a voltage value (e.g., 4.7V) increased by a predesignated value rather than a full-charge voltage (e.g., 4.35V) of the battery module326of the ear-wearable device320). Alternatively, according to an embodiment, the first comparator430may be configured to compare the voltage value applied to the interface470and a voltage value that is obtained by subtracting a predesignated offset voltage value (e.g., 0.1V) from the predetermined first critical voltage value (e.g., 4.7V).

When a voltage value currently applied to the interface reaches the first critical voltage value (or a voltage value obtained by subtracting the predesignated offset voltage value (e.g., 0.1V) from the first critical voltage value (e.g., 4.7V)), the first comparator430according to an embodiment may output a high signal (e.g., a (+) signal) to the current reference control circuit410. When a voltage value currently applied to the interface does not reach the first critical voltage value (or a voltage value obtained by subtracting the predesignated offset voltage value (e.g., 0.1V) from the first critical voltage value (e.g., 4.7V)), the first comparator430according to an embodiment may output a low signal (e.g., a (−) signal) to the current reference control circuit410.

The first error amplifier440according to an embodiment may compare an error between the magnitude of a charging current applied to the interface470and the first critical current, and may amplify the error according to a designated ratio (e.g., a gain of the first error amplifier440). The first error amplifier440according to an embodiment may output, as the first control signal, a signal including information about the amplified error to the first selection circuit460. For example, according to an embodiment, when the error has been amplified, a saturated value may be output as the first control signal based on the gain of the first error amplifier440.

The second error amplifier450according to an embodiment may compare an error between the magnitude of the voltage value applied to the interface470and the first critical voltage value (e.g., 4.7V), and may amplify the error according to a designated ratio (e.g., a gain of the second error amplifier450). The second error amplifier450according to an embodiment may output, as a second control signal, a signal including information about the amplified error to the first selection circuit460. According to an embodiment, when the error has been amplified (e.g., when a voltage applied to the interface470is 4.0V and the first critical voltage is 4.7V), a saturated value may be output as the second control signal based on the gain of the second error amplifier450.

The first selection circuit460according to an embodiment may output the third control signal to the charging current control circuit420. The third control signal according to an embodiment may include a control signal that is output from an error amplifier having a smaller error value among an amplified error (or difference) value included in the first control signal output from the first error amplifier440and an amplified error value included in the second control signal output from the second error amplifier450. For example, when the second control signal output by the second error amplifier450includes, as an amplified error value, a high-level saturated value among the high-level (e.g., (+)) saturated value and a low-level (e.g., (−)) saturated value for the second error amplifier450(e.g., when the voltage applied to the interface470is 4.0V, the first critical voltage value is 4.7V, and the gain of the second error amplifier450is 50,000), while the first control signal output by the first error amplifier440includes, as an amplified error value, a value between a high-level saturated value and a low-level saturated value for the first error amplifier440because the charging current and the first critical current maintain almost identical values by control (e.g., when the magnitude of a charging current applied to the interface470is 1.999 A, the first critical current value is 2.00 A, and the gain of the first error amplifier440is 3,000, in which case the output of the first error amplifier440may be 3V), the first control signal output by the first error amplifier440may be selected as the third control signal, and the third control signal may be output to the charging current control circuit420.

FIG. 5is a block diagram illustrating an example configuration of a second charger500included in the ear-wearable device320according to various embodiments. Referring toFIG. 5, the second charger500according to an embodiment may include a MOSFET510, a third error amplifier520, a fourth error amplifier530, and a second selection circuit540. The second charger500according to an embodiment may be electrically connected to the battery module326.

The MOSFET510according to an embodiment may be electrically connected to the interface470. The MOSFET510according to an embodiment may function as a resistor. According to an embodiment, when a resistance value of the MOSFET510increases, the voltage value applied to the interface470may increase. In relation to the MOSFET510according to an embodiment, the resistance value of the MOSFET510may be increased by adjusting a gate voltage (e.g. decreasing a gate voltage) based on a sixth control signal output from the second selection circuit540. The sixth control signal according to an embodiment may include a control signal that is output from an error amplifier having a smaller error value among an amplified error (or difference) value included in a fourth control signal output from the third error amplifier520and an amplified error value included in a fifth control signal output from the fourth error amplifier530. The fourth control signal, the fifth control signal, and the sixth control signal according to an embodiment may be analog signals. The second selection circuit540according to an embodiment, for example, may adjust a resistance value of the MOSFET510based on a mapping table in which a correlation between an amplified error value and the magnitude of an output current is defined. Alternatively, after outputting the sixth control signal, the second selection circuit540according to an embodiment may adjust a gate voltage of the MOSFET510so as to have a resistance value increased by a predesignated value. When a current value of the battery module326is less than the second critical current value and when a voltage value of the battery is smaller than the second critical voltage value, the MOSFET510according to an embodiment may be fully turned on (e.g., when the resistance value of the MOSFET510is equal to or less than a specific value). According to an embodiment, even when the resistance of the MOSFET510is infinite, a voltage value applied to the interface470may not exceed the first critical voltage value.

The third error amplifier520according to an embodiment may compare an error between the magnitude of a battery current and the second critical current value, and may amplify the error according to a designated ratio (e.g., a gain of the third error amplifier520). The third error amplifier520according to an embodiment may output, as the fourth control signal, a signal including information about the amplified error to the second selection circuit540. For example, according to an embodiment, when the error has been amplified, a value saturated at a high-level (e.g., (+)) or low-level (e.g., (−)) may be output as the fourth control signal based on the gain of the third error amplifier520.

The fourth error amplifier530according to an embodiment may compare an error between the magnitude of a battery voltage and the second critical voltage value (e.g., a full-charge voltage of a battery, 4.35V), and may amplify the error according to a designated ratio (e.g., a gain of the fourth error amplifier530). The fourth error amplifier530according to an embodiment may output, as the fifth control signal, a signal including information about the amplified error to the second selection circuit540. According to an embodiment, when the error has been amplified, a value saturated at a high-level (e.g., (+)) or low-level (e.g., (−)) may be output as the fifth control signal based on the gain of the fourth error amplifier530.

The second selection circuit540according to an embodiment may output the sixth control signal to the MOSFET510. The sixth control signal according to an embodiment may include a control signal that is output from an error amplifier having a smaller error value among the amplified error (or difference) value included in the fourth control signal output from the third error amplifier520and the amplified error value included in the fifth control signal output from the fourth error amplifier530. For example, the fourth control signal output by the third error amplifier520may include, as an amplified error value, the high-level saturated value among the high-level saturated value and the low-level saturated value for the third error amplifier520. Further, when the fifth control signal output by the fourth error amplifier530includes, as an amplified error value, the low-level saturated value among the high-level saturated value and the low-level saturated value for the fourth error amplifier530, the fifth control signal output by the fourth error amplifier530may be selected as the sixth control signal, and the sixth control signal may be output to the MOSFET510. The resistance value of the MOSFET510according to an embodiment may be adjusted by the sixth control signal. For example, the second selection circuit540according to an embodiment may adjust (e.g., increase) the resistance value of the MOSFET510using a mapping table in which a correlation between the amplified error value and the resistance value (or gate voltage value) of the MOSFET510is defined. Alternatively, the gate voltage of the MOSFET510according to an embodiment may also be controlled by the second selection circuit540so as to be adjusted based on a predesignated value. In the second selection circuit540according to an embodiment, when all of the fourth control signal and the fifth control signal have high-level saturated values, the sixth control signal may have the high-level saturated value included in the fourth control signal or the fifth control signal, in which case the magnitude of resistance of the MOSFET510may be maintained (in other words, the MOSFET may remain in a fully turned-on state).

FIG. 6is diagram flowchart illustrating an example operation of stopping (in other words, completing) charging of an external electronic device (e.g., the ear-wearable device320) when a charging current value output from the charging device310reaches a termination current value according to various embodiments.FIG. 7includes graphs illustrating an example operation of charging a battery according to the function or operation illustrated inFIG. 6according to various embodiments.FIG. 7illustrates a graph710regarding control of a charging current, a graph720regarding a change in an interface voltage, and a graph730regarding a change in a battery voltage.

Referring toFIG. 6, in operation610, the charging device310according to an embodiment may detect contact of the external electronic device (e.g., the ear-wearable device320) with the interface470. In operation620, the charging device310according to an embodiment may increase and output a value of a charging current for charging the battery module326of the external electronic device (e.g., the ear-wearable device320).FIG. 7illustrates a function or operation711of outputting a charging current while increasing the magnitude thereof.

In operation630, the charging device310according to an embodiment may determine whether a voltage value applied to the interface470has reached a first critical voltage value. The charging device310(e.g., the first comparator430) according to an embodiment may sense a voltage value currently applied to the interface470, and may compare the sensed voltage value with the first critical voltage value. When the voltage value currently applied to the interface470reaches the first critical voltage value (630—Yes), the charging device310(e.g., the first comparator430) according to an embodiment may output a high signal (e.g., a (+) signal) to the current reference control circuit410. When the voltage value currently applied to the interface does not reach the first critical voltage value (630—No), the first comparator430according to an embodiment may output a low signal (e.g., a (−) signal) to the current reference control circuit410.FIG. 7illustrates the case721in which an interface voltage reaches the first critical voltage value (e.g., 4.7V) by an increase in a resistance value of the MOSFET510.

When the voltage value applied to the interface470has reached the first critical voltage value (e.g., 4.7V) (operation630—Yes), the charging device310according to an embodiment may decrease, in operation640, the charging current value until the voltage value applied to the interface470falls below the first critical voltage value. When a high signal is received from the first comparator430, the charging device310(e.g., the current reference control circuit410) according to an embodiment may decrease the first critical current value by a predesignated value (e.g., 50 mA). The charging device310according to an embodiment may repeatedly perform operation630and operation640until the voltage value applied to the interface470falls below the first critical voltage value. Thus, the first critical current value may be gradually/continuously decreased.FIG. 7illustrates a function or operation712by which a charging current is decreased based on the voltage applied to the interface470reaching a first critical voltage721and a function or operation713of charging the battery module326using a charging current (e.g.,2.00A) having the decreased magnitude.

In operation650, the charging device310according to an embodiment may determine whether the decreased charging current value has reached a termination current. When the decreased charging current value has reached the termination current (650—Yes), the charging device310according to an embodiment may complete, in operation660, charging of the battery module326(e.g., may continuously output the current reaching the termination current or may stop outputting of the charging current). For example, when the charging current value is less than a termination current value (e.g., 0.2 A), the current reference control circuit410may change the first critical current value to 0 to make an output charging current have a value of 0, thereby completing charging of the battery module326. When the decreased charging current value has not reached the termination current (650—No), the charging device310according to an embodiment may determine, in operation670, whether the voltage value applied to the interface470has reached the first critical voltage value again.FIG. 7illustrates the case722in which the voltage value applied to the interface470has reached the first critical voltage value again. When the voltage value applied to the interface470has reached the first critical voltage value again (operation670—Yes), the charging device310according to an embodiment may perform operation640again.FIG. 7illustrates a function or operation714by which the charging current is decreased again when the voltage value applied to the interface470reaches the first critical voltage value again. When the voltage value applied to the interface470has not reached the first critical voltage value again (operation670—No), the charging device310according to an embodiment may perform operation650again. The above-described method of charging of the battery module326can reduce the difference between an interface voltage and a battery cell voltage, and thus can have an advantageous effect of reducing charging loss.

FIG. 8is a circuit diagram illustrating example configurations of a first charger400and a second charger500according to various embodiments. The second charger500according to an embodiment may further include a control circuit for controlling the MOSFET510although the control circuit is not illustrated.

Referring toFIG. 8, the charging device310according to an embodiment may include the first charger400. The first charger400according to an embodiment may include at least one among a current reference control circuit410, a charging current control circuit420, a first comparator430, a first error amplifier440, a second error amplifier450, and a first selection circuit460. The current reference control circuit410according to an embodiment may be electrically connected to the first comparator430. The first comparator430according to an embodiment may include at least one calculation amplifier. The first comparator430according to an embodiment may be electrically connected to the second error amplifier450. Each of the first error amplifier440and the second error amplifier450according to an embodiment may include at least one calculation amplifier. A first critical current value may be input into one end of the first error amplifier440according to an embodiment, and a charging current value may be input into the other end thereof. The first critical voltage value may be input into one end of the second error amplifier450according to an embodiment, and a voltage value of an interface470may be input into the other end thereof. The first error amplifier440and the second error amplifier450according to an embodiment may be electrically connected to the first selection circuit460. The first selection circuit460according to an embodiment may include at least two diodes.

The ear-wearable device310according to an embodiment may include the second charger500. The second charger500herein may include at least one among at least one MOSFET510, a third error amplifier520, a fourth error amplifier530, a second selection circuit540, and a battery module326. The at least one MOSFET510according to an embodiment may be electrically connected to the second selection circuit540. Each of the third error amplifier520and the fourth error amplifier530according to an embodiment may include at least one calculation amplifier. The second selection circuit540according to an embodiment may include at least two diodes. A second critical current value may be input into one end of the third error amplifier520according to an embodiment, and a battery current value may be input into the other end thereof. A second critical voltage value may be input into one end of the fourth error amplifier530according to an embodiment, and a battery voltage value may be input into the other end thereof.

FIG. 9is a flowchart illustrating an example operation of increasing resistance of the MOSFET510included in the second charger500according to various embodiments.

Referring toFIG. 9, in operation910, the second charger500according to an embodiment (e.g., the third error amplifier520) may calculate and amplify an error between the battery current value and the second critical current value to output a fourth control signal. In operation920, the second charger500according to an embodiment (e.g., the fourth error amplifier530) may calculate and amplify an error between the battery voltage value and the second critical voltage value to output a fifth control signal. In operation930, the second charger500according to an embodiment (e.g., the second selection circuit540) may determine whether there is a smaller value among the fourth control signal and the fifth control signal. When there is a smaller value among the fourth control signal and the fifth control signal (930—Yes), the second charger500according to an embodiment (e.g., the second selection circuit540) may increase, in operation940, the resistance of the MOSFET510based on the smaller value among the fourth control signal and the fifth control signal. When the resistance of the MOSFET510according to an embodiment is increased, the voltage of the interface470may be increased.