CN116742738A

CN116742738A - Wireless charging receiver and wireless charging system including the same

Info

Publication number: CN116742738A
Application number: CN202310257581.6A
Authority: CN
Inventors: 金铉秀; 文诚佑
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2022-03-11
Filing date: 2023-03-09
Publication date: 2023-09-12

Abstract

A wireless charging receiver and a wireless charging system including the same are provided. The wireless charging receiver may be configured to wirelessly receive electrical power from the wireless charging transmitter. The wireless charging receiver may include an inductor inductively coupled to the wireless charging transmitter, a rectifier connected to the inductor and configured to rectify a signal received from the inductor, a DC-DC converter configured to convert a DC signal received from the rectifier, a switch block configured to receive a common voltage generated from the DC-DC converter and including a first switch, and a first capacitor configured to receive the common voltage from the switch block and connected to the inductor at a first node n1, wherein the common voltage is not zero (0).

Description

Wireless charging receiver and wireless charging system including the same

Cross Reference to Related Applications

The present application claims priority and ownership of the korean patent application No. 10-2022-0030746, filed on the korean intellectual property office on the 3 rd month 11 of 2022, and the korean patent application No. 10-2022-0083863, filed on the korean intellectual property office on the 7 th month 7 of 2022, each of which is incorporated herein by reference in its entirety.

Technical Field

The present inventive concept relates to a wireless charging receiver and a wireless charging system including the same.

Background

Wireless Power Transfer (WPT), also known as wireless charging technology, may replace existing wired power transfer technology. A wireless charging transmitter for wireless charging may supply power (e.g., electrical power) to a wireless charging receiver for wireless charging, independent of a charging cable. For example, when a mobile phone is charged, wireless charging may be directly performed without connecting the mobile phone to a charging cable. There are several implementations of wireless charging technology. At present, the electromagnetic induction wireless charging technology is widely applied to the field of household appliances. Based on electromagnetic induction wireless charging technology, the wireless power consortium defines an international wireless charging standard Qi (simply Qi standard) that is compatible with all chargeable electronic devices.

The wireless charging transmitters currently on the market for wireless charging are mostly single coil wireless charging transmitters based on Qi standard. The interaction between the wireless charging transmitter and the wireless charging receiver includes three steps of selection, connectivity testing (ping), and power transfer. In the ping step, the wireless charging transmitter transmits a ping pulse energy in an attempt to check whether the object includes a wireless charging receiver. After the ping pulse energy received by the wireless charging receiver reaches a threshold of the wireless charging receiver, the wireless charging receiver establishes a power connection to the wireless charging transmitter such that the wireless charging transmitter inspection object includes the wireless charging receiver. This is the so-called successful ping. After a successful ping the interaction proceeds to the next step, the power transfer step. The space in which the wireless charging transmitter can successfully pin the wireless charging receiver may be referred to as a degree of freedom.

Disclosure of Invention

Some example embodiments of the inventive concepts provide a wireless charging transmitter and/or wireless charging receiver with improved product reliability via improved wireless charging performance and/or reliability based on the wireless charging transmitter and/or wireless charging receiver being configured to remove, reduce, or minimize noise (e.g., referred to as acoustic noise, audible noise, or singing (singing) noise) of an audible frequency band that may otherwise occur during communication between the wireless charging transmitter and the wireless charging receiver from signals generated by amplitude modulation (e.g., amplitude Shift Keying (ASK)) during communication procedures between the wireless charging transmitter and the wireless charging receiver.

Some example embodiments of the inventive concepts provide a wireless charging system including a wireless charging transmitter and/or wireless charging receiver with improved product reliability via improving wireless charging performance and/or reliability thereof based on the wireless charging transmitter and/or wireless charging receiver being configured to remove, reduce, or minimize noise in an audible frequency band from signals generated by amplitude modulation (e.g., amplitude Shift Keying (ASK)) during a communication process between the wireless charging transmitter and the wireless charging receiver.

The exemplary embodiments of the inventive concept are not limited to those mentioned above, and some exemplary embodiments of the inventive concept not mentioned herein will be clearly understood by those skilled in the art from the following description of the inventive concept.

According to some example embodiments of the inventive concepts, the wireless charging receiver may be configured to wirelessly receive electrical power from the wireless charging transmitter. The wireless charging receiver may include: an inductor configured to be inductively coupled to the wireless charging transmitter, a rectifier connected to the inductor and configured to rectify a signal received from the inductor, a DC-DC converter configured to convert a DC signal received from the rectifier, a switching block configured to receive a common voltage generated from the DC-DC converter and including a first switch, and a first capacitor configured to receive the common voltage from the switching block and connected to the inductor at a first node n1, wherein the common voltage is non-zero (0).

According to some example embodiments of the inventive concepts, there is provided a wireless charging receiver that may be configured to wirelessly receive electric power from a wireless charging transmitter, modulate an amplitude of an AC signal received through a first capacitor based on the wirelessly received electric power, and transmit the AC signal whose amplitude is modulated to the wireless charging transmitter, wherein the first capacitor is configured to receive the AC signal through a first node, receive a common voltage other than 0 through a second node different from the first node, and remove noise of an audible frequency band included in the AC signal whose amplitude is modulated.

According to some example embodiments of the inventive concepts, a wireless charging system is provided, which may include a wireless charging transmitter configured to generate charging electric power; and a wireless charging receiver configured to wirelessly receive the charging electric power from the wireless charging transmitter. The wireless charging receiver may include an inductor inductively coupled to the wireless charging transmitter, a rectifier connected to the inductor and configured to rectify a signal received from the inductor, a DC-DC converter configured to convert a DC signal received from the rectifier, a switch block configured to receive a common voltage generated from the DC-DC converter and including a first switch, and a first capacitor configured to receive the common voltage from the switch block and connected to the inductor at a first node n1, wherein the common voltage is not zero (0).

Details of some example embodiments are included in the detailed description and the accompanying drawings.

Drawings

The above and other aspects and features of the inventive concept will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

fig. 1 is an example block diagram illustrating a wireless charging system according to some example embodiments.

Fig. 2 and 3 are example block diagrams specifically illustrating the interior of a wireless charging system according to some example embodiments.

Fig. 4 is an example timing diagram illustrating operation of a wireless charging receiver of a wireless charging system according to some example embodiments.

Fig. 5 is an example diagram illustrating the effect of removing, reducing, or minimizing noise of an audible frequency band according to the operation of a wireless charging receiver according to some example embodiments.

Fig. 6 is an example block diagram illustrating an electronic system to which a wireless charging system including a wireless charging receiver according to some example embodiments may be applied.

Detailed Description

Elements described with reference to terms such as units, modules and blocks used in the detailed description or terms such as receiver or transmitter (or) and the functional blocks shown in the drawings may be implemented in software, hardware or a combination thereof. Illustratively, the software may be machine code, firmware, embedded code, and application software. For example, the hardware may include circuitry, electronic circuitry, a processor, a computer, an integrated circuit core, a pressure sensor, an inertial sensor, a microelectromechanical system (MEMS), a passive device, or a combination thereof.

Referring to fig. 1, a wireless charging system 1 includes a wireless charging transmitter 10 and a wireless charging receiver 20. The wireless charging transmitter 10 may forward power to the wireless charging receiver 20 to perform wireless charging of the wireless charging receiver 20.

The wireless charging receiver 20 may be an article (e.g., a unit, instance, etc.) of mobile User Equipment (UE), access terminal, subscriber unit, subscriber station, mobile device, remote station, remote terminal, user terminal, or user agent. The access terminal may be a cellular telephone, a handheld device with wireless communication capabilities, a computing device, a device in a vehicle, a wearable device, a terminal of a 5G system, a future evolved Public Land Mobile Network (PLMN), etc. In detail, the wireless charging receiver 20 may be a mobile phone, a tablet computer (pad), a computer having a wireless transceiving function, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal for industrial control, a wireless terminal for autonomous driving, a wireless terminal for telemedicine surgery, a wireless terminal for smart grid, a wireless terminal for traffic safety, a wireless terminal for smart city, a wireless terminal for smart home, etc.

The wireless charging receiver 20 may also be a wireless charging electronic device, a smart phone, a tablet PC, an electronic book reader, a desktop PC, a laptop PC, a netbook computer, a workstation, a server, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), an MP3 player, an ambulatory medical device, a camera or a wearable device (smart glasses, a head-mounted device (HMD), an electronic garment, an electronic bracelet, an electronic necklace, an electronic application accessory (or application accessory), an electronic tattoo, a smart mirror or a smart watch).

The wireless charging receiver 20 may also be a smart home appliance. The smart home appliances may be, for example, a Television (TV), a Digital Video Disc (DVD) player, an audio player, a refrigerator, an air conditioner, a vacuum cleaner, an oven, a stove, a washing machine, an air cleaner, a set-top box, a home automation control panel, a security control panel, a TV box (e.g., a samsung HomeSync) ^TM Apple TV ^TM Or google TV ^TM ) Game console (e.g. Xbox) ^TM Or PlayStation ^TM ) Electronic dictionary, electronic key, camcorder or digital photo frame. The wireless charging receiver 20 may also be various medical devices (e.g., various portable medical devices such as blood glucose meters, heart rate meters, blood pressure meters, and thermometers), magnetic Resonance Angiography (MRA) equipment, magnetic Resonance Imaging (MRI) equipment, computed Tomography (CT) equipment, medical camcorder or ultrasound equipment, navigation devices, global Positioning System (GPS) wireless charging receivers, event Data Recorders (EDRs), flight Data Recorders (FDRs), vehicle infotainment devices, marine electronics (e.g., navigation devices for boats or gyroscopes), avionics, security devices, vehicle audio bodies (head units), industrial or home robots, automated Teller Machines (ATM), point of sale (POS) or internet of things (IoT) devices for stores (e.g., light bulbs, various sensors, electricity or gas meters, water sprayers, fire alarms, temperature controllers, street lamps, toasters, fitness equipment, thermal gauges, etc.), avionics, etc. A water tank, a heater or a boiler). The wireless charging receiver 20 may also be part of a piece of furniture or building/structure, an electronic substrate, an electronic signature receiving device, a projector, or various meters (e.g., a water meter, an electricity meter, or a gas meter).

In some example embodiments, the wireless charging receiver 20 may be one or a combination of the aforementioned devices. A wireless charging receiver according to some example embodiments may be a flexible electronic device. Furthermore, the wireless charging receiver according to some example embodiments of the inventive concepts is not limited to the foregoing apparatus, and may be a new wireless charging receiver introduced according to the development of the technology.

Referring to fig. 2, the wireless charging transmitter 10 and the wireless charging receiver 20 of the wireless charging system 1 according to some example embodiments may be shown as series-series (SS) compensation equivalent circuits of loosely coupled transformers. In some example embodiments, the implementation of the wireless charging transmitter 10 and the wireless charging receiver 20 may be a parallel-parallel (PP) compensation equivalent circuit, a series-parallel (SP) compensation equivalent circuit, or a parallel-series (PS) compensation equivalent circuit, but the detailed implementation is not limited thereto. In the inventive concept, only SS compensation is used for description.

In addition to electromagnetic induction wireless charging techniques, the wireless charging receiver 20 provided in some example embodiments of the inventive concepts may also use magnetic resonance wireless charging techniques, near Field Communication (NFC) wireless charging techniques, or microwave wireless charging techniques. The technique used in detail is not limited thereto. In the inventive concept, only electromagnetic induction wireless charging technology is used for description.

The data communication mode between the wireless charging transmitter 10 and the wireless charging receiver 20 may be wireless communication, such as in-band (in-band) communication, bluetooth communication, zigBee communication, or Wi-Fi communication.

The transmission controller 100 for wireless charging may be, for example, a wireless charging transmission-related module. The transmission controller 100 may include a Direct Current (DC) power supply of the wireless charging transmitter 10, a DC/AC conversion module of the wireless charging transmitter 10, a series matching capacitor of the wireless charging transmitter 10, and a control module of the wireless charging transmitter 10. The wireless charging transmitter 10 processes a Direct Current (DC) input to the wireless charging transmitter 10 by using a module related to the wireless charging transmitter 10 and an inductor L1 serving as a transmission coil, and then transmits the DC current to a receiving coil (e.g., an inductor L2) of the wireless charging receiver 20 by using the inductor L1 serving as the transmission coil.

The process in which the wireless charging transmitter 10 processes the direct current by using the transmission controller 100 may include the following steps. The DC power source of the wireless charging transmitter 10 is configured to provide (e.g., generate, transmit, etc.) charging power. As described herein, "power," "charging power," and the like may be interchangeably referred to herein as "electrical power," "charging electrical power," and the like. The DC/AC conversion module in the transmission controller 100 is connected to the DC power of the wireless charging transmitter 10, receives the DC current output from the DC power of the wireless charging transmitter 10, and converts the received direct current into Alternating Current (AC) to output. The series matching capacitor in the transmission controller 100 is connected to an inductor L1 serving as a transmission coil to form an oscillation circuit. The oscillation circuit is connected to the DC/AC conversion module of the wireless charging transmitter 10, receives the alternating current output from the DC/AC conversion module of the wireless charging transmitter 10, and supplies the alternating current to the transmitting coil. By coupling the inductor L1 serving as the transmitting coil and the inductor L2 serving as the receiving coil of the wireless charging receiver 20, the power of the inductor L1 serving as the transmitting coil is forwarded (e.g., wirelessly transmitted) to the inductor L2 serving as the receiving coil. The control modules in the transmission controller 100 may be connected to the DC power supply of the wireless charging transmitter 10, the DC/ACA conversion module of the wireless charging transmitter 10, the series matching capacitor of the wireless charging transmitter 10, and the inductor L1 serving as a transmission coil, respectively, and configured to exchange control parameters with each module to achieve control of each module.

The wireless charging receiver 20 includes an inductor L2 serving as a receiving coil configured to receive (e.g., wirelessly receive) power (e.g., wirelessly receive electric power, charging electric power, etc., generated, transmitted, wirelessly transmitted, etc., by the wireless charging transmitter 10) from the wireless charging transmitter 10, a rectifier 200, a DC-DC converter 210, and a switching block 220.

Inductor L2 may be configured to inductively couple to inductor L1 of wireless charging transmitter 10. The inductor L2 may be configured to wirelessly receive electric power (e.g., charging power) from the inductor L1 of the wireless charging transmitter 10. Inductor L2 may be connected to series-matched capacitors C1 and C2 of wireless charging receiver 20 to form an oscillating circuit of wireless charging receiver 20. For example, the first node n1 and the first capacitor C1, which are one end of the inductor L2, may be connected (e.g., directly connected or indirectly connected) to each other. Further, the second node n2 and the second capacitor C2, which are the other ends of the inductor L2, may be connected (e.g., directly connected or indirectly connected) to each other.

The wireless charging receiver 20 according to some example embodiments may include various numbers (e.g., amounts) of capacitors, as well as capacitors connected in various connection schemes, and is not limited to the corresponding figures.

For example, the wireless charging receiver 20 according to some example embodiments may include a capacitor connected only to the first node n 1. In another example, the wireless charging receiver 20 according to some example embodiments may include two or more capacitors connected to the first node n1 between the first node n1 and the switch block 220 (e.g., directly therebetween or indirectly therebetween). Further, in another example, the wireless charging receiver 20 according to some example embodiments may include two or more capacitors connected to the second node n2 between (e.g., directly between or indirectly between) the second node n2 and the switching block 220.

In some example embodiments, power received through the inductor L2 (e.g., power received wirelessly from the inductor L1 of the wireless charging transmitter 10 at the inductor L2, charging power, electrical power, charging electrical power, etc.) may be oscillated and converted to AC (e.g., alternating current) by the first capacitor C1 and the second capacitor C2. Hereinafter, the power converted into AC is collectively referred to as an AC signal. It can thus be appreciated that the wireless charging receiver 20 can be configured to generate an AC signal based on such that power (e.g., charging power, electrical power, charging electrical power) received wirelessly from the wireless charging transmitter 10 at the inductor L2 is oscillated and converted to AC.

The rectifier 200 is connected to the inductor L2. The rectifier 200 is configured to rectify a signal received from the inductor L2, wherein such signal may include an AC signal generated by the first capacitor C1 and the second capacitor C2 oscillating and being converted into an AC signal based on the power received through the inductor L2. In some example embodiments, the rectifier 200 receives and rectifies the ac signal. The rectifier 200 generates an output voltage Vrect based on the received AC signal (e.g., based on rectifying the AC signal). The output voltage Vrect may be a stable output from which the voltage variation is removed.

The output voltage Vrect may be sent to the DC-DC converter 210. The DC-DC converter 210 may be a Low Drop Out (LDO) as a linear regulator, and is not limited to the current exemplary embodiment shown in the current drawing. Not limited to the present exemplary embodiment, the DC-DC converter 210 may be any other circuit that changes the power level from the output voltage Vrect to the common voltage Vcm.

The common voltage Vcm generated by the DC-DC converter 210 is not zero (0). For example, the common voltage Vcm may have a non-zero magnitude (e.g., may not have any zero magnitude), which may be a positive or negative magnitude. For example, the common voltage Vcm (e.g., the magnitude of the common voltage Vcm) generated by the DC-DC converter 210 may be greater than zero (e.g., may have a positive magnitude that is non-zero) and may be less than a maximum value of the AC signal forwarded to the first node n 1. For example, the amplitude of the common voltage Vcm may be smaller than the maximum amplitude and/or the amplitude of the AC signal forwarded to the first node n 1. In some example embodiments, for example, the common voltage Vcm generated by the DC-DC converter 210 may be greater than zero and may be less than a maximum value of the AC signal forwarded to the second node n 2. For example, the amplitude of the common voltage Vcm may be smaller than the maximum amplitude and/or the amplitude of the AC signal forwarded to the second node n 2.

The common voltage Vcm generated by the DC-DC converter 210 is forwarded to the switching block 220. The switch block 220 includes a plurality of switches SW1 and SW2 (e.g., a first switch SW1 and a second switch SW 2). The number (e.g., amount) of the switches SW1 and SW2 included in the switch block 220 is not limited to the present exemplary embodiment shown in the present drawing, and may vary depending on the number of capacitors connected to the inductor L2. For example, in some example embodiments, the switch block 220 may include a single (first) switch SW1.

The first switch SW1 of the switching block 220 may be connected to the first capacitor C1 at the third node n 3. Further, the second switch SW2 of the switching block 220 may be connected to the second capacitor C2 at the fourth node n 4. In some example embodiments, the first switch SW1 and the second switch SW2 of the switch block 220 may be connected in parallel to separate respective capacitors C1 and C2 via separate respective nodes n3 and n 4.

Each of the switches SW1 and SW2 may receive the common voltage Vcm, and may forward the common voltage Vcm to the capacitors C1 and C2. For example, when the first switch SW1 is closed (e.g., while the first switch SW1 is closed, conducting, etc.), the first switch SW1 may forward the common voltage Vcm to the first capacitor C1 through the third node n 3. In another example, when the second switch SW2 is closed (e.g., while the second switch SW2 is closed, conducting, etc.), the second switch SW2 may forward the common voltage Vcm to the second capacitor C2 through the fourth node n 4.

The operation in which each of the switches SW1 and SW2 is closed (turned on) may be controlled by the reception controller 230 for wireless charging.

The one or more switches included in the switch block 220 of the wireless charging receiver 20 according to some example embodiments may include one or more transistors T1 and T2, as shown in fig. 3. For example, the first switch SW1 and the second switch SW2 shown in fig. 2 may each include separate one or more transistors.

For example, the first switch SW1 may include a first transistor T1 and the second switch SW2 may include a second transistor T2.

The description by fig. 3 can be applied to fig. 2, and thus the description will be continued with reference to fig. 2.

Subsequently, referring to fig. 2 and 3, the wireless charging receiver 20 according to some example embodiments may generate power (or AC signal) forwarded by the wireless charging transmitter 10 and wirelessly received at the wireless charging receiver 20 via the inductor L2 as an output voltage Vrect rectified by the rectifier 200, and may perform charging by using the output voltage Vrect.

At this time, the wireless charging receiver 20 may determine (e.g., based on the operation of the reception controller 230) that the load transistor R formed in the wireless charging receiver 20 is due to _L Whether the internally generated power (e.g., the magnitude of the generated power, such as the magnitude of the common voltage Vcm, the magnitude of the output voltage Vrect, the magnitude and/or amplitude of the AC signal, etc.) of the wireless charging receiver 20 is insufficient or exceeds a threshold (e.g., less than, equal to, or greater than a threshold magnitude that may be stored at the receiving controller 230).

The wireless charging receiver 20, in which it is determined that the appropriate charging power is not formed, transmits power information therein to the wireless charging transmitter 10 (e.g., in response to such determination).

At this time, the wireless charging receiver 20 transmits (send) a signal including power information from the inductor L2 to the inductor L1 to transmit (transmit) the power information to the wireless charging transmitter 10. Wireless charging receiver 20 may forward a signal including power information to wireless charging transmitter 10 using Amplitude Shift Keying (ASK).

At this time, noise of an audible frequency band (e.g., collectively referred to as acoustic noise, audible noise, or singing (singing) noise, and hereinafter referred to as audible noise) may be generated in the signal forwarded from the wireless charging receiver 20 to the wireless charging transmitter 10.

However, according to some example embodiments, noise of the audible frequency band may be removed, reduced, or minimized by the common voltage Vcm received via the switching block 220 connected to the capacitors C1 and C2 of the wireless charging receiver 20.

That is, when the switch of the switch block 220 is turned on (e.g., closed), noise of an audible frequency band included in the signal forwarded from the wireless charging receiver 20 to the wireless charging transmitter 10 may be removed, reduced, or minimized by the common voltage Vcm transmitted to the capacitors C1 and C2. Accordingly, the wireless charging receiver 20 may be configured to remove, reduce, or minimize noise in an audible frequency band (e.g., referred to as acoustic noise, audible noise, or singing noise) that may otherwise occur during communication between the wireless charging transmitter 10 and the wireless charging receiver 20 based on the wireless charging receiver 20 including the switching block 220 including at least the first switch SW1 (e.g., including at least the first switch SW1 and the second switch SW 2) and/or the DC-DC converter 210 and/or the receiving controller 230, e.g., based on operation of such at least one switch to transmit the common voltage Vcm to the capacitors C1 and C2 of the wireless charging receiver 20, in a signal forwarded from the wireless charging receiver 20 to the wireless charging transmitter 10 by amplitude modulation (e.g., amplitude Shift Keying (ASK).

Hereinafter, detailed operations of the wireless charging receiver 20 according to some example embodiments will be described with reference to the timing diagram of fig. 4.

Fig. 4 is an example timing diagram illustrating operation of a wireless charging receiver of a wireless charging system according to some example embodiments. It will be appreciated that the vertical axis in each of the graphs 1 to 4 shown in fig. 4 is the magnitude (e.g., value) of the voltage, and the horizontal axis in each of the graphs 1 to 4 shown in fig. 4 is the time elapsed during operation of the wireless charging receiver.

Referring to fig. 2 through 4, the wireless charging receiver 20 according to some example embodiments may receive the AC signal of the first node n1 through the inductor L2. At this time, the maximum value of the AC signal forwarded to the first node n1 may be, for example, the first node maximum value v_n1. The AC signal (e.g., the time variation of the voltage amplitude of the AC signal) forwarded to the first node n1 is represented by a first Graph 1.

At this time, a voltage may be formed (e.g., generated) at one end (e.g., the fourth node n4 or the third node n 3) of the capacitors C1 and C2. For convenience of description, a voltage formed at the third node n3 will be described, the third node n3 being one end of the first capacitor C1 connected to the first node n1 (e.g., an opposite end of the first capacitor C1 with respect to the end of the first node n 1).

For reference, the description of the voltage formed at the third node n3 connected to one end of the first capacitor C1 of the first node n1 may be applied to the description of the voltage formed at the fourth node n4 of one end of the second capacitor C2 (e.g., opposite end of the second capacitor C2 with respect to the end of the second node n 2).

The voltage (e.g., the magnitude of the voltage) formed at the third node n3, which is one end of the first capacitor C1, is represented by a second Graph 2.

In detail, the waveform of the third node n3 is the same as the waveform of the AC signal of the first node n1, and the first node n1 is one end of the first capacitor C1. However, in a period in which the switches SW1 and SW2 of the switch block 220 are closed (on), the voltage of the third node n3, which is one end of the first capacitor C1, has the potential of the common voltage Vcm, instead of the waveform of the AC signal of the first node n 1.

For reference, the fourth Graph 4 is a Graph of an operation voltage of the first switch SW1 of the switching block 220, but the fourth Graph 4 may be applied to a description of an operation of the second switch SW2 of the switching block 220. In the fourth Graph 4, the voltage (e.g., the magnitude of the voltage) for the operation in which the first switch SW1 is closed (turned on) is collectively referred to as the on-voltage v_on.

For example, when the first switch SW1 of the switch block 220 is switched from off (off) to on (on) at a first time point t1 and then is switched from on to off at a fifth time point t5, so that the first switch SW1 starts to be closed at the first time point t1 and ends at the fifth time point t5, the third node n3, which is one end of the first capacitor C1, has the common voltage Vcm from the first time point t1 to the fifth time point t 5.

Similarly, the voltage of the third node n3, which is one end of the first capacitor C1, has the common voltage Vcm from a sixth point in time t6 at which the first switch SW1 of the switch block 220 is closed (turned on) (e.g., the first switch SW1 is changed from open to closed at the sixth point in time t 6) to a point in time at which the first switch SW1 is opened (turned off).

At this time, a voltage may be formed across the capacitors C1 and C2. For convenience of description, a voltage formed across the first capacitor C1 connected to the first node n1 will be described.

For reference, the description of the voltage formed across (e.g., opposite) the first capacitor C1 connected to the first node n1 may be applied to the description of the voltage formed across (e.g., opposite) the second capacitor C2 connected to the second node n 2.

The voltage formed across the first capacitor C1 connected to the first node n1 (e.g., the voltage across the first capacitor C1 between opposite ends of the first capacitor C1) is represented by a third Graph 3.

In detail, since there is no potential to be charged across the first capacitor C1 during a period in which the switches SW1 and SW2 of the switch block 220 are turned off (off) (e.g., from zero (0) time to the first time point t 1), the voltage becomes 0 during such a period.

For example, the voltage between the first node n1 and the third node n3, which are both ends of the first capacitor C1, becomes 0 until a first time point t1, wherein the first switch SW1 of the switch block 220 is opened (turned off) to the first time point t1, wherein the first switch SW1 of the switch block 220 is closed (turned on) at the first time point t 1.

Similarly, from the fifth time point t5 when the first switch SW1 of the switch block 220 is opened (turned off) to the sixth time point t6 when the first switch SW1 is closed (turned on), the voltage between the first node n1 and the third node n3 as both ends of the first capacitor C1 becomes 0.

At this time, the capacitors C1 and C2 of the wireless charging receiver 20 according to some example embodiments receive the common voltage Vcm from the switching block 220 for a certain period of time (e.g., the first to fifth time points t1 to t 5). As a result, the voltages applied to both ends of the capacitors C1 and C2 are shifted as much as the level of the common voltage Vcm, so that noise of the audible band can be reduced or removed.

The third Graph 3 shows that the common voltage Vcm (e.g., the magnitude of the common voltage Vcm) is half (one-half) of the first node maximum value v_n1 (e.g., the magnitude of the first node maximum value v_n1).

When the common voltage (e.g., the magnitude of the common voltage) of the wireless charging receiver 20 according to some example embodiments is greater than 0 and less than half (e.g., less than half) of the first node maximum value v_n1, noise of an audible frequency band included in a signal transmitted from the wireless charging receiver 20 to the wireless charging transmitter 10 may be attenuated (e.g., reduced, minimized, or removed). Further, when the common voltage of the wireless charging receiver 20 according to some example embodiments is greater than half of the first node maximum value v_n1 and less than the first node maximum value v_n1, noise of an audible frequency band included in a signal transmitted from the wireless charging receiver 20 to the wireless charging transmitter 10 may be attenuated.

Further, when the common voltage of the wireless charging receiver 20 according to some example embodiments is half of the first node maximum value v_n1, noise of an audible frequency band included in a signal transmitted from the wireless charging receiver 20 to the wireless charging transmitter 10 may be removed, reduced, or minimized.

Referring to the third Graph 3, it can be seen that from the first time point t1 to the fifth time point t5 at which the first switch SW1 is closed (on), the voltage applied to both ends of the first capacitor C1 vibrates (e.g., oscillates between-v_n1/2 to v_n1/2) based on the zero (0) potential.

That is, from the first time point t1 to the fifth time point t5, based on the zero (0) potential, both ends of the first capacitor C1 form a symmetrical waveform having half (v_n1/2) of the first node maximum value v_n1 as the maximum value and the other half (-v_n1/2) of the first node maximum value v_n1 as the minimum value.

As a result, from the first time point t1 to the fifth time point t5 at which (e.g., during) the first switch SW1 is closed (on), noise of an audible frequency band included in a signal formed across the first capacitor C1 can be reduced, minimized, or removed.

That is, the voltage applied between the first node n1 and the third node n3 is reduced to-v_n1/2, which is half of the first node maximum value v_n1, at the first time point t1, and then increased to-v_n1, which is half of the first node maximum value v_n1, at the second time point t2, is reduced to-v_n1/2, which is half of the first node maximum value v_n1, at the third time point t3, and is increased to-v_n1, which is half of the first node maximum value v_n1, again, at the third time point t 4.

The effect of reducing or removing, or minimizing noise of an audible frequency band by the common voltage Vcm formed inside the wireless charging receiver 20 according to some example embodiments will be described with reference to the graph of fig. 5.

Fig. 5 is an example graph illustrating the effect of removing, reducing, or minimizing noise of an audible frequency band according to the operation of a wireless charging receiver according to some example embodiments.

Referring to fig. 2 to 5, the graphs of fig. 5 are graphs of Fast Fourier Transforms (FFTs) performed on signals between a first node n1 and a third node n3 among capacitors C1 and C2 of the wireless charging receiver 20, the first node n1 and the third node n3 being both ends of the first capacitor C1 according to some example embodiments.

In the graph of fig. 5, the solid line is a fourier transform result graph of the wireless charging receiver 20 in which the common voltage Vcm is not generated, and the broken line is a graph of the fourier transform result of the wireless charging receiver 20 according to some example embodiments.

Subsequently, referring to fig. 2 to 5, it is noted that by the common voltage Vcm forwarded to one end (e.g., the third node n3 and the fourth node n 4) of the capacitors C1 and C2 of the wireless charging receiver 20, noise of an audible frequency band (e.g., a 2kHz band) included in the signals generated at both ends of the capacitors C1 and C2 is reduced to-16.9 dB according to some example embodiments.

This is in contrast to the case where the noise of the audible frequency band (e.g., 2kHz band) included in the signal generated by the wireless charging receiver 20 in which the common voltage Vcm is not generated is 9.62 dB.

Referring to fig. 6, in an electronic system 600 to which the wireless charging system described with reference to fig. 1 to 5 may be applied, an electronic device 601 may perform communication with an electronic device 602 via a first network 698 (e.g., a short range wireless communication network) or may perform communication with an electronic device 604 or a server 608 via a second network 699 (e.g., a remote wireless communication network). According to some example embodiments, the electronic device 601 may communicate with the electronic device 604 via a server 608. According to some example embodiments, the electronic device 601 may include a processor 620, a memory 630, an input module 650, a sound output module 655, a display module 660, an audio module 670, a sensor module 676, an interface 677, a connection terminal 678, a haptic module 679, a camera module 680, a power management module 688, a battery 689, a communication module 690, a subscriber identification module 696, or an antenna module 697. In some example embodiments, at least one of these components (e.g., connection terminal 678) may be omitted, or one or more other components may be added to electronic device 601. In some example embodiments, some of these components (e.g., the sensor module 676, the camera module 680, or the antenna module 697) may be integrated into one component (e.g., the display module 660).

The processor 620 may, for example, execute software (e.g., program 640) to control at least one other component (e.g., hardware or software component) of the electronic device 601 connected to the processor 620 and may perform various data processing or calculations. According to some example embodiments, the processor 620 may store commands or data received from other components (e.g., the sensor module 676 or the communication module 690) in the volatile memory 632, process commands or data stored in the volatile memory 632, and store the resulting data in the non-volatile memory 634 as at least part of data processing or computation. According to some example embodiments, the processor 620 may include a main processor 621 (e.g., a central processing unit or an application processor) or a secondary processor 623 (e.g., a graphics processing unit, a Neural Processing Unit (NPU), an image signal processor, a sensor hub processor, or a communication processor), which may operate independently of the main processor 621 or together with the main processor 621. For example, when the electronic device 601 includes a main processor 621 and an auxiliary processor 623, the auxiliary processor 623 may be configured to use lower power than the main processor 621 or to be dedicated to particular functions. The auxiliary processor 623 may be implemented separately from the main processor 621 or as part of the main processor 621.

For example, the auxiliary processor 623 may control at least some functions or states associated with at least one of the components of the electronic device 601 (e.g., the display module 660, the sensor module 676, or the communication module 690) on behalf of the main processor 621 when the main processor 621 is in an inactive (e.g., sleep) state, or the auxiliary processor 623 may control at least some functions or states associated with at least one of the components of the electronic device 601 (e.g., the display module 660, the sensor module 676, or the communication module 690) with the main processor 621 when the main processor 621 is in an active (e.g., application executing) state. According to some example embodiments, the auxiliary processor 623 (e.g., an image signal processor or a communication processor) may be implemented as part of a functionally related other component (e.g., the camera module 680 or the communication module 690). According to some example embodiments, the auxiliary processor 623 (e.g., a neural network processing unit) may include hardware structures dedicated to processing artificial intelligence models. The artificial intelligence model may be generated by machine learning. Such learning may be performed, for example, in the electronic device 601 executing the artificial intelligence, or may be performed via a separate server (e.g., server 608). The learning algorithm may include, but is not limited to, 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 one of a Deep Neural Network (DNN), a Convolutional Neural Network (CNN), a Recurrent Neural Network (RNN), a boltzmann machine limited (RBM), a Deep Belief Network (DBN), a bi-directional recurrent deep neural network (BRDNN), a deep Q network, or a combination of two or more thereof, but is not limited thereto. In addition to hardware structures, the artificial intelligence model may additionally or in some example embodiments include software structures.

The memory 630 may store various data used by at least one component of the electronic device 601 (e.g., the processor 620 or the sensor module 676). The data may include, for example, input data or output data for software (e.g., program 640) and commands associated with the software. Memory 630 may include volatile memory 632 or nonvolatile memory 634.

Programs 640 may be stored as software in memory 630 and may include, for example, an operating system 642, middleware 644, or applications 646.

The input module 650 may receive commands or data from outside the electronic device 601 (e.g., a user) to be used for components of the electronic device 601 (e.g., the processor 620). The input module 650 may include, for example, a microphone, a mouse, a keyboard, keys (e.g., buttons) or a digital pen (e.g., a stylus).

The sound output module 655 may output an acoustic signal to the outside of the electronic device 601. The sound output module 655 may include, for example, a speaker or a receiver. The speaker may be used for general purposes such as multimedia reproduction or recording reproduction. The receiver may be used to receive an incoming call. According to some example embodiments, the receiver may be implemented separately from the speaker or as part of the speaker.

The display module 660 may visually provide information to an exterior (e.g., a user) of the electronic device 601. The display module 660 may comprise, for example, a display, a holographic device or a projector, and a control circuit for controlling the respective device. According to some example embodiments, the display module 660 may include a touch sensor configured to sense a touch, or a pressure sensor configured to measure the strength of a force generated by a touch.

The audio module 670 may convert sound into electrical signals and vice versa. According to some example embodiments, the audio module 670 may obtain sound via the input module 650, or may output sound via the sound output module 655 or an external electronic device (e.g., electronic device 602) connected directly or wirelessly to the electronic device 601 (e.g., a speaker or earphone).

The sensor module 676 may sense an operational state (e.g., power or temperature) or an external environmental state (e.g., user state) of the electronic device 601 and may generate an electrical signal or data value corresponding to the sensed state. According to some example embodiments, the sensor module 676 may include, for example, a gesture sensor, a gyroscope sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an Infrared (IR) sensor, a biological sensor, a temperature sensor, a humidity sensor, or an illuminance sensor.

The interface 677 may support one or more specified protocols that may be used to directly or wirelessly connect the electronic device 601 to an external electronic device (e.g., the electronic device 602). According to some example embodiments, the interface 677 may include, for example, a High Definition Multimedia Interface (HDMI), a Universal Serial Bus (USB) interface, an SD card interface, or an audio interface.

The connection terminal 678 may include a connector through which the electronic device 601 may be physically connected to an external electronic device (e.g., the electronic device 602). According to some example embodiments, the connection terminal 678 may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (e.g., a headphone connector).

The haptic module 679 may convert the electrical signal into mechanical stimulus (e.g., vibration or motion) or electrical stimulus that the user can recognize through touch or motor feel. According to some example embodiments, the haptic module 679 may include, for example, a motor, a piezoelectric element, or an electro-stimulation device.

The camera module 680 may take still images and moving pictures. According to some example embodiments, the camera module 680 may include one or more lenses, an image sensor, an image signal processor, or a flash.

The power management module 688 may manage power supplied to the electronic device 601. According to some example embodiments, the power management module 688 may be implemented as at least a portion of a Power Management Integrated Circuit (PMIC), for example.

The battery 689 may supply power to at least one component of the electronic device 601. According to some example embodiments, the battery 689 may include, for example, a non-rechargeable disposable battery, a rechargeable battery (secondary battery), or a fuel cell.

The communication module 690 may support establishment of a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 601 and an external electronic device (e.g., the electronic device 602, the electronic device 604, or the server 608), as well as communication through the established communication channel. The communication module 690 may include one or more communication processors (e.g., application processors) operating independently of the processor 620 and supporting direct (e.g., wired) or wireless communication. According to some example embodiments, the communication module 690 may include a wireless communication module 692 (e.g., a cellular communication module, a local area wireless communication module, or a Global Navigation Satellite System (GNSS) communication module) or a wired communication module 694 (e.g., a Local Area Network (LAN) communication module or a power line communication module). Corresponding ones of these communication modules may perform communication with the external electronic device 604 via a first network 698 (e.g., a short-range communication network such as bluetooth, wireless fidelity (WiFi) direct link, or infrared data association (IrDA)) or a second network 699 (e.g., a remote communication network such as a conventional cellular network, a 5G network, a next-generation communication network, the internet, or a computer network (e.g., LAN or WAN)). These different types of communication modules may be integrated into one component (e.g., a single chip) or may be implemented with multiple separate components (e.g., multiple chips). The wireless communication module 692 may identify or authenticate the electronic device 601 within a communication network, such as the first network 698 or the second network 699, by using subscriber information (e.g., an International Mobile Subscriber Identifier (IMSI)) stored in the subscriber identification module 696.

The wireless communication module 692 may support a 5G network subsequent to a 4G network and next generation communication technologies, such as a New Radio (NR) access technology. NR access technologies may support enhanced mobile broadband (emmbb) for high capacity data, terminal power minimization, large-scale machine type communication (mctc), or Ultra Reliable and Low Latency Communication (URLLC). The wireless communication module 692 may support, for example, a high frequency band (e.g., millimeter-to-wave (mmWave) band) to achieve a high data transmission rate.

The wireless communication module 692 may support various techniques for ensuring performance in the high frequency band, such as beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, or massive antennas. The wireless communication module 692 may support various requirements defined in the electronic device 601, an external electronic device (e.g., the electronic device 604), or a network system (e.g., the second network 699). According to some example embodiments, wireless communication module 692 may support a peak data rate (e.g., 20Gbps or higher) for implementing an eMBB, a lost coverage (e.g., 164dB or lower) for implementing an emtc, or a U-plane delay (e.g., downlink (DL) and Uplink (UL) of 0.5 milliseconds or less, respectively, or a round trip of 1 millisecond or less) for implementing a URLLC.

The antenna module 697 may transmit signals or power to or receive signals or power from an outside (e.g., an external electronic device). According to some example embodiments, the antenna module 697 may include an antenna including a radiator formed of a conductor or conductive pattern formed on a substrate (e.g., PCB). According to some example embodiments, the antenna module 697 may include a plurality of antennas (e.g., array antennas). In this case, for example, at least one antenna suitable for a communication scheme used in a communication network (such as the first network 698 or the second network 699) may be selected from a plurality of antennas by the communication module 690. Signals or power may be transmitted or received between the communication module 690 and an external electronic device via the selected at least one antenna. According to some example embodiments, other components besides radiators, such as a Radio Frequency Integrated Circuit (RFIC), may additionally be formed as part of the antenna module 697.

According to some example embodiments, the antenna module 697 may form a mmWave antenna module. According to some example embodiments, an mmWave antenna module may include a printed circuit board, an RFIC capable of supporting a specified high frequency band (e.g., an mmWave frequency band) disposed on or adjacent to a first surface (e.g., a lower surface) of the printed circuit board, and a plurality of antennas (e.g., array antennas) capable of transmitting or receiving signals of the specified high frequency band disposed on or adjacent to a second surface (e.g., an upper surface or a side) of the printed circuit board.

At least a portion of the above components may be connected to each other through a communication method between peripheral devices, such as a bus, general Purpose Input and Output (GPIO), serial Peripheral Interface (SPI), or Mobile Industrial Processor Interface (MIPI), and may exchange signals (e.g., commands or data) with each other.

According to some example embodiments, commands or data may be sent or received between the electronic device 601 and the external electronic device 604 via a server 608 connected to the second network 699. The external electronic devices 602 and 604 may be the same or different kinds of devices as the electronic device 601. According to some example embodiments, all or some of the operations performed in electronic device 601 may be performed in one or more of external electronic devices 602, 604, and 608. For example, when the electronic device 601 needs to perform a function or service automatically or in response to a request from a user or another device, the electronic device 601 may request one or more external electronic devices to perform at least a portion of the function or service instead of performing the function or service itself. One or more external electronic devices that have received the request may perform at least a portion of the requested function or service, or additional functions or services associated with the request, and may forward the result of the execution to the electronic device 601.

The electronic device 601 may process the results as is or in addition and provide the results as at least a portion of a response to the request. To this end, for example, cloud computing, distributed computing, mobile Edge Computing (MEC), or client-server computing techniques may be used. The electronic device 601 may provide ultra-low latency services by using, for example, distributed computing or mobile edge computing. In some example embodiments, the external electronic device 604 may include an internet of things (IoT) device. The server 608 may be a smart server based on machine learning and/or neural networks. According to some example embodiments, the external electronic device 604 or the server 608 may be included in the second network 699. The electronic device 601 may be applied to smart services (e.g., smart home, smart city, smart car, or healthcare) based on 5G communication technology and IoT-related technology.

Electronic devices according to some example embodiments disclosed herein may be various types of devices. The electronic device may include, for example, a portable communication device (e.g., a smart phone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a household appliance. The electronic apparatus according to example embodiments of the inventive concepts is not limited to the above-described apparatus.

As described herein, any device, system, module, unit, block, controller, circuit, term such as receiver or transmitter (or), or (or)) used in the detailed description, functional block shown in the figures, and/or any portion thereof according to any example embodiment (including but not limited to wireless charging system 1, wireless charging transmitter 10, wireless charging receiver 20, transmit controller 100, rectifier 200, DC-DC converter 210, switch block 220, receive controller 230, electronic system 600, electronic device 601, electronic device 602, electronic device 604, server 608, second network 699, processor 620, main processor 621, auxiliary processor 623, memory 630, volatile memory 632, non-volatile memory 634, internal memory 636, external memory 638, program 640, operating system 642, middleware 644, application 646, input module 650, sound output module 655, display module 660, audio module 670, sensor module 676, interface 677, connection terminal 678, haptic module 679, camera 699, 688, power management module 698, battery module 696, power management module 690, antenna 696, and/or the like may be implemented in a communication system 600, including as examples, a combination of hardware, a communication system, a communication module, a wireless module 696, a communication module, a wireless module, a communication module such as may be implemented by way of one or more of these, or a plurality of communication modules, or the like, such as may include one or more of hardware, or a combination of hardware, and/or the terms such as may be used in the detailed description. For example, the processing circuitry may more particularly include, but is not limited to, a Central Processing Unit (CPU), an Arithmetic Logic Unit (ALU), a Graphics Processing Unit (GPU), an Application Processor (AP), a Digital Signal Processor (DSP), a microcomputer, a Field Programmable Gate Array (FPGA) and programmable logic unit, a microprocessor, an Application Specific Integrated Circuit (ASIC), a neural Network Processing Unit (NPU), an Electronic Control Unit (ECU), an Image Signal Processor (ISP), and the like. In some example embodiments, the processing circuitry may include a non-transitory computer-readable storage device (e.g., memory) storing a program of instructions, such as a Solid State Drive (SSD); and a processor (e.g., CPU) configured to execute a program of instructions to perform functions and/or methods performed by some or all of the functions and/or methods described in the detailed description, the functional blocks shown in the figures, and/or any of its components used in any of the devices, systems, modules, units, blocks, controllers, circuits, terms such as receivers or transmitters (or) and/or any of its components (including any of the methods according to any of the example embodiments).

Some example embodiments of the present document may be implemented as software (e.g., program 640) comprising one or more commands stored in a storage medium (e.g., internal memory 636 or external memory 638) readable by a machine (e.g., electronic device 601). For example, a processor (e.g., processor 620) of a machine (e.g., electronic device 601) may invoke at least one of the one or more commands from the storage medium and execute it. This enables the machine to be operated to perform at least one function in accordance with the at least one command invoked. The one or more commands may include code generated by a compiler or code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. In some example embodiments, the term "non-transitory" means that the storage medium is tangible and does not include signals (e.g., electromagnetic waves). The term "non-transitory" does not distinguish between the case where data is semi-permanently stored in a storage medium and the case where data is temporarily stored in a storage medium.

According to some example embodiments, methods according to some example embodiments disclosed herein may be provided by inclusion in a computer program product. The computer program product may be provided as a product between a seller and a buyer And (5) transaction. The computer program product may be distributed in the form of a machine-readable storage medium, such as a compact disk read only memory (CD-ROM), or may be distributed via an application store, such as a play store ^TM ) Online distribution (e.g., download or upload), or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product may be at least temporarily stored or generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

Although some example embodiments of the inventive concepts have been described above with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that the inventive concepts are not limited thereto and may be implemented in many different forms without departing from the technical spirit or essential characteristics thereof. Accordingly, it should be understood that the embodiments set forth herein are illustrative in all respects only and not limiting.

Claims

1. A wireless charging receiver configured to wirelessly receive electrical power from a wireless charging transmitter, the wireless charging receiver comprising:

an inductor configured to inductively couple to the wireless charging transmitter,

A rectifier connected to the inductor, the rectifier configured to rectify a signal received from the inductor;

a DC-DC converter configured to convert a direct current DC signal received from the rectifier;

a switching block configured to receive a common voltage generated from the DC-DC converter, the switching block including a first switch; and

a first capacitor configured to receive the common voltage from the switching block, the first capacitor connected to the inductor at a first node,

wherein the common voltage is not zero.

2. The wireless charging receiver of claim 1, further comprising:

a second capacitor connected to the inductor, the second capacitor also connected to a second node different from the first node,

wherein the switch block further comprises a second switch,

wherein the second capacitor is connected to the second switch, and

wherein the second switch is configured to forward the common voltage to the second capacitor.

3. The wireless charging receiver of claim 1, further comprising a receive controller configured to control the switch block.

4. The wireless charging receiver of claim 3, wherein the receive controller is configured to control the common voltage to be forwarded to the first capacitor from the first point in time to the second point in time when the first switch is closed from the first point in time to the second point in time.

5. The wireless charging receiver of claim 1, wherein the signal received in the first node is a first alternating current, AC, signal and the magnitude of the common voltage is half of a maximum value of the first AC signal.

6. The wireless charging receiver of claim 2, wherein

The signal received at the first node is a first alternating current, AC, signal, and the magnitude of the common voltage is half the maximum value of the first AC signal,

receiving a second AC signal in a second node different from the first node, and

the second AC signal is the same signal as the first AC signal.

7. The wireless charging receiver of claim 1, wherein the first switch is a transistor.

8. A wireless charging receiver configured to

The electrical power is received wirelessly from a wireless charging transmitter,

modulating an amplitude of an Alternating Current (AC) signal received through the first capacitor based on the wirelessly received electric power, an

Transmitting an AC signal whose amplitude is modulated to the wireless charging transmitter,

wherein the first capacitor is configured to

An AC signal is received by a first node,

receiving a common voltage other than 0 through a second node different from the first node, and

Noise of an audible frequency band included in the AC signal whose amplitude is modulated is removed.

9. The wireless charging receiver of claim 8, wherein the common voltage has an amplitude that is half of a maximum value of the AC signal.

10. The wireless charging receiver of claim 8, further comprising a switch block comprising a first switch configured to send the common voltage to a first capacitor.

11. The wireless charging receiver of claim 10, wherein the first switch is a transistor.

12. The wireless charging receiver of claim 8, wherein the common voltage is generated based on converting a direct current, DC, signal formed by rectifying an AC signal.

13. The wireless charging receiver of claim 8, wherein the common voltage is applied from a first point in time to a second point in time.

14. The wireless charging receiver of claim 8, further comprising a second capacitor configured to receive an AC signal, the second capacitor connected to a common voltage.

15. A wireless charging system, comprising:

a wireless charging transmitter configured to generate charging electric power; and

A wireless charging receiver configured to wirelessly receive charging electric power from the wireless charging transmitter,

wherein the wireless charging receiver comprises

An inductor inductively coupled to the wireless charging transmitter,

a rectifier connected to the inductor, the rectifier configured to rectify a signal received from the inductor,

wherein the common voltage is not zero.

16. The wireless charging system of claim 15, further comprising:

a second capacitor connected to the inductor at a second node different from the first node,

wherein the switch block further comprises a second switch,

wherein the second capacitor is connected to the second switch, and

17. The wireless charging system of claim 15, further comprising a receive controller configured to control the switch block.

18. The wireless charging system of claim 17, wherein the receive controller is configured to control the common voltage to be forwarded to the first capacitor from the first point in time to the second point in time when the first switch is closed from the first point in time to the second point in time.

19. The wireless charging system of claim 15, wherein the signal received in the first node is a first alternating current, AC, signal and the common voltage has an amplitude that is half of a maximum value of the first AC signal.

20. The wireless charging system of claim 15, wherein the first switch is a transistor.