CN114128080A

CN114128080A - Wireless charging device

Info

Publication number: CN114128080A
Application number: CN202180004142.3A
Authority: CN
Inventors: 李健雄; 汪海翔
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2022-03-01
Also published as: WO2022170460A1

Abstract

The application discloses a wireless charging device, which is coupled to an antenna and a battery and used for charging the battery according to an electric field signal received from the antenna. The wireless charging device comprises a low-frequency blocking circuit, a rectifying circuit, a charging path control circuit, a filter capacitor, an overvoltage protection circuit, a battery management circuit, a near field communication controller and a matched filter circuit. The low-frequency blocking circuit is used for blocking low-frequency noise in the electric field signal. The rectifying circuit is used for converting the electric field signal into a direct current signal. The charging path control circuit is used for switching on or switching off a charging path of the battery according to the charging control signal. The filter capacitor is used for smoothing the wave form of the direct current signal when the charging path is conducted. The overvoltage protection circuit is used for reducing the voltage value of the direct current signal when the voltage of the direct current signal exceeds a critical value. The battery management circuit is used for providing charging power to the battery according to the direct current signal. The near field communication controller is used for generating a charging control signal.

Description

Wireless charging device

Technical Field

The present disclosure relates to wireless charging devices, and more particularly, to a wireless charging device sharing an antenna with nfc.

Background

Because intelligent wearing equipment and small-size smart machine are more and more high to the waterproof nature of product requirement, therefore traditional charging connector can't accord with high waterproof nature demand usually. In addition, the efficiency of wireless charging also gradually promotes, consequently wireless charging just becomes the charging methods that intelligent wearing equipment and small-size smart machine used often. In the wireless charging process, necessary communication is often required, and the communication information includes device anti-counterfeiting authentication, product pairing, wireless charging handshake, charging parameter monitoring and charging process monitoring, and is usually performed through near field communication. In addition, because the volume of intelligent wearing equipment and small-size smart machine is less, therefore near field communication and wireless charging often can share the same antenna coil, so-called wireless charging and communication integration to reach the purpose that reduces the space demand.

However, wireless charging requires a large capacitor to stabilize the waveform of the charging voltage, which affects the matching impedance of the nfc during transmitting and receiving signals through the antenna, and thus the signal quality of the nfc is difficult to improve. In contrast, the matching impedance required for near field communication also results in a smaller conduction angle of the rectifier, thereby reducing the efficiency of wireless charging. Since the wireless charging circuit and the near field communication circuit need to share the same line, there is a mutual restriction between the charging efficiency and the communication quality, and how to improve the wireless charging efficiency without affecting the quality of the near field communication under the condition of sharing the antenna becomes a problem to be solved in the field.

Disclosure of Invention

It is an object of the present application to disclose a wireless charging apparatus capable of sharing an antenna with near field communication to solve the above-mentioned problems.

An embodiment of the present application provides a wireless charging device, coupled to an antenna and a battery, for charging the battery according to an electric field signal received from the antenna. The wireless charging device comprises a low-frequency blocking circuit, a rectifying circuit, a charging path control circuit, a filter capacitor, an overvoltage protection circuit, a battery management circuit, a near field communication controller and a matched filter circuit. The low-frequency blocking circuit is coupled to the antenna and used for blocking low-frequency noise in the electric field signal. The rectifying circuit is coupled to the low-frequency blocking circuit and used for converting the electric field signal into a direct current signal. The charging path control circuit is coupled to the rectifying circuit and used for switching on or switching off the charging path of the direct current signal to the battery according to a charging control signal. The filter capacitor is coupled to the charging path control circuit, and is used for smoothing the waveform of the direct current signal when the charging path is conducted. The overvoltage protection circuit is coupled to the filter capacitor and used for reducing the voltage value of the direct current signal when the voltage of the direct current signal exceeds a critical value. The battery management circuit is coupled to the overvoltage protection circuit and used for providing a charging power source to the battery according to the direct current signal. The near field communication controller is coupled to the charging path control circuit and used for generating the charging control signal and a near field communication signal. The matching filter circuit is coupled to the antenna and the near field communication controller for providing an impedance matched with the antenna to transmit the near field communication signal through the antenna.

The wireless charging device can share the antenna with the near field communication, and the paths of the near field communication and the wireless charging can be separated, so that the wireless charging efficiency can be improved under the condition that the quality of the near field communication is not influenced.

Drawings

Fig. 1 is a functional block diagram of a wireless charging device according to an embodiment of the present application.

Fig. 2 is another schematic diagram of the wireless charging device of fig. 1.

Fig. 3 is a schematic diagram of a wireless charging device according to another embodiment of the present application.

Detailed Description

The following disclosure provides various embodiments or illustrations that can be used to implement various features of the disclosure. The embodiments of components and arrangements described below serve to simplify the present disclosure. It is to be understood that such descriptions are merely illustrative and are not intended to limit the present disclosure. For example, in the description that follows, forming a first feature on or over a second feature may include certain embodiments in which the first and second features are in direct contact with each other; and may also include embodiments in which additional elements are formed between the first and second features described above, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or characters in the various embodiments. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Moreover, spatially relative terms, such as "under," "below," "over," "above," and the like, may be used herein to facilitate describing a relationship between one element or feature relative to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass a variety of different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Although numerical ranges and parameters setting forth the broad scope of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain standard deviations found in their respective testing measurements. As used herein, "about" generally refers to actual values within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "about" means that the actual value falls within the acceptable standard error of the mean, subject to consideration by those of ordinary skill in the art to which this application pertains. It is understood that all ranges, amounts, values and percentages used herein (e.g., to describe amounts of materials, length of time, temperature, operating conditions, quantitative ratios, and the like) are modified by the term "about" in addition to the experimental examples or unless otherwise expressly stated. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, these numerical parameters are to be understood as meaning the number of significant digits recited and the number resulting from applying ordinary carry notation. Herein, numerical ranges are expressed from one end to the other or between the two ends; unless otherwise indicated, all numerical ranges set forth herein are inclusive of the endpoints.

Fig. 1 is a functional block diagram of a wireless charging device 100 according to an embodiment of the present application. In the present embodiment, the wireless charging device 100 is coupled to the antenna AT1 and the battery BT1, and can charge the battery BT1 according to the electric field signal ES1 received from the antenna AT 1.

The wireless charging device 100 may include a low frequency blocking circuit 110, a rectifying circuit 120, a charging path control circuit 130, and a filter capacitor C_FAn overvoltage protection circuit 140, a battery management circuit 150, a matched filter circuit 160, and a near field communication controller 170.

The low frequency blocking circuit 110 may be coupled to the antenna AT1 and may block low frequency noise in the electric field signal ES 1. The rectifying circuit 120 may be coupled to the low frequency blocking circuit 110, and may convert the electric field signal ES1 transmitted in the form of ac power into a dc signal DS 1. The charging path control circuit 130 may be coupled to the rectifying circuit 120 and may be configured to control the charging path according to a charging control signal SIG_CCThe charging path of the direct current signal DS1 to the battery BT1 is turned on or off.

Filter capacitor C_FMay be coupled to the charging path control circuit 130, and may smooth the waveform of the dc signal DS1 when the charging path is turned on. The overvoltage protection circuit 140 may be coupled to the filter capacitor C_FWhen the voltage of the DC signal DS1 exceeds a threshold, the over-voltage protection circuit 140 can reduce the DC voltageThe voltage value of signal DS 1. The battery management circuit 150 may be coupled to the overvoltage protection circuit 140 and may provide charging power to the battery BT1 according to the dc signal DS 1.

The nfc controller 170 may be coupled to the charging path control circuit 130, and may generate a charging control signal SIG_CCTo control the charging path control circuit 130 to turn on or off the charging path of the dc signal DS1 to the battery BT 1. For example, when the near field communication controller 170 does not perform near field communication via the antenna AT1, the near field communication controller 170 may turn on the charging path to the battery BT1 by the charging path control circuit 130, and when the near field communication controller 170 needs to transmit a near field communication signal via the antenna AT1, the near field communication controller 170 may turn off the charging path to the battery BT1 by the charging path control circuit 130.

In addition, the matched filter circuit 160 may be coupled to the antenna AT1 and the nfc controller 170. When the near field communication controller 170 intends to send a near field communication signal through the antenna AT1, the matched filter circuit 160 may provide an impedance matched to the antenna AT1 to send the near field communication signal through the antenna AT 1. In this embodiment, when the near field communication controller 170 stops generating the near field communication signal, the near field communication controller 170 may adjust the signal SIG by the impedance in addition to controlling the charging path control circuit 130 to turn on the charging path_IAThe matched filter circuit 160 is controlled to increase the impedance of the matched filter circuit 160, thereby reducing the wirelessly charged electric field signal ES1 entering the near field communication controller 170 through the matched filter circuit 160. In contrast, when the near field communication controller 170 intends to transmit the near field communication signal through the antenna AT1, the near field communication controller 170 may control the charging path control circuit 130 to cut off the charging path, and may also adjust the signal SIG through the impedance_IATo control the matched filter circuit 160 to adjust the impedance of the matched filter circuit 160 for transmission of the near field communication signal.

Since the nfc controller 170 can control the charging path control circuit 130 to turn on or off the charging path according to whether the nfc signal needs to be transmitted through the antenna AT1, and can correspondingly adjust the impedance of the matched filter circuit 160, the wireless communication system is not limited theretoThe charging device 100 can separate the paths of the near field communication and the wireless charging, and reduce the mutual restriction between the wireless charging efficiency and the near field communication quality, thereby improving the wireless charging efficiency without affecting the quality of the near field communication. However, in some other embodiments, in the case where the matching filter circuit 160 provides a fixed impedance, if the electric field signal ES1 can be effectively reduced from entering the near field communication controller 170, and the near field communication signal can also enter the near field communication controller 170 through the matching filter circuit 160 when near field communication is performed, the matching filter circuit 160 can be kept providing the fixed impedance, and the near field communication controller 170 may not separately generate the impedance adjustment signal SIG_IATo control matched filter circuit 160.

Fig. 2 is another schematic diagram of the wireless charging device 100. In fig. 2, the lf blocking circuit 110 may include a first capacitor C1 and a second capacitor C2. The first capacitor C1 has a first terminal and a second terminal, and the first terminal of the first capacitor C1 may be coupled to the first terminal of the antenna AT 1. The second capacitor C2 has a first terminal and a second terminal, the first terminal of the second capacitor C2 may be coupled to the second terminal of the first capacitor C1, and the second terminal of the second capacitor C2 may be coupled to the second terminal of the antenna AT 1. In the embodiment, the first capacitor C1 can block low-frequency noise in the electric field signal ES1, and the second capacitor C2 and the first capacitor C1 can also divide the voltage of the electric field signal ES1, so that the rectifying circuit 120 can receive a voltage in an appropriate range.

The rectifying circuit 120 includes a first inductor L1, a second inductor L2, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The first inductor L1 has a first terminal and a second terminal, and the first terminal of the first inductor L1 may be coupled to the second terminal of the first capacitor C1. The second inductor L2 has a first terminal and a second terminal, and the first terminal of the second inductor L2 may be coupled to the second terminal of the second capacitor C2.

The first diode D1 has a first terminal and a second terminal, the first terminal of the first diode D1 may be coupled to the second terminal of the first inductor L1, and the second terminal of the first diode D1 may be coupled to the output terminal of the rectifying circuit 120. The second diode D2 has a first terminal and a second terminal, the first terminal of the second diode D2 may be coupled to the second terminal of the second inductor L2, and the second terminal of the second diode D2 may be coupled to the output terminal of the rectifier circuit 120. The third diode D3 has a first terminal and a second terminal, the first terminal of the third diode D3 may be coupled to the ground GND, and the second terminal of the third diode D3 may be coupled to the second terminal of the first inductor L1. The fourth diode D4 has a first terminal and a second terminal, the first terminal of the fourth diode D4 may be coupled to the ground GND, and the second terminal of the fourth diode D4 may be coupled to the second terminal of the second inductor L2.

In the present embodiment, the first terminals of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 may be anode terminals, and the second terminals of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 may be cathode terminals. In the rectifier circuit 120, the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 can rectify the electric field signal ES1, so as to convert the electric field signal ES1, which is originally input in the form of alternating current, into a direct current signal DS 1.

In addition, since the electric field signal ES1 is an alternating current, if the electric field signal ES1 attenuates during transmission, the conduction angles of the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 may be small. Furthermore, since the first capacitor C1 and the second capacitor C2 are high-pass filter elements, it is difficult to increase the conduction angle of the electric field signal ES1 to the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4. In contrast, the first inductor L1 and the second inductor L2 can generate self-induced electromotive force, so that the change of the wave form of the electric field signal ES1 is gradual, the conduction angle of the electric field signal ES1 to the first diode D1, the second diode D2, the third diode D3 and the fourth diode D4 is increased, and the efficiency of wireless charging is improved.

Because the wireless charging device 100 can separate the paths of the near field communication and the wireless charging, in the rectifying circuit 120, the first inductor L1 and the second inductor L2 for increasing the conduction angle can improve the efficiency of the invalid charging on the one hand, and on the other hand, the requirement of the impedance matching condition by the matched filter circuit on the near field communication path is not affected, and conversely, the conduction angle of the rectifying circuit cannot be improved because the matching circuit required by the near field communication is considered, so that the wireless charging device 100 of the embodiment can well consider the quality of the near field communication and the better charging efficiency.

In some embodiments, if the conduction angle of the rectifier circuit 120 can meet the requirement, the first inductor L1 and the second inductor L2 may be omitted, and the first terminal of the first diode D1 may be coupled to the second terminal of the first capacitor C1, the first terminal of the second diode D2 may be coupled to the second terminal of the second capacitor C2, the second terminal of the third diode D3 may be coupled to the second terminal of the first capacitor C1, and the second terminal of the fourth diode D4 may be coupled to the second terminal of the second capacitor C2.

In fig. 1, the charge path control circuit 130 may include a first transistor T1, a second transistor T2, a control driver 132, and a first resistor R1. The first transistor T1 has a first terminal, a second terminal, and a control terminal, the second terminal of the first transistor T1 is coupled to the ground GND, and the control terminal of the first transistor T1 receives the charging control signal SIG_CC. The second transistor T2 has a first terminal, a second terminal and a control terminal, the first terminal of the second transistor T2 can receive the DC signal DS1, and the second terminal of the second transistor T2 can be coupled to the filter capacitor C_F. The first resistor R1 has a first terminal and a second terminal, the first terminal of the first resistor R1 may be coupled to the first terminal of the second transistor T2, and the second terminal of the first resistor R1 may be coupled to the control terminal of the second transistor T2.

The control driver 132 may be coupled to the first terminal of the first transistor T1 and the control terminal of the second transistor T2, and the control driver 132 may turn on or off the second transistor T2 according to a voltage of the first terminal of the first transistor T1 to turn on or off the charging path. In this embodiment, the control driver 132 may include a third transistor T3, the third transistor T3 has a first terminal, a second terminal and a control terminal, the first terminal of the third transistor T3 may be coupled to the control terminal of the second transistor T2, the second terminal of the third transistor T3 may be coupled to the ground terminal GND, and the control terminal of the third transistor T3 may be coupled to the first terminal of the first transistor T1.

For example, the first transistor T1 and the third transistor T3 may be, for example but not limited to, N-type transistors, and the second transistor T2 may be, for example but not limited to, P-type transistors. In this case, when the charge control signal SIG_CCWhen the voltage level is high, the first transistor T1 is turned on, and the voltage level at the control terminal of the third transistor T3 is pulled down to a low level close to the system voltage GND, so that the third transistor T3 is turned off. At this time, when the charging path control circuit 130 has received the dc signal DS1, the dc signal DS1 will raise the control terminal voltage of the second transistor T2 through the first resistor R1, so that the second transistor T2 is turned off, and the charging path of the dc signal DS1 to the battery BT1 is turned off. On the other hand, if the charging control signal SIG_CCThe first transistor T1 is turned off when the voltage is low. In the present embodiment, the control terminal of the third transistor T3 can receive a bias voltage related to the electric field signal ES1, so that when the wireless charging device 100 receives the electric field signal ES1 and the first transistor T1 is turned off, the third transistor T3 is turned on, such that the control terminal voltage of the second transistor T2 is pulled down to a low level close to the system voltage GND, and the second transistor T2 is turned on, such that the charging path of the dc signal DS1 to the battery BT1 is turned on.

That is, the near field communication controller 170 may adjust the charging control signal SIG_CCAccordingly, the charging path of the dc signal DS1 to the battery BT1 is turned on or off. In addition, in fig. 2, the wireless charging device 100 may further include an electric field detection circuit 180. The electric field detection circuit 180 may generate the charge detection signal CD1 related to the voltage level of the dc signal DS1 according to the dc signal DS1, such that the nfc controller 170 may further generate the charge control signal SIG according to the charge detection signal CD1_CC。

For example, the nfc controller 170 may determine the strength of the dc signal DS1 according to the charging detection signal CD 1. When the dc signal DS1 is larger, indicating that there is a power supply available for wireless charging, the nfc controller 170 can control charging without sending the nfc signal through the antenna AT1Signal SIG_CCIs at low potential to correspondingly conduct the charging path of the direct current signal DS1 to the battery BT 1. In contrast, when the dc signal DS1 is too small, indicating that there is no external power source for wireless charging, the nfc controller 170 may enable the charging control signal SIG_CCIs at a high potential to correspondingly cut off the charging path of the direct current signal DS1 to the battery BT 1.

In the present embodiment, the electric field detection circuit 180 may include a filter clamping unit 182 and a voltage dividing unit 184. The filtering clamping unit 182 may filter the dc signal DS1 to generate the electric field reference signal ER1, and the voltage dividing unit 184 may divide the electric field reference signal ER1 to generate the charge detection signal CD 1.

The filter clamping unit 182 may include a third resistor R3, a fourth capacitor C4, and a first clamping diode TSV 1. The third resistor R3 has a first end and a second end, and the first end of the third resistor R3 can receive the dc signal DS 1. The fourth capacitor C4 has a first terminal and a second terminal, the first terminal of the fourth capacitor C4 may be coupled to the second terminal of the third resistor R3 and may output the electric field reference signal ER1, and the second terminal of the fourth capacitor C4 may be coupled to the ground GND. The first clamping diode TSV1 has a first end and a second end, the first end of the first clamping diode TSV1 may be coupled to a first end of the fourth capacitor C4, and the second end of the first clamping diode TSV1 may be coupled to a second end of the fourth capacitor C4. In the present embodiment, the third resistor R3 and the fourth capacitor C4 can filter the dc signal DS1, so that the waveform of the electric field reference signal ER1 is stable. In addition, the first clamping diode TSV1 may provide a voltage relief path to clamp the electric field reference signal ER1 within a safe voltage range when the voltage of the dc signal DS1 is too large. In this case, the first terminal of the first transistor T1 and the control terminal of the third transistor T3 may be coupled to the second terminal of the third resistor R3 for receiving the electric field reference signal ER1 as a bias voltage during operation.

The voltage divider 184 includes a fourth resistor R4 and a fifth resistor R5. The fourth resistor has a first end and a second end, and the first end of the fourth resistor R4 can receive the electric field reference signal ER 1. The fifth resistor R5 has a first end and a second end, the first end of the fifth resistor R5 may be coupled to the second end of the fourth resistor R4 and may output the charge detection signal CD1, and the second end of the fifth resistor R5 may be coupled to the ground GND. In the present embodiment, the fourth resistor R4 and the fifth resistor R5 divide the electric field reference signal ER1 to generate the charge detection signal CD 1.

In the embodiment, the wireless charging device 100 detects the dc signal DS1 through the electric field detection circuit 180 to generate the charging detection signal CD1, but the disclosure is not limited thereto. In some other embodiments, the wireless charging device 100 can detect the presence of the wireless charging field through other types or structures of detection circuits. For example, the wireless charging device 100 may use an electric field detection circuit capable of detecting an alternating current to detect the electric field signal ES1 to generate a corresponding charging detection signal, so that the nfc controller 170 can determine whether a wireless charging electric field exists, and further turn on or off a charging path of the battery BT 1. In some embodiments, if the nfc controller 170 can determine the timing of the wireless charging in other manners, the wireless charging apparatus 100 may omit the electric field detection circuit 180, as shown in fig. 1.

In fig. 2, the overvoltage protection circuit 140 may include a first voltage divider 142, a second voltage divider 144, a sixth resistor R6, and a fourth transistor T4. The first voltage divider 142 has a first end and a second end, and the first end of the first voltage divider 142 can receive the dc signal DS 1. The second voltage divider 144 has a first end and a second end, the first end of the second voltage divider 144 may be coupled to the second end of the first voltage divider 142, and the second end of the second voltage divider 144 may be coupled to the ground GND. In the present embodiment, the first voltage divider 142 and the second voltage divider 144 are implemented by resistors, and the first voltage divider 142 and the second voltage divider 144 can divide the dc signal DS1 to generate the overvoltage reference signal OV 1.

The sixth resistor R6 has a first end and a second end, and the first end of the sixth resistor R6 can receive the dc signal DS 1. The fourth transistor T4 has a first terminal, a second terminal, and a control terminal, the first terminal of the fourth transistor T4 may be coupled to the second terminal of the sixth resistor R6, the second terminal of the fourth transistor T4 may be coupled to the ground GND, and the control terminal of the fourth transistor T4 may be coupled to the second terminal of the first voltage divider 142. The fourth transistor T4 turns on a voltage-relief path formed by the fourth transistor T4 and the sixth resistor R6 according to the over-voltage reference signal OV1 to reduce the voltage level of the dc signal DS 1.

In some embodiments, if the overvoltage reference signal OV1 makes the fourth transistor T4 operate in the saturation region, once the voltage of the dc signal DS1 is too large, the fourth transistor T4 will be completely turned off, and the dc signal DS1 will flow into the ground GND through the voltage-dropping path, so that the battery management circuit 150 cannot charge the battery BT1 according to the dc signal DS 1. However, in the present embodiment, the overvoltage reference signal OV1 can be set to a proper range by the first voltage divider 142 and the second voltage divider 144, so that the fourth transistor T4 can operate mainly in a linear region, and therefore the fourth transistor T4 can control the conduction degree of the voltage-relief path according to the magnitude of the overvoltage reference signal OV 1. In this way, the dc signal DS1 passing through the overvoltage protection circuit 140 can be maintained within a proper voltage range within a limited range, and the time for the battery management circuit 150 to receive the dc signal DS1 and charge the battery BT1 is prolonged, so that the charging efficiency of the wireless charging device 100 can be further improved.

In this case, in order to provide real-time protection when the dc signal DS1 is over-voltage, the over-voltage protection circuit 140 may further include a second clamping diode TSV2, the second clamping diode TSV2 has a first end and a second end, the first end of the second clamping diode TSV2 may receive the dc signal DS1, and the second end of the second clamping diode TSV2 may be coupled to the ground GND. As a result, when the dc signal DS1 is over-voltage, the second clamping diode TSV2 is turned on, and a voltage relief path is provided to prevent the battery management circuit 150 from being damaged due to receiving high voltage.

In addition, the over-voltage protection circuit 140 may further include a third voltage division element 146 and a fourth voltage division element 148. The third voltage divider 146 has a first end and a second end, the first end of the third voltage divider 146 can receive the dc signal DS1, and the second end of the third voltage divider 146 can output the over voltage detection signal OD 1. The fourth voltage dividing element 148 has a first end and a second end, the first end of the fourth voltage dividing element 148 may be coupled to the second end of the third voltage dividing element 146, and the second end of the fourth voltage dividing element 148 may be coupled to the ground GND. In the present embodiment, the third voltage divider 146 is a clamping diode, and the fourth voltage divider 148 is a resistor.

The third voltage divider 146 and the fourth voltage divider 148 may divide the dc signal DS1 to generate an over-voltage detection signal OD1, and the nfc controller 170 may determine whether the dc signal DS1 is over-voltage according to the over-voltage detection signal OD1 and may generate a charging control signal SIG accordingly_CCTo turn on or off the charging path of battery BT 1. In addition, the third voltage division element 146 and the fourth voltage division element 148 can also be used to provide a voltage relief path for the dc signal DS1, so as to further achieve the function of overvoltage protection, so that the operation of the wireless charging device 100 is safer.

In fig. 1, the wireless charging device 100 may further include a power management circuit 190, and the power management circuit 190 may be coupled to the battery management circuit 150. In this case, the battery management circuit 150 may output the power supply to the power management circuit 190 according to the dc signal DS1, and the power management circuit 190 may provide the power required by the nfc controller 170 according to the power supply. That is, the electric power obtained by the wireless charging may be used not only to charge the battery BT1 but also to be supplied to the near field communication controller 170, thereby more efficiently using the power obtained by the wireless charging.

Since the wireless charging device 100 can separate the paths of the near field communication and the wireless charging, the wireless charging device 100 can provide the inductors L1 and L2 in the rectifying circuit 120 to increase the conduction angles of the diodes D1, D2, D3 and D4 in the rectifying circuit 120, thereby increasing the efficiency of the wireless charging. In addition, the electric field detection circuit 180 can generate the charging detection signal CD1 for the nfc controller 170 to determine whether the electric field signal ES1 capable of providing wireless charging exists, and accordingly turn on or off the charging path control circuit 130, so that the wireless charging device 100 can switch between the wireless charging function and the nfc function more smoothly. Furthermore, since the overvoltage protection circuit 140 can set the overvoltage reference signal OV1 in a proper range, so that the fourth transistor T4 can operate mainly in a linear region, the dc signal DS1 passing through the overvoltage protection circuit 140 can be maintained within a proper voltage range to a limited extent, and the time for the battery management circuit 150 to receive the dc signal DS1 and charge the battery BT1 is prolonged, so that the charging efficiency of the wireless charging device 100 can be further improved.

Fig. 3 is a schematic diagram of a wireless charging device 200 according to another embodiment of the present application. The wireless charging device 200 has a similar structure to the wireless charging device 100 and can operate according to similar principles. The wireless charging device 200 may include a low frequency blocking circuit 210, a rectifying circuit 220, a charging path control circuit 230, and a filter capacitor C_FThe power supply circuit comprises an overvoltage protection circuit 240, a battery management circuit 250, a matched filter circuit 260, a near field communication controller 270, a filter clamping unit 282 and a power supply management circuit 290.

In fig. 3, the lf blocking circuit 210 may include a first capacitor C1, a second capacitor C2, and a third capacitor C3. A first capacitor C1 and a second capacitor C2. The first capacitor C1 has a first terminal and a second terminal, and the first terminal of the first capacitor C1 may be coupled to the first terminal of the antenna AT 1. The second capacitor C2 has a first terminal and a second terminal, and the first terminal of the second capacitor C2 may be coupled to the second terminal of the first capacitor C1. The third capacitor C3 has a first terminal and a second terminal, the first terminal of the third capacitor C3 may be coupled to the second terminal of the antenna AT1, and the second terminal of the third capacitor C3 may be coupled to the second terminal of the second capacitor C2. In the embodiment, the first capacitor C1 and the third capacitor C3 can block low-frequency noise in the electric field signal ES1, and the second capacitor C2 and the first capacitor C1 and the third capacitor C3 can divide the voltage of the electric field signal ES1, so that the rectifying circuit 220 can receive a voltage in an appropriate range.

In addition, the wireless charging device 200 may generate the bias voltages required by the transistors T1B and T3 in the charging path control circuit 230 through the filter clamping unit 282. That is, in the embodiment of fig. 3, the wireless charging device 200 does not provide the charging detection signal CD1 to the nfc controller 270 through the electric field detection circuit 180. In this case, the charging detection signal CD1 may be generated by other circuits for the nfc controller 270 to determine whether the electric field signal ES1 exists, or in some embodiments, the nfc controller 270 may control the charging path control circuit 230 according to other signals or other rules.

Furthermore, in fig. 3, the charging path control circuit 230 may change the mosfet T1 in the charging path control circuit 130 to be a bipolar transistor T1B, and the charging path control circuit 230 may further include a second resistor R2. The second resistor R2 has a first terminal and a second terminal, the first terminal of the second resistor R2 is coupled to the control terminal of the first transistor T1B, and the second terminal of the second resistor R2 is coupled to the second terminal of the first transistor T1B.

Similarly, in some embodiments, the second transistor T2 and the third transistor T3 may be implemented by bipolar transistors instead. However, since the third transistor T3 is disposed on the charging path to the battery BT1, it is necessary to turn on a larger current, in this case, it is helpful to select a mosfet with a smaller on-resistance to implement the third transistor T3 to improve the overall charging efficiency.

Furthermore, in the over-voltage protection circuit 240, the first voltage divider 242 is implemented by a clamping diode, and the second voltage divider 244 is implemented by a resistor. The first voltage divider 242 and the second voltage divider 244 may divide the dc signal DS1 to generate the over voltage reference signal OV 1. That is, the first voltage divider 242 may be implemented with a clamping diode or a resistor according to the system requirement. Similarly, the third voltage divider component 246 may also be implemented with a clamping diode or resistor. For example, in fig. 3, the third voltage divider component 246 is a clamping diode and the fourth voltage divider component 218 is a resistor.

In summary, the wireless charging device provided in the embodiments of the present application can separate the paths of near field communication and wireless charging, so that the efficiency of wireless charging can be improved without affecting the quality of near field communication. For example, the wireless charging device may include an inductor in the rectifier circuit to increase a conduction angle of the rectifier circuit, so as to improve the wireless charging efficiency. In addition, the wireless charging device can judge whether an electric field signal capable of providing wireless charging exists or not, and accordingly the charging path control circuit is turned on or off, so that the wireless charging device can be switched between the wireless charging function and the near field communication function more smoothly. Moreover, because the overvoltage protection circuit of the wireless charging device can set the overvoltage reference signal in a proper range, the time for the battery management circuit to receive the direct-current signal and charge the battery can be prolonged, and the charging efficiency of the wireless charging device can be further improved.

The foregoing description has set forth briefly the features of certain embodiments of the present application so that those skilled in the art may more fully appreciate the various aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should understand that they can still make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. A wireless charging device, coupled to an antenna and a battery, for charging the battery according to an electric field signal received from the antenna, the wireless charging device comprising:

the low-frequency blocking circuit is coupled to the antenna and used for blocking low-frequency noise in the electric field signal;

the rectifying circuit is coupled with the low-frequency blocking circuit and used for converting the electric field signal into a direct current signal;

the charging path control circuit is coupled with the rectifying circuit and used for switching on or switching off a charging path of the direct current signal to the battery according to a charging control signal;

a filter capacitor, coupled to the charging path control circuit, for smoothing a waveform of the dc signal when the charging path is turned on;

the overvoltage protection circuit is coupled to the filter capacitor and used for reducing the voltage value of the direct current signal when the voltage of the direct current signal exceeds a critical value;

the battery management circuit is coupled to the overvoltage protection circuit and used for providing a charging power supply to the battery according to the direct current signal;

a near field communication controller coupled to the charging path control circuit for generating the charging control signal and a near field communication signal; and

a matched filter circuit coupled to the antenna and the near field communication controller for providing an impedance matched to the antenna to transmit the near field communication signal through the antenna.

2. The wireless charging apparatus of claim 1, wherein the low frequency blocking circuit comprises:

a first capacitor having a first terminal and a second terminal, the first terminal of the first capacitor being coupled to a first terminal of the antenna; and

a second capacitor having a first end and a second end, the first end of the second capacitor being coupled to the second end of the first capacitor, and the second end of the second capacitor being coupled to the second end of the antenna;

wherein:

the first capacitor is used for blocking the low-frequency noise in the electric field signal; and

the second capacitor and the first capacitor are used for dividing the electric field signal.

3. The wireless charging apparatus of claim 2, wherein the low frequency blocking circuit further comprises:

a third capacitor having a first end and a second end, the first end of the third capacitor being coupled to the second end of the antenna, and the second end of the third capacitor being coupled to the second end of the second capacitor;

wherein:

the third capacitor is used for blocking the low-frequency noise in the electric field signal; and

the second capacitor and the third capacitor are used for dividing the electric field signal.

4. The wireless charging device according to claim 2 or 3, wherein the rectifying circuit comprises:

a first diode having a first end and a second end, the first end of the first diode being coupled to the second end of the first capacitor, and the second end of the first diode being coupled to an output end of the rectifier circuit;

a second diode having a first terminal and a second terminal, the first terminal of the second diode being coupled to the second terminal of the second capacitor, and the second terminal of the second diode being coupled to the output terminal of the rectifier circuit;

a third diode having a first end and a second end, the first end of the third diode being coupled to ground, and the second end of the third diode being coupled to the second end of the first capacitor; and

a fourth diode having a first end and a second end, the first end of the fourth diode being coupled to the ground end, and the second end of the fourth diode being coupled to the second end of the second capacitor;

the first diode, the second diode, the third diode and the fourth diode are used for rectifying the electric field signal to generate the direct current signal.

5. The wireless charging device of claim 4, wherein the rectification circuit further comprises:

a first inductor having a first end and a second end, the first end of the first inductor being coupled to the second end of the first capacitor, and the second end of the first inductor being coupled to the first end of the first diode; and

a second inductor having a first end and a second end, the first end of the second inductor being coupled to the second end of the second capacitor, and the second end of the second inductor being coupled to the first end of the second diode;

wherein the first inductor and the second inductor are used to increase a conduction angle of the electric field signal to the first diode, the second diode, the third diode, and the fourth diode.

6. The wireless charging apparatus of any of claims 1-5, wherein the charging path control circuit comprises:

a first transistor having a first terminal, a second terminal, and a control terminal, wherein the second terminal of the first transistor is coupled to a ground terminal, and the control terminal of the first transistor is configured to receive the charging control signal;

a second transistor having a first terminal, a second terminal and a control terminal, wherein the first terminal of the second transistor is used for receiving the DC signal, and the second terminal of the second transistor is coupled to the filter capacitor;

a control driver coupled to the first terminal of the first transistor and the control terminal of the second transistor, the control driver being configured to turn on or off the second transistor according to a voltage of the first terminal of the first transistor, so that the charging path is turned on or off; and

a first resistor having a first end and a second end, the first end of the first resistor being coupled to the first end of the second transistor, and the second end of the first resistor being coupled to the control end of the second transistor.

7. The wireless charging apparatus of claim 6, wherein the control driver comprises:

a third transistor having a first terminal, a second terminal, and a control terminal, the first terminal of the third transistor being coupled to the control terminal of the second transistor, the second terminal of the third transistor being coupled to the ground terminal, and the control terminal of the third transistor being coupled to the first terminal of the first transistor.

8. The wireless charging apparatus of claim 6, wherein the charging path control circuit further comprises:

a second resistor having a first end and a second end, the first end of the second resistor being coupled to the control end of the first transistor, and the second end of the second resistor being coupled to the second end of the first transistor.

9. The wireless charging apparatus of claim 6, wherein:

the first transistor is a metal-oxide-semiconductor field effect transistor or a bipolar transistor; and

the second transistor is a metal oxide semiconductor field effect transistor or a bipolar transistor.

10. The wireless charging device of any one of claims 6-9, further comprising an electric field detection circuit for generating a charging detection signal according to the dc signal, wherein the charging detection signal is related to a voltage level of the dc signal, and the nfc controller generates the charging control signal according to at least the charging detection signal.

11. The wireless charging apparatus of claim 10, wherein the electric field detection circuit comprises:

the filtering clamping unit is used for filtering the direct current signal to generate an electric field reference signal; and

the voltage division unit is used for generating the charging detection signal by dividing the electric field reference signal.

12. The wireless charging apparatus of claim 11, wherein the filter clamping unit comprises:

a third resistor having a first end and a second end, the first end of the third resistor being configured to receive the dc signal;

a fourth capacitor having a first end and a second end, the first end of the fourth capacitor being coupled to the second end of the third resistor for outputting the electric field reference signal, and the second end of the fourth capacitor being coupled to the ground terminal; and

a first clamping diode having a first end and a second end, the first end of the first clamping diode being coupled to the first end of the fourth capacitor, and the second end of the first clamping diode being coupled to the second end of the fourth capacitor.

13. The wireless charging apparatus of claim 11 or 12, wherein the voltage dividing unit comprises:

a fourth resistor having a first end and a second end, the first end of the fourth resistor being configured to receive the electric field reference signal;

a fifth resistor having a first end and a second end, the first end of the fifth resistor being coupled to the second end of the fourth resistor and configured to output the charging detection signal, and the second end of the fifth resistor being coupled to the ground.

14. The wireless charging apparatus of any of claims 1-13, wherein the over-voltage protection circuit comprises:

a first voltage division component having a first end and a second end, the first end of the first voltage division component being configured to receive the dc signal;

a second voltage divider component having a first end and a second end, the first end of the second voltage divider component coupled to the second end of the first voltage divider component, and the second end of the second voltage divider component coupled to ground;

a sixth resistor having a first end and a second end, the first end of the sixth resistor being configured to receive the dc signal;

a fourth transistor having a first terminal, a second terminal, and a control terminal, the first terminal of the fourth transistor being coupled to the second terminal of the sixth resistor, the second terminal of the fourth transistor being coupled to the ground terminal, and the control terminal of the fourth transistor being coupled to the second terminal of the first voltage divider component; and

a second clamping diode having a first end and a second end, the first end of the second clamping diode for receiving the DC signal, and the second end of the second clamping diode coupled to the ground terminal;

wherein:

the first voltage division component and the second voltage division component are used for dividing the direct current signal to generate an overvoltage reference signal; and

the fourth transistor is used for turning on a voltage relief path formed by the fourth transistor and the sixth resistor together according to the overvoltage reference signal so as to reduce the voltage value of the direct current signal.

15. The wireless charging device according to claim 14, wherein the fourth transistor is operated in a linear region to control a conduction degree of the voltage-relief path according to a magnitude of the over-voltage reference signal.

16. The wireless charging apparatus of claim 14, wherein:

the first voltage division component is a resistor or a clamping diode; and

the second voltage division component is a resistor.

17. The wireless charging apparatus of claim 14, wherein the overvoltage protection circuit further comprises:

a third voltage divider having a first end and a second end, the first end of the third voltage divider being configured to receive the dc signal, and the second end of the third voltage divider being configured to output an over-voltage detection signal; and

a fourth voltage divider component having a first end and a second end, the first end of the fourth voltage divider component being coupled to the second end of the third voltage divider component, and the second end of the fourth voltage divider component being coupled to the ground end;

wherein the near field communication controller generates the charging control signal at least according to the over-voltage detection signal.

18. The wireless charging apparatus of claim 17, wherein:

the third voltage division component is a resistor or a clamping diode; and

the fourth voltage division component is a resistor.

19. The wireless charging apparatus of claim 1, wherein:

when the near field communication controller stops generating the near field communication signal, the near field communication controller generates the charging control signal to enable the charging path control circuit to conduct the charging path and enable the impedance of the matched filter circuit to be increased; or

When the near field communication controller generates the near field communication signal and transmits the near field communication signal through the matched filter circuit and the antenna, the near field communication controller generates the charging control signal to enable the charging path control circuit to cut off the charging path and enable the impedance of the matched filter circuit to be reduced.

20. The wireless charging apparatus of any of claims 1-19, further comprising a power management circuit coupled to the battery management circuit, wherein:

the battery management circuit is further used for outputting and supplying power to the power management circuit according to the direct current signal; and

the power management circuit is used for providing power required by the near field communication controller according to the supply power.