Circuit, control method and electronic device for reusing wireless charging SOC chip as NFC chip

Abstract

The present invention relates to a circuit, control method, and electronic device for multiplexing a wireless charging SOC chip as an NFC chip. The circuit comprises a wireless charging coil, an NFC coil, a coil selection circuit, an NFC demodulation circuit, an NFC signal detection circuit, a wireless charging SOC chip, and an AP main control chip. The wireless charging coil and the NFC coil are respectively connected to the coil selection circuit, which is respectively connected to the wireless charging SOC chip and the AP main control chip, and the wireless charging SOC chip is connected to the AP main control chip. The wireless charging coil, the NFC demodulation circuit, and the NFC signal detection circuit are sequentially connected. The NFC demodulation circuit is connected to the wireless charging SOC chip. The NFC signal detection circuit is respectively connected to the wireless charging SOC chip and the AP main control chip. By providing the NFC demodulation circuit, the NFC signal detection circuit, the wireless charging SOC chip, and the AP main control chip, the present invention enables the wireless charging SOC chip to implement both wireless charging mode and NFC mode, eliminating the need for multiple chips. This not only saves resources but also reduces costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic equipment, and particularly relates to a circuit, a control method, and an electronic device for multiplexing a wireless charging SOC chip as an NFC chip. Background Art

[0002] With the popularization of electronic devices, wireless charging technology has been widely used. Low-power wireless charging often adopts electromagnetic induction. Currently, Qi protocol wireless charging is widely used in smart devices such as mobile phones. Qi is the "wireless charging" standard launched by the Wireless Power Consortium (WPC), the world's first standardization organization to promote wireless charging technology. It has two major characteristics: convenience and versatility. Wireless charging is both a transmitter and a receiver. In low-power charging devices such as smart watches, it usually only has the function of a receiver. The wireless charging SOC chip on the receiving end supports the Qi wireless charging protocol and is used in products such as smart watches, smartphones, and tablets.

[0003] Near Field Communication (NFC) is an emerging technology that enables devices (such as mobile phones) to exchange data when in close proximity. It is an evolution of contactless radio frequency identification (RFID) and interconnection technologies. By integrating an inductive card reader, inductive card, and point-to-point communication functions on a single chip, it enables applications such as mobile payment, electronic ticketing, and access control using mobile terminals. For example, NXP's NFC controller chip, the PN80T, also includes an embedded secure element (SE).

[0004] In the current state of the art, the NFC controller chip and wireless charging receiver chip in smartwatches are typically implemented as two separate chips, each performing these two functions separately. This wastes resources and increases the cost of the final product. For small devices like smartwatches, the most commonly used NFC function is card emulation mode. However, the NFC controller chip and the wireless charging receiver chip contain many modules with similar functions. For example, both chips contain an ARM Cortex M0 microprocessor core, communicate with the AP processor using an I2C interface, include a rectifier circuit module, and use ASK modulation from the transmitter to the receiver, resulting in a waste of resources. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a circuit, control method and electronic device for reusing a wireless charging SOC chip as an NFC chip, so as to solve the problem in the prior art that the NFC controller chip and the wireless charging receiver chip in the same electronic device have many modules with similar functions, resulting in resource waste.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a circuit for multiplexing a wireless charging SOC chip as an NFC chip, comprising: a wireless charging coil, an NFC coil, a coil selection circuit, an NFC demodulation circuit, an NFC signal detection circuit, a wireless charging SOC chip, and an AP main control chip;

[0007] The wireless charging coil and the NFC coil are respectively connected to the coil selection circuit, the coil selection circuit is respectively connected to the wireless charging SOC chip and the AP main control chip, and the wireless charging SOC chip is connected to the AP main control chip;

[0008] The NFC coil, the NFC demodulation circuit, and the NFC signal detection circuit are connected in sequence;

[0009] The NFC demodulation circuit is connected to the wireless charging SOC chip;

[0010] The NFC signal detection circuit is connected to the wireless charging SOC chip and the AP main control chip respectively;

[0011] When the NFC demodulation circuit outputs a high level, it drives the NFC signal detection circuit to output a low level signal, causing the AP main control chip to send an NFC coil access selection signal to the coil selection circuit, and the coil selection circuit connects the NFC coil to the wireless charging SOC chip;

[0012] When the NFC demodulation circuit outputs a low level, it drives the NFC signal detection circuit to output a high level signal, causing the AP main control chip to send a wireless charging coil access signal to the coil selection circuit, and the coil selection circuit connects the wireless charging coil to the wireless charging SOC chip.

[0013] Furthermore, it also includes:

[0014] A voltage converter is connected to the AP main control chip, the wireless charging SOC chip and the battery respectively, and is used to receive the control signal of the AP main control chip and supply the voltage output by the battery to the wireless charging SOC chip.

[0015] Furthermore, the NFC demodulation circuit includes: an envelope detection circuit and a low-pass filter circuit connected to the envelope detection circuit;

[0016] The envelope detection circuit is used to obtain the baseband signal output by the NFC coil;

[0017] The low-pass filter circuit is used to perform filtering processing on the baseband signal.

[0018] Furthermore, the envelope detection circuit includes: a first resistor, a first diode, a second resistor and a first capacitor;

[0019] An anode of the first diode is connected to the output end of the NFC coil, a cathode of the first diode is connected to one end of a first resistor, the other end of the first resistor is respectively connected to one end of a second resistor and one end of a first capacitor, and the other end of the second resistor and the other end of the first capacitor are both grounded.

[0020] Furthermore, the low-pass filter circuit includes: a third resistor and a second capacitor;

[0021] One end of the third resistor is connected to the other end of the first resistor, the other end of the third resistor is connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

[0022] Furthermore, the NFC signal detection circuit includes: a voltage stabilizing diode, a controllable switch tube and a fourth resistor;

[0023] The cathode of the voltage stabilizing diode is connected to the output end of the NFC demodulation circuit, and the anode of the voltage stabilizing diode is grounded;

[0024] The control end of the controllable switch tube is connected to the output end of the NFC demodulation circuit, the first end of the controllable switch tube is connected to the fourth resistor, and the second end of the controllable switch tube is grounded.

[0025] Furthermore, the wireless charging SOC chip includes: a rectifier bridge, a decoding circuit, a timer and a microprocessor;

[0026] The rectifier bridge is used to provide operating voltage to the decoding circuit, timer and microprocessor;

[0027] The microprocessor is used to control the decoding circuit to adjust the decoding parameters so as to decode the signal output by the wireless charging coil or the NFC coil accordingly;

[0028] The microprocessor is further configured to control the timer to enter a PWM mode, so as to process the decoded signal and output a modulated baseband signal of NFC.

[0029] An embodiment of the present application provides an electronic device, which uses a circuit in which the wireless charging SOC chip provided in any of the above embodiments is reused as an NFC chip.

[0030] The present application provides a control method for multiplexing a wireless charging SOC chip as an NFC chip, including:

[0031] Receive signals output by the NFC demodulation circuit and the NFC signal detection circuit;

[0032] When the AP main control chip detects that the signal output by the NFC signal detection circuit is converted from a high level to a low level, the coil selection circuit is driven to connect the NFC coil to the wireless charging SOC chip;

[0033] When the wireless charging SOC chip detects that the signal output by the NFC demodulation circuit is at a low level, it drives the NFC signal detection circuit to output a high level signal. The AP main control chip drives the coil selection circuit according to the high level signal to connect the wireless charging coil to the wireless charging SOC chip, so that the wireless charging SOC chip wirelessly charges the terminal to which the AP main control chip belongs.

[0034] Furthermore, it also includes:

[0035] When the wireless charging SOC chip detects that the signal output by the NFC demodulation circuit is at a low level, it generates a wireless charging connection signal to the AP main control chip.

[0036] Furthermore, after the coil selection circuit connects the NFC coil to the wireless charging SOC chip, the method further includes:

[0037] The wireless charging SOC chip receives the signal output by the NFC coil and decodes the signal; specifically, it includes:

[0038] Obtaining the signal width of the signal and storing it in a buffer;

[0039] Splitting the buffer according to a preset time length, accumulating and calculating the signal width in each split buffer, and determining that the signal is at a low level if the accumulated signal width in the buffer is less than a first preset threshold;

[0040] If the accumulated signal width is greater than a second preset threshold, splitting the accumulated signal width in the buffer according to the second preset threshold to obtain multiple data buffers;

[0041] Decoding the plurality of data buffers to obtain data bits;

[0042] Whether to perform NFC signal transmission is determined according to the data bit.

[0043] Furthermore, when the coil selection circuit connects the NFC coil to the wireless charging SOC chip, it also includes:

[0044] The AP main control chip sends a control signal to the voltage converter, and the voltage converter supplies the voltage output by the battery to the wireless charging SOC chip according to the control signal.

[0045] Furthermore, it also includes:

[0046] When the NFC data interaction is completed or the NFC data interaction time exceeds the preset time, the AP main control chip sends a wireless charging coil access signal to the coil selection circuit to connect the wireless charging coil to the wireless charging SOC chip.

[0047] An embodiment of the present application provides an electronic device, which applies the control method of multiplexing a wireless charging SOC chip as an NFC chip provided in any of the above embodiments.

[0048] The present invention adopts the above technical solution, and the beneficial effects that can be achieved include:

[0049] The present invention provides a circuit, control method, and electronic device for multiplexing a wireless charging SOC chip as an NFC chip. By configuring an NFC demodulation circuit, an NFC signal detection circuit, a wireless charging SOC chip, and an AP main control chip, the present invention enables the wireless charging SOC chip to operate in both wireless charging and NFC modes, eliminating the need for multiple chips. This not only saves resources but also reduces costs. Furthermore, the technical solution provided by this application enables the NFC coil to be made smaller by externally supplying an operating voltage to the wireless charging SOC chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 This is a schematic diagram of the structure of the circuit of the wireless charging SOC chip of the present invention being reused as an NFC chip;

[0052] Figure 2 This is a schematic diagram of the internal structure of the wireless charging SOC chip of the present invention;

[0053] Figure 3 A schematic diagram of the structure of the rectifier bridge provided by the present invention;

[0054] Figure 4 This is a schematic structural diagram of the coil selection circuit of the present invention.

[0055] Figure 5 This is a schematic diagram of the steps of the control method of the present invention for multiplexing a wireless charging SOC chip into an NFC chip;

[0056] Figure 6 Schematic diagram of the QiASK baseband and NFC ASK baseband provided by the present invention;

[0057] Figure 7 A decoding schematic diagram is provided for the circuit of the wireless charging SOC chip multiplexed as an NFC chip in the present invention. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0059] The following describes, with reference to the accompanying drawings, a circuit, control method, and electronic device for reusing a wireless charging SOC chip as an NFC chip, provided in an embodiment of the present application.

[0060] like Figure 1 As shown, the wireless charging SOC chip provided in the embodiment of the present application is multiplexed as an NFC chip circuit, including: a wireless charging coil 1, an NFC coil 2, a coil selection circuit 3, an NFC demodulation circuit 4, an NFC signal detection circuit 5, a wireless charging SOC chip 6 and an AP main control chip 7;

[0061] The wireless charging coil 1 and the NFC coil 2 are respectively connected to the coil selection circuit 3, and the coil selection circuit 3 is respectively connected to the wireless charging SOC chip 6 and the AP main control chip 7, and the wireless charging SOC chip 6 is connected to the AP main control chip 7;

[0062] The NFC coil 2, the NFC demodulation circuit 4 and the NFC signal detection circuit 5 are connected in sequence;

[0063] The NFC demodulation circuit 4 is connected to the wireless charging SOC chip 6;

[0064] The NFC signal detection circuit 5 is connected to the wireless charging SOC chip 6 and the AP main control chip 7 respectively;

[0065] When the NFC demodulation circuit 4 outputs a high level, it drives the NFC signal detection circuit 5 to output a low level signal, causing the AP main control chip 7 to send a signal to select the NFC coil 2 to be connected to the coil selection circuit 3. The coil selection circuit 3 connects the NFC coil 2 to the wireless charging SOC chip 6;

[0066] When the NFC demodulation circuit 4 outputs a low level, it drives the NFC signal detection circuit 5 to output a high level signal, causing the AP main control chip 7 to send a wireless charging coil 1 access signal to the coil selection circuit 3, and the coil selection circuit 3 connects the wireless charging coil 1 to the wireless charging SOC chip 6.

[0067] The working principle of the circuit of the wireless charging SOC chip multiplexed as the NFC chip provided in the present application is as follows: two coils are set in the present application, one of which is the wireless charging coil 1 and the other is the NFC coil 2, wherein the wireless charging coil 1 is used to wirelessly charge the terminal, and the NFC coil 2 is used to realize the data interaction function with the terminal. The operating frequency of the wireless charging coil 1 is less than 200KHz, and the NFC communication operating frequency is 13.56MHz. The wireless charging coil 1 is used to output one AC signal; the NFC coil 2 is used to output another AC signal; the coil selection circuit 3 is used to select one of the two AC signals to be output to the wireless charging SOC chip 6, thereby realizing the wireless charging function or the NFC data transmission function. It should be noted that the technical solution provided by the present application is to enable the battery to be charged through the wireless charging function when the terminal product has no power at all, and the coil selection circuit 3 selects the wireless charging coil by default.

[0068] The NFC demodulation circuit 4 in this application modulates and demodulates the baseband signal output by the NFC coil 2 and outputs an NFC_dmod signal. The NFC_dmod signal is transmitted to the wireless charging SOC chip 6 and the NFC signal detection circuit 5 respectively. The NFC signal detection circuit 5 outputs an NFC_DET signal based on the NFC_dmod signal. Specifically, when the NFC_dmod signal is high, the NFC_DET signal is output as a low level. When the NFC_dmod signal is output as a low level, the NFC_DET signal is output as a high level by default. When the AP main control chip 7 detects that the NFC_DET signal is converted from a high level to a low level, it pulls up the Coil_Select signal so that the coil selection circuit 3 selects the NFC coil 2 access signal and connects the NFC coil 2 to the wireless charging SOC chip 6. When the NFC_dmod signal is output as a low level, the wireless charging SOC chip 6 enters the wireless charging mode and drives the NFC signal detection circuit 5 to output a high level signal, so that the AP main control chip 7 sends a wireless charging coil 1 access signal to the coil selection circuit 3, connecting the wireless charging coil 1 to the wireless charging SOC chip 6. For example, when NFC data transmission is completed, it switches to the default wireless charging function.

[0069] Specifically, the NFC_DET signal is connected to the GPIO port of the AP main control chip 7. When the NFC_dmod signal output is low, when the user places it on the wireless charging transmitter, the difference from the 13.56MHz resonance point of NFC is relatively large. At this time, the NFC_dmod signal is low, and the coil selection circuit 3 selects the wireless charging coil 1 for connection. The wireless charging SOC chip 6 detects the wireless charging AC signal and notifies the terminal AP main control chip 7 through the wireless charging conduction signal to realize the wireless charging function. When the user places it on the NFC transmitter, the NFC coil 2 is under the action of the 13.56MHz energy field, the NFC_dmod signal is high, and the output NFC_DET signal changes from high to low. The AP main control chip 7 detects the level change and considers that the user is placed on the NFC transmitter. By pulling the Coil_Select signal high, the NFC coil 2 is selected to be connected to the wireless charging SOC chip 6.

[0070] In some embodiments, such as Figure 1 As shown, the circuit provided by this application also includes:

[0071] The voltage converter 8 is connected to the AP main control chip 7, the wireless charging SOC chip 6 and the battery 9 respectively, and is used to receive the control signal of the AP main control chip 7 and supply the voltage output by the battery 9 to the wireless charging SOC chip 6.

[0072] In some embodiments, the NFC coil 2 of some electronic devices, such as smart glasses, is relatively small. When the NFC coil 2 is relatively small, it may not be able to obtain sufficient energy from the coil to power the wireless charging SoC chip 6. In this case, the voltage converter 8 activates the Boost circuit to output 5V from the terminal's battery to the Vout pin of the wireless charging SoC chip 6 to power the wireless charging SoC chip 6. This allows the wireless charging SoC chip 6 to operate even in the absence of an energy field during ASK modulation and easily sample the low-level width of the Miller code.

[0073] In some embodiments, the NFC demodulation circuit 4 includes: an envelope detection circuit 41 and a low-pass filter circuit 42 connected to the envelope detection circuit 41;

[0074] The envelope detection circuit 41 is used to obtain the baseband signal output by the NFC coil 2;

[0075] The low-pass filter circuit 42 is used to filter the baseband signal.

[0076] Among them, such as Figure 1 As shown, the envelope detection circuit 41 includes: a first resistor R1, a first diode D1, a second resistor R2 and a first capacitor C1;

[0077] The anode of the first diode D1 is connected to the output end of the NFC coil 2, the cathode of the first diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is respectively connected to one end of the second resistor R2 and one end of the first capacitor C1, and the other end of the second resistor R2 and the other end of the first capacitor C1 are both grounded.

[0078] The low-pass filter circuit 42 includes: a third resistor R3 and a second capacitor C2;

[0079] One end of the third resistor R3 is connected to the other end of the first resistor R1 , the other end of the third resistor R3 is connected to one end of the second capacitor C2 , and the other end of the second capacitor C2 is grounded.

[0080] In some embodiments, the NFC signal detection circuit 5 includes: a voltage stabilizing diode D2, a controllable switch Q1 and a fourth resistor R4;

[0081] The cathode of the voltage stabilizing diode D2 is connected to the output end of the NFC demodulation circuit 4, and the anode of the voltage stabilizing diode D2 is grounded;

[0082] The control end of the controllable switch tube Q1 is connected to the output end of the NFC demodulation circuit 4 , the first end of the controllable switch tube Q1 is connected to the fourth resistor R1 , and the second end of the controllable switch tube Q1 is grounded.

[0083] It can be understood that the first resistor R1 is used for voltage division, and the function of the voltage regulator diode D2 is to protect the input of the controllable switch tube Q1. Among them, the first resistor R1, the first diode D1, the second resistor R2 and the first capacitor C1 form an envelope detection circuit to obtain the baseband signal emitted by the NFC coil. The third resistor R3 and the second capacitor C2 form a low-pass filter circuit. Among them, when the controllable switch tube Q1 adopts a MOS tube, the gate of the MOS tube is connected to the other end of the third resistor R3, the drain of the MOS tube is connected to the fourth resistor R4, and the source of the MOS tube is grounded.

[0084] In some embodiments, such as Figure 2 As shown, the wireless charging SOC chip 6 includes: a rectifier bridge 61, a decoding circuit 62, a timer 63 and a microprocessor 64;

[0085] The rectifier bridge 61 is used to provide operating voltage to the decoding circuit 62, the timer 63 and the microprocessor 64;

[0086] The microprocessor 64 is used to control the decoding circuit 62 to adjust the decoding parameters to decode the signal output by the wireless charging coil 1 or the NFC coil 2 accordingly;

[0087] The microprocessor 64 is further configured to control the timer 63 to enter a PWM mode, so as to process the decoded signal and output a modulated baseband signal of NFC.

[0088] Specifically, the rectifier bridge 61 in this application is a full-bridge rectifier, such as Figure 3 As shown, the rectifier bridge 61 includes multiple MOS transistors and corresponding diodes. When the coil area is small and insufficient energy is obtained from the NFC coil, the rectifier bridge 61 turns on the boost current and enables the MOS transistors in the rectifier bridge 61 to perform full-bridge rectification, providing operating voltage to the decoding circuit 62, timer 63, and microprocessor 64. At this time, the wireless charging SOC chip 6 is powered on and reset, and the internal Cortex M0 microprocessor is started. When the wireless charging SOC chip 6 detects that the NFC_DET signal is low, the wireless charging SOC chip 6 switches to NFC operating mode and performs NFC card emulation in NFC operating mode. The wireless charging SOC chip 6 initializes decoding parameters, and the decoding circuit 62 increases the decoding rate from 2Kbps in the Qi protocol to 106Kbps. In NFC operating mode, the timer 63 is initialized to PWM mode to output the NFC modulated baseband signal, thereby enabling NFC communication between the wireless charging SOC chip 6 and the AP main control chip 7. Specifically, it receives the REQA command in the NFC protocol and responds with the ATQA command. After entering the APDU communication stage, the wireless charging SOC chip 6 sends a wireless charging conduction signal to the AP main control chip 7 and enters the NFC data transparent transmission mode.

[0089] In some embodiments, the wireless charging SOC chip 6 and the AP main control chip 7 are connected via an IIC bus.

[0090] Specifically, in this application, the AP main control chip 7 transmits and receives data with the wireless charging SOC chip 6 through the IIC bus to realize the application of NFC.

[0091] like Figure 4 As shown, the coil selection circuit 3 provided by the present application includes:

[0092] A first sub-selection circuit 31 and a second sub-selection circuit 32, wherein the first sub-selection circuit 31 and the second sub-selection circuit 32 are connected in parallel, wherein the first sub-selection circuit 31 includes: a first field effect transistor P1A, a third capacitor C3, a fifth resistor R5, a second field effect transistor P1B, a sixth resistor R6, a fourth capacitor C4, and a fifth capacitor C5;

[0093] Among them, the source of the first field effect transistor P1A is connected to one end of the third capacitor C3, one end of the fifth resistor R5, and then to the source of the second field effect transistor P1B; the gate of the first field effect transistor P1A is connected to the other end of the third capacitor C3, the other end of the fifth resistor R5, and then to the gate of the second field effect transistor P1B; the drain of the second field effect transistor P1B is connected to one end of the sixth resistor R6 and one end of the fourth capacitor C4; the other end of the sixth resistor R6 is connected to one end of the fifth capacitor C5, and the other end of the fourth capacitor C4 is connected to the other end of the fifth capacitor C5.

[0094] The second sub-selection circuit 32 includes: a third field effect transistor P2A, a sixth capacitor C6, a seventh resistor R7, a fourth field effect transistor P2B, an eighth resistor R8, a seventh capacitor C7 and an eighth capacitor C8;

[0095] The source of the third field-effect transistor P2A is connected to one end of the sixth capacitor C6, one end of the seventh resistor R7, and then to the source of the fourth field-effect transistor P2B. The gate of the third field-effect transistor P2A is connected to the other end of the sixth capacitor C6, the other end of the seventh resistor R7, and then to the gate of the fourth field-effect transistor P2B. The drain of the fourth field-effect transistor P2B is connected to one end of the eighth resistor R8 and one end of the seventh capacitor C7. The other end of the eighth resistor R8 is connected to one end of the eighth capacitor C8, and the other end of the seventh capacitor C7 is connected to the other end of the eighth capacitor C8.

[0096] The drain of the first field effect transistor P1A is connected to the drain of the third field effect transistor P2A.

[0097] An embodiment of the present application provides an electronic device, which uses a circuit in which the wireless charging SOC chip provided in any of the above embodiments is reused as an NFC chip.

[0098] like Figure 5 As shown, an embodiment of the present application provides a control method for multiplexing a wireless charging SOC chip as an NFC chip. The control method adopts the circuit of multiplexing a wireless charging SOC chip as an NFC chip provided in any of the above embodiments. The control method includes:

[0099] S101, receiving signals output by the NFC demodulation circuit 4 and the NFC signal detection circuit 5;

[0100] S102, when the AP main control chip 7 detects that the signal output by the NFC signal detection circuit 5 is converted from a high level to a low level, it drives the coil selection circuit 3 to connect the NFC coil 2 to the wireless charging SOC chip 6;

[0101] S103, when the wireless charging SOC chip 6 detects that the signal output by the NFC demodulation circuit 4 is at a low level, it drives the NFC signal detection circuit 5 to output a high level signal, and the AP main control chip 7 drives the coil selection circuit 3 according to the high level signal to connect the wireless charging coil (1) to the wireless charging SOC chip 6, so that the wireless charging SOC chip 6 performs wireless charging on the terminal to which the AP main control chip 7 belongs.

[0102] In some embodiments, the present invention further comprises:

[0103] When the wireless charging SOC chip 6 detects that the signal output by the NFC demodulation circuit 4 is at a low level, it generates a wireless charging connection signal to the AP main control chip 7 .

[0104] Among them, the NFC demodulation circuit 4 outputs the NFC_dmod signal, and the NFC signal detection circuit 5 outputs the NFC_DET signal according to the NFC_dmod signal; when the user places it on the wireless charging transmitter, the NFC_dmod signal is low, the wireless charging SOC chip 6 detects that the NFC_dmod signal is low, the coil selection circuit 3 selects the wireless charging coil 1 to connect, the wireless charging SOC chip 6 detects the wireless charging AC signal, generates a wireless charging conduction signal and sends it to the AP main control chip 7. At this time, the wireless charging SOC chip 6 works in wireless charging mode. When the user places the device on the NFC transmitter, the NFC demodulation circuit 4 outputs the NFC_dmod signal as a high level. After the controllable switch tube Q1 is turned on, the NFC_DET signal changes from a high level to a low level. The terminal AP main control chip 7 detects the level change from high level to low level and does not receive the wireless charging conduction signal. It is considered that the user places the device on the NFC transmitter. By pulling the Coil_Select signal high, the NFC coil 2 is selected to be connected to the wireless charging SOC chip 6. When the wireless charging SOC chip 6 detects that the NFC signal detection circuit 5 outputs a low level signal, the NFC data transmission between the transmitting end to which the wireless charging SOC chip 6 belongs and the terminal to which the AP main control chip 7 belongs is realized.

[0105] It should be noted that if Figure 6As shown, the communication baseband signals of Qi wireless chargers differ slightly from those of NFC, but both utilize ASK modulation. In Type A mode, the ASK modulation depth emitted by the NFC transmitter is 100%, the baseband is Modified Miller, and the rate is 106 kbit / s. The demodulation circuit parameters of the two Qi wireless chargers differ from those of NFC. The internal firmware of the wireless charger SoC chip 6 defaults to the Qi wireless charger decoding program. When the AP main control chip 7 recognizes NFC mode, it notifies the wireless charger SoC chip 6 via the IIC bus to enter NFC communication mode. At this point, the wireless charger SoC chip 6 uses the Miller decoding circuit and simultaneously communicates NFC protocol commands. After completing the NFC REQA (Request Command, Type A) and Anticipation Loop, and entering application data transmission, the wireless charger SoC chip 6 sends the received data to the AP main control chip 7 via the IIC bus, exchanging the card emulation APDU (Application Protocol Data Unit) application data, thus implementing NFC card emulation functionality. This application connects the demodulated baseband signal to the DMOD pin of the wireless charging Qi protocol, and uses the Qi protocol decoding circuit inside the chip to obtain the length of bit0 and bit1.

[0106] In some embodiments, after the coil selection circuit 3 connects the NFC coil 2 to the wireless charging SOC chip 6, the method further includes:

[0107] The wireless charging SOC chip 6 receives the signal output by the NFC coil 2 and decodes the signal; specifically, it includes:

[0108] Obtaining the signal width of the signal and storing it in a buffer;

[0109] Splitting the buffer according to a preset time length, accumulating and calculating the signal width in each split buffer, and determining that the signal is at a low level if the accumulated signal width in the buffer is less than a first preset threshold;

[0110] If the accumulated signal width is greater than a second preset threshold, splitting the accumulated signal width in the buffer according to the second preset threshold to obtain multiple data buffers;

[0111] Decoding the plurality of data buffers to obtain data bits;

[0112] Whether to perform NFC signal transmission is determined according to the data bit.

[0113] In some embodiments, before storing the signal width of the signal in the buffer, the method further includes:

[0114] Perform filtering processing on the signal.

[0115] Specifically, such as Figure 7 As shown, the rectifier bridge 61 includes a pair of MOS transistors and diodes. The wireless charging SOC chip 6 detects the signal output by the NFC demodulation circuit 4, obtains the signal width of the NFC_dmod signal through the internal comparator C, and generates a wireless charging conduction signal. After receiving the wireless charging conduction signal, the signal Pause width is stored in the buffer Buffer. The internal comparator C of the wireless charging SOC chip 6 determines the voltage drop of the body diode inside the full-bridge MOS transistor to restore the operating frequency fc of the NFC coil 2. Figure 6 As shown, because there's no notch in Pause Y, two Pause storage units can't be parsed into a single bit. Considering the potential for glitches or jitter in the Pause width, the Pause width buffer needs to be filtered. The buffer is broken down into a preset duration of 64 / fc. The Pause widths of the 64 / fc period buffer are then accumulated. If the value is less than the first preset threshold of 32 / fc, a low-level Pause is considered.

[0116] This method polls and compares the Pause width in the filtered buffer. If the buffer width is greater than 128 / fc us, 128 / fc us is subtracted from the buffer, splitting it into two buffers to form a bit-width buffer. The bits are then decoded from the bit-width buffer. The method first finds the start sequence "sequence Z." Starting at address 0, the Pause width buffer is polled. If the first buffer shows a low-level Pause for a duration less than 64 / fc and greater than 10 / fc, it is considered the start sequence. If the value in the first storage cell in the bit-width buffer is greater than the value in the second cell, and both are less than 8, sequence X is decoded as 1b. If the value in the bit-width buffer is greater than or equal to 9, it is decoded as sequence Y, which is decoded as 0b. If the value in the second storage cell in the bit-width buffer is greater than the value in the first cell, sequence Z is interpreted as a start signal. NFC data transmission is initiated when the signal is interpreted as a start signal.

[0117] In some embodiments, when the coil selection circuit 3 connects the NFC coil 2 to the wireless charging SOC chip 6, the method further includes:

[0118] The AP main control chip 7 sends a control signal to the voltage converter 8 , and the voltage converter 8 supplies the voltage output by the battery 9 to the wireless charging SOC chip 6 according to the control signal.

[0119] When the NFC coil 2 is too small to allow the wireless charging SOC chip 6 to receive sufficient energy from the coil, the boost current is turned on, and the MOS transistors in the rectifier bridge are enabled for full-bridge rectification. This application uses an external power supply to power the wireless charging SOC chip 6 when decoding and correcting the Miller code. This allows the wireless charging SOC chip 6 to operate even in the absence of an energy field during 100% ASK modulation and easily sample the low-level width of the Miller code.

[0120] In some embodiments, the present invention further comprises:

[0121] When the NFC data interaction is completed or the NFC data interaction time exceeds the preset time, the AP main control chip 7 sends a wireless charging coil 1 access signal to the coil selection circuit 3 to connect the wireless charging coil 1 to the wireless charging SOC chip 6.

[0122] Specifically, when the NFC communication ends or times out, the AP main control chip 7 pulls Coil_Select low so that the coil selection circuit 3 connects the wireless charging coil 1 to the wireless charging SOC chip 6, and the wireless charging mode is restored.

[0123] An embodiment of the present application provides an electronic device, which applies the control method of multiplexing a wireless charging SOC chip as an NFC chip provided in any of the above embodiments.

[0124] In summary, the present invention provides a circuit, control method, and electronic device for multiplexing a wireless charging SOC chip as an NFC chip, including a wireless charging coil, an NFC coil, a coil selection circuit, an NFC demodulation circuit, an NFC signal detection circuit, a wireless charging SOC chip, and an AP main control chip; the wireless charging coil and the NFC coil are respectively connected to the coil selection circuit, the coil selection circuit is respectively connected to the wireless charging SOC chip and the AP main control chip, and the wireless charging SOC chip is connected to the AP main control chip; the wireless charging coil, the NFC demodulation circuit, and the NFC signal detection circuit are connected in sequence; the NFC demodulation circuit is connected to the wireless charging SOC chip; and the NFC signal detection circuit is respectively connected to the wireless charging SOC chip and the AP main control chip. By providing the NFC demodulation circuit, the NFC signal detection circuit, the wireless charging SOC chip, and the AP main control chip, the present invention enables the wireless charging SOC chip to implement both wireless charging mode and NFC mode, eliminating the need for multiple chips, thereby saving resources and reducing costs.

[0125] It can be understood that the control method embodiment provided above corresponds to the circuit embodiment above, and the corresponding specific contents can be referenced to each other and will not be repeated here.

[0126] Those skilled in the art will appreciate that the embodiments of the present application can be provided as control methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) that contain computer-usable program code.

[0127] The present application is described with reference to the flowcharts and / or block diagrams of the control methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0128] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction control method, which is implemented in the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0129] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0130] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A circuit for multiplexing a wireless charging SOC chip as an NFC chip, characterized in that: include: Wireless charging coil (1), NFC coil (2), coil selection circuit (3), NFC demodulation circuit (4), NFC signal detection circuit (5), wireless charging SOC chip (6) and AP main control chip (7); The wireless charging coil (1) and the NFC coil (2) are respectively connected to the coil selection circuit (3), the coil selection circuit (3) is respectively connected to the wireless charging SOC chip (6) and the AP main control chip (7), and the wireless charging SOC chip (6) is connected to the AP main control chip (7); The NFC coil (2), the NFC demodulation circuit (4) and the NFC signal detection circuit (5) are connected in sequence; The NFC demodulation circuit (4) is connected to the wireless charging SOC chip (6); The NFC signal detection circuit (5) is connected to the wireless charging SOC chip (6) and the AP main control chip (7) respectively; When the NFC demodulation circuit (4) outputs a high level, it drives the NFC signal detection circuit (5) to output a low level signal, causing the AP main control chip (7) to send a signal to the coil selection circuit (3) to select the NFC coil (2) to be connected, and the coil selection circuit (3) connects the NFC coil (2) to the wireless charging SOC chip (6); When the NFC demodulation circuit (4) outputs a low level, it drives the NFC signal detection circuit (5) to output a high level signal, causing the AP main control chip (7) to send a wireless charging coil (1) access signal to the coil selection circuit (3), and the coil selection circuit (3) connects the wireless charging coil (1) to the wireless charging SOC chip (6).

2. The circuit according to claim 1, wherein: Also includes: A voltage converter (8) is connected to the AP main control chip (7), the wireless charging SOC chip (6) and the battery (9) respectively, and is used to receive a control signal from the AP main control chip (7) and supply the voltage output by the battery (9) to the wireless charging SOC chip (6).

3. The circuit according to claim 1 or 2, characterized in that The NFC demodulation circuit (4) comprises: an envelope detection circuit (41) and a low-pass filter circuit (42) connected to the envelope detection circuit (41); The envelope detection circuit (41) is used to obtain the baseband signal output by the NFC coil; The low-pass filter circuit (42) is used to perform filtering processing on the baseband signal.

4. The circuit according to claim 3, characterized in that The envelope detection circuit (41) comprises: a first resistor (R1), a first diode (D1), a second resistor (R2) and a first capacitor (C1); The anode of the first diode (D1) is connected to the output end of the NFC coil (2), the cathode of the first diode (D1) is connected to one end of a first resistor (R1), the other end of the first resistor (R1) is respectively connected to one end of a second resistor (R2) and one end of a first capacitor (C1), and the other end of the second resistor (R2) and the other end of the first capacitor (C1) are both grounded.

5. The circuit according to claim 4, characterized in that The low-pass filter circuit (42) comprises: a third resistor (R3) and a second capacitor (C2); One end of the third resistor (R3) is connected to the other end of the first resistor (R1), the other end of the third resistor (R3) is connected to one end of the second capacitor (C2), and the other end of the second capacitor (C2) is grounded.

6. The circuit according to claim 1, wherein: The NFC signal detection circuit (5) comprises: a voltage stabilizing diode (D2), a controllable switch tube (Q1) and a fourth resistor (R4); The cathode of the voltage stabilizing diode (D2) is connected to the output end of the NFC demodulation circuit (4), and the anode of the voltage stabilizing diode (D2) is grounded; The control end of the controllable switch tube (Q1) is connected to the output end of the NFC demodulation circuit (4), the first end of the controllable switch tube (Q1) is connected to the fourth resistor (R4), and the second end of the controllable switch tube (Q1) is grounded.

7. The circuit according to claim 2, characterized in that The wireless charging SOC chip (6) comprises: a rectifier bridge (61), a decoding circuit (62), a timer (63) and a microprocessor (64); The rectifier bridge (61) is used to provide an operating voltage to the decoding circuit, the timer, and the microprocessor; The microprocessor (64) is used to control the decoding circuit (62) to adjust decoding parameters so as to decode the signal output by the wireless charging coil (1) or the NFC coil (2) accordingly; The microprocessor (64) is further used to control the timer (63) to enter the PWM mode, so as to process the decoded signal and output a modulated baseband signal of NFC.

8. A control method for reusing a wireless charging SOC chip as an NFC chip, characterized in that: The control method adopts the circuit according to any one of claims 1 to 7, and the control method includes: receiving signals output by the NFC demodulation circuit (4) and the NFC signal detection circuit (5); When the AP main control chip (7) detects that the signal output by the NFC signal detection circuit (5) is converted from a high level to a low level, it drives the coil selection circuit (3) to connect the NFC coil (2) to the wireless charging SOC chip (6); When the wireless charging SOC chip (6) detects that the signal output by the NFC demodulation circuit (4) is at a low level, the NFC signal detection circuit (5) outputs a high level signal, and the AP main control chip (7) drives the coil selection circuit (3) according to the high level signal to connect the wireless charging coil (1) to the wireless charging SOC chip (6), so that the wireless charging SOC chip (6) performs wireless charging on the terminal to which the AP main control chip (7) belongs.

9. The control method according to claim 8, characterized in that: Also includes: When the wireless charging SOC chip (6) detects that the signal output by the NFC demodulation circuit (4) is at a low level, it generates a wireless charging connection signal to the AP main control chip (7).

10. The control method according to claim 8, characterized in that: After the coil selection circuit (3) connects the NFC coil (2) to the wireless charging SOC chip (6), the method further includes: The wireless charging SOC chip (6) receives the signal output by the NFC coil (2) and decodes the signal; specifically, it includes: Obtaining the signal width of the signal and storing it in a buffer; Splitting the buffer according to a preset time length, accumulating and calculating the signal width in each split buffer, and determining that the signal is at a low level if the accumulated signal width in the buffer is less than a first preset threshold; If the accumulated signal width is greater than a second preset threshold, splitting the accumulated signal width in the buffer according to the second preset threshold to obtain multiple data buffers; Decoding the plurality of data buffers to obtain data bits; Whether to perform NFC signal transmission is determined according to the data bit.

11. The control method according to claim 8, characterized in that: When the coil selection circuit (3) connects the NFC coil (2) to the wireless charging SOC chip (6), it also includes: The AP main control chip (7) sends a control signal to the voltage converter (8), and the voltage converter (8) supplies the voltage output by the battery (9) to the wireless charging SOC chip (6) according to the control signal.

12. The control method according to claim 8, characterized in that: Also includes: When the NFC data interaction is completed or the NFC data interaction time exceeds a preset time, the AP main control chip (7) sends a wireless charging coil (1) access signal to the coil selection circuit (3), connecting the wireless charging coil (1) to the wireless charging SOC chip (6).

13. An electronic device, characterized in that: A circuit in which the wireless charging SOC chip as described in any one of claims 1 to 7 is reused as an NFC chip.

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