CN216979769U - Circuit and electronic equipment for multiplexing wireless SOC (System on chip) charging chip into NFC (near field communication) chip - Google Patents

Abstract

The utility model relates to a circuit and electronic equipment for reusing a wireless charging SOC chip as an NFC chip, wherein the circuit comprises a wireless charging coil, an NFC coil, a coil selection circuit, an NFC demodulation circuit, an NFC signal detection circuit, the wireless charging SOC chip and an AP main control chip; the wireless charging coil and the NFC coil are respectively connected with a coil selection circuit, the coil selection circuit is respectively connected with a wireless charging SOC chip and an AP main control chip, and the wireless charging SOC chip is connected with 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 with the wireless charging SOC chip; and the NFC signal detection circuit is respectively connected with the wireless charging SOC chip and the AP main control chip. According to the utility model, the wireless charging SOC chip can realize the wireless charging mode and the NFC mode by arranging the NFC demodulation circuit, the NFC signal detection circuit, the wireless charging SOC chip and the AP main control chip, and a plurality of chips are not required to be arranged, so that not only can resources be saved, but also the cost can be reduced.

Description

Circuit and electronic equipment for multiplexing wireless SOC (System on chip) charging chip into NFC (near field communication) chip

Technical Field

The utility model belongs to the technical field of electronic equipment, and particularly relates to a circuit for multiplexing a wireless charging SOC chip into an NFC chip and electronic equipment.

Background

With the popularization of electronic devices, wireless charging technology is widely used, electromagnetic induction type is often adopted for low-power wireless charging, and wireless charging of Qi protocol is widely used in smart devices such as mobile phones and the like at present. Qi is a Wireless charging standard which is provided by the Wireless charging alliance (WPC for short), which is the first global organization for promoting Wireless charging technology, and has two characteristics of convenience and universality. The wireless charging device is a transmitting end and a receiving end, and generally has the function of the receiving end in low-power charging equipment such as a smart watch. The wireless charging SOC chip at the receiving end supports a Qi wireless charging protocol and is applied to products such as a smart watch, a smart phone and a tablet personal computer.

Near Field Communication (NFC for short) is an emerging technology, devices (such as mobile phones) using the NFC technology can exchange data when they are close to each other, and is integrated and evolved from non-contact Radio Frequency Identification (RFID) and interconnection technology, and by integrating functions of an induction card reader, an induction card and point-to-point Communication on a single chip, applications such as mobile payment, electronic ticketing, door access, and the like are realized by using a mobile terminal. NFC controller chips PN80T, PN80T, such as NXP, also contain embedded Secure Elements (SE).

In the related art, the NFC controller chip and the wireless charging and receiving chip in the current smart watch generally implement these two functions for two chips, which is relatively wasteful in terms of resources and also increases the cost of the final product. The NFC functionality is most used daily for small devices such as smartwatches in the card emulation mode. And many modules with similar functions are arranged in the NFC controller chip and the wireless charging and receiving chip, for example, the two chips both include an ARM Cortex M0 microprocessor core, both use the IIC interface to communicate with the processor of the AP, both include a rectifier circuit module, and both use ASK modulation from the transmitting end to the receiving end, which causes resource waste.

SUMMERY OF THE UTILITY MODEL

In view of this, an object of the present invention is to overcome the defects in the prior art, and provide a circuit and an electronic device for multiplexing a wireless charging SOC chip into an NFC chip, so as to solve the problem in the prior art that a plurality of modules with similar functions exist in an NFC controller chip and a wireless charging receiving chip in the same electronic device, which causes resource waste.

In order to realize the above purpose, the utility model adopts the following technical scheme: a circuit that wireless SOC chip of charging multiplexing is the NFC chip, a circuit that wireless SOC chip of charging multiplexing is the NFC chip includes: the wireless charging system 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 with a coil selection circuit, the coil selection circuit is respectively connected with the wireless charging SOC chip and the AP main control chip, and the wireless charging SOC chip is connected with the AP main control chip;

the NFC coil, the NFC demodulation circuit and the NFC signal detection circuit are sequentially connected;

the NFC demodulation circuit is connected with the wireless charging SOC chip;

the NFC signal detection circuit is respectively connected with the wireless charging SOC chip and the AP main control chip;

when the NFC demodulation circuit outputs a high level, the NFC signal detection circuit is driven to output a low level signal, so that the AP main control chip sends an NFC coil access selection signal to the coil selection circuit, and the coil selection circuit accesses the NFC coil to the wireless charging SOC chip;

when the NFC demodulation circuit outputs a low level, the NFC signal detection circuit is driven to output a high level signal, so that the AP main control chip sends a wireless charging coil access signal to the coil selection circuit, and the coil selection circuit accesses the wireless charging coil to the wireless charging SOC chip.

Further, the method also comprises the following steps:

and the voltage converter is respectively connected with the AP main control chip, the wireless charging SOC chip and the battery, and is used for receiving a control signal of the AP main control chip and supplying the voltage output by the battery to the wireless charging SOC chip.

Further, the NFC demodulation circuit includes: the low-pass filter circuit is connected with the envelope detection circuit;

the envelope detection circuit is used for acquiring a baseband signal output by the NFC coil;

the low-pass filter circuit is used for filtering the baseband signal.

Further, the envelope detection circuit includes: the circuit comprises a first resistor, a first diode, a second resistor and a first capacitor;

the anode of the first diode is connected with the output end of the NFC coil, the cathode of the first diode is connected with one end of a first resistor, the other end of the first resistor is connected with one end of a second resistor and one end of a first capacitor respectively, and the other end of the second resistor and the other end of the first capacitor are grounded.

Further, the low-pass filter circuit includes: a third resistor and a second capacitor;

one end of the third resistor is connected with the other end of the first resistor, the other end of the third resistor is connected with one end of the second capacitor, and the other end of the second capacitor is grounded.

Further, the NFC signal detection circuit includes: the voltage stabilizing diode, the controllable switching tube and the fourth resistor;

the cathode of the voltage stabilizing diode is connected with the output end of the NFC demodulation circuit, and the anode of the voltage stabilizing diode is grounded;

the control end of the controllable switch tube is connected with the output end of the NFC demodulation circuit, the first end of the controllable switch tube is connected with the fourth resistor, and the second end of the controllable switch tube is grounded.

Further, the wireless charging SOC chip includes: the device comprises a rectifier bridge, a decoding circuit, a timer and a microprocessor;

the rectifier bridge is used for providing working voltage for the decoding circuit, the timer and the microprocessor;

the microprocessor is used for controlling the decoding circuit to adjust decoding parameters so as to correspondingly decode signals output by the wireless charging coil or the NFC coil;

the microprocessor is further used for controlling the timer to enter a PWM mode so as to process the decoded signal and output a modulation baseband signal of NFC.

Further, the wireless charging SOC chip (6) is connected with the AP main control chip (7) through an IIC bus.

The embodiment of the application provides an electronic device, and the wireless charging SOC chip provided by any one of the above embodiments is applied to a circuit which is reused as an NFC chip.

By adopting the technical scheme, the utility model can achieve the following beneficial effects:

the utility model provides a circuit and an electronic device for reusing a wireless charging SOC chip as an NFC chip. In addition, the technical scheme that this application provided can make the NFC coil can be done littleer through the outside to wireless SOC chip that charges provides operating voltage.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a circuit in which a wireless charging SOC chip is reused as an NFC chip according to the present invention;

FIG. 2 is a schematic diagram of an internal structure of a wireless charging SOC chip according to the present invention;

FIG. 3 is a schematic structural diagram of a rectifier bridge according to the present invention;

fig. 4 is a schematic diagram of a coil selection circuit according to the present invention.

FIG. 5 is a schematic diagram illustrating steps of a control method for reusing a wireless charging SOC chip as an NFC chip according to the present invention;

fig. 6 is a schematic diagram of a Qi ASK baseband and an NFC ASK baseband provided by the present invention;

fig. 7 is a schematic decoding diagram provided by a circuit for multiplexing the wireless charging SOC chip into the NFC chip according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

A specific circuit and an electronic device for multiplexing a wireless charging SOC chip into an NFC chip provided in the embodiments of the present application are described below with reference to the accompanying drawings.

As shown in fig. 1, the circuit for multiplexing the wireless charging SOC chip provided in the embodiment of the present application into an NFC chip includes: the wireless charging system comprises 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;

the wireless charging coil 1 and the NFC coil 2 are respectively connected with a coil selection circuit 3, the coil selection circuit 3 is respectively connected with the wireless charging SOC chip 6 and the AP main control chip 7, and the wireless charging SOC chip 6 is connected with the AP main control chip 7;

the NFC coil 2, the NFC demodulation circuit 4 and the NFC signal detection circuit 5 are sequentially connected;

the NFC demodulation circuit 4 is connected with the wireless charging SOC chip 6;

the NFC signal detection circuit 5 is respectively connected with the wireless charging SOC chip 6 and the AP main control chip 7;

when the NFC demodulation circuit 4 outputs a high level, the NFC signal detection circuit 5 is driven to output a low level signal, so that the AP main control chip 7 sends an access signal for selecting the NFC coil 2 to the coil selection circuit 3, and the coil selection circuit 3 accesses the NFC coil 2 to the wireless charging SOC chip 6;

when the NFC demodulation circuit 4 outputs a low level, the NFC signal detection circuit 5 is driven 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, and the coil selection circuit 3 accesses the wireless charging coil 1 to the wireless charging SOC chip 6.

The application provides a multiplexing theory of operation who is the circuit of NFC chip of wireless SOC chip does, sets up two coils in this application, and one of them is wireless coil 1 that fills, and another is NFC coil 2, and wherein, wireless coil 1 that fills is used for wirelessly charging the terminal, and NFC coil 2 is used for realizing the data interaction function with the terminal. The working frequency of the wireless charging coil 1 is less than 200KHz, and the working frequency of NFC communication is 13.56 MHz. The wireless charging coil 1 is used for outputting an AC signal; the NFC coil 2 is used for outputting another path of AC signal; coil selection circuit 3 is arranged in selecting one of two ways of AC signals to export to wireless SOC chip 6 that charges to realize wireless charging function or NFC data transmission function, it should be said that, the technical scheme that this application provided can charge for the battery through wireless charging function in order to under the terminal product does not have the electric condition at all, and coil selection circuit 3 defaults to select to insert wireless coil that charges.

The NFC demodulation circuit 4 in this application carries out modem to the baseband signal of NFC coil 2 output, outputs NFC _ dmod signal, and NFC _ dmod signal transmits respectively to wireless SOC chip 6 and NFC signal detection circuit 5 that fills, and NFC signal detection circuit 5 basis NFC _ dmod signal output NFC _ DET signal specifically is, and when NFC _ dmod signal is the high level, NFC _ DET signal output is the low level, and when NFC _ dmod signal output is the low level, NFC _ DET signal is acquiescent to export and is the high level. When the AP main control chip 7 detects that the NFC _ DET signal is converted from a high level to a low level, the Coil _ Select signal is pulled up, so that the Coil selection circuit 3 selects the NFC Coil 2 to access a signal, and the NFC Coil 2 is accessed to the wireless charging SOC chip 6; when the NFC _ dmod signal output is at a low level, the wireless charging SOC chip 6 is in a 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, and the wireless charging coil 1 is accessed to the wireless charging SOC chip 6. For example, when the NFC data transmission is finished, the function is switched to the default wireless charging function.

Specifically, the NFC _ DET signal is connected to a GPIO port of the AP main control chip 7. When the signal output of the NFC _ dmod is at a low level, wherein when a user puts on a wireless charging transmitter, the difference between the signal output of the NFC _ dmod and the 13.56MHz resonance point of the NFC is relatively large, at this time, the signal of the NFC _ dmod is at a low level, the coil selection circuit 3 selects the wireless charging coil 1 to access, the wireless charging SOC chip 6 detects a wireless charging AC signal, and notifies the terminal AP main control chip 7 through a wireless charging conduction signal, thereby implementing a wireless charging function. When a user is placed on the NFC transmitter, under the action of the energy field of 13.56MHz, the NFC _ dmod signal of the NFC coil 2 is at a high level, the output NFC _ DET signal changes from a high level to a low level, and the AP main control chip 7 detects the level change, and then 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.

In some embodiments, as shown in fig. 1, the circuit provided by the present application further includes:

and the voltage converter 8 is respectively connected with the AP main control chip 7, the wireless charging SOC chip 6 and the battery 9, and is used for receiving a control signal of the AP main control chip 7 and supplying the voltage output by the battery 9 to the wireless charging SOC chip 6.

In some embodiments, because the NFC coil 2 of some electronic devices is relatively small, devices such as smart glasses; when the NFC coil 2 is small, enough energy may not be obtained from the coil to the wireless charging SOC chip 6, and at this time, the voltage converter 8 opens the Boost circuit to output 5V from the battery of the terminal to the Vout pin of the wireless charging SOC chip 6, so as to supply power to the wireless charging SOC chip 6. Therefore, the wireless charging SOC chip 6 can work under the condition of no energy field during ASK modulation, and the low level width of miller code can be easily sampled.

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;

the envelope detection circuit 41 is configured to obtain a baseband signal output by the NFC coil 2;

the low-pass filter circuit 42 is configured to perform filtering processing on the baseband signal.

As shown in fig. 1, the envelope detection circuit 41 includes: 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 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.

The low-pass filter circuit 42 includes: 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.

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

the cathode of the zener diode D2 is connected to the output end of the NFC demodulation circuit 4, and the anode of the zener 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 R1, and the second end of the controllable switch tube Q1 is grounded.

It can be understood that the first resistor R1 is used for voltage division, and the zener diode D2 is used for protecting the input of the controllable switch tube Q1. The first resistor R1, the first diode D1, the second resistor R2 and the first capacitor C1 form an envelope detection circuit, and a baseband signal sent by the NFC coil is obtained. The third resistor R3 and the second capacitor C2 form a low-pass filter circuit. When the controllable switch tube Q1 adopts a MOS transistor, the gate of the MOS transistor is connected to the other end of the third resistor R3, the drain of the MOS transistor is connected to the fourth resistor R4, and the source of the MOS transistor is grounded.

In some embodiments, as shown in fig. 2, the wireless charging SOC chip 6 includes: a rectifier bridge 61, a decoding circuit 62, a timer 63, and a microprocessor 64;

the rectifier bridge 61 is used for providing an operating voltage for the decoding circuit 62, the timer 63 and the microprocessor 64;

the microprocessor 64 is used for controlling the decoding circuit 62 to adjust decoding parameters so as to correspondingly decode the signal output by the wireless charging coil 1 or the NFC coil 2;

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.

Specifically, the rectifier bridge 61 in the present application is a full-bridge rectifier, as shown in fig. 3, the rectifier bridge 61 includes a plurality of MOS transistors and corresponding diodes; when the coil area is small NFC, when the coil can not obtain enough energy from the rectifier bridge 61, the boost current is opened, meanwhile, the MOS tube in the rectifier bridge 61 is enabled to carry out full-bridge rectification, the working voltage is provided for the decoding circuit 62, the timer 63 and the microprocessor 64, the wireless charging SOC chip 6 is powered on and reset at the moment, and the internal Cortex M0 microprocessor is started. When the wireless charging SOC chip 6 detects that the NFC _ DET signal is at a low level, the wireless charging SOC chip 6 is switched to an NFC working mode, and NFC card simulation is carried out in the NFC working mode. The wireless charging SOC chip 6 initializes the decoding parameters, and the decoding circuit 62 increases the decoding rate from 2Kbps to 106Kbps in the Qi protocol. The initialization timer 63 is in a PWM mode in the NFC operating mode, and is used to output a modulation baseband signal of NFC, so as to implement NFC communication between the wireless charging SOC chip 6 and the AP main control chip 7. Specifically, the REQA command in the NFC protocol is received to reply to 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 the NFC data transparent transmission mode is entered.

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

Specifically, in the application, the AP main control chip 7 receives and transmits data with the wireless charging SOC chip 6 through the IIC bus, so as to implement NFC application.

As shown in fig. 4, the present application provides a coil selection circuit 3 including:

a first sub-selection circuit 31 and a second sub-selection circuit 32, the first sub-selection circuit 31 being connected in parallel with the second sub-selection circuit 32, wherein the first sub-selection circuit 31 comprises: the circuit comprises 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;

the source of the first fet P1A is connected to one end of the third capacitor C3, one end of the fifth resistor R5 is connected to the source of the second fet P1B, the gate of the first fet P1A is connected to the other end of the third capacitor C3, the other end of the fifth resistor R5 is connected to the gate of the second fet P1B, the drain of the second fet 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.

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

the source of the third field-effect transistor P2A is connected to one end of a sixth capacitor C6, one end of a seventh resistor R7 is connected to the source of a 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 is connected 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 an eighth resistor R8 and one end of a 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.

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

The embodiment of the application provides an electronic device, and the wireless charging SOC chip provided by any one of the above embodiments is applied to a circuit which is reused as an NFC chip.

As shown in fig. 5, an embodiment of the present application provides a control method for multiplexing a wireless charging SOC chip into an NFC chip, where the control method adopts a circuit for multiplexing the wireless charging SOC chip provided in any one of the above embodiments into the NFC chip, and the control method includes:

s101, receiving signals output by the NFC demodulation circuit 4 and the NFC signal detection circuit 5;

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, driving the coil selection circuit 3 to access the NFC coil 2 to the wireless charging SOC chip 6;

and S103, when the wireless charging SOC chip 6 detects that the signal output by the NFC demodulation circuit 4 is in a low level, the NFC signal detection circuit 5 is driven to output a high level signal, the AP main control chip 7 drives the coil selection circuit 3 to access the wireless charging coil (1) to the wireless charging SOC chip 6 according to the high level signal, and the wireless charging SOC chip 6 wirelessly charges a terminal to which the AP main control chip 7 belongs.

In some embodiments, further comprising:

and when the wireless charging SOC chip 6 detects that the signal output by the NFC demodulation circuit 4 is at a low level, generating a wireless charging conduction signal with the AP main control chip 7.

The NFC demodulation circuit 4 outputs an NFC _ dmod signal, and the NFC signal detection circuit 5 outputs an NFC _ DET signal according to the NFC _ dmod signal; when a user puts the wireless charging transmitter, the NFC _ dmod signal is at a low level, the wireless charging SOC chip 6 detects that the NFC _ dmod signal is at the low level, the coil selection circuit 3 selects the wireless charging coil 1 to access, the wireless charging SOC chip 6 detects a wireless charging AC signal, a wireless charging conduction signal is generated and sent to the AP main control chip 7, and at the moment, the wireless charging SOC chip 6 works in a mode of wireless charging. When a user is placed on the NFC transmitter, the NFC demodulation circuit 4 outputs an NFC _ dmod signal which is at a high level, the signal is conducted through the controllable switch tube Q1, the NFC _ DET signal is changed from the high level to a low level, the terminal AP main control chip 7 detects the level change from the high level to the low level, and the wireless charging conduction signal is not received, the user is considered to be placed on the NFC transmitter, the Coil _ Select signal is pulled high, the NFC Coil 2 is selected to be connected to the wireless charging SOC chip 6, and when the wireless charging SOC chip 6 detects that the NFC signal detection circuit 5 outputs the 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 achieved.

It should be noted that, as shown in fig. 6, the communication baseband signal of Qi wireless communication is different from the communication baseband signal of NFC to some extent, but the modulation modes are ASK modulation, the ASK modulation depth emitted by the transmitter of NFC in type a mode is 100%, the baseband is Modified Miller, and the rate is 106 Kbit/s. The demodulation circuit parameters of the two Qi wireless charging are different from those of NFC. The internal firmware program of the wireless charging SOC chip 6 defaults to a Qi wireless charging decoding program, and when the AP main control chip 7 identifies the NFC mode, the wireless charging SOC chip 6 is informed to enter the NFC communication mode through the IIC bus. At this time, the wireless charging SOC chip 6 uses the Miller decoding circuit and simultaneously performs NFC protocol command communication. When the Application Data transmission of the REQA (Request Command, Type a) and the anticancer LOOP of the NFC is completed, the wireless SOC chip 6 sends the received Data to the AP main control chip 7 through the IIC bus, and performs the exchange of Application Data of the card-simulated APDU (Application Protocol Data Unit — Application Protocol Data Unit), thereby implementing the NFC card simulation function. The method receives the demodulated baseband signal to the dmod pin of the wireless Qi charging protocol, and obtains the lengths of bit0 and bit1 by using a decoding circuit of the Qi protocol inside a chip.

In some embodiments, after the coil selection circuit 3 accesses 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; the method specifically comprises the following steps:

acquiring the signal width of the signal and storing the signal width to a buffer area;

splitting the buffer area according to a preset time length, performing accumulation calculation on the signal width in each split buffer area, and determining that the signal is at a low level if the accumulated signal width in the buffer area is smaller than a first preset threshold;

if the accumulated signal width is larger than a second preset threshold, splitting the accumulated signal width in the buffer area by using the second preset threshold to obtain a plurality of data buffer areas;

decoding the data buffers to obtain data bits;

and judging whether to transmit the NFC signal according to the data bit.

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

and carrying out filtering processing on the signals.

Specifically, as shown in fig. 7, the rectifier bridge 61 includes a pair of MOS transistors and a diode, the wireless charging SOC chip 6 detects a signal output by the NFC demodulation circuit 4, obtains a signal width of an NFC _ dmod signal through the internal comparator C, generates a wireless charging conduction signal, and stores the signal width Pause in the Buffer after receiving the wireless charging conduction signal. And the working frequency fc of the NFC coil 2 is recovered by judging the voltage drop of the internal body diode of the full-bridge MOS tube through the internal comparator C of the wireless charging SOC chip 6. As shown in fig. 6, since there is no groove in the middle of the Pause Y, 2 Pause storage units cannot be resolved into 1 bit. Considering that the Pause width may have glitches or jitter, the Pause width buffer needs to be filtered. And (3) disassembling the buffer area buffer into a preset time length of 64/fc, accumulating the Pause width of the buffer in a 64/fc period, and considering the buffer area buffer as low-level Pause if the buffer area buffer is smaller than a first preset threshold value of 32/fc.

The method polls and compares the Pause width in the Buffer area Buffer after filtering, if the Buffer width is larger than 128/fc us, the 128/fc us is subtracted from the Buffer, and the Buffer is divided into 2 buffers to obtain the bit width Buffer. And decoding the bit through the bit width Buffer. The specific method is to find the start sequence 'sequence Z', and by starting polling the Pause width Buffer from the 0 address, if the first Buffer is low level Pause, less than 64/fc and greater than 10/fc time, the sequence is considered as the start sequence. If the value in the first storage unit is greater than the second unit value in the bit width Buffer and both are less than 8, then the sequence X is considered to be decoded as 1 b. If the median bit width Buffer is greater than or equal to 9, then decode to sequence Y decodes to 0 b. If the value in the second storage unit is larger than the first unit value in the bit width Buffer, the sequence Z is considered to be resolved into a start signal. And when the signal is analyzed to be a start signal, NFC data transmission is carried out.

In some embodiments, when the coil selection circuit 3 accesses the NFC coil 2 to the wireless charging SOC chip 6, the method further 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.

When the NFC coil 2 is small in area and the wireless charging SOC chip 6 cannot obtain enough energy from the coil, boost current is turned on, and meanwhile, the MOS tube in the rectifier bridge is enabled to conduct full-bridge rectification. This application uses external power source to charge the SOC chip 6 power supply for wireless when decoding and revising miller code, can make wireless SOC chip 6 that fills also can work under the condition that does not have the energy field when the ASK modulation of 100%, and the low level width of miller code that can very easy sampling.

In some embodiments, further comprising:

when data interaction is completed or the data interaction time exceeds the preset time, the AP main control chip 7 sends an access signal of the wireless charging coil 1 to the coil selection circuit 3, and the wireless charging coil 1 is accessed to the wireless charging SOC chip 6.

Specifically, when the NFC communication is finished or is overtime, the AP main control chip 7 pulls down the Coil _ Select, so that the Coil selection circuit 3 accesses the wireless charging Coil 1 to the wireless charging SOC chip 6, and the wireless charging mode is recovered.

The embodiment of the application provides an electronic device, and a control method for multiplexing a wireless charging SOC chip provided by any one of the above embodiments into an NFC chip is applied.

In summary, the present invention provides a circuit and an electronic device for multiplexing a wireless charging SOC chip into 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 master control chip; the wireless charging coil and the NFC coil are respectively connected with a coil selection circuit, the coil selection circuit is respectively connected with a wireless charging SOC chip and an AP main control chip, and the wireless charging SOC chip is connected with 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 with the wireless SOC chip; the NFC signal detection circuit is connected with the AP main control chip through the wireless charging SOC chip. According to the utility model, the wireless charging SOC chip can realize the wireless charging mode and the NFC mode by arranging the NFC demodulation circuit, the NFC signal detection circuit, the wireless charging SOC chip and the AP main control chip, and a plurality of chips are not required to be arranged, so that not only can resources be saved, but also the cost can be reduced.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (9)

1. A circuit for multiplexing a wireless charging SOC chip into an NFC chip is characterized by comprising: the wireless charging system comprises 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);

the wireless charging coil (1) and the NFC coil (2) are respectively connected with a coil selection circuit (3), the coil selection circuit (3) is respectively connected with the wireless charging SOC chip (6) and the AP main control chip (7), and the wireless charging SOC chip (6) is connected with the AP main control chip (7);

the NFC coil (2), the NFC demodulation circuit (4) and the NFC signal detection circuit (5) are sequentially connected;

the NFC demodulation circuit (4) is connected with the wireless charging SOC chip (6);

the NFC signal detection circuit (5) is respectively connected with the wireless charging SOC chip (6) and the AP main control chip (7);

when the NFC demodulation circuit (4) outputs a high level, the NFC signal detection circuit (5) is driven to output a low level signal, the AP main control chip (7) sends an NFC coil (2) selection access signal to the coil selection circuit (3), and the coil selection circuit (3) accesses the NFC coil (2) to the wireless charging SOC chip (6);

when the NFC demodulation circuit (4) outputs a low level, the NFC signal detection circuit (5) is driven to output a high level signal, the AP main control chip (7) sends a wireless charging coil (1) access signal to the coil selection circuit (3), and the coil selection circuit (3) accesses the wireless charging coil (1) to the wireless charging SOC chip (6).

2. The circuit of claim 1, further comprising:

and the voltage converter (8), the voltage converter (8) is respectively connected with the AP main control chip (7), the wireless charging SOC chip (6) and the battery (9) and is used for receiving a control signal of the AP main control chip (7) and supplying 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 for acquiring a baseband signal output by the NFC coil;

the low-pass filter circuit (42) is used for filtering the baseband signal.

4. A circuit according to claim 3, characterized in that said envelope detection circuit (41) comprises: a first resistor (R1), a first diode (D1), a second resistor (R2), and a first capacitor (C1);

the positive pole of first diode (D1) is connected the output of NFC coil (2), the one end of first resistance (R1) is connected to the negative pole of first diode (D1), the one end of second resistance (R2), the one end of first electric capacity (C1) are connected respectively to the other end of first resistance (R1), the other end of second resistance (R2) and the other end of first electric capacity (C1) all ground connection.

5. The circuit according to claim 4, wherein the low-pass filtering 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, characterized in that 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 with 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 with the output end of the NFC demodulation circuit (4), the first end of the controllable switch tube (Q1) is connected with 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 for providing working voltage for the decoding circuit, the timer and the microprocessor;

the microprocessor (64) is used for controlling the decoding circuit (62) to adjust decoding parameters so as to correspondingly decode the signal output by the wireless charging coil (1) or the NFC coil (2);

the microprocessor (64) is also used for controlling the timer (63) to enter a PWM mode so as to process the decoded signal and output a modulation baseband signal of NFC.

8. The circuit of claim 1,

the wireless charging SOC chip (6) is connected with the AP main control chip (7) through an IIC bus.

9. An electronic device characterized by applying the circuit of multiplexing the wireless charging SOC chip of any of claims 1-8 as an NFC chip.

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