TPMS receiver supporting Bluetooth connection and tire pressure monitoring system

Abstract

The utility model belongs to the technical field of automotive electronics, and particularly relates to a TPMS (tire pressure monitoring system) receiver supporting Bluetooth connection and a tire pressure monitoring system. The TPMS receiver comprises a high-frequency receiving circuit used for receiving a wireless radio frequency signal sent by a sensor module in a tire; the first signal end of the single chip microcomputer is electrically connected with the data end of the high-frequency receiving circuit, and the single chip microcomputer is used for obtaining tire monitoring data according to the wireless radio frequency signal; the data end of the Bluetooth communication circuit is electrically connected with the second signal end of the single chip microcomputer, and the Bluetooth communication circuit is used for converting the tire monitoring data into Bluetooth wireless signals; the data end of the low-frequency driving circuit is electrically connected with the third signal end of the single chip microcomputer, and the low-frequency driving circuit is used for generating a sensor trigger signal and realizing matching with the sensor module, so that the technical scheme of the TPMS receiver which can realize autonomous matching of receiving and transmitting and is smaller in structure is realized.

Description

Technical Field

[0001] This utility model belongs to the field of automotive electronics technology, and in particular relates to a TPMS receiver and tire pressure monitoring system that supports Bluetooth connectivity. Background Technology

[0002] A direct wireless tire pressure monitoring system (TPMS) consists of two parts: an in-tire sensor module and a TPMS receiver. The sensor module, typically mounted on the wheel hub, monitors the real-time pressure and temperature inside the tire. When abnormal conditions such as high or low pressure or high temperature occur, it promptly sends alarm information wirelessly to the TPMS receiver. The TPMS receiver receives, processes, and displays the current pressure and temperature inside the tire; it is usually installed inside the vehicle. Most existing TPMS receivers have an LCD screen to display information such as tire temperature and pressure. The matching of the TPMS receiver and the in-tire sensor module is usually completed by the vehicle manufacturer before the vehicle leaves the factory, which presents the following problems in use:

[0003] When car owners need to replace or adjust their tires, they can only go to 4S stores or professional repair shops to match the tire sensor modules with the TPMS receiver, which is not only time-consuming and laborious, but also has high after-sales costs.

[0004] LCD screens are not conducive to the hidden design of TPMS receivers, not only taking up space on the center console, but also affecting the aesthetics of the car interior.

[0005] Therefore, there is a need for a TPMS receiver technology solution that can autonomously match transmission and reception and has a more compact structure. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model provides a TPMS receiver and tire pressure monitoring system that supports Bluetooth connection.

[0007] This utility model provides a TPMS receiver that supports Bluetooth connectivity, comprising:

[0008] A high-frequency receiving circuit is used to receive wireless radio frequency signals emitted by the sensor module inside the tire.

[0009] The microcontroller has its first signal terminal electrically connected to the data terminal of the high-frequency receiving circuit, and is used to acquire tire monitoring data based on the wireless radio frequency signal;

[0010] The Bluetooth communication circuit has its data terminal electrically connected to the second signal terminal of the microcontroller, and is used to convert the tire monitoring data into Bluetooth wireless signals.

[0011] The low-frequency drive circuit has its data terminal electrically connected to the third signal terminal of the microcontroller to generate a sensor trigger signal and achieve matching with the sensor module.

[0012] In one possible implementation, a vibration detection circuit is also included, whose data terminal is electrically connected to the fourth signal terminal of the microcontroller.

[0013] In one possible implementation, the vibration detection circuit includes a vibration sensor, a first resistor, and a first capacitor;

[0014] The first conductive pin of the vibration sensor is electrically connected to the first end of the first resistor and the first end of the first capacitor, and serves as the data terminal of the vibration detection circuit. Its second conductive pin is electrically connected to the second end of the first capacitor and grounded.

[0015] The second terminal of the first resistor is connected to the operating voltage.

[0016] In one possible implementation, the low-frequency drive circuit is constructed using a half-bridge drive method.

[0017] In one possible implementation, the low-frequency drive circuit is constructed based on a transistor, a low-frequency coil, a capacitor, and a resistor.

[0018] In one possible implementation, a speaker circuit is also included, the input of which is electrically connected to the control terminal of the microcontroller.

[0019] In one possible implementation, the speaker circuit includes a speaker, a first NPN transistor, a second resistor, and a second capacitor;

[0020] The positive terminal of the loudspeaker is electrically connected to the first terminal of the second capacitor and connected to the operating voltage, while its negative terminal is electrically connected to the collector of the first NPN transistor.

[0021] The emitter of the first NPN transistor is electrically connected to ground, and its base is electrically connected to the first terminal of the second resistor;

[0022] The second end of the second resistor serves as the input terminal of the speaker circuit;

[0023] The second terminal of the second capacitor is electrically grounded.

[0024] In one possible implementation, a power conversion circuit is also included, with its input terminal electrically connected to the vehicle power supply and its output terminal electrically connected to the power supply terminals of the high-frequency receiving circuit, the microcontroller, and the Bluetooth communication circuit, respectively, for stepping down the voltage provided by the vehicle power supply to the operating voltage.

[0025] In one possible implementation, the high-frequency receiving circuit includes a high-frequency receiving antenna, a π-type matching circuit, a connecting capacitor, and a wireless receiving chip;

[0026] The output terminal of the high-frequency receiving antenna is electrically connected to the input terminal of the π-type matching circuit;

[0027] The output terminal of the π-type matching circuit is electrically connected to the first terminal of the connecting capacitor;

[0028] The second end of the connecting capacitor is electrically connected to the radio frequency signal input terminal of the wireless receiver chip;

[0029] The data terminal of the wireless receiver chip serves as the data terminal of the high-frequency receiver circuit.

[0030] This utility model also provides a tire pressure monitoring system, including a sensor module and a TPMS receiver as described above;

[0031] The sensor module is installed inside the tire and wirelessly connected to the TPMS receiver.

[0032] The technical solution provided by this utility model has at least the following beneficial effects:

[0033] By setting up a Bluetooth communication circuit, a mobile APP can be used to replace the LCD screen for display and control based on Bluetooth communication technology, making the TPMS receiver smaller and easier to install in a hidden location without affecting the interior layout and aesthetics. By setting up a low-frequency drive circuit, autonomous matching between the receiver (TPMS receiver) and the transmitter (sensor module) can be achieved, and only slight modifications to the microcontroller program are needed to adapt to sensor models from different manufacturers, making it highly versatile. Attached Figure Description

[0034] Figure 1 A structural block diagram of a TPMS receiver supporting Bluetooth connectivity is provided for an embodiment of this utility model;

[0035] Figure 2 A circuit diagram of the vibration detection circuit provided in this embodiment of the utility model;

[0036] Figure 3 Circuit diagram of the low-frequency drive circuit provided in the embodiment of this utility model;

[0037] Figure 4 The circuit diagram of the speaker circuit provided in the embodiment of this utility model;

[0038] Figure 5 Circuit schematic diagram of the microcontroller and Bluetooth communication circuit provided for embodiments of this utility model;

[0039] Figure 6 Circuit diagram of the power conversion circuit provided in the embodiment of this utility model;

[0040] Figure 7 Circuit diagram of the high-frequency receiving circuit provided in the embodiment of this utility model;

[0041] Figure 8 A structural block diagram of a tire pressure monitoring system provided in this embodiment of the present invention;

[0042] In the attached diagram, 10 is the high-frequency receiving circuit; 20 is the microcontroller; 30 is the Bluetooth communication circuit; 40 is the low-frequency driving circuit; 50 is the vibration detection circuit; 60 is the speaker circuit; and 70 is the power conversion circuit. Detailed Implementation

[0043] To enhance understanding of this utility model, it will be described in further detail below with reference to the accompanying drawings and embodiments. These embodiments are only used to explain this utility model and do not limit the scope of protection of this utility model.

[0044] Please refer to Figures 1 to 7 This utility model provides a TPMS receiver that supports Bluetooth connectivity, comprising:

[0045] The high-frequency receiving circuit 10 is used to receive the wireless radio frequency signals emitted by the sensor module inside the tire.

[0046] The microcontroller 20 has its first signal terminal electrically connected to the data terminal of the high-frequency receiving circuit 10, and is used to acquire tire monitoring data based on the wireless radio frequency signal;

[0047] Bluetooth communication circuit 30, whose data terminal is electrically connected to the second signal terminal of the microcontroller 20, is used to convert the tire monitoring data into Bluetooth wireless signals;

[0048] The low-frequency drive circuit 40 has its data terminal electrically connected to the third signal terminal of the microcontroller 20, and is used to generate a sensor trigger signal to achieve matching with the sensor module.

[0049] In this embodiment, the sensor module is implemented based on a conventional tire pressure monitoring sensor chip. Currently, mainstream tire pressure monitoring sensor chips (such as Infineon's SP40) support the reception and demodulation of low-frequency signals (typically 125kHz), which makes it possible to achieve independent configuration of the sensor module and TPMS receiver within the tire. The high-frequency receiving circuit 10 can adopt a conventional design. The microcontroller 20 can be a conventional model, such as the STM8L152C6 chip. This chip is an ultra-low-power STM8 core microcontroller based on a Harvard architecture, with a maximum internal clock of 16MHz and a three-stage pipeline; it supports operating voltages from 1.8V to 3.6V, five low-power management modes, up to 41 available I / O ports, and a maximum programming FLASH capacity of 32KB; it has an internal LCD boost pump capable of driving 4×28 segment displays. The microcontroller 20 can parse tire monitoring data from the wireless radio frequency signal. The tire monitoring data includes tire pressure and temperature readings. The Bluetooth communication circuit 30 can use a conventional Bluetooth communication module, such as the HC-05 Bluetooth module. Based on Bluetooth communication technology, the traditional LCD screen of the TPMS receiver can be replaced by the Bluetooth pairing function of a smartphone and a mobile APP, reducing the size of the TPMS receiver. The microcontroller 20 can send the current tire pressure and temperature detection values ​​to the mobile APP for display via the Bluetooth communication circuit 30, and simultaneously receive control commands (such as switching between configuration mode and working mode) from the mobile APP. The low-frequency drive circuit 40 can adopt a conventional design with a low-frequency drive frequency of 125kHz and an amplitude (ASK) modulation mode. It is used to send a low-frequency trigger signal, i.e., a sensor trigger signal, to the tire sensor (i.e., the sensor module) to achieve autonomous matching between the tire sensor ID and the TPMS receiver. This application solves the problems of large size and inability to autonomously match transmission and reception in traditional TPMS receivers by integrating the Bluetooth communication circuit 30 and the low-frequency drive circuit 40.

[0050] In one specific implementation, such as Figure 5The microcontroller 20 uses an STM8L152C6 chip, denoted as D1. The Bluetooth communication circuit 30 uses an HC-O5 module, denoted as D2. D1 sends the current detection data (tire pressure and temperature detection values) to the user's mobile APP for display via D2, and simultaneously receives control commands from the mobile APP (such as switching between configuration mode and working mode). The HC-O5 module is a simple wireless communication device based on the Bluetooth 2.0 protocol, with 6 pins. The VCC and GND pins are used for power supply. The RXD pin is connected to the transmit pin 3 of the USART serial port of the microcontroller 20 to receive the detection data sent by the microcontroller 20; the TXD pin is connected to the receive pin 4 of the USART serial port of the microcontroller 20 to send control commands from the mobile APP to the microcontroller 20; EN is the enable pin, and if set to low, the HC-O5 module is disabled; the high or low level output of the STATE pin indicates the status of the HC-O5 module, outputting a high level when connected and a low level when disconnected.

[0051] In one possible implementation, a vibration detection circuit 50 is also included, whose data terminal is electrically connected to the fourth signal terminal of the microcontroller 20.

[0052] In one possible implementation, such as Figure 2 The vibration detection circuit 50 includes a vibration sensor S1, a first resistor R1, and a first capacitor C1;

[0053] The first conductive pin of the vibration sensor S1 is electrically connected to the first resistor R1 and the first end of the first capacitor C1, and serves as the data terminal of the vibration detection circuit 50. Its second conductive pin is electrically connected to the second end of the first capacitor C1 and grounded.

[0054] The second terminal of the first resistor R1 is connected to the operating voltage.

[0055] In this embodiment, the vibration sensor S1 can be a conventional spring-loaded vibration switch. When stationary, its first conductive pin and second conductive pin are disconnected; during vibration, the first conductive pin and second conductive pin are in intermittent contact due to the elastic movement of the internal spring. The first resistor R1 is a conventional resistor. The first capacitor C1 is a conventional capacitor.

[0056] In one specific implementation, the operating voltage can be 3V. When there is vibration, the vibration sensor S1 generates a pulse signal at the ZDJC terminal; when at rest, the ZDJC terminal is always at a high level.

[0057] In one possible implementation, the low-frequency drive circuit 40 is constructed using a half-bridge drive method.

[0058] In one possible implementation, such as Figure 3 The low-frequency drive circuit 40 is constructed based on transistors, low-frequency coils, capacitors, and resistors.

[0059] In this embodiment, the low-frequency drive circuit 40 adopts a half-bridge drive method, specifically composed of four transistors (Q1, Q2, Q3, Q4), several resistors (R3, R4, R5, R6, R7, R8, R9, R10), several capacitors (C3, C4, C5, C6), and a low-frequency coil LX. It has a small number of components and low cost. The microcontroller 20 outputs two symmetrical square wave pulse signals LF+ and LF- with a frequency of 125kHz. When LF+ is a positive pulse and LF- is a negative pulse, the positive pulse passes through coupling capacitor C3 to filter out low-frequency components, and then through current-limiting resistor R3 to reach the base of power amplifier transistor Q1. The negative pulse passes through coupling capacitor C4 to filter out low-frequency components, and then through current-limiting resistor R4 to reach the base of power amplifier transistor Q3. Q1 and Q2 are turned on successively, while Q3 and Q4 are both turned off, and the low-frequency coil resonant circuit composed of LX and C6 begins to charge. When LF+ is a negative pulse and LF- is a positive pulse, the negative pulse is filtered out by coupling capacitor C3 to remove low-frequency components, and then passes through current-limiting resistor R3 to reach the base of power amplifier transistor Q1. The positive pulse is filtered out by coupling capacitor C4 to remove low-frequency components, and then passes through current-limiting resistor R4 to reach the base of power amplifier transistor Q3. Q1 and Q2 are cut off, and Q3 and Q4 are turned on successively. The low-frequency coil resonant circuit composed of LX and C6 begins to discharge, thereby generating a 125kHz sinusoidal current in the low-frequency coil LX, and generating a 125kHz low-frequency radiated electromagnetic field around the low-frequency coil. In practical implementation, diodes D1 and D2 can be connected between the base and emitter of Q1 and Q3 respectively to protect transistors Q1 and Q3. Since Class A, B, and C power amplifier transistors have low efficiency, while Class D power amplifier transistors can theoretically reach 100% efficiency and operate in switching mode with low loss and easily improved transmit power, Class D power amplifier transistors should be preferred.

[0060] In one possible implementation, a speaker circuit 60 is also included, the input of which is electrically connected to the control terminal of the microcontroller 20.

[0061] In this embodiment, the speaker circuit 60 can be implemented based on a conventional buzzer and transistor. The microcontroller 20 outputs high and low levels to control the conduction and cutoff of the transistor, thereby controlling the buzzer.

[0062] In one possible implementation, such as Figure 4 The speaker circuit 60 includes a speaker H1, a first NPN transistor Qn1, a second resistor R2, and a second capacitor C2;

[0063] The positive terminal of the loudspeaker H1 is electrically connected to the first terminal of the second capacitor C2 and connected to the operating voltage, while its negative terminal is electrically connected to the collector of the first NPN transistor Qn1.

[0064] The emitter of the first NPN transistor Qn1 is electrically connected to ground, and its base is electrically connected to the first terminal of the second resistor R2;

[0065] The second end of the second resistor R2 serves as the input terminal of the speaker circuit 60;

[0066] The second terminal of the second capacitor C2 is electrically grounded.

[0067] In this embodiment, the operating voltage can be 3V. The speaker H1 is a standard model. The first NPN transistor Qn1 is a standard NPN transistor. The second resistor R2 is a standard resistor. The second capacitor C2 is a standard capacitor.

[0068] In practical implementation, under the control of the microcontroller 20, the wireless radio frequency signal from the tire's internal sensor is decoded into a digital signal by the high-frequency receiving circuit 10 and then sent to the Bluetooth communication circuit 30. This module sends data to the mobile APP receiver for display via wireless communication and simultaneously receives control commands from the mobile APP (such as switching between configuration mode and working mode). In case of abnormal air pressure or temperature, the microcontroller 20 can drive the speaker H1 to issue an alarm to remind the driver.

[0069] In one possible implementation, a power conversion circuit 70 is also included, with its input terminal electrically connected to the vehicle power supply and its output terminal electrically connected to the power supply terminals of the high-frequency receiving circuit 10, the microcontroller 20, and the Bluetooth communication circuit 30, respectively, for stepping down the voltage provided by the vehicle power supply to the operating voltage.

[0070] In this embodiment, the vehicle power supply can provide 12V voltage, and the operating voltage can be 3V.

[0071] In one specific implementation, such as Figure 6 The power conversion circuit 70 mainly consists of a power interface XS1, a PTC thermistor R11, a transient voltage suppressor V1, a diode D3, an inductor L1, several capacitors (C7 to C12), and a power management chip D3. The power management chip can be a BD3570FP.

[0072] In one possible implementation, such as Figure 7 The high-frequency receiving circuit 10 includes a high-frequency receiving antenna ANT, a π-type matching circuit, a connecting capacitor 3, and a wireless receiving chip D4.

[0073] The output terminal of the high-frequency receiving antenna ANT is electrically connected to the input terminal of the π-type matching circuit;

[0074] The output terminal of the π-type matching circuit is electrically connected to the first terminal of the connecting capacitor C13;

[0075] The second end of the connecting capacitor C13 is electrically connected to the radio frequency signal input terminal of the wireless receiver chip D4;

[0076] The data terminal of the wireless receiver chip D4 serves as the data terminal of the high-frequency receiver circuit.

[0077] In this embodiment, the π-type matching circuit can be composed of inductor L2 and capacitors C14 and C15. The wireless receiver chip D4 can be an MC33596. The STROBE, SCLK, MOSI, MISO, CONFB, and RSSIC pins of the wireless receiver chip D4 are connected to the corresponding pins of the microcontroller 20 (STM8L152C6 chip). The MC33596 supports both ASK and FSK signal modulation modes. At a data rate of 2.4kbps, the FSK receiver sensitivity can reach -108dBm, with a modulation frequency range of 300MHz to 915MHz. It integrates a low-noise amplifier, mixer, programmable phase-locked loop, intermediate frequency amplifier, signal strength indicator circuit, and data management module. Only a few external components are needed to construct the RF front-end of the tire pressure receiver. Whenever the control signal on the CONFB pin is low, the MC33596 enters configuration mode, with the STM8L152C6 chip acting as the master and the MC33596 as the slave. The STM8L152C6 chip configures the internal registers of the MC33596 via the SPI serial port, including RF signal frequency selection, signal modulation mode setting, data transmission rate setting, signal preamble setting, and enabling the field strength test module. When the control signal on the CONFB pin is high and the STROBE pin is also high, the MC33596 enters receive mode and automatically begins demodulating, encoding, storing, and transmitting the received data to the STM8L152C6. The RSSIC pin controls the RF signal strength sampling mode. When the RSSIC pin is at a falling edge, the signal strength sampling is in single-point mode, and the RSSI register will hold the signal strength of that sampling point. When the RSSIC pin is high, the signal strength sampling is in continuous mode, and the value of the RSSI register will be continuously updated with continuous sampling.

[0078] like Figure 8 This utility model also provides a tire pressure monitoring system, including a sensor module and a TPMS receiver as described above;

[0079] The sensor module is installed inside the tire and wirelessly connected to the TPMS receiver.

[0080] The above embodiments should not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent conversion fall within the protection scope of the present invention.

Claims

1. A TPMS receiver supporting Bluetooth connectivity, characterized in that, include: A high-frequency receiving circuit is used to receive wireless radio frequency signals emitted by the sensor module inside the tire. The microcontroller has its first signal terminal electrically connected to the data terminal of the high-frequency receiving circuit, and is used to acquire tire monitoring data based on the wireless radio frequency signal; The Bluetooth communication circuit has its data terminal electrically connected to the second signal terminal of the microcontroller, and is used to convert the tire monitoring data into Bluetooth wireless signals. The low-frequency drive circuit has its data terminal electrically connected to the third signal terminal of the microcontroller to generate a sensor trigger signal and achieve matching with the sensor module.

2. The TPMS receiver according to claim 1, characterized in that, It also includes a vibration detection circuit, whose data terminal is electrically connected to the fourth signal terminal of the microcontroller.

3. The TPMS receiver according to claim 2, characterized in that, The vibration detection circuit includes a vibration sensor, a first resistor, and a first capacitor; The first conductive pin of the vibration sensor is electrically connected to the first end of the first resistor and the first end of the first capacitor, and serves as the data terminal of the vibration detection circuit. Its second conductive pin is electrically connected to the second end of the first capacitor and grounded. The second terminal of the first resistor is connected to the operating voltage.

4. The TPMS receiver according to claim 1, characterized in that, The low-frequency drive circuit is constructed using a half-bridge drive method.

5. The TPMS receiver according to claim 4, characterized in that, The low-frequency drive circuit is constructed based on transistors, low-frequency coils, capacitors, and resistors.

6. The TPMS receiver according to claim 1, characterized in that, It also includes a speaker circuit, the input of which is electrically connected to the control terminal of the microcontroller.

7. The TPMS receiver according to claim 6, characterized in that, The speaker circuit includes a speaker, a first NPN transistor, a second resistor, and a second capacitor; The positive terminal of the loudspeaker is electrically connected to the first terminal of the second capacitor and connected to the operating voltage, while its negative terminal is electrically connected to the collector of the first NPN transistor. The emitter of the first NPN transistor is electrically connected to ground, and its base is electrically connected to the first terminal of the second resistor; The second end of the second resistor serves as the input terminal of the speaker circuit; The second terminal of the second capacitor is electrically grounded.

8. The TPMS receiver according to claim 1, characterized in that, It also includes a power conversion circuit, whose input is electrically connected to the vehicle power supply, and whose output is electrically connected to the power supply terminals of the high-frequency receiving circuit, the microcontroller, and the Bluetooth communication circuit, respectively, for stepping down the voltage provided by the vehicle power supply to the operating voltage.

9. The TPMS receiver according to claim 1, characterized in that, The high-frequency receiving circuit includes a high-frequency receiving antenna, a π-type matching circuit, a connecting capacitor, and a wireless receiving chip. The output terminal of the high-frequency receiving antenna is electrically connected to the input terminal of the π-type matching circuit; The output terminal of the π-type matching circuit is electrically connected to the first terminal of the connecting capacitor; The second end of the connecting capacitor is electrically connected to the radio frequency signal input terminal of the wireless receiver chip; The data terminal of the wireless receiver chip serves as the data terminal of the high-frequency receiver circuit.

10. A tire pressure monitoring system, characterized in that, Includes a sensor module and a TPMS receiver as described in any one of claims 1 to 9; The sensor module is installed inside the tire and wirelessly connected to the TPMS receiver.

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