Balloon pressure sensor system and blood pressure measuring method

Abstract

The invention provides a balloon pressure sensor system and a blood pressure measuring method, and relates to the technical field of sensors. A flexible printed circuit board is arranged in a target balloon catheter in a penetrating mode, and a silicon piezoresistive pressure sensor is fixed to the first end of the flexible printed circuit board; therefore, the silicon piezoresistive pressure sensor can accurately measure the initial pressure value of the position where the tip of the balloon sleeving the target balloon catheter is located in real time, and the blood pressure state of the position where the balloon is located is accurately judged according to the target pressure value obtained by the microcontroller in a vascular operation. Through the filtering operation of the hardware signal processing module and the microcontroller, the sensor voltage signal representing the initial pressure intensity value is processed and corrected, a more accurate target pressure intensity value is obtained, and the practicability of the silicon piezoresistive pressure sensor is improved. The display screen system is controlled to display the target pressure intensity value, the pressure intensity condition of the position where the tip end of the balloon is located is better presented to a user, and the user can apply the target balloon catheter more efficiently.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a balloon pressure sensor system and a blood pressure measurement method. Background Art

[0002] Since the blood vessels in the human body are very tortuous, doctors usually use interventional surgical instruments to treat patients. However, interventional surgical instruments cannot sense various external forces, so pressure sensors are needed to detect various pressure changes as feedback during vascular surgery.

[0003] Existing solutions usually set the pressure sensor inside the balloon to measure the balloon pressure and local blood pressure. Due to the installation position of the pressure sensor, there are errors in the obtained local blood pressure, and the accuracy is poor. Moreover, existing pressure sensors are easily affected by their own performance and environmental factors, which also reduces the accuracy of their measurement results. Summary of the Invention

[0004] The present invention provides a balloon pressure sensor system and a blood pressure measurement method to solve the defects existing in the related art.

[0005] The present invention provides a balloon pressure sensor system, including: a silicon piezoresistive pressure sensor, a flexible printed circuit board, and an integrated processing module. The integrated processing module includes a hardware signal processing module, a microcontroller, and a display system connected in sequence; The flexible printed circuit board is disposed through the target balloon catheter. The silicon piezoresistive pressure sensor is fixed to the first end of the flexible printed circuit board for real-time measurement of the initial pressure value at the tip of the balloon sleeved on the target balloon catheter, and outputting a sensor voltage signal representing the initial pressure value; The second end of the flexible printed circuit board is connected to the integrated processing module for transmitting the sensor voltage signal to the hardware signal processing module; The hardware signal processing module is used for amplifying and low-pass filtering the sensor voltage signal to obtain a target voltage signal; The microcontroller is used for determining a sensor pressure signal based on the target voltage signal, filtering out high-frequency noise in the sensor pressure signal to obtain a target pressure value, and controlling the display system to display the target pressure value.

[0006] According to a balloon pressure sensor system provided by the present invention, the integrated processing module further includes an independent button; The independent button is connected to the microcontroller for transmitting a button signal triggered by a user to the microcontroller; The microcontroller is also used to configure the balloon pressure sensor system based on the key signal.

[0007] According to a balloon pressure sensor system provided by the present invention, the key signal is used to set a reference pressure value; The microcontroller is also used for: Collecting sampling values of the target voltage signal continuously for multiple times and calculating the average value of each sampling value; Calculating a zero-point offset based on the average value and the reference voltage value corresponding to the reference pressure value; Wherein, the zero-point offset is used to perform zero-point calibration on the target voltage signal.

[0008] According to a balloon pressure sensor system provided by the present invention, the sensor voltage signal is a differential-mode voltage signal, and the differential-mode voltage signal includes a positive output signal and a negative output signal of the piezoresistive pressure sensor; The hardware signal processing module includes a first voltage follower circuit, a second voltage follower circuit, a differential amplifier circuit, and a second-order active low-pass filter circuit; The first voltage follower circuit is used to perform impedance transformation and signal isolation on the positive output signal to obtain a first transformed signal; The second voltage follower circuit is used to perform impedance transformation and signal isolation on the negative output signal to obtain a second transformed signal; The positive-phase input terminal of the differential amplifier circuit is used to access the first transformed signal, the inverting input terminal is used to access the second transformed signal, and the output terminal is used to output a differential amplified signal; The second-order active low-pass filter circuit is used to perform low-pass filtering on the differential amplified signal to obtain the target voltage signal.

[0009] According to a balloon pressure sensor system provided by the present invention, the microcontroller is specifically used for: Converting the target voltage signal into a digital signal; Calculating the sensor pressure signal based on the digital signal and applying the sensitivity of the piezoresistive pressure sensor; Filtering high-frequency noise in the sensor pressure signal based on a first-order Kalman filter algorithm to obtain the target pressure value.

[0010] According to a balloon pressure sensor system provided by the present invention, the display screen system includes a display screen and a driving chip, the driving chip is communicatively connected to the microcontroller, and the driving chip is connected to the display screen; The microcontroller is also used to process the target pressure value at each moment into an image signal and transmit the image signal to the driving chip; The driving chip is used to compile the image signal into a driving signal, and based on the driving signal, control the display screen to display.

[0011] According to a balloon pressure sensor system provided by the present invention, the piezoresistive pressure sensor includes a Wheatstone circuit, and the Wheatstone circuit includes semiconductor strain gauges; The microcontroller is further configured to: apply an excitation voltage to the Wheatstone circuit, so that the semiconductor strain gauges sense the external pressure at the position where the tip of the balloon is located, and the Wheatstone circuit outputs the sensor voltage signal.

[0012] According to a balloon pressure sensor system provided by the present invention, the integrated processing module further includes a first USB interface; The first USB interface is used to connect to a power source or burn a program into the microcontroller.

[0013] According to a balloon pressure sensor system provided by the present invention, the integrated processing module further includes a second USB interface; The second USB interface is used to connect to a power source or a host computer; The microcontroller is further configured to transmit the target pressure value to the host computer; The host computer is used to apply the target pressure value.

[0014] The present invention provides a blood pressure measurement method, which is implemented by applying the above-mentioned balloon pressure sensor system.

[0015] The balloon pressure sensor system and the blood pressure measurement method provided by the present invention. Since the flexible printed circuit board is disposed through the target balloon catheter, and the piezoresistive pressure sensor is fixed to the first end of the flexible printed circuit board, the initial pressure value at the position where the tip of the balloon sleeved on the target balloon catheter is located can be measured in real time and accurately by the piezoresistive pressure sensor. Furthermore, the blood pressure state at the position where the balloon is located can be accurately judged according to the target pressure value obtained by the microcontroller during a vascular operation. Through the filtering operations of the hardware signal processing module and the microcontroller, the sensor voltage signal representing the initial pressure value can be processed and corrected to obtain a more accurate target pressure value, improving the practicability of the piezoresistive pressure sensor. The system can display the target pressure value by controlling the display screen system, and can better present the pressure condition at the position where the tip of the balloon is located to the user, enabling the user to more efficiently apply the target balloon catheter. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the present invention or related technologies, the following will briefly introduce the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 is a schematic structural diagram of the balloon pressure sensor system provided by the present invention.

[0018] Figure 2 is a partial structural schematic diagram of the flexible printed circuit board in the balloon pressure sensor system provided by the present invention.

[0019] Figure 3 is a schematic structural diagram of the PCB main board in the balloon pressure sensor system provided by the present invention.

[0020] Figure 4 is a schematic structural diagram of the differential amplifier circuit in the balloon pressure sensor system provided by the present invention.

[0021] Figure 5 is a schematic structural diagram of the second-order active low-pass filter circuit in the balloon pressure sensor system provided by the present invention.

[0022] Figure 6 is a schematic structural diagram of the electronic device provided by the present invention. Detailed Embodiments

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0024] Since the existing solutions usually set the pressure sensor inside the balloon, resulting in errors in the obtained local blood pressure and poor accuracy, and the pressure sensor is affected by its own performance and environmental factors, the accuracy of its measurement results will also decrease. Based on this, an embodiment of the present invention provides a balloon pressure sensor system.

[0025] Figure 1 is a schematic structural diagram of the balloon pressure sensor system provided in the embodiment of the present invention, as Figure 1As shown in the figure, the balloon pressure sensor system includes: a silicon piezoresistive pressure sensor 1, a flexible printed circuit board (FPCB) 2, and an integrated processing module 3. The integrated processing module 3 includes a hardware signal processing module 31, a microcontroller 32, and a display screen system 33 that are connected in sequence; The flexible printed circuit board 2 is disposed through the target balloon catheter 4. The silicon piezoresistive pressure sensor 1 is fixed to the first end of the flexible printed circuit board 2 and is used to measure in real time the initial pressure value at the tip of the balloon 5 sleeved on the target balloon catheter 4, and output a sensor voltage signal representing the initial pressure value; The second end of the flexible printed circuit board 2 is connected to the integrated processing module 3 and is used to transmit the sensor voltage signal to the hardware signal processing module 31; The hardware signal processing module 31 is used to amplify and perform low-pass filtering on the sensor voltage signal to obtain a target voltage signal; The microcontroller 32 is used to determine a sensor pressure signal based on the target voltage signal, filter out high-frequency noise in the sensor pressure signal to obtain a target pressure value, and control the display screen system 33 to display the target pressure value.

[0026] Specifically, in the balloon pressure sensor system provided in the embodiments of the present invention, the model of the silicon piezoresistive pressure sensor 1 used can be XGZP0703, and the measurement range is 0 - 750 mmHg. The silicon piezoresistive pressure sensor 1 can be made of the piezoresistive effect of single crystal silicon. Four equivalent semiconductor strain gauges are diffused in a specific direction on the silicon diaphragm and connected into a Wheatstone bridge as a force sensing element.

[0027] The semiconductor strain gauge utilizes the piezoresistive effect, with a larger change in resistance and higher sensitivity. When an external pressure is applied to the silicon piezoresistive pressure sensor 1, the silicon diaphragm will deform, and the semiconductor strain gauges attached thereto will also deform, thereby changing the resistance value.

[0028] The silicon piezoresistive pressure sensor 1 forms a sealed vacuum chamber through a silicon-silicon bonding process, which is used to form a vacuum reference chamber to meet the form of the absolute pressure output of the sensor.

[0029] Since the silicon piezoresistive pressure sensor 1 realizes the conversion of stress on the silicon diaphragm and electrical signals by constructing a Wheatstone bridge with semiconductor strain gauges, four equivalent semiconductor strain gauges must be placed at the maximum strain of the silicon diaphragm to meet its high-sensitivity characteristics.

[0030] Such as Figure 2As shown, the pads of the silicon piezoresistive pressure sensor 1 are connected to the pads 22 on the first surface 21 of the first end of the flexible printed circuit board 2 by gold wires 23 using the thermocompression wire bonding technology, so as to fix the silicon piezoresistive pressure sensor 1 on the first surface 21 of the first end of the flexible printed circuit board 2.

[0031] As Figure 2 shown, there may be 4 pads 22 arranged on the first surface 21 of the first end of the flexible printed circuit board 2, and each pad may be an immersion gold pad with an immersion gold thickness of 2 μm.

[0032] After the silicon piezoresistive pressure sensor 1 is fixed to the first end of the flexible printed circuit board 2, the silicon piezoresistive pressure sensor 1 can be encapsulated using polydimethylsiloxane encapsulation, so that the silicon piezoresistive pressure sensor 1 can adapt to the liquid environment.

[0033] The flexible printed circuit board 2 may be a flexible board with a length of 20 (cm) and a width of 2.5 (mm), and its slender shape is suitable for being arranged in the soft cavity of the target balloon catheter 4. A balloon 5 is sleeved on one end of the target balloon catheter 4 close to the silicon piezoresistive pressure sensor 1. The initial pressure value at the tip of the balloon 5 can be measured in real time by the silicon piezoresistive pressure sensor 1, and a sensor voltage signal representing the initial pressure value is output. This sensor voltage signal may be a differential mode voltage signal.

[0034] The second end of the flexible printed circuit board 2 is connected to the integrated processing module 3 for transmitting the sensor voltage signal to the hardware signal processing module 31. The second surface of the second end of the flexible printed circuit board 2 may include a wire harness with 4 signal interfaces for connecting to the integrated processing module 3. Among them, the first surface 21 of the first end of the flexible printed circuit board 2 and the second surface of the second end of the flexible printed circuit board 2 are arranged opposite to each other.

[0035] The integrated processing module 3 may include a PCB main board 35. This PCB main board 35 serves as a carrier for all the electronic components and electrical components in the integrated processing module 3, that is, the hardware signal processing module 31 and the microcontroller 32 may be integrated on the PCB main board 35. This PCB main board 35 may be a double-layer rigid circuit board with a size of 6.5 (cm) × 6.5 (cm).

[0036] As Figure 3 shown, a sensing strip interface 36 may be configured on the PCB main board 35, and the sensing strip interface 36 may include 4 pins. The 4 signal interfaces on the second surface of the second end of the flexible printed circuit board 2 may be respectively connected to the 4 pins of the sensing strip interface 36 in one-to-one correspondence.

[0037] The hardware signal processing module 31 collects the sensor voltage signal through the sensor bar interface 36 on the PCB main board 35, and can amplify and low-pass filter the sensor voltage signal to obtain the target voltage signal.

[0038] The microcontroller 32 can collect the target voltage signal and determine the sensor pressure signal according to the sensitivity of the piezoresistive pressure sensor. By filtering out the high-frequency noise in the sensor pressure signal, the target pressure value is obtained. Here, the microcontroller 32 is the core of the integrated processing module 3, responsible for processing the data received by the integrated processing module 3 and supporting the communication between the integrated processing module 3 and external devices. Here, the microcontroller 32 can be an STC8051U single-chip microcomputer, whose hardware uses a DIP40 package, has 40 external pins, the operating main frequency of the microcontroller 32 is 42 MHz, and the main frequency of the floating-point / trigonometric function operation unit can reach 100 MHz, meeting the signal processing requirements of this module. The microcontroller 32 can be integrated with rich device resources, including 6 16-bit timers, 2 high-speed synchronous / asynchronous serial ports, two high-speed asynchronous serial ports, 2 groups of advanced PWM, three groups of hardware serial peripheral interfaces (Serial Peripheral interface, SPI), and 15-channel 12-bit (bit) high-speed analog-to-digital converters (Analog-to-Digital Converter, ADC). The program storage FLASH capacity of this microprocessor is 64 KB, and the data storage SRAM capacity is 34 KB. The working voltage range is 1.9 V - 5.5 V, and the working temperature is -40 °C to 125 °C, with a certain anti-interference ability.

[0039] As Figure 1 and Figure 3 shown, the PCB main board 35 also includes a display system slot 34, and the display system slot 34 can be a 7-hole female row for connecting the display system 33, and this display system 33 can be a 7-pin 0.96-inch OLED display system.

[0040] The microcontroller 32 can send the target pressure value to the display system 33 through the display system slot 34 and control the display system 33 to display the target pressure value. The microcontroller 32 can also first convert the target pressure value into an image signal and send the image signal to the display system 33 for display. This image signal can be a curve graph signal obtained from the target pressure values at each moment.

[0041] When the target balloon catheter is inserted into the blood vessel, the blood pressure value at the tip of the balloon sleeved on the target balloon catheter can be measured in real time and accurately through the piezoresistive pressure sensor.

[0042] In addition, as Figure 1As shown, the balloon 5 is also sleeved outside the balloon inflation catheter 6, and the inner cavity of the balloon 5 is connected to one end of the balloon inflation catheter 6, and the other end of the balloon inflation catheter 6 is connected to an inflation device for inflating the balloon 5 and performing other treatments.

[0043] In the balloon pressure sensor system provided in the embodiment of the present invention, since the flexible printed circuit board is disposed through the target balloon catheter and the silicon piezoresistive pressure sensor is fixed to the first end of the flexible printed circuit board, the initial pressure value at the tip position of the balloon sleeved on the target balloon catheter can be measured in real time and accurately by the silicon piezoresistive pressure sensor. Furthermore, the blood pressure state at the position of the balloon can be accurately judged according to the target pressure value obtained by the microcontroller during a vascular operation. Through the filtering operations of the hardware signal processing module and the microcontroller, the sensor voltage signal representing the initial pressure value can be processed and corrected to obtain a more accurate target pressure value, improving the practicality of the silicon piezoresistive pressure sensor. The system can display the target pressure value through the control of the display screen system, and can better present the pressure condition at the tip position of the balloon to the user, enabling the user to more efficiently apply the target balloon catheter.

[0044] On the basis of the above embodiment, as Figure 3 shown, the integrated processing module 3 further includes an independent button 310; The independent button 310 is connected to the microcontroller 32 and is used to transmit the button signal triggered by the user to the microcontroller 32; The microcontroller 32 is further used to configure the balloon pressure sensor system based on the button signal.

[0045] Specifically, the integrated processing module 3 may include an independent button 310. The independent button is also called a button switch and is composed of an insert, a base, a shrapnel, a button, and a cover plate. When in use, pressure can be applied in the switch operation direction under the condition of meeting the operating force to turn on the button switch. When the pressure is withdrawn, the button switch is turned off. Its internal structure realizes on-off by the force on the metal carbon sheet.

[0046] The number of independent buttons 310 in the integrated processing module 3 can be set as needed and is not specifically limited here. Figure 3 Only the case where the integrated processing module 3 includes 4 independent buttons 310 is shown here. Each independent button 310 can be connected to the microcontroller 32 through an input / output (IO) interface.

[0047] The user can trigger a key signal by pressing different independent keys and transmit the key signal to the microcontroller 32. An embedded program is configured in the microcontroller 32. This embedded program can include a key scanning algorithm. When the microcontroller 32 runs this key scanning algorithm, it can detect the quasi-bidirectional IO port corresponding to the independent key. When it detects that the quasi-bidirectional IO port corresponding to the independent key is turned on, it performs 5 ms of software debouncing, and then detects the level of this quasi-bidirectional IO port again. If the level of the quasi-bidirectional IO port is low, it determines that the state of the independent key is "pressed". If the level of the quasi-bidirectional IO port is high, it determines that the state of the independent key is "released". By using nested while loops, each time the independent key is quickly pressed and then released (the counter counting time is within 2 s), it is used as a key signal and fed back to the microcontroller. Each time the independent key is long-pressed (the counter counting time exceeds 2 s), it is used as a continuous key signal and fed back to the microcontroller; Furthermore, the microcontroller 32 can use the received key signal to configure the balloon pressure sensor system. For example, it can realize the switching between different measurement standards and zero calibration. Here, different measurement standards can be different units of the target pressure value. For example, it can be mmHg or kPa, etc.

[0048] In the embodiment of the present invention, the integrated processing module can be configured with independent keys, and the interaction between the user and the balloon pressure sensor system is realized through the independent keys, thereby realizing the personalized configuration of the balloon pressure sensor system.

[0049] Based on the above embodiment, the key signal is used to set the reference pressure value; The microcontroller is further configured to: Continuously collect the sampling values of the target voltage signal multiple times and calculate the average value of each sampling value; Calculate the zero-point offset based on the average value and the reference voltage value corresponding to the reference pressure value; Wherein, the zero-point offset is used to perform zero calibration on the target voltage signal.

[0050] Specifically, the user can set the reference pressure value through different independent keys, and thus the key signal triggered by the independent key is used to set the reference pressure value.

[0051] Furthermore, the microcontroller 32 can perform mean filtering and zero calibration by using the reference voltage value corresponding to the reference pressure value. The microcontroller 32 can continuously collect the sampling values of the target voltage signal multiple times. For example, it can continuously collect the sampling values of the target voltage signal 20 times, and then calculate the average value of each sampling value. Thereafter, the microcontroller 32 can use the average value and the reference voltage value to calculate the zero-point offset, and this zero-point offset can be the difference between the average value and the reference voltage value.

[0052] In subsequent operations, this zero offset can be subtracted from the target voltage signal to achieve zero calibration of the target voltage signal.

[0053] In the embodiments of the present invention, zero calibration filtering is achieved through the reference pressure value set by the user, which can eliminate the zero drift that may be caused by the manufacturing process, environmental temperature changes, or long-term use of the piezoresistive pressure sensor. Moreover, through the reference pressure value set by the user, it can be ensured that the measurement results of the piezoresistive pressure sensor at different time points are comparable, improving data consistency. In addition, the reference pressure value can be used as a compensation reference for environmental interferences (such as temperature and humidity), reducing the influence of external factors on the measurement accuracy of the piezoresistive pressure sensor.

[0054] Based on the above embodiments, the sensor voltage signal is a differential-mode voltage signal, and the differential-mode voltage signal includes the positive output signal and the negative output signal of the piezoresistive pressure sensor; The hardware signal processing module includes a first voltage follower circuit, a second voltage follower circuit, a differential amplifier circuit, and a second-order active low-pass filter circuit; The first voltage follower circuit is used to perform impedance transformation and signal isolation on the positive output signal to obtain a first transformed signal; The second voltage follower circuit is used to perform impedance transformation and signal isolation on the negative output signal to obtain a second transformed signal; The positive input terminal of the differential amplifier circuit is used to access the first transformed signal, the negative input terminal is used to access the second transformed signal, and the output terminal is used to output a differential amplified signal; The second-order active low-pass filter circuit is used to perform low-pass filtering on the differential amplified signal to obtain the target voltage signal.

[0055] Specifically, the sensor voltage signal can be a differential-mode voltage signal, that is, the piezoresistive pressure sensor can include a positive output terminal and a negative output terminal. The positive output terminal is used to output a positive output signal, the negative output terminal is used to output a negative output signal, and the positive output signal and the negative output signal form a differential-mode voltage signal.

[0056] Since the equivalent resistance inside the piezoresistive pressure sensor is about 5 kΩ, impedance mismatch between the piezoresistive pressure sensor and the differential amplifier circuit will cause oscillation phenomena. Therefore, to ensure that the sensor voltage signal output by the piezoresistive pressure sensor can be input into the differential amplifier circuit without loss, a first voltage follower circuit and a second voltage follower circuit are respectively introduced at the positive output terminal and the negative output terminal of the piezoresistive pressure sensor.

[0057] Here, both the first voltage follower circuit and the second voltage follower circuit can be emitter followers. The characteristics of an emitter follower are high input resistance, high signal transfer efficiency, low output resistance, and strong load - driving ability, which can isolate the mutual interference between the front and rear circuits.

[0058] The emitter follower can include an OP07 operational amplifier chip. The OP07 operational amplifier chip is a low - noise, non - chopper - stabilized bipolar operational amplifier chip. Due to its very low input offset voltage, the OP07 operational amplifier chip does not require additional zero - adjustment measures in many application scenarios. Moreover, with characteristics such as low input bias current and high open - loop gain, the OP07 is suitable for high - gain and high - precision amplification environments.

[0059] The non - inverting input terminal of the first voltage follower circuit can be connected to the positive - pole output terminal of the piezoresistive pressure sensor, and the inverting input terminal of the first voltage follower circuit can be connected to the output terminal of the first voltage follower circuit. Through the first voltage follower circuit, impedance transformation and signal isolation can be performed on the positive - pole output signal of the piezoresistive pressure sensor to obtain a first transformed signal, and this first transformed signal is output through the output terminal.

[0060] The inverting input terminal of the second voltage follower circuit can be connected to the negative - pole output terminal of the piezoresistive pressure sensor, and the inverting input terminal of the second voltage follower circuit can be connected to the output terminal of the second voltage follower circuit. Through the second voltage follower circuit, impedance transformation and signal isolation can be performed on the negative - pole output signal of the piezoresistive pressure sensor to obtain a second transformed signal, and this second transformed signal is output through the output terminal.

[0061] Since the first voltage follower circuit and the second voltage follower circuit can only isolate the two - end circuits and have no voltage - amplification function, a differential amplifier circuit is also required to amplify the millivolt - level first transformed signal and second transformed signal output by the first voltage follower circuit and the second voltage follower circuit.

[0062] The non - inverting input terminal of the differential amplifier circuit is connected to the output terminal of the first voltage follower circuit for accessing the positive - pole amplified signal. The inverting input terminal of the differential amplifier circuit is connected to the output terminal of the second voltage follower circuit for accessing the negative - pole amplified signal. The output terminal of the differential amplifier circuit is used to output the differential amplified signal.

[0063] As Figure 4 shown, the differential amplifier circuit can include a differential amplifier U1, a feedback resistor R1, an inverting - terminal resistor R2, a non - inverting - terminal resistor R3, and a grounding resistor R4. The non - inverting input terminal of the differential amplifier U1 is the non - inverting input terminal of the differential amplifier circuit for accessing the positive - pole amplified signal , and the inverting input terminal of the differential amplifier U1 is the inverting input terminal of the differential amplifier circuit for accessing the negative - pole amplified signal The output terminal of the differential amplifier U1 is the output terminal of the differential amplification circuit, which is used to output the differential amplification signal GAIN_OUT.

[0064] Here, the differential amplifier U1 can be an OPA227 operational amplifier chip, and the resistance value of the feedback resistor R1 can be 47 kΩ. The differential amplification signal GAIN_OUT can be a voltage signal amplified 47 times.

[0065] The OPA227 operational amplifier chip has low noise (3 nV / ), wide bandwidth (8 MHz, 2.3 V / μs), and high common-mode rejection ratio (138 dB).

[0066] According to the concept of virtual short and virtual open of the ideal operational amplifier, the relationship between the differential amplification signal and the positive input amplification signal Out+ and the negative input amplification signal Out- can be calculated. If R1 = R4 and R2 = R3, then: .

[0067] For example, R1 and R4 can both be set to 47 kΩ, and R2 and R3 can both be set to 1 kΩ.

[0068] In the embodiment of the present invention, the adopted second-order active low-pass filter circuit has the functions of stable gain, wide frequency range, and buffering the output signal. As Figure 5 shown, the second-order active low-pass filter circuit can include an operational amplifier U2, a first input terminal resistor R5, a second input terminal resistor R6, a first capacitor C1, and a second capacitor C2. The first input terminal resistor R5 and the second input terminal resistor R6 are connected in series to the inverting input terminal of the operational amplifier U2, and the inverting input terminal of the operational amplifier U2 is grounded through the first capacitor C1. The non-inverting input terminal of the operational amplifier U2 is connected to the output terminal of the operational amplifier U2. One end of the second capacitor C2 is connected between the first input terminal resistor R5 and the second input terminal resistor R6, and the other end of the second capacitor C2 is connected to the output terminal of the operational amplifier U2.

[0069] If R5 = R6 = R and C1 = C2 = C, the amplification factor of the second-order active low-pass filter circuit can be calculated by the following formula: ; where is the passband gain of the operational amplifier U2, is the amplification factor of the second-order active low-pass filter circuit, that is, the gain, is the natural angular frequency, related to the cut-off frequency f, is the complex frequency, and j is the imaginary unit. Let 1 / RC = , is the target natural angular frequency, If it is the target cut-off frequency, the above formula can be equivalent to: ; Let , then the relationship between the cut-off frequency f and the target cut-off frequency can be deduced as: ; From the above formula, it can be obtained that the target cut-off frequency can be set by changing C and R . Therefore, set C = 4.7 μF and R = 1 kΩ, that is, both R5 and R6 can take the value of 1 kΩ, and the capacitance values of C1 and C2 can both take the value of 4.7 μF.

[0070] The inverting input terminal of the operational amplifier U2 is used to access the differential amplified signal GAIN_OUT. The operational amplifier U2 can perform low-pass filtering on the differential amplified signal GAIN_OUT and output the target voltage signal FILTE_OUT through the output terminal.

[0071] Here, the operational amplifier U2 can be an OP07 operational amplifier chip.

[0072] By connecting the positive output terminal and the negative output terminal of the piezoresistive pressure sensor to the oscilloscope, a fast Fourier transform is performed on the sensor voltage signal output by the piezoresistive pressure sensor to clarify the distribution frequency bands of the sensor voltage signal and the noise. It can be seen from this that the noise of the piezoresistive pressure sensor is mainly distributed in 35 Hz - 50 Hz, and since the piezoresistive pressure sensor is applied to measure human blood pressure, theoretically the sensor voltage signal is mainly distributed in 1 - 5 Hz. Therefore, in the embodiment of the present invention, a second-order active low-pass filter circuit is used to filter out the noise distributed in 35 Hz - 50 Hz in the differential amplified signal, and the target voltage signal FILTE_OUT is obtained and output.

[0073] In the embodiment of the present invention, through the first voltage follower circuit and the second voltage follower circuit, the oscillation phenomenon caused by the impedance mismatch between the piezoresistive pressure sensor and the differential amplification circuit can be avoided. Through the differential amplification circuit, the millivolt-level first transformed signal and second transformed signal can be effectively amplified for subsequent processing. Through the second-order active low-pass filter circuit, the differential amplified signal can be filtered to achieve the purpose of suppressing noise and improving the signal-to-noise ratio.

[0074] On the basis of the above embodiment, the microcontroller is specifically used for: Converting the target voltage signal into a digital signal; Based on the digital signal, applying the sensitivity of the piezoresistive pressure sensor to calculate the sensor pressure signal; Based on the first-order Kalman filter algorithm, filtering out the high-frequency noise in the sensor pressure signal to obtain the target pressure value.

[0075] Specifically, the target voltage signal FILTE_OUT is converted by the analog-to-digital converter (ADC) integrated inside the microcontroller to obtain a digital signal.

[0076] The microcontroller uses the digital signal, combines with the sensitivity of the silicon piezoresistive pressure sensor, and adopts the sensitivity linear fitting equation to calculate the sensor pressure signal.

[0077] The embedded program configured in the microcontroller may also include a first-order Kalman filtering algorithm. Through this first-order Kalman filtering algorithm, the high-frequency noise in the sensor pressure signal can be filtered out, and then a stable target pressure value can be obtained. Here, the essence of the first-order Kalman filtering algorithm is a first-order Kalman filter, and the first-order Kalman filter is a high-efficiency recursive filter (i.e., an autoregressive filter), which processes the noisy input and observation signals based on the linear state space representation to obtain the system state or the true signal.

[0078] The dynamic model of the first-order Kalman filtering algorithm can be represented by a Markov chain, and this Markov chain is established on a linear operator disturbed by Gaussian noise (i.e., normal distribution noise). The state of the dynamic model can be represented by a vector with real numbers as elements. As the discrete time increases, this linear operator acts on the current state of the dynamic model and generates a new state, and some noise will be introduced. At the same time, some known control information of the dynamic model will also be added.

[0079] Assume that the true state of the dynamic model at time k evolves from the true state at time k - 1 , then there is a state equation: ; where is the state transition matrix acting on at time k; is the input control matrix acting on the input vector at time k; is the process noise at time k, which conforms to a multivariate normal distribution with a mean of 0 and a process noise covariance matrix at time k of , that is .

[0080] A measurement of the true state of the dynamic model at time k satisfies the observation equation: ; where is the observation matrix at time k, which is used to map the true state space at time k into the observation space, is the observation noise at time k, which follows a multivariate normal distribution with a mean of 0 and an observation noise covariance matrix at time k of , that is .

[0081] Initial state and the process noise and observation noise at each time are all independent of each other.

[0082] The prior error covariance matrix of the predicted value at time k is calculated through the posterior error covariance matrix at time k-1 and the process noise covariance matrix at time k , and the formula is as follows: ; where is the prior state estimate at time k, is the state estimate at time k-1.

[0083] Furthermore, the posterior error covariance matrix of the predicted value at time k is obtained through the prior error covariance matrix at time k calculated and the Kalman gain , and the formula is as follows: ; where is the posterior state estimate at time k.

[0084] The above process is the state update step of the first-order Kalman filtering algorithm. By adjusting and the tracking performance and smoothness of the filtering curve for the sensor pressure signal can be improved. In the embodiments of the present invention, can take a value of 0.1, can take a value of 0.01.

[0085] In the embodiments of the present invention, through the first-order Kalman filtering algorithm, the high-frequency noise in the sensor pressure signal is filtered out, so that the obtained target pressure value has no high-frequency noise and is more accurate.

[0086] On the basis of the above embodiments, the display screen system includes a display screen and a driving chip, the driving chip is communicatively connected to the microcontroller, and the driving chip is connected to the display screen; The microcontroller is further configured to process the target pressure values at each time into image signals and transmit the image signals to the driving chip; The driving chip is configured to compile the image signals into driving signals and control the display screen to display based on the driving signals.

[0087] Specifically, the driving chip can be physically connected to the microcontroller through the display system slot 34, and information transmission can be achieved through chip select ports such as the serial clock access (SCL) pin, reset pin (RES), serial data access (SDA), chip select pin (CS), data / command selection pin (DC), etc.

[0088] The driving chip can be an SSD1306 chip, which is a 7-pin 0.96-inch single-chip CMOS OLED / PLED driver with a controller for an OLED dot matrix graphic display system.

[0089] The SSD1306 chip can be composed of 128 column outputs (SEG) and 64 row outputs (COM), and is designed specifically for a common cathode OLED panel. The SSD1306 chip can have a built-in contrast controller, display RAM (GDDRAM), and oscillator, thereby reducing the number of external components and power consumption.

[0090] The SSD1306 chip can be sent to the display screen by a generally built-in controller through a hardware-selected 6800 / 8000 series general parallel interface, I2C interface, or hardware SPI.

[0091] The microcontroller can process the target pressure value at each moment into an image signal and transmit the image signal to the driving chip. The implementation principle of this process is as follows: The driving chip is in page addressing mode, with a total of 8 pages, and each page has 8 rows of pixels; the microcontroller, as the host, sends the instruction 0xb(a) to the driving chip, which acts as the slave, to set the starting page to page a, and sends the instructions 0x0(b) and 0x1(c) to set the starting address to bc (hexadecimal); at this time, the host sends multiple hexadecimal data representing the image signal to the slave, and the slave can light up the pixels corresponding to each data from the starting address of the starting page from left to right.

[0092] Thereafter, the driving chip compiles the image signal into a driving signal, sends the driving signal to the display screen, and controls the display screen to display the target intensity value at each moment in the form of an image, for example, displaying the target intensity value at each moment in the form of a curve graph.

[0093] In the embodiment of the present invention, by means of the display screen system, the target intensity value at each moment is displayed, enabling the user to more intuitively understand the pressure change at the tip of the balloon on the target balloon catheter.

[0094] Based on the above embodiment, the silicon piezoresistive pressure sensor includes a Wheatstone circuit, and the Wheatstone circuit includes semiconductor strain gauges; The microcontroller is further configured to: apply an excitation voltage to the Wheatstone circuit, so that the semiconductor strain gauge senses the external pressure at the position of the tip of the balloon, and the Wheatstone circuit outputs the sensor voltage signal.

[0095] Specifically, the microcontroller can apply an excitation voltage to the Wheatstone circuit through a flexible printed circuit board. The excitation voltage can be 5V. When the Wheatstone circuit is turned on and the semiconductor strain gauge senses the external pressure at the position of the tip of the balloon, the Wheatstone circuit outputs the sensor voltage signal.

[0096] In the embodiment of the present invention, through the Wheatstone circuit, the sensor voltage signal can be quickly sensed, thereby ensuring the high sensitivity of the silicon piezoresistive pressure sensor.

[0097] Based on the above embodiment, as Figure 3 shown, the integrated processing module 3 further includes a first USB interface 38; The first USB interface 38 is used to connect to a power source or burn an embedded program into the microcontroller.

[0098] Based on the above embodiment, as Figure 3 shown, the integrated processing module 3 further includes a second USB interface 39; The second USB interface 39 is used to connect to a power source or a host computer. The integrated processing module 3 can communicate with the host computer through the USART serial port protocol; The microcontroller is further configured to transmit the target pressure value to the host computer; The host computer is used to apply the target pressure value.

[0099] It can be understood that both the first USB interface and the second USB interface are connected to the USB2.0 serial bus integrated inside the microcontroller, including 6 bidirectional endpoints, supporting 4 transfer modes (control transfer, interrupt transfer, bulk transfer, and isochronous transfer respectively), and each endpoint has a 64-byte buffer. This part is used to burn the written embedded program.

[0100] Based on the above embodiment, the integrated processing module 3 further includes a reset button 37 for resetting the integrated processing module 3.

[0101] Based on the above embodiments, when the STC8051U single-chip microcontroller is used as the microcontroller in the embodiments of the present invention, the P1.0~P1.7 pins of the STC8051U single-chip microcontroller are used as ADC acquisition channels. Among them, the P1.0~P1.3 pins are floating inputs and are connected to empty header pins for collecting external signals of the integrated processing module 3. The P1.4 pin is directly connected to the operational amplifier for collecting the sensor voltage signal output by the silicon piezoresistive pressure sensor. The P1.5~P1.7 are connected to the filtering circuit for collecting the filtered signals; P3.0 and P3.1 are used as DM and DP signal ports respectively and are connected to the first USB interface; P3.2~P3.6 are used as SCL, RES, SDA, CS, and DC chip select ports respectively for connecting the driver chip; P0.0 and P0.1 are used as RxD3 and TxD3 for USART serial port protocol communication, and the baud rate is set to 115200; P2.0~P2.3 are respectively connected to 4 independent buttons for facilitating the transmission of button signals.

[0102] The embedded program in the microcontroller is implemented in C language and is used to implement and process the signals output by the sampling hardware signal processing circuit, as well as the algorithms for implementing the human-computer interaction function, which may include creating status flag bits, state machine scanning flag bits and performing task scheduling, first-order Kalman filtering algorithm, mean filtering and zero calibration algorithm, button scanning algorithm, USART serial port protocol communication, etc.

[0103] Among them, the status flag bit is used to provide a working standard for the state machine in the microcontroller. The state machine scans the current status flag bit and preferentially assigns the tasks executed by the microcontroller to the tasks corresponding to the current flag bit.

[0104] Based on the above embodiments, the embodiments of the present invention also provide a blood pressure measurement method, which can be implemented by using the balloon pressure sensor system provided in the above embodiments. The execution subject can be the integrated processing module in the balloon pressure sensor system. The processing process is detailed in the above embodiments and will not be repeated here.

[0105] Figure 6 An example of the physical structure diagram of an electronic device is shown in Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640. Among them, the processor 610, the communication interface 620, and the memory 630 complete mutual communication through the communication bus 640. The processor 610 can call the logical instructions in the memory 630 to execute the blood pressure measurement method provided in the above embodiments.

[0106] In addition, when the logical instructions in the above-mentioned memory 630 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the related technology, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0107] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program that can be stored on a computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the blood pressure measurement methods provided in the above-mentioned various embodiments.

[0108] On another aspect, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is implemented to execute the blood pressure measurement methods provided in the above-mentioned various embodiments. This computer-readable storage medium can be either a non-transitory computer-readable storage medium or a transitory computer-readable storage medium, and no specific limitation is made here.

[0109] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative labor.

[0110] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution or the part that contributes to the related technology can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A balloon pressure sensor system, characterized in that, Comprising: A silicon piezoresistive pressure sensor, a flexible printed circuit board, and an integrated processing module. The integrated processing module includes a hardware signal processing module, a microcontroller, and a display screen system that are connected in sequence; The flexible printed circuit board is disposed through the target balloon catheter. The silicon piezoresistive pressure sensor is fixed to the first end of the flexible printed circuit board and is used to measure in real time the initial pressure value at the tip of the balloon sleeved on the target balloon catheter, and output a sensor voltage signal representing the initial pressure value; The second end of the flexible printed circuit board is connected to the integrated processing module and is used to transmit the sensor voltage signal to the hardware signal processing module; The hardware signal processing module is used to amplify and perform low-pass filtering on the sensor voltage signal to obtain a target voltage signal; The microcontroller is used to determine a sensor pressure signal based on the target voltage signal, filter out high-frequency noise in the sensor pressure signal to obtain a target pressure value, and control the display screen system to display the target pressure value.

2. The balloon pressure sensor system according to claim 1, wherein The integrated processing module further includes an independent button; The independent button is connected to the microcontroller and is used to transmit a button signal triggered by the user to the microcontroller; The microcontroller is further used to configure the balloon pressure sensor system based on the button signal; 3. The balloon pressure sensor system according to claim 2, wherein The button signal is used to set a reference pressure value; The microcontroller is further used for: Continuously collecting multiple sampling values of the target voltage signal and calculating the average value of each sampling value; Calculating a zero-point offset based on the average value and the reference voltage value corresponding to the reference pressure value; Wherein, the zero-point offset is used to perform zero-point calibration on the target voltage signal.

4. The balloon pressure sensor system according to claim 1, characterized in that, The sensor voltage signal is a differential-mode voltage signal, and the differential-mode voltage signal includes a positive output signal and a negative output signal of the silicon piezoresistive pressure sensor; The hardware signal processing module includes a first voltage follower circuit, a second voltage follower circuit, a differential amplifier circuit, and a second-order active low-pass filter circuit; The first voltage follower circuit is used to perform impedance transformation and signal isolation on the positive output signal to obtain a first transformed signal; The second voltage follower circuit is used to perform impedance transformation and signal isolation on the negative output signal to obtain a second transformed signal; The positive input terminal of the differential amplifier circuit is used to access the first transformed signal, the negative input terminal is used to access the second transformed signal, and the output terminal is used to output a differential amplified signal; The second-order active low-pass filter circuit is used to perform low-pass filtering on the differential amplified signal to obtain the target voltage signal.

5. The balloon pressure sensor system according to claim 1, characterized in that The microcontroller is specifically used for: Converting the target voltage signal into a digital signal; Calculating the sensor pressure signal based on the digital signal and applying the sensitivity of the silicon piezoresistive pressure sensor; Filtering out high-frequency noise in the sensor pressure signal based on a first-order Kalman filtering algorithm to obtain the target pressure value.

6. The balloon pressure sensor system according to claim 1, characterized in that, The display screen system includes a display screen and a driving chip. The driving chip is communicatively connected to the microcontroller, and the driving chip is connected to the display screen; The microcontroller is further configured to process the target pressure values at each moment into an image signal and transmit the image signal to the driving chip; The driving chip is configured to compile the image signal into a driving signal and control the display screen to display based on the driving signal.

7. The balloon pressure sensor system according to claim 1, wherein The piezoresistive pressure sensor includes a Wheatstone circuit, and the Wheatstone circuit includes semiconductor strain gauges; The microcontroller is further configured to: apply an excitation voltage to the Wheatstone circuit so that the semiconductor strain gauges sense the external pressure at the position where the tip of the balloon is located, and the Wheatstone circuit outputs the sensor voltage signal.

8. The balloon pressure sensor system according to any one of claims 1-7, characterized in that, The integrated processing module further includes a first USB interface; The first USB interface is used to connect to a power source or burn a program into the microcontroller.

9. The balloon pressure sensor system according to any one of claims 1-7, characterized in that The integrated processing module further includes a second USB interface; The second USB interface is used to connect to a power source or a host computer; The microcontroller is further configured to transmit the target pressure value to the host computer; The host computer is used to apply the target pressure value.

10. A blood pressure measurement method, characterized in that, It is implemented by applying the balloon pressure sensor system according to any one of claims 1-9.

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