Vital sign detection circuit and device
By adopting multi-stage filtering amplification technology in the vital sign detection circuit, the problem of poor signal filtering effect in the existing technology is solved, signal processing with higher gain and less noise is achieved, and the accuracy and ability of signal acquisition are improved.
Patent Information
- Application Number
- CN202421461205.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-25
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-06-25
AI Technical Summary
The signal filtering effect in existing vital sign monitoring equipment is poor and cannot meet the signal acquisition needs in complex environments.
A multi-stage filter amplification vital sign detection circuit is designed, including first-stage, second-stage and third-stage filter amplification units. Through multi-stage filter amplification, the signal will be processed with higher gain and less noise.
This circuit can capture micro-moving signals that cannot be captured by conventional filtering and amplification circuits, improve the signal performance and accuracy, and enhance the signal acquisition ability in complex environments.
Smart Images
Figure CN222827215U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of circuits, and in particular to a vital sign detection circuit and a corresponding device. Background Art
[0002] Vital sign monitoring is an important branch of the medical field. It can help doctors know the health status of patients in a timely manner and provide important support for the diagnosis and treatment of patients. Traditional vital sign detection methods generally involve direct contact with patients, such as using a thermometer to measure body temperature and a sphygmomanometer to measure blood pressure. This contact detection method has the problem of causing cross infection and large errors.
[0003] In recent years, non-contact vital sign detection technology has received widespread attention. Among them, the technology based on Doppler radar is widely used. It does not require contact with the patient's body, but only requires remote monitoring of the patient, which can greatly reduce the possibility of cross-infection and improve the accuracy of detection.
[0004] In the practical application of Doppler radar technology, signal filtering is the key link in signal acquisition. Signal filtering refers to the process of suppressing and removing the noise interference in the signal to obtain the desired signal components. However, the signal filtering effect of the vital signs monitoring equipment currently on the market is not good and cannot meet the signal acquisition requirements in complex environments. Summary of the invention
[0005] The present application provides a vital sign detection circuit and device, which solves the problem of poor signal filtering effect in the prior art and obtains a signal with higher gain and lower noise.
[0006] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:
[0007] In a first aspect, the present application provides a vital sign detection circuit, comprising:
[0008] The power supply unit is used to provide three DC voltages of 5V, 3.3V and 1.65V for the entire circuit;
[0009] A Doppler sensor unit, used for acquiring original vital sign signals and generating I signals and Q signals;
[0010] The primary filtering unit includes an I signal primary filtering and amplifying circuit and a Q signal primary filtering and amplifying circuit, and performs primary filtering and amplifying on the I signal and the Q signal respectively;
[0011] A signal processing unit, used to process the filtered and amplified signal and transmit it to the control end, and receive control instructions from the control end;
[0012] Input and output unit, used to provide general input and output ports;
[0013] A communication unit, used for providing an external communication channel for the signal processing unit;
[0014] The display unit is used to provide indicator light display.
[0015] In a possible implementation, the detection circuit further includes:
[0016] The secondary filtering unit comprises an I signal secondary filtering and amplifying circuit and a Q signal secondary filtering and amplifying circuit, and is used for performing secondary filtering and amplifying on the signal after the primary filtering and amplification.
[0017] In a possible implementation, the detection circuit further includes:
[0018] The three-stage filtering unit is used to perform three-stage filtering and amplification on the signal after the two-stage filtering and amplification.
[0019] In a possible implementation, the three-stage filtering unit includes:
[0020] The I signal three-stage high-gain filtering and amplifying circuit is used to perform three-stage high-gain filtering and amplifying on the I signal after the second-stage filtering;
[0021] The Q signal three-stage high-gain filtering and amplifying circuit is used for performing three-stage high-gain filtering and amplifying on the Q signal after the second-stage filtering.
[0022] In a possible implementation, the three-stage filtering unit includes:
[0023] The I signal three-stage low-gain filtering and amplifying circuit is used to perform three-stage low-gain filtering and amplifying on the I signal after the second-stage filtering;
[0024] The Q signal three-stage low-gain filtering and amplifying circuit is used for performing three-stage low-gain filtering and amplifying on the Q signal after the second-stage filtering.
[0025] In a possible implementation, the signal processing unit includes an MCU, a startup area setting circuit, a debugging circuit, a reset circuit, and an extended sampling circuit.
[0026] In a possible implementation, the input-output unit includes a mode switching unit, a data switching unit, and a general data input-output unit.
[0027] In a possible implementation, the communication unit includes a WiFi communication circuit or a 485 communication circuit.
[0028] In a second aspect, the present application provides a nursing alarm device, comprising:
[0029] A PCB board is provided with the above-mentioned vital sign detection circuit.
[0030] In a possible implementation, the PCB board includes:
[0031] Master substrate: equipped with a secondary filter amplifier unit, a tertiary low-gain filter amplifier unit, a tertiary high-gain filter amplifier unit, a signal processing unit, an input and output unit, a communication unit, a display unit, and 5V, 3.3V, and 1.65V power supply circuits;
[0032] Sub substrate: It is equipped with a Doppler sensor unit, a first-stage filter amplifier unit, and 3.3V and 1.65V power supply circuits.
[0033] The technical solution provided by the embodiments of the present application may have the following beneficial effects:
[0034] The circuit adopts a multi-stage filtering and amplification method to enhance the performance of tiny signals at the signal processing end, so that the vital signs monitoring system can capture micro-motion signals that conventional filtering and amplification circuits cannot capture.
[0035] The circuit board is divided into a master substrate and a sub substrate. The sub substrate provides the original low-gain filtered and amplified signal. The master substrate further filters and amplifies the low-gain filtered and amplified signal provided by the sub substrate to obtain a signal with higher gain and lower noise. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0038] Figure 1 A schematic diagram of the circuit structure of a Doppler sensor unit and a first-stage filter amplifier unit of a vital sign detection circuit provided in an embodiment of the present application;
[0039] Figure 2 It is a schematic diagram of the circuit principle of the MCU of the signal processing unit;
[0040] Figure 3 A schematic diagram of a circuit for setting a circuit for a startup region of a signal processing unit;
[0041] Figure 4 It is a circuit principle schematic diagram of a debugging circuit of a signal processing unit;
[0042] Figure 5 is a circuit principle schematic diagram of a reset circuit of a signal processing unit;
[0043] Figure 6 It is a circuit principle schematic diagram of an extended sampling circuit of a signal processing unit;
[0044] Figure 7 It is a circuit principle schematic diagram of the WiFi communication circuit of the communication unit;
[0045] Figure 8 It is a circuit principle diagram of the 485 communication circuit of the communication unit;
[0046] Fig. 9 It is a schematic diagram of the circuit principle of the display unit;
[0047] Fig.10 It is a circuit principle diagram of the I signal two-stage filtering and amplifying circuit;
[0048] Fig.11 It is a circuit principle diagram of a Q signal secondary filtering and amplifying circuit;
[0049] Fig.12 It is a circuit principle diagram of a three-stage high-gain filter amplifier circuit for an I signal;
[0050] Fig.13 It is a circuit principle diagram of a three-stage high-gain filter amplifier circuit for Q signals;
[0051] Fig.14 It is a circuit principle diagram of a three-stage low-gain filter amplifier circuit for an I signal;
[0052] Fig.15 It is a circuit principle diagram of a Q signal three-stage low-gain filter amplifier circuit;
[0053] Fig.16 It is a schematic diagram of the circuit principle that the power supply unit provides 3.3V and 1.65V voltages for the sub board;
[0054] Fig.17 This is a schematic diagram of the circuit principle that the power supply unit provides 3.3V and 1.65V voltages for the master board;
[0055] Fig.18 It is a schematic diagram of a power adapter in which the power supply unit provides 5V voltage to the master board. DETAILED DESCRIPTION
[0056] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.
[0057] In order to better understand the present application, the implementation methods of the present application are explained in detail below with reference to the accompanying drawings.
[0058] Embodiment 1
[0059] The present application provides a vital sign alarm circuit, comprising a power supply unit, a Doppler sensor unit, a primary filtering unit, a signal processing unit, an input and output unit, a communication unit, and a display unit.
[0060] Figure 1 It is a Doppler sensor unit and a first-stage filtering and amplifying unit.
[0061] The Doppler sensor unit is one of the core components of the enhanced vital sign detection circuit board and is the information sensing end of the circuit board system. The sensor uses 24GHz (also 60GHz, 77GHz, 80GHz) microwave Doppler technology to detect moving and micro-moving targets. It integrates antennas, radio frequency units, intermediate frequency amplifiers, microcontrollers and regulators in a small package, which can be used for equipment control of human body sensing.
[0062] The sensor (NJR4262) has a supply voltage range of 3.3V-5.5V, a rated operating current of 45mA, and a rated EIRP of 40mW.
[0063] In order to filter out the high and low frequency noise of the current, capacitors are used for filtering, and the filter capacitors are C119 and C121. Capacitor C119 uses CC0603MRX5R6BB106 from YAGEO, and capacitor C121 uses C0603X7R104K101NT from Sanyear.
[0064] The first-stage filter amplifier unit includes an I-signal first-stage filter amplifier circuit and a Q-signal first-stage filter amplifier circuit.
[0065] The core component of the I signal first-stage filter amplifier circuit adopts the operational amplifier U103 (to simplify the design, the three sub-components of U103, U103A, U103B, and U103C, are used), using the LMV324IPWR of TEXAS INSTRUMENTS, the capacitors C108, C109, and C110 are Sanyear's C0603X7R104K101NT, the capacitors C111, C112, and C113 are YAGEO's CC0603MRX5R6BB106, the capacitors C114, C115, and C116 are TDK's CGA3E3X5R1A155M080AB, the capacitor C117 is YAGEO's CC0603KRX7R0BB221, the capacitor C118 is SAMSUNG's CL10B331KB8NNNC, and the capacitor C120 is Murata's Manufacturing's GRM188C80E476ME05D, capacitor C122 uses Sanyear's C0603X5R226M160NT, resistors R105, R106, and R113 use YAGEO's RC0603JR-07510KL, resistors R107, R109, and R114 use YAGEO's RC0603JR-0710KL, resistor R108 uses Panasonic's ERJ3GEY0R00V, resistors R110 and R111 use YAGEO's RT0603CRE07100KL, and resistor R112 uses YAGEO's RC0603JR-07390KL.
[0066] The core component of the Q signal first-stage filter amplifier circuit is the operational amplifier U104 (to simplify the design, the three sub-components of U104, U104A, U104B, and U104C, are used), using TEXAS INSTRUMENTS's LMV324IPWR, capacitors C123, C124, and C125 are Sanyear's C0603X7R104K101NT, capacitors C126, C127, and C128 are YAGEO's CC0603MRX5R6BB106, capacitors C129, C130, and C131 are TDK's CGA3E3X5R1A155M080AB, capacitor C132 is YAGEO's CC0603KRX7R0BB221, capacitor C133 is SAMSUNG's CL10B331KB8NNNC, and capacitor C134 is Murata's Manufacturing's GRM188C80E476ME05D, capacitor C135 uses Sanyear's C0603X5R226M160NT, resistors R115, R116, and R123 use YAGEO's RC0603JR-07510KL, resistors R117, R119, and R124 use YAGEO's RC0603JR-0710KL, resistor R118 uses Panasonic's ERJ3GEY0R00V, resistors R120 and R121 use YAGEO's RT0603CRE07100KL, and resistor R122 uses YAGEO's RC0603JR-07390KL.
[0067] Figure 2-Figure 6 Together they form a signal processing unit, which is responsible for data processing, peripheral control, etc. of the circuit board. This part includes MCU (control unit), startup area setting circuit, debugging circuit, reset circuit, and extended sampling circuit.
[0068] like Figure 2 As shown, the MCU uses the STM32F103C8T6 of STMICROELECTRONICS. This MCU is a 32-bit microcontroller chip based on the ARMCortex-M3 core STM32 series. The operating voltage range of this MCU is 2V-3.6V, the program storage Flash capacity is 64KB, the static random access memory SRAM capacity is 20KB, and the maximum frequency can reach 72MHz. This MCU has rich peripheral resources, including multiple general-purpose I / O pins, serial communication interfaces, timers, analog-to-digital converters (ADCs), SPI, I2C, etc., which can meet various application requirements and support multiple communication protocols and buses, such as CAN, USB, Ethernet, etc., which can easily communicate with other devices.
[0069] like Figure 3 As shown, the startup area setting circuit includes resistors R64 and R65, and the two resistors are RC0603JR-0710KL of YAGEO.
[0070] like Figure 4 As shown, the debugging circuit unit includes resistors, capacitors and interface plug-ins. The auxiliary circuit includes components such as resistors R59, R60, R61, R62, and R67, which are RC0603JR-0733KL from YAGEO, capacitor C59 is C0603X7R104K101NT from Sanyear, and interface plug-in DEBUG is ST-FH-127-0017 (separated for use) from Stride Electronics.
[0071] like Figure 5 As shown, the reset circuit unit includes a key switch, a resistor, and a capacitor. The auxiliary circuit includes components, specifically, the key switch NRST uses TS-1101-CW of XKB Connection (China Star Kun), the resistor R66 uses RC0603JR-0710KL of YAGEO, and the capacitor C60 uses C0603X7R104K101NT of Sanyear.
[0072] like Figure 6 As shown, the extended sampling circuit unit includes resistors, capacitors and interface plug-ins. The auxiliary circuit includes components such as resistor R68, which uses YAGEO's RC0603JR-0733KL, capacitor C61, which uses YAGEO's CC0603MRX5R6BB106, capacitor C62, which uses Sanyear's C0603X7R104K101NT, and interface plug-in "Extension" uses ST-FH-127-0017 (open for use) from Stride Electronics.
[0073] The input and output units include a mode switching unit, a data switching unit, and a general data input and output unit.
[0074] The mode switching unit includes components, specifically the dip switch SW1 adopts TS-1101-CW of XKB Connection (China Xingkun).
[0075] The data switching unit plug-in "Data Switch" uses Megastar's ZX-PZ2.54-2-5PZZ.
[0076] The general data input and output unit includes a serial port interface unit, an expansion interface unit, and a 485 communication interface unit. The "serial port" plug-in of the serial port interface unit and the plug-in of the expansion interface unit are both ST-FH-127-0017 (separated for use) from Stride Electronics.
[0077] Figure 7 , Figure 8 Together they form a communication unit, which includes a Wifi communication circuit and a 485 communication circuit.
[0078] The core component of the Wifi communication circuit uses Espressif's ESP32WROOM32, capacitor C64 uses YAGEO's CC0603MRX5R6BB106, capacitors C66 and C70 use Sanyear's C0603X7R104K101NT, capacitor C68 uses YAGEO's CC0603KRX5R8BB105, resistors R69 and R70 use YAGEO's RC0603JR-0710KL, the push switches WRST and DOWN use XKB Connection's TS-1101-CW, and the interface plug-in "channel selection" uses Megastar's ZX-PZ2.54-2-5PZZ.
[0079] The core component of the 485 communication circuit is Texas Instruments' SN65176BDR, capacitor C72 is YAGEO's CC0603MRX5R6BB106, capacitor C73 is Sanyear's C0603X7R104K101NT, resistors R73, R74, R75, and R76 are YAGEO's RC0603JR-0733KL, resistor R77 is YAGEO's RC0603FR-07120RL, resistor R78 is Panasonic's ERJ3GEY0R00V, and the interface plug-in is ST-FH-127-0017 (broken apart for use) from Skytron Electronics.
[0080] Fig. 9 The display unit shown includes a light emitting diode LED and a resistor. Specifically, the light emitting diode LED1 adopts NCD0603G1 of Nationstar Optoelectronics, the light emitting diode LED2 adopts NCD0603B1 of Nationstar Optoelectronics, and the resistors R71 and R72 adopt SY0603BD1KP of NCD0603B1.
[0081] Example 2
[0082] On the basis of Example 1, a secondary filtering and amplifying unit is added, and the secondary filtering and amplifying unit includes an I signal secondary filtering and amplifying circuit and a Q signal secondary filtering and amplifying circuit, which are used to perform secondary filtering and amplifying on the signal after the primary filtering and amplification.
[0083] Fig.10 The figure shows the I signal secondary filter amplifier circuit. The left side of resistor R8 is the input terminal, which is connected to the output terminal of the I signal primary filter amplifier circuit. The core component is the operational amplifier U4 (to simplify the design, the two sub-components of U4, U4A and U4B, are used), and the LMV324IPWR of TEXAS INSTRUMENTS is used. The capacitors C13, C14, C15, and C27 are Sanyear's C0603X7R104K101NT, the capacitors C19 and C21 are YAGEO's CC0603MRX5R6BB106, the capacitors C25 and C26 are TDK's CGA3E3X5R1A155M080AB, the capacitor C28 is YAGEO's CC0603KRX7R0BB221, the capacitor C29 is SAMSUNG's CL10B331KB8NNN, and the capacitor C3 is 0 uses Murata Manufacturing's GRM188C80E476ME05D, capacitor C31 uses Sanyear's C0603X5R226M160NT, resistor R8 uses YAGEO's RC0603JR-0710KL, resistors R5, R6, and R22 use YAGEO's RC0603JR-07510KL, resistors R17 and R18 use YAGEO's RT0603CRE07100KL, and resistor R20 uses YAGEO's RC0603JR-07390KL.
[0084] Fig.11The figure shows the Q signal secondary filter amplifier circuit. The left side of the resistor R35 is the input terminal, which is connected to the output terminal of the Q signal primary filter amplifier circuit. The core component is the operational amplifier U6 (to simplify the design, the two sub-components of U6, U6A and U6B, are specifically used). The LMV324IPWR of TEXAS INSTRUMENTS is used. The capacitors C36, C37, C38, and C50 are Sanyear's C0603X7R104K101NT. The capacitors C42 and C44 are YAGEO's CC0603MRX5R6BB106. The capacitors C48 and C49 are TDK's CGA3E3X5R1A155M080AB. The capacitor C51 is YAGEO's CC0603KRX7R0BB221. The capacitor C52 is SAMSUNG's CL10B331KB8NNN. The capacitor C53 is The one used is Murata Manufacturing's GRM188C80E476ME05D, the capacitor C54 is Sanyear's C0603X5R226M160NT, the resistor R35 is YAGEO's RC0603JR-0710KL, the resistors R32, R33, and R49 are YAGEO's RC0603JR-07510KL, the resistors R44 and R45 are YAGEO's RT0603CRE07100KL, and the resistor R47 is YAGEO's RC0603JR-07390KL.
[0085] Example 3
[0086] On the basis of Embodiment 2, a third-stage filtering and amplifying unit is further added to perform third-stage filtering and amplification on the signal after the second-stage filtering and amplification.
[0087] 1) Structure 1:
[0088] The three-stage filtering unit includes:
[0089] The I signal three-stage high-gain filtering and amplifying circuit is used for performing three-stage high-gain filtering and amplifying on the I signal after the second-stage filtering.
[0090] See also Fig.12The left side of resistor R11 is the input end, which is connected to the output end of the I signal secondary filter amplifier circuit. The I signal three-stage high-gain filter amplifier circuit includes operational amplifiers U4 and U5 (to simplify the design, specifically use U4C of U4 and U5A and U5B of U5), both of which use LMV324IPWR of TEXAS INSTRUMENTS, capacitors C16 and C22 use C1608X7S0J685K080AC of TDK, capacitors C17, C18, C23 and C24 use CC0603MRX5R6BB106 of YAGEO, capacitor C20 uses C0603X7R104K101NT of Sanyear, resistor R7 uses WR06X182JTL of Walsin, and resistor R9 uses Vishay Intertechnology's TNPW06033K20BEEA, resistor R10 uses VishayIntertechnology's PCAN0603E2501BST5, R11 uses Stackpole Electronics' RMCF0603FT64K9, R12 uses Vishay Intertechnology's TNPW0603126KBEEA, resistor R13 uses YAGEO's RT0603BRD0767K3L, resistor R14 uses YAGEO's RC0603FR-07120RL, resistor R15 uses Walsin's WR06X1300FTL, resistor R16 uses YAGEO's RC0603FR-07200RL, resistor R19 uses Stackpole Electronics' RMCF0603FT6K19, and resistors R21 and R23 use YAGEO's RC0603JR-0710KL.
[0091] The Q signal three-stage high-gain filtering and amplifying circuit is used for performing three-stage high-gain filtering and amplifying on the Q signal after the second-stage filtering.
[0092] See also Fig.13The left side of resistor R38 is the input end, which is connected to the output end of the Q signal secondary filter amplifier circuit. The Q signal tertiary high-gain filter amplifier circuit includes operational amplifiers U6 and U7 (to simplify the design, specifically use U6C of U6 and U7A and U7B of U7), both of which use LMV324IPWR of TEXAS INSTRUMENTS, capacitors C39 and C45 use C1608X7S0J685K080AC of TDK, capacitors C40, C41, C46 and C47 use CC0603MRX5R6BB106 of YAGEO, capacitor C43 uses C0603X7R104K101NT of Sanyear, resistor R34 uses WR06X182JTL of Walsin, and resistor R36 uses Vishay Intertechnology's TNPW06033K20BEEA, resistor R37 uses VishayIntertechnology's PCAN0603E2501BST5, R38 uses Stackpole Electronics' RMCF0603FT64K9, R39 uses Vishay Intertechnology's TNPW0603126KBEEA, resistor R40 uses YAGEO's RT0603BRD0767K3L, resistor R41 uses YAGEO's RC0603FR-07120RL, resistor R42 uses Walsin's WR06X1300FTL, resistor R43 uses YAGEO's RC0603FR-07200RL, resistor R46 uses Stackpole Electronics' RMCF0603FT6K19, and resistors R48 and R50 use YAGEO's RC0603JR-0710KL.
[0093] 2) Structure 2:
[0094] The three-stage filtering unit includes:
[0095] The I signal three-stage low-gain filtering and amplifying circuit is used for performing three-stage low-gain filtering and amplifying on the I signal after the second-stage filtering.
[0096] See also Fig.14The left side of resistor R26 is the input end, which is connected to the output end of the I signal secondary filter amplifier circuit. The I signal tertiary filter amplifier circuit includes operational amplifiers U4 and U5 (to simplify the design, specifically use U4D component of U4 and U5C component of U5), both of which are made of TEXAS INSTRUMENTS's LMV324IPWR, capacitors C32 and C34 use TDK's C1608X5R1E335KT000E, capacitors C33 and C35 use TDK's C1608X7S0J685K080AC, resistors R26 and R27 use YAGEO's AC0603FR-0727KL, resistors R24 and R25 use YAGEO's RC0603FR-073K9L, resistors R28 and R29 use Walsin's WR06X8200FTL, and resistors R30 and R31 use YAGEO's RC0603JR-0710KL.
[0097] The Q signal three-stage low-gain filtering and amplifying circuit is used for performing three-stage low-gain filtering and amplifying on the Q signal after the second-stage filtering.
[0098] See also Fig.15 The left side of resistor R53 is the input end, which is connected to the output end of the Q signal secondary filter amplifier circuit. The Q signal tertiary filter amplifier circuit includes operational amplifiers U6 and U7 (to simplify the design, specifically use U6D component of U6 and U7C component of U7), both of which use TEXAS INSTRUMENTS's LMV324IPWR, capacitors C55 and C57 use TDK's C1608X5R1E335KT000E, capacitors C56 and C58 use TDK's C1608X7S0J685K080AC, resistors R53 and R54 use YAGEO's AC0603FR-0727KL, resistors R51 and R52 use YAGEO's RC0603FR-073K9L, resistors R55 and R56 use Walsin's WR06X8200FTL, and resistors R57 and R58 use YAGEO's RC0603JR-0710KL.
[0099] 3) Structure 3:
[0100] The three-stage filtering unit also includes:
[0101] The I signal three-stage high-gain filter amplifier circuit, the Q signal three-stage high-gain filter amplifier circuit, the I signal three-stage low-gain filter amplifier circuit, and the Q signal three-stage low-gain filter amplifier circuit have the same circuit principles as above.
[0102] The present application also provides a nursing alarm device, including a PCB board, on which the above-mentioned vital sign detection circuit is arranged.
[0103] The PCB board is divided into two circuit boards, namely the master substrate and the sub substrate. The sub substrate provides the original low-gain filtered amplified signal, and the master substrate further filters and amplifies the low-gain filtered amplified signal provided by the sub substrate to obtain a signal with higher gain and less noise.
[0104] The master substrate is provided with a secondary filter amplifier unit, a tertiary low-gain filter amplifier unit, a tertiary high-gain filter amplifier unit, a signal processing unit, an input and output unit, a communication unit, a display unit, and 5V, 3.3V, and 1.65V power supply circuits;
[0105] The sub substrate is provided with a Doppler sensor unit, a first-stage filtering and amplifying unit, and 3.3V and 1.65V power supply circuits.
[0106] In actual applications, the signal flows from the sensor side of the sub-substrate to the first-stage filter amplifier unit, then flows to the second-stage filter amplifier unit and the third-stage filter amplifier unit through the wires between the master substrate and the sub-substrate, and then flows to the signal processing unit. After being processed by the MCU, the preliminary judgment result is uploaded to the control end, and then the control end performs status judgment. The final judgment result is displayed on the user-side web page. If an alarm is generated, the relevant nursing staff will assist in handling it.
[0107] The master substrate and sub substrate (hereinafter referred to as the master substrate and sub substrate as a whole is a circuit board) are powered by a 5V / 2A adapter. Since the circuit requires three different voltages of 5V, 3.3V, and 1.65V, and in order to maintain low power supply noise, the power supplies of the analog circuit part and the digital circuit part are separated and powered independently.
[0108] See also Fig.16 The power supply circuit of the sub substrate includes a first electromagnetic compatibility processing unit and a first voltage conversion unit.
[0109] The first electromagnetic compatibility processing unit includes a resettable fuse and a diode. The auxiliary circuit includes components, specifically, the resettable fuse F101 adopts SMD050F-2 of Littelfuse, and the diode D101 adopts 1N4148 of NXP.
[0110] The first voltage conversion unit is an independent power supply for the sub-substrate. When the power supply from the master substrate to the sub-substrate is unstable and there is crosstalk such as high ripple, the independent power supply of the sub-substrate is used. This is a redundant design. The actual working environment is not harsh, so it is not installed. The voltage conversion unit includes 3.3V voltage and 1.6V voltage output, both of which are power supplies for analog circuits.
[0111] The 3.3V power supply part of the first voltage conversion unit includes a fourth low-dropout linear regulator (LDO), a resistor, and a reliable power input interface. The auxiliary circuit includes components, specifically the fourth low-dropout linear regulator U101 uses JRC's NJM2881F33, capacitor C101 uses YAGEO's CC0603MRX5R6BB106, capacitor C103 uses YAGEO's CC0603KRX5R8BB105, and capacitors C102 and C105 use Sanyear's C0603X7R104K101NT. The reliable power input interface J101 adopts a surface-mount pad design without placing connectors. The wires connecting the master and sub substrates are soldered here one by one.
[0112] The 1.65V power supply part of the first voltage conversion unit includes resistors and capacitors. The capacitor C106 is CC0603MRX5R6BB106 from YAGEO, the capacitor C107 is C0603X7R104K101NT from Sanyear, and the resistors R103 and R104 are RC0603JR-0710KL from YAGEO.
[0113] See also Fig.17 and Fig.18 The power supply circuit of the master substrate includes a second electromagnetic compatibility processing unit, a second voltage conversion unit and a power adapter.
[0114] The power adapter is connected through the Type-C interface, and the Type-C interface socket uses XUNPU's TYPEC-304-ACP16.
[0115] The second voltage conversion unit mainly uses two chips, NJM2881F33 and AMS1117-3.3. NJM2881F33 is a low-dropout voltage regulator with ON / OFF control function. Advanced bipolar technology achieves low noise, high ripple suppression and low quiescent current. It is mounted on SOT-23-5 (MTP5) in a small package and corresponds to a 1.0μF ceramic capacitor. Its input voltage is 4.3V-9.3V, the output voltage is 3.3V, and the maximum output current is 0.3A. AMS1117-3.3 is a low-dropout linear regulator with an output voltage of 3.3V, which has the advantages of wide input voltage range, small temperature drift and good linearity. Its input voltage range is 4.5V-15V, the output voltage is 3.3V, and the maximum output current is 1.5A.
[0116] The 3.3V voltage and 1.65V voltage of the analog part of the master substrate are provided by the first LDO.
[0117] The 3.3V voltage part of the analog part of the master substrate includes: low-dropout linear regulator (LDO), capacitors, and resistors. The auxiliary circuit includes components, specifically, the first low-dropout linear regulator U1 uses JRC's NJM2881F33, capacitors C4 and C7 use Sanyear's C0603X7R104K101NT, capacitor C3 uses YAGEO's CC0603MRX5R6BB106, and resistor R2 uses YAGEO's RC0603JR-0710KL. The 1.65V voltage part of the analog part of the master substrate includes capacitors and resistors. The auxiliary circuit includes components, specifically capacitors C1 and C5 use CC0603MRX5R6BB106 from YAGEO, capacitors C2 and C6 use C0603X7R104K101NT from Sanyear, resistors R1 and R2 use RC0603JR-0710KL from YAGEO, and resistor R63 uses ERJ3GEY0R00V from PANASONIC.
[0118] The 3.3V voltage part of the communication unit of the digital part of the master substrate includes: a third LDO and a capacitor. The auxiliary circuit includes components, specifically capacitor C11 uses Sanyear's C0603X7R104K101NT, and capacitor C12 uses YAGEO's CC0603MRX5R6BB106.
[0119] The 3.3V voltage part of the digital part of the master substrate, except for the communication unit, includes: the second LDO, resistors, and capacitors. The auxiliary circuit includes components, specifically, the low-voltage dropout linear regulator U2 uses JRC's NJM2881F33, the resistor R4 uses YAGEO's RC0603JR-0710KL, the capacitor C8 uses YAGEO's CC0603MRX5R6BB106, and the capacitors C9 and C10 use Sanyear's C0603X7R104K101NT.
[0120] The second electromagnetic compatibility processing unit includes: a resettable fuse and a chip inductor. The resettable fuse uses Littelfuse's SMD050F-2, and the chip inductor uses MURATA's DFE18SANR24ME0L.
[0121] Current overload protection devices are placed in the voltage supply circuit of the master substrate to protect electronic equipment and circuits from damage and ensure the safe operation of the system. The resettable fuse can detect overcurrent in the circuit and quickly disconnect the circuit when overcurrent occurs to prevent excessive current from damaging equipment or wires. The ground plane of the analog circuit and the ground plane of the digital circuit are connected at only one point, and the two grounds are connected to a common location to reduce the crosstalk of high-frequency digital signal noise to the analog part. On the master substrate, the digital part and the analog part are connected at a single point through a chip inductor.
[0122] The master substrate and sub substrate also have the following designs:
[0123] 1) The master substrate and sub substrate are connected by wires, and the relative positions are fixed by the sensor direction adjustment mechanism.
[0124] 2) The production process of the board uses FR4-TG150 material and immersion gold process, which has better physical properties and better signal transmission performance than ordinary FR4 materials.
[0125] 3) Both the sub-substrate and the master-substrate adopt a two-layer stacking structure, which is the top signal layer and the bottom signal layer. The top signal layer and the bottom signal layer are copper-clad with GND network and a via array is placed to improve the heat dissipation capacity of the board and reduce the loop area of the signal to improve the anti-interference ability of the board.
[0126] 4) Both the master substrate and the sub substrate have reasonably partitioned and isolated the analog signal part and the digital signal part, so that the high-frequency signal and the low-frequency signal are separated, further enhancing the anti-interference ability of the circuit board.
[0127] 5) Teardrops are placed on both the master substrate and the sub substrate to prevent the circuit board pads from falling off and smooth the impedance, enhancing the signal transmission performance of the circuit board.
[0128] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.
Claims
1. A vital sign detection circuit, characterized in that: include: The power supply unit is used to provide three DC voltages of 5V, 3.3V and 1.65V for the entire circuit; A Doppler sensor unit, used for acquiring original vital sign signals and generating I signals and Q signals; The primary filtering unit includes an I signal primary filtering and amplifying circuit and a Q signal primary filtering and amplifying circuit, and performs primary filtering and amplifying on the I signal and the Q signal respectively; A signal processing unit, used to process the filtered and amplified signal and transmit it to the control end, and receive control instructions from the control end; Input and output unit, used to provide general input and output ports; A communication unit, used for providing an external communication channel for the signal processing unit; The display unit is used to provide indicator light display.
2. A vital sign detection circuit according to claim 1, characterized in that: The detection circuit also includes: The secondary filtering unit comprises an I signal secondary filtering and amplifying circuit and a Q signal secondary filtering and amplifying circuit, and is used for performing secondary filtering and amplifying on the signal after the primary filtering and amplification.
3. A vital sign detection circuit according to claim 2, characterized in that: The detection circuit also includes: The three-stage filtering unit is used to perform three-stage filtering and amplification on the signal after the two-stage filtering and amplification.
4. A vital sign detection circuit according to claim 3, characterized in that: The three-stage filtering unit includes: The I signal three-stage high-gain filtering and amplifying circuit is used to perform three-stage high-gain filtering and amplifying on the I signal after the second-stage filtering; The Q signal three-stage high-gain filtering and amplifying circuit is used for performing three-stage high-gain filtering and amplifying on the Q signal after the second-stage filtering.
5. A vital sign detection circuit according to claim 3, characterized in that: The three-stage filtering unit includes: The I signal three-stage low-gain filtering and amplifying circuit is used to perform three-stage low-gain filtering and amplifying on the I signal after the second-stage filtering; The Q signal three-stage low-gain filtering and amplifying circuit is used for performing three-stage low-gain filtering and amplifying on the Q signal after the second-stage filtering.
6. A vital sign detection circuit according to any one of claims 1 to 5, characterized in that: The signal processing unit includes an MCU, a startup area setting circuit, a debugging circuit, a reset circuit, and an extended sampling circuit.
7. A vital sign detection circuit according to any one of claims 1 to 5, characterized in that: The input-output unit includes a mode switching unit, a data switching unit, and a general data input-output unit.
8. A vital sign detection circuit according to any one of claims 1 to 5, characterized in that: The communication unit includes a WiFi communication circuit or a 485 communication circuit.
9. A vital sign detection device, characterized in that: include: A PCB board, wherein the vital sign detection circuit according to claim 1 is arranged on the PCB board.
10. A vital sign detection device according to claim 9, characterized in that the PCB board include: Master substrate: equipped with a secondary filter amplifier unit, a tertiary low-gain filter amplifier unit, a tertiary high-gain filter amplifier unit, a signal processing unit, an input and output unit, a communication unit, a display unit, and 5V, 3.3V, and 1.65V power supply circuits; Sub substrate: It is equipped with a Doppler sensor unit, a first-stage filter amplifier unit, and 3.3V and 1.65V power supply circuits.