Full-range vacuum transmitter master control circuit based on thermal conductivity chip
By designing a differential sampling circuit based on dual MEMS thermal conductivity chips, the problems of detection accuracy and temperature drift of traditional thermal conductivity sensors in environmental vacuum detection are solved, achieving high-precision and low-noise vacuum detection.
Patent Information
- Application Number
- CN202520375865.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2035-03-05
AI Technical Summary
Traditional thermal conductivity sensors suffer from problems such as low detection sensitivity, large detection error, large temperature drift, difficulty in compensating for ambient temperature, and cross-influence in environmental vacuum detection.
A differential sampling circuit design based on dual MEMS thermal conductivity chips is adopted. The open and sealed MEMS chips are used to detect the ambient vacuum value and generate differential signals respectively. Combined with signal processing unit, data processing unit and power management unit, the detection accuracy is improved and temperature drift is reduced.
It achieves high-precision environmental vacuum detection, has low noise characteristics and strong low-temperature drift performance, and is suitable for environmental vacuum detection.
Smart Images
Figure CN223856628U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the environment vacuum degree detection technical field of the circuit module relates to the full range vacuum transmitter master control circuit based on thermal conductivity chip. BACKGROUND
[0002] Because the traditional thermal conductivity sensor utilizes the characteristic that the temperature of the sensor changes with the change of the number of gas molecules of the measured vacuum environment, realizes the detection of the environmental vacuum degree, has many problems such as low detection sensitivity, big detection error, big temperature drift, difficult environmental temperature compensation, cross influence and the like. SUMMARY
[0003] The utility model discloses at least solve one of the technical problems in the prior art, and for this, the utility model embodiment proposes full range vacuum transmitter master control circuit based on thermal conductivity chip, the differential sampling circuit design of high-performance full range vacuum transmitter based on double MEMS thermal conductivity chip, greatly improves the detection precision of environmental vacuum degree and the problem of big temperature drift.
[0004] According to the embodiment of the utility model discloses a kind of full range vacuum transmitter master control circuit based on thermal conductivity chip, comprising: sensor analog front-end unit, signal processing unit, data processing unit, power management unit;
[0005] Sensor analog front-end unit includes thermal conductivity chip, converts the pressure change of target vacuum environment into tiny electrical signal, as the signal source of signal processing part;
[0006] Signal processing unit, the tiny electrical signal generated by the sensor analog front-end part is conditioned and amplified into sampling signal;
[0007] Data processing unit includes single-chip microcomputer, converts the sampling signal of signal processing unit into digital signal, and carries out communication output;
[0008] Power management unit provides power supply for sensor analog front-end unit, signal processing unit, data processing unit.
[0009] Further, sensor analog front-end unit includes open MEMS chip, open MEMS chip includes heater and thermocouple, open MEMS chip includes heater and thermocouple, open MEMS chip heater pin HEATER2 is grounded, open MEMS chip heater pin HEATER1 pin is connected with one end of open MEMS chip power supply control circuit resistance R2, open MEMS chip ground terminal GND 7th, 8th, 2nd, 5th pin is connected in parallel with ground, and open MEMS chip thermocouple TH+ and TH- end output electrical signal AN2 according to environmental temperature change.
[0010] Further, the signal processing unit includes a sealed MEMS chip, and the thermal conduction generates a fixed electrical signal AN3; the sealed MEMS chip includes a heater and a thermocouple, and the sealed MEMS chip is powered by the data processing unit single-chip microcomputer control, the heater pin HEATER1 of the sealed MEMS chip is grounded, the HEATER2 pin is connected to one end of the power supply control circuit resistor R2, the 7th, 8th, 2nd and 5th pins of the sealed MEMS chip are connected in parallel to the ground, and the thermocouple TH+ and TH- ends of the sealed MEMS chip output an electrical signal AN3 according to the change of the ambient temperature.
[0011] Further, the power management unit includes a power management chip and a peripheral circuit, the power management unit includes a power management chip and a peripheral circuit, the first pin IN end and the third pin EN / NC end of the power management chip are connected in parallel to the external power input end VDD end, the first capacitor one end and the second capacitor one end, the second pin GND end of the power management chip is connected in parallel to the first capacitor the other end and the second capacitor the other end; the fifth pin output OUT end of the power management chip is connected in parallel to the third capacitor one end, the fourth capacitor one end and the VHT end; the third capacitor the other end and the fourth capacitor the other end are connected in parallel to the ground.
[0012] Further, the sensor signal sensing unit is connected with the signal processing unit and the power management unit, the first pin VOREG and the second pin VREFP of the data processing unit single-chip microcomputer are connected in parallel with one end of the sixth capacitor and one end of the third resistor, the third pin VREFN and the fourth pin AVSS of the single-chip microcomputer are connected in parallel with one end of the sixth capacitor and one end of the fifth capacitor, the other end of the fifth capacitor is connected in parallel with the other end of the third resistor, the eighth pin VDDVIN end of the single-chip microcomputer, and the power management output VHT end, the fifth pin VCM end of the single-chip microcomputer is connected in parallel with the first pin TH- end of the first MEMS chip thermocouple and the first pin TH- end of the first MEMS chip thermocouple, the eighth pin AN2 end of the single-chip microcomputer is connected with one end of the seventh capacitor and the third pin TH+ end of the first MEMS chip, the ninth pin AN3 end of the single-chip microcomputer is connected with the other end of the seventh capacitor and the third pin TH+ end of the second MEMS chip, the forty-seventh pin PA2 / XT2 / PTCK0 / OCDSCK / ICPCK end of the single-chip microcomputer is connected with the second pin ICPCK end of the first socket, the forty-sixth pin PA0 / XT1 / PTP0 / PTP0I / OCDSDA / ICPDA end of the single-chip microcomputer is connected with the second pin ICPDA end of the first socket, the fourth pin GND end of the first socket is grounded, the first pin VDD of the first socket is connected with the external power supply VDD end, the fortieth pin PA6 / SDIA / STCK / SCK / SCL of the single-chip microcomputer is connected in parallel with the thirty-seventh pin PB3 / SDIA / SDO / TX of the single-chip microcomputer, the fourth pin SCL end of the second socket, and one end of the second bidirectional voltage stabilizing diode, the thirty-ninth pin of the single-chip microcomputer is connected in parallel with one end of the first bidirectional voltage stabilizing diode and the third pin SDA end of the second socket, the first pin VDD end of the second socket is connected in parallel with one end of the third bidirectional voltage stabilizing diode and the external power supply VDD end, the other end of the third bidirectional voltage stabilizing diode is connected in parallel with the other end of the second bidirectional voltage stabilizing diode and the other end of the first bidirectional voltage stabilizing diode and grounded, the second pin GND end of the second socket is grounded, the first pin of the second socket is connected in parallel with the fourth pin VDD end of the third socket, the second pin GND end of the second socket is connected in parallel with the third pin GND end of the third socket, the third pin SDA end of the second socket is connected in parallel with the second pin SDA end of the third socket, the fourth pin SCL end of the second socket is connected in parallel with the first pin SCL end of the third socket, the fifth pin VOUT end of the second socket and the fourth pin of the temperature and humidity sensor chip are connected in parallel with the fifth pin of the third socket.
[0013] Further, the power supply control circuit is connected with the power management unit and the data processing unit, the power management unit outputs VHT end and one end of the first resistor in parallel, the first field effect tube source S end of the second pin is connected with the first field effect tube gate G end of the first pin in parallel, the third pin drain of the first field effect tube is connected with one end of the second resistor, the other end of the second resistor is connected with the first opening MEMS chip sixth pin HEATER2 of the sensor analog front end part, the second closed MEMS chip sixth pin HEATER2 of the signal adjustment part in parallel.
[0014] Further, the temperature drift processing unit is further included, the temperature drift processing unit includes a temperature drift operational amplifier processing chip, the data processing unit single-chip computer eleventh pin PE1 / AN5 / OPIP pin, that is, the DAC output end is connected with the temperature drift operational amplifier processing chip non-inverting input end first pin, the temperature drift operational amplifier processing chip inverting input end third pin is connected with one end of the fourth resistor and one end of the fifth resistor in parallel, the other end of the fifth resistor is connected with the temperature drift operational amplifier processing chip fourth pin and one end of the fourth bidirectional voltage stabilizing diode, the temperature drift operational amplifier processing chip second pin is connected with the ground, the other end of the fifth resistor and the third socket fifth pin VOUT end are connected, the other end of the fourth bidirectional voltage stabilizing diode is connected with the ground, the temperature drift operational amplifier processing chip fifth pin is connected with one end of the eighth capacitor and the external power supply input VDD end in parallel, the other end of the eighth capacitor is connected with the ground.
[0015] Further, the temperature and humidity sensor is further included, the temperature and humidity sensor includes a temperature and humidity sensor chip, the temperature and humidity sensor chip fourth pin GND end is connected with one end of the eleventh capacitor in parallel with the ground, the temperature and humidity sensor chip first pin SDA end is connected with the data processing unit single-chip computer thirty-fourth pin PC5 / SDOA / SDI / SDA / RX end I2C1_SDA end and one end of the tenth resistor in parallel, the data processing unit single-chip computer thirty-fifth pin PC5 / SCSA / SDO / TX end I2C1_SDL end and one end of the ninth resistor are connected in parallel, the other end of the ninth resistor and the other end of the tenth resistor are connected with the other end of the eleventh capacitor, the temperature and humidity sensor chip third pin VDD end and the power management unit VHT end in parallel,
[0016] Further, a pressure sensor processing unit is further included, the pressure sensor processing unit includes a pressure sensor chip, the pressure sensor chip is connected with ground in parallel through a second pin GND end, an eighth pin GND end, and a tenth capacitor other end; a power management unit VHT end is connected with the first pin VDD end of the pressure sensor, a tenth capacitor one end, a third pin VDDIO end of the pressure sensor chip, a sixth resistor one end, a seventh resistor one end, and an eighth resistor one end in parallel; a seventh pin CSB end of the pressure sensor chip is connected with a sixth resistor other end; a sixth pin SDA / MOSI end of the pressure sensor chip is connected with a seventh resistor other end and an I2C2_SDA end of a single-chip microcomputer; a fifth pin SCL / SCLK end of the pressure sensor chip is connected with an eighth resistor other end and an I2C2_SCL end of the single-chip microcomputer.
[0017] The technical scheme provided by the embodiment of the utility model has differential circuit design based on double MEMS thermal conductivity chips, one MEMS thermal conductivity chip is opened, used for detecting environmental vacuum value, and the other MEMS thermal conductivity chip is closed, used for generating differential signal. BRIEF DESCRIPTION OF DRAWINGS
[0018] The above and / or additional aspects and advantages of the utility model will become apparent and more readily appreciated from the following description of the embodiments, with reference to the following drawings, in which:
[0019] Figure 1 It is full range vacuum transmitter main control circuit sensor analog front end unit schematic diagram based on thermal conductivity chip of the utility model embodiment;
[0020] Figure 2 It is signal processing unit schematic diagram based on thermal conductivity chip of the utility model embodiment's full range vacuum transmitter main control circuit;
[0021] Figure 3 It is power management unit schematic diagram based on thermal conductivity chip of the utility model embodiment's full range vacuum transmitter main control circuit;
[0022] Figure 4 It is data processing unit schematic diagram based on thermal conductivity chip of the utility model embodiment's full range vacuum transmitter main control circuit;
[0023] Figure 5 It is principle diagram based on thermal conductivity chip of the utility model embodiment's full range vacuum transmitter main control circuit;
[0024] Figure 6 It is power supply control circuit schematic diagram based on thermal conductivity chip of the utility model example's full range vacuum transmitter main control circuit;
[0025] Figure 7 It is the full range vacuum transmitter master control circuit temperature drift processing unit schematic view based on thermal conductivity chip of the utility model example;
[0026] Figure 8 It is the full range vacuum transmitter master control circuit temperature and humidity sensor unit schematic view based on thermal conductivity chip of the utility model example;
[0027] Figure 9 It is the full range vacuum transmitter master control circuit pressure sensor unit schematic view based on thermal conductivity chip of the utility model example. DETAILED DESCRIPTION
[0028] The embodiments of the utility model are described in detail below, the example of the embodiments is shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.
[0029] Referring to Figures 1 to 9 The utility model discloses a full range vacuum transmitter master control circuit based on thermal conductivity chip, including four parts, respectively as follows: sensor analog front end part, signal conditioning part, data processing unit, power supply part.
[0030] The connection relation of each part is as follows:
[0031] Sensor analog front end part, the pressure change of target vacuum environment is converted into small electric signal according to linear law, and is used as the signal source of signal processing part.
[0032] Signal conditioning part, the small electric signal generated by sensor analog front end part is conditioned and amplified into low noise and low temperature drift sampling signal.
[0033] Data processing unit, this part adopts a singlechip, converts sampling signal into digital signal and carries out communication transmission.
[0034] Power supply part provides power supply for sensor analog front end part, signal conditioning part and data processing unit.
[0035] Referring to Figure 1 And Figure 5 The sensor analog front end part of the full range vacuum transmitter based on thermal conductivity chip of this embodiment is described as follows:
[0036] The sensor analog front-end part uses an open MEMS chip to sense the vacuum value of the external environment. After a specified voltage is applied between HEATER1 and HEATER2, a stable heat source is generated between HEATER1 and HEATER2, and the heat of the heat source is transmitted to other solid surfaces through gas molecules in the environment. A thermocouple is arranged between TH+ and TH-, and the thermocouple generates a small electrical signal according to the heat transmitted by the gas molecules. The greater the change in the target environment vacuum degree, the greater the temperature difference generated by the thermocouple, and the greater the change in the electrical signal AN2.
[0037] In the embodiment, the circuit connection relationship of the sensor analog front-end part is as follows:
[0038] The sensor analog front-end part includes an open MEMS chip, the MEMS chip includes a heater and a thermocouple, and the sensor analog front-end is powered by a power management unit. The power management unit includes a power output VHT end and a power input VIN end. The MEMS chip includes heater pins HEATER1 and HEATER2, wherein the pin HEATER1 is grounded, and the HEATER2 pin is connected to one end of a power supply control circuit resistor R2, which provides a 1.5V voltage to provide a heating power supply for the heater of the MEMS chip. The ground end GND of the MEMS chip is connected in parallel to the 7th, 8th, 2nd and 5th pins, and the thermocouple TH+ and TH- end outputs an electrical signal AN2 according to the change in the ambient temperature generated by the heater.
[0039] In the embodiment, the open MEMS chip can be selected from the model PTCD20-SMD04S_REF.
[0040] Referring to Figure 2 and Figure 5 , the signal processing part of the full-range vacuum transmitter based on the thermal conductivity chip of the embodiment is described as follows:
[0041] The signal adjustment part uses a sealed MEMS chip, and the sealed dry nitrogen has a fixed volume concentration, and the electrical signal AN3 generated by the thermal conductivity is fixed at a constant temperature. AN2 and AN3 form a differential signal input to the ADC interface of the single-chip microcomputer.
[0042] The sealed MEMS chip includes a heater and a thermocouple, and the data processing unit single-chip microcomputer controls power supply of the sealed MEMS chip, the power management unit includes a power output VHT end and a power input VIN end, the sealed MEMS chip includes heater pins HEATER1 and HEATER2, wherein the pin HEATER1 is grounded, and the HEATER2 pin is connected to one end of a power supply control circuit resistor R2, and the end provides a 1.5V voltage as a heating power supply for the MEMS chip heater. The sealed MEMS chip is connected in parallel to the ground end GND of the 7th, 8th, 2nd and 5th pins, and the thermocouple TH+ and TH- ends output an electrical signal AN3 according to the environmental temperature change generated by the heater.
[0043] In the embodiment, the sealed MEMS chip can be selected from the model PTCD20-SMD04S_REF.
[0044] Referring to Figure 3 and Figure 5 , the power supply part is exemplified, wherein VDD is an external power supply end, VIN is an input power supply, VHT is a power management unit output power supply, which provides a microprocessor chip power supply voltage and an ADC sampling bias voltage; GND, a common ground part.
[0045] The power management unit includes a power management chip and a peripheral circuit, the power management unit includes a power management chip and a peripheral circuit, the power management chip first pin IN end, the third pin EN / NC end and the external power input end VDD end, the first capacitor one end, the second capacitor one end are connected in parallel; the second pin GND end of the power management chip is connected in parallel to the other end of the first capacitor and the other end of the second capacitor; the fifth pin output OUT end of the power management chip is connected in parallel to the one end of the third capacitor, the one end of the fourth capacitor and the VHT end; the other end of the third capacitor and the other end of the fourth capacitor are connected in parallel to the ground.
[0046] Referring to Figure 5 and Figure 6 , the sensor analog front-end part and the signal adjustment part are controlled by the single-chip microcomputer, and the power supply control circuit is as follows: the power management unit output VHT end and the first resistor one end are connected in parallel; the 16th pin PD5 / AN10 end of the single-chip microcomputer and the first pin gate G end of the first field effect tube are connected in parallel; the third pin drain of the first field effect tube is connected to the one end of the second resistor, and the other end of the second resistor is connected in parallel to the sixth pin HEATER2 of the first open MEMS chip of the sensor analog front-end part and the sixth pin HEATER2 of the second closed MEMS chip of the signal adjustment part.
[0047] The single-chip microcomputer controls the power supply of the MEMS chip heater, and specifically controls the MEMS chip heater through the PD5 / AN10 pin VHT_EN end of the single-chip microcomputer.
[0048] The power control chip in the embodiment can be selected as TC1055-3.3.
[0049] Referring to Figure 4 and Figure 5 , the data processing unit of the full-range vacuum transmitter based on the thermal conductivity chip in the embodiment is described as follows:
[0050] The data processing unit is processed by a single-chip microcomputer, and the ADC pin receives the differential signal (AN2, AN3) transmitted from the signal conditioning part. The single-chip microcomputer converts the analog signal into a data signal, and performs software filtering, digital gain adjustment, calibration, and other processing, and finally sends the information to the upper computer through IIC communication.
[0051] In the embodiment, the single-chip microcomputer can be selected as BH66F5250.
[0052] Please refer to Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 In the embodiment, the circuit connection of the sensor signal sensing part, the signal processing unit, and the power management unit is further described, wherein VDD is an input power supply, VHT provides a single-chip microcomputer power supply voltage and an ADC sampling bias voltage, and the power supply of the MEMS chip is described as follows:
[0053] The first pin VOREG and the second pin VREFP of the single-chip microcomputer are connected in parallel with one end of the sixth capacitor and one end of the third resistor; the third pin VREFN and the fourth pin AVSS of the single-chip microcomputer are connected in parallel with one end of the sixth capacitor and one end of the fifth capacitor; the other end of the fifth capacitor, the other end of the third resistor, the VDDVIN end of the 48th pin of the single-chip microcomputer, and the VHT end of the power management output are connected in parallel; the VCM end of the fifth pin of the single-chip microcomputer is connected in parallel with the TH- end of the first pin of the second MEMS chip thermocouple and the TH- end of the first MEMS chip thermocouple; the AN2 end of the eighth pin of the single-chip microcomputer is connected with one end of the seventh capacitor and the TH+ end of the third pin of the first MEMS chip; the AN3 end of the ninth pin of the single-chip microcomputer is connected with the other end of the seventh capacitor and the TH+ end of the third pin of the second MEMS chip; the PA2 / XT2 / PTCK0 / OCDSCK / ICPCK end of the 47th pin of the single-chip microcomputer is connected with the ICPCK end of the second pin of the first socket; the PA0 / XT1 / PTP0 / PTP0I / OCDSDA / ICPDA end of the 46th pin of the single-chip microcomputer is connected with the ICPDA end of the second pin of the first socket; the GND end of the fourth pin of the first socket is grounded; the VDD end of the first pin of the first socket is connected with the external power supply VDD end;
[0054] The 40th pin PA6 / SDIA / STCK / SCK / SCL of the single-chip microcomputer is connected in parallel with the 37th pin PB3 / SDIA / SDO / TX of the single-chip microcomputer, the 4th pin SCL end of the 2nd socket, and the one end of the 2nd bidirectional voltage stabilizing diode; the 39th pin of the single-chip microcomputer is connected in parallel with the one end of the 1st bidirectional voltage stabilizing diode and the 3rd pin SDA end of the 2nd socket; the 1st pin VDD end of the 2nd socket is connected in parallel with the one end of the 3rd bidirectional voltage stabilizing diode and the external power supply VDD end; the other end of the 3rd bidirectional voltage stabilizing diode is connected in parallel with the other end of the 2nd bidirectional voltage stabilizing diode and the other end of the 1st bidirectional voltage stabilizing diode and grounded; the 2nd pin GND end of the 2nd socket is grounded; the 1st pin of the 2nd socket is connected in parallel with the 4th pin VDD end of the 3rd socket; the 2nd pin GND end of the 2nd socket is connected in parallel with the 3rd pin GND end of the 3rd socket; the 3rd pin SDA end of the 2nd socket is connected in parallel with the 2nd pin SDA end of the 3rd socket; the 4th pin SCL end of the 2nd socket is connected in parallel with the 1st pin SCL end of the 3rd socket; the 5th pin VOUT end of the 2nd socket and the 4th pin of the temperature and humidity sensor chip are connected in parallel with the 5th pin of the 3rd socket.
[0055] The model of the single-chip microcomputer in the embodiment can be selected as BH66F5250.
[0056] After being processed by the signal processing unit microprocessor chip, the analog signal output by the signal sensing unit is converted into a data signal, and software filtering, digital gain adjustment, calibration, and other processing are performed, and finally the information is sent to the upper computer through IIC communication. In the embodiment, a first interface socket J2 is provided for the upper computer to call.
[0057] Please refer to Figure 7 , in order to further improve the temperature drift, the temperature drift operational amplifier processing part is further described as follows:
[0058] The 11th pin PE1 / AN5 / OPIP of the data processing unit single-chip microcomputer, i.e. the DAC output end, is connected with the 1st pin of the temperature drift operational amplifier processing chip in-phase input end; the 3rd pin of the temperature drift operational amplifier processing chip anti-phase input end is connected in parallel with the one end of the 4th resistor and the 5th resistor, the other end of the 5th resistor is connected with the 4th pin of the temperature drift operational amplifier processing chip and the one end of the 4th bidirectional voltage stabilizing diode; the 2nd pin of the temperature drift operational amplifier processing chip is grounded; the other end of the 5th resistor is connected with the 5th pin VOUT end of the 3rd socket; the other end of the 4th bidirectional voltage stabilizing diode is grounded; the 5th pin of the temperature drift operational amplifier processing chip is connected in parallel with the one end of the 8th capacitor and the external power supply input VDD end, and the other end of the 8th capacitor is grounded.
[0059] The model of the temperature drift operational amplifier processing chip can be selected as TP5591U.
[0060] Please refer to Figure 8 , in order to further obtain temperature and humidity data, a temperature and humidity sensor is used, and the temperature and humidity sensor part is described as follows:
[0061] The fourth pin GND end of the temperature and humidity sensor chip is connected in parallel with one end of the eleventh capacitor and grounded; the first pin SDA end of the temperature and humidity sensor chip is connected in parallel with one end of the tenth resistor and the 34th pin PC5 / SDOA / SDI / SDA / RX end I2C1_SDA end of the data processing unit single-chip microcomputer; the 35th pin PC5 / SCSA / SDO / TX end I2C1_SDL end of the data processing unit single-chip microcomputer is connected in parallel with one end of the ninth resistor; the other end of the ninth resistor, the other end of the tenth resistor, the other end of the eleventh capacitor, the third pin VDD end of the temperature and humidity sensor chip and the VHT end of the power management unit are connected in parallel;
[0062] The temperature and humidity sensor chip can be selected from the model SHT41, and the sensor chip adopts I2C communication.
[0063] Please refer to Figure 9 In order to obtain pressure data, a pressure sensor processing unit can also be included, and the circuit connection is as follows:
[0064] The second pin GND end, the eighth pin GND end and the other end of the tenth capacitor of the pressure sensor chip are connected in parallel and grounded; the VHT end of the power management unit is connected in parallel with the first pin VDD end of the pressure sensor, one end of the tenth capacitor, the third pin VDDIO end of the pressure sensor chip, one end of the sixth resistor, one end of the seventh resistor and one end of the eighth resistor; the seventh pin CSB end of the pressure sensor chip is connected with the other end of the sixth resistor; the sixth pin SDA / MOSI end of the pressure sensor chip is connected with the other end of the seventh resistor and the I2C2_SDA end of the single-chip microcomputer; the fifth pin SCL / SCLK end of the pressure sensor chip is connected with the other end of the eighth resistor and the I2C2_SCL end of the single-chip microcomputer.
[0065] The pressure sensor chip can be selected from the model CPS122.
[0066] According to the vacuum transmitter designed according to the above scheme, it can be seen through actual test that the module has better detection effect on high vacuum degree of the environment, small volume, fast response, flexible data subsequent transmission and processing, strong customizability, and can be conveniently accessed in various electronic systems, and the vacuum detection function of other electronic systems in need can be conveniently expanded. Since the size of the selected core sensing element is small, the preheating is ultra-fast after starting, and the preheating, detection and dormancy can be completed within 300ms. Since it is not like a vacuum transmitter based on electrochemical principle that has material loss, the patent product has an ultra-long service life.
[0067] The utility model embodiment has been described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range possessed by ordinary skilled in the art without departing from the purpose of the utility model.
[0068] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separated, that is, can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs.
[0069] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0070] Although the embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.
Claims
1. A full range vacuum transmitter master control circuit based on a thermal conductivity chip, characterized in that, The application relates to a sensor analog front-end unit, a signal processing unit, a data processing unit and a power management unit. The sensor analog front-end unit comprises a thermal conductivity chip which converts the pressure change of a target vacuum environment into a micro electric signal as a signal source of a signal processing part. The signal processing unit processes and amplifies the micro electric signal generated by the sensor analog front-end part into a sampling signal. The data processing unit comprises a single-chip microcomputer which converts the sampling signal of the signal processing unit into a digital signal and performs communication output. The power management unit provides power supply for the sensor analog front-end unit, the signal processing unit and the data processing unit. The sensor analog front-end unit comprises an open MEMS chip which comprises a heater and a thermocouple, the open MEMS chip heater pin HEATER2 is grounded, the open MEMS chip heater pin HEATER1 is connected with one end of an open MEMS chip power supply control circuit resistor R2, the open MEMS chip ground end GND is connected with the 7th, 8th, 2nd and 5th pins in parallel, and the open MEMS chip thermocouple TH+ and TH- end output an electric signal AN2 according to the change of the ambient temperature. The signal processing unit comprises a sealed MEMS chip which generates a fixed electric signal AN3 through thermal conduction, the sealed MEMS chip comprises a heater and a thermocouple, the sealed MEMS chip is powered by the single-chip microcomputer of the data processing unit, the sealed MEMS chip heater pin HEATER1 is grounded, the HEATER2 pin is connected with one end of a power supply control circuit resistor R2, the 7th, 8th, 2nd and 5th pins of the sealed MEMS chip are connected with the ground in parallel, and the sealed MEMS chip thermocouple TH+ and TH- end output an electric signal AN3 according to the change of the ambient temperature.
2. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, The power management unit comprises a power management chip and a peripheral circuit, the power management unit comprises a power management chip and a peripheral circuit, the 1st pin IN end and the 3rd pin EN / NC end of the power management chip are connected with the external power input end VDD end, the 1st capacitor one end and the 2nd capacitor one end in parallel, the 2nd pin GND end of the power management chip is connected with the other end of the 1st capacitor and the other end of the 2nd capacitor in parallel, the 5th pin output OUT end of the power management chip is connected with the 3rd capacitor one end, the 4th capacitor one end and the VHT end in parallel, and the other end of the 3rd capacitor and the other end of the 4th capacitor are connected with the ground in parallel.
3. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, 4. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, The sensor signal sensing unit is connected with the signal processing unit, power management unit, the data processing unit single-chip microcomputer 1st pin VOREG, 2nd pin VREFP and 6th capacitor one end, 3rd resistor one end are connected in parallel; single-chip microcomputer 3rd pin VREFN, 4th pin AVSS and 6th capacitor one end, 5th capacitor one end are connected in parallel; 5th capacitor other end and 3rd resistor other end, single-chip microcomputer 8th pin VDDVIN end, power management output VHT end are connected in parallel; single-chip microcomputer 5th pin VCM end and 2nd MEMS chip thermocouple 1st pin TH- end, 1st MEMS chip thermocouple TH- end are connected in parallel; single-chip microcomputer 8th pin AN2 end and 7th capacitor one end, 1st MEMS chip 3rd pin TH+ end are connected; single-chip microcomputer 9th pin AN3 end and 7th capacitor other end, 2nd MEMS chip 3rd pin TH+ end are connected; single-chip microcomputer 47th pin PA2 / XT2 / PTCK0 / OCDSCK / ICPCK end and 1st socket 2nd pin ICPCK end are connected; single-chip microcomputer 46th pin PA0 / XT1 / PTP0 / PTP0I / OCDSDA / ICPDA end and 1st socket 2nd pin ICPDA end are connected; 1st socket 4th pin GND end is grounded; first socket 1st pin VDD is connected with external power supply VDD end; the single-chip microcomputer 40th pin PA6 / SDIA / STCK / SCK / SCL and single-chip microcomputer 37th pin PB3 / SDIA / SDO / TX, 2nd socket 4th pin SCL end, 2nd bidirectional voltage stabilizing diode one end are connected in parallel; single-chip microcomputer 39th pin and 1st bidirectional voltage stabilizing diode one end, 2nd socket 3rd pin SDA end are connected in parallel; 2nd socket 1st pin VDD end and external power supply VDD end 3rd bidirectional voltage stabilizing diode one end are connected in parallel; 3rd bidirectional voltage stabilizing diode other end and 2nd bidirectional voltage stabilizing diode other end, 1st bidirectional voltage stabilizing diode other end are connected in parallel and grounded; 2nd socket 2nd pin GND end is grounded; 2nd socket 1st pin and 3rd socket 4th pin VDD end are connected in parallel; 2nd socket 2nd pin GND end and 3rd socket 3rd pin GND end are connected in parallel; 2nd socket 3rd pin SDA end and 3rd socket 2nd pin SDA end are connected in parallel; 2nd socket 4th pin SCL end and 3rd socket 1st pin SCL end are connected in parallel; 2nd socket 5th pin VOUT end, temperature and humidity sensor chip 4th pin and 3rd socket 5th pin are connected in parallel.
5. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1 or 2, wherein, The power supply control circuit is connected with the power management unit and the data processing unit, the power management unit outputs VHT end and one end of the first resistor in parallel, the first end of the first field effect tube and the source S end of the second pin are connected in parallel; the 16th pin PD5 / AN10 end of the data processing unit single-chip microcomputer and the first pin gate G end of the first field effect tube are connected in parallel; the third pin drain of the first field effect tube is connected with one end of the second resistor, and the other end of the second resistor is connected with the sixth pin HEATER2 of the first opening MEMS chip of the sensor analog front-end part, and the sixth pin HEATER2 of the second closed MEMS chip of the signal adjustment part are connected in parallel.
6. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, The temperature drift processing unit further includes a temperature drift operational amplifier processing chip, the 11th pin PE1 / AN5 / OPIP pin of the data processing unit single-chip microcomputer, that is, the DAC output end is connected with the first pin of the in-phase input end of the temperature drift operational amplifier processing chip; the third pin of the anti-phase input end of the temperature drift operational amplifier processing chip is connected with one end of the fourth resistor and one end of the fifth resistor in parallel, the other end of the fifth resistor is connected with the fourth pin of the temperature drift operational amplifier processing chip and one end of the fourth bidirectional voltage stabilizing diode; the second pin of the temperature drift operational amplifier processing chip is connected with the ground; the other end of the fifth resistor is connected with the fifth pin VOUT end of the third socket; the other end of the fourth bidirectional voltage stabilizing diode is connected with the ground; the fifth pin of the temperature drift operational amplifier processing chip is connected with one end of the eighth capacitor and the external power input VDD end in parallel, and the other end of the eighth capacitor is connected with the ground.
7. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, The temperature and humidity sensor unit further includes a temperature and humidity sensor chip, the fourth pin GND end of the temperature and humidity sensor chip is connected with one end of the eleventh capacitor in parallel and connected with the ground; the first pin SDA end of the temperature and humidity sensor chip is connected with the 34th pin PC5 / SDOA / SDI / SDA / RX end I2C1_SDA end of the data processing unit single-chip microcomputer, one end of the tenth resistor in parallel; the 35th pin PC5 / SCSA / SDO / TX end I2C1_SDL end of the data processing unit single-chip microcomputer is connected with one end of the ninth resistor in parallel; the other end of the ninth resistor and the other end of the tenth resistor are connected with the other end of the eleventh capacitor, the third pin VDD end of the temperature and humidity sensor chip and the VHT end of the power management unit in parallel.
8. The thermal conductivity probe-based, full-range vacuum transmitter master circuit of claim 1, wherein, The pressure sensor unit further includes a pressure sensor chip, the second pin GND end, the eighth pin GND end and the other end of the tenth capacitor of the pressure sensor chip are connected with the ground in parallel; the VHT end of the power management unit is connected with the first pin VDD end of the pressure sensor, one end of the tenth capacitor, the third pin VDDIO end of the pressure sensor chip, one end of the sixth resistor, one end of the seventh resistor and one end of the eighth resistor in parallel; the seventh pin CSB end of the pressure sensor chip is connected with the other end of the sixth resistor; the sixth pin SDA / MOSI end of the pressure sensor chip is connected with the other end of the seventh resistor and the I2C2_SDA end of the single-chip microcomputer; the fifth pin SCL / SCLK end of the pressure sensor chip is connected with the other end of the eighth resistor and the I2C2_SCL end of the single-chip microcomputer.