Full-scale high-precision vacuum gauge master control circuit based on MEMS technology

Abstract

The utility model discloses a full-scale high-precision vacuum gauge master control circuit based on MEMS technology, which relates to the field of vacuum degree detection and comprises a power supply unit, a master control unit and a pressure sensor unit. The power supply unit supplies power to the main control unit and the pressure sensor unit; the main control unit comprises a main control chip and a sensor unit, and obtains vacuum and pressure information through communication with the pressure sensor and the thermocouple sensor; according to the pressure sensor unit, by reading a pressure sensor, external equipment can obtain pressure readings with higher precision near the atmospheric pressure. The beneficial effects are realized as follows: the MEMS thermal conductive chip is adopted, the circuit is simple, the size is small, the cost is low, and the piezoresistive sensor is adopted to detect more accurately.

Description

Technical Field

[0001] The utility model relates to the technical field of vacuum degree detection, in particular to a full-range high-precision vacuum gauge main control circuit based on MEMS technology. Background Art

[0002] The main principles for measuring vacuum degree are: film capacitance, Pirani and anion technology. The vacuum gauges designed based on these three technical principles have their own shortcomings. Pirani vacuum gauge is a mechanical vacuum gauge that uses the effect of temperature on the number of gas molecules to measure gas pressure. The measurement accuracy of Pirani vacuum gauge is not high, and the measurement range of Pirani vacuum gauge is relatively limited. It is generally suitable for the measurement of rough pressure vacuum, and there are problems such as steam interference in high vacuum environment. Due to its mechanical structure, it is easily affected by vibration and temperature, so it cannot be used in high temperature and high radiation environment. Capacitive vacuum gauge is a sensor vacuum gauge that uses changes in gas properties to measure gas pressure. Capacitive vacuum gauge has certain requirements for the test environment, such as extremely high requirements for vacuum quality, no gas or steam contamination is allowed, the test environment should be dry, clean and stable, and care should be taken to avoid manual damage to the electrode during use. Vacuum gauges designed with anion technology usually use the hot cathode ionization method. The disadvantages are that the reading is related to the type of gas, and different curves are required for different gases; the filament is in an incandescent state, and a sudden leak in the vacuum system or a sudden increase in pressure will damage the filament; the gas is adsorbed on the cathode and the collecting surface, which is prone to measurement errors; at low pressure, the discharge phenomenon between the gauge housing and the electrode affects the reading. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the embodiment of the utility model proposes a full-range high-precision vacuum gauge main control circuit based on MEMS technology. The technical solution of the utility model adopts a MEMS thermal conductivity chip to measure the vacuum degree through the principle of thermal conductivity, that is, the Pirani principle, which not only overcomes the problems of inaccurate measurement of the Pirani vacuum gauge in the prior art and the influence of the mechanical structure, but also adopts a MEMS thermal conductivity chip, which has the advantages of simple circuit, small size and low cost, and the piezoresistive sensor is used for more accurate detection.

[0004] According to an embodiment of the utility model, a full-range high-precision vacuum gauge main control circuit based on MEMS technology comprises: a power supply unit, a main control unit, and a pressure sensor unit;

[0005] The power supply unit supplies power to the main control unit and the pressure sensor unit;

[0006] The main control unit includes a main control chip and a sensor unit, and acquires vacuum and pressure information by communicating with a pressure sensor and a thermocouple sensor;

[0007] The pressure sensor unit enables an external device to obtain a more accurate pressure reading near atmospheric pressure by reading the pressure sensor.

[0008] Furthermore, the power supply unit includes a power supply control chip, a power supply VDD end is connected in parallel with one end of a fourth capacitor and a first pin of the power supply control chip, and the other end of the fourth capacitor is connected in parallel with a second pin of the power supply control chip and is grounded; an enable end of a third pin of the power supply control chip is connected to an LDOEN end; a fifth pin of the power supply control chip is connected to one end of a fifth capacitor and outputs an operating voltage of 1.2V; and the other end of the fifth capacitor C5 is grounded.

[0009] Further, the thermocouple sensor includes a first heat source pin HEATER1, a second heat source pin HEATER2, a positive thermal resistor pin TH+ and a negative thermal resistor pin TH-, a thermopile is connected between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, when a specified voltage is applied between the first heat source pin HEATER1 and the second heat source pin HEATER2, a stable heat source is generated between the first heat source pin and the second heat source pin, and heat is transferred to the surface of the thermopile through the gas molecules in the measured environment, when the target gas concentration in the measured environment changes, an electrical signal difference can be generated between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, and a differential signal is detected; the positive electrode TH+ of the thermocouple sensor is connected in parallel with one end of the sixth capacitor and the fifteenth pin of the main control chip, and the other end of the sixth capacitor is connected to the fourteenth pin of the main control chip and the first resistor pin. The first and second terminals are connected in parallel, the other end of the first resistor is connected to the second pin of the main control chip, the negative electrode TH- of the thermocouple sensor is connected in parallel with one end of the third capacitor and the sixteenth pin VCM of the main control chip; the other end of the third capacitor is grounded; one end of the power supply VDD is connected in parallel with the first capacitor and the nineteenth pin of the main control chip, and the other end of the first capacitor is connected in parallel with the twentieth pin of the main control chip; the 1.2V voltage terminal is connected to one end of the second resistor, the other end of the second resistor is connected in parallel with the eighteenth pin of the main control chip and one end of the second capacitor, and the other end of the second capacitor is connected in parallel with the seventeenth pin of the main control chip and the twentieth pin of the main control chip; the ninth pin of the main control chip U is connected to the SDA terminal; the eleventh pin of the main control chip is connected in parallel with the twelfth pin of the main control chip and the SCL terminal; the fifth pin of the main control chip is connected to the LDOEN terminal; the eighth pin of the main control chip is connected to the ICPCK terminal; the seventh pin of the main control chip is connected to the ICPDA terminal.

[0010] Further, the pressure sensor unit includes a pressure sensor chip, one end of the power supply VDD is connected in parallel with one end of the seventh capacitor, the first pin of the pressure sensor chip, and the third pin of the pressure sensor chip; the other end of the seventh capacitor is connected in parallel with the second pin of the pressure sensor chip and is grounded; the eighth pin of the pressure sensor chip is grounded; the sixth pin of the pressure sensor chip is connected to the SDA end; and the fifth pin of the pressure sensor chip is connected to the SCL end.

[0011] Furthermore, the pressure sensor chip is CPS122.

[0012] Furthermore, the main control chip is BH66F5242.

[0013] Furthermore, the power chip is TPL730F12.

[0014] The technical solution provided by the embodiment of the utility model is a thermal conductivity chip developed based on MEMS technology. The circuit module for measuring vacuum degree is designed, which has the advantages of simple circuit, small size and low cost. At the same time, a piezoresistive sensor is added near atmospheric pressure, combined with the thermal conductivity chip, so that the pressure near atmospheric pressure is detected more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 A structural diagram of the power supply part of a full-range high-precision vacuum gauge main control circuit based on MEMS technology provided in an embodiment of the utility model;

[0017] Figure 2 A schematic diagram of the main control part structure of a full-range high-precision vacuum gauge main control circuit based on MEMS technology provided by an embodiment of the utility model;

[0018] Figure 3 A schematic diagram of the structure of a pressure sensor portion of a full-range high-precision vacuum gauge main control circuit based on MEMS technology provided in an embodiment of the utility model;

[0019] Figure 4 A schematic diagram of a main control circuit of a full-range high-precision vacuum gauge based on MEMS technology is provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0021] Reference Figures 1 to 4 The utility model discloses a full-range high-precision vacuum gauge main control circuit based on MEMS technology. The electronic module structure can be divided into three parts, namely a power supply part, a main control part, and a pressure sensor part.

[0022] The relationship between the parts is:

[0023] The power supply part provides working voltage for the sensor part and the controller.

[0024] The main control part, including a microcontroller (ie, MCU) and a sensor, obtains vacuum and pressure information from the sensor in real time through certain communications.

[0025] The pressure sensor part allows external devices to obtain more accurate pressure readings near atmospheric pressure by reading the pressure sensor.

[0026] The overall working principle is that the MCU reads the vacuum degree information from the sensor part through IIC communication, and then obtains the pressure information from the pressure sensor part to provide pressure data for external devices.

[0027] Reference Figure 1 The specific working process of the power supply part of this embodiment is described as follows:

[0028] Power supply: refer to Figure 1 The power supply part includes a power supply voltage regulator chip and peripheral circuits. This embodiment uses a low temperature drift linear regulator (i.e., LDO) to provide a stable working voltage for the sensor, hereinafter referred to as the power supply chip. The circuit diagram of the power supply part is described as follows:

[0029] The power supply VDD end of the power supply unit is connected in parallel with one end of the fourth capacitor C4 and the first pin of the power supply chip U2 of the power supply unit, and the other end of the fourth capacitor C4 is connected in parallel with the second pin of the power supply chip U2 and is grounded; the enable end of the third pin of the power supply chip U2 is connected to the LDOEN end; the fifth pin of the power supply chip U2 is connected to one end of the fifth capacitor C5, and the output working voltage is 1.2V; the other end of the fifth capacitor C5 is grounded.

[0030] In this embodiment, the power supply part includes a power control chip U2, and its model can be selected as: TPL730F12.

[0031] Reference Figure 2The main control part includes a microcontroller MCU (i.e., a main control chip U1), a thermocouple sensor and peripheral circuits. The main control part is mainly designed around the ADC of the MCU to detect the signal of the thermocouple sensor.

[0032] The thermocouple sensor U3 includes a first heat source pin HEATER1, a second heat source pin HEATER2, a positive thermal resistor pin TH+ and a negative thermal resistor pin TH-, a thermopile is connected between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, when a specified voltage is applied between the first heat source pin HEATER1 and the second heat source pin HEATER2, a stable heat source is generated between the first heat source pin and the second heat source pin, and the heat is transferred to the surface of the thermopile through the gas molecules in the measured environment, when the target gas concentration in the measured environment changes, an electrical signal difference can be generated between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, and a differential signal is detected; the positive electrode TH+ of the thermocouple sensor is connected in parallel with one end of the sixth capacitor C6 and the fifteenth pin of the main control chip U1, the other end of the sixth capacitor C6 is connected in parallel with the fourteenth pin of the main control chip U1 and one end of the first resistor R1, and the other end of the first resistor R1 is connected in parallel with the main control The second pin of the chip U1 is connected, the negative electrode TH- of the thermocouple sensor U3 is connected in parallel with one end of the third capacitor C3 and the sixteenth pin VCM of the main control chip U1; the other end of the third capacitor C3 is grounded; one end of the power supply VDD is connected in parallel with the first capacitor C1 and the nineteenth pin of the main control chip U1, and the other end of the first capacitor C1 is connected in parallel with the twentieth pin of the main control chip U1 and is grounded; the 1.2V voltage end is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected in parallel with the eighteenth pin of the main control chip U1 and one end of the second capacitor C2, and the other end of the second capacitor C2 is connected in parallel with the seventeenth pin of the main control chip U1 and the twentieth pin of the main control chip U1; the ninth pin of the main control chip U1 is connected to the SDA end; the eleventh pin of the main control chip U1 and the twelfth pin are connected in parallel to the SCL end; the fifth pin of the main control chip U1 is connected to the LDOEN end; the eighth pin of the main control chip U1 is connected to the ICPCK end; the seventh pin of the main control chip U1 is connected to the ICPDA end.

[0033] In this embodiment, the main control chip can be selected as BH66F5242.

[0034] Reference Figure 3 In order to obtain better detection accuracy, this embodiment adds a pressure sensor to detect the atmospheric pressure. The pressure sensor part provides pressure reference data for external equipment or transmitters.

[0035] One end of the power supply VDD is connected in parallel with one end of the seventh capacitor C7, the first pin of the pressure sensor chip U4, and the third pin of the pressure sensor chip U4; the other end of the seventh capacitor C7 is connected in parallel with the second pin of the pressure sensor chip U4 and grounded; the eighth pin of the pressure sensor chip U4 is grounded; the sixth pin of the pressure sensor chip U4 is connected to the SDA end; the fifth pin of the pressure sensor chip U4 is connected to the SCL end; the external device obtains pressure information through the SDA end and controls the pressure sensor through the SCL end.

[0036] In this embodiment, the pressure sensor may be of model CPS122.

[0037] The utility model proposes a full-range high-precision vacuum gauge main control circuit based on MEMS technology. Its overall working principle is to detect the vacuum degree through a thermocouple sensor, the MCU reads the vacuum information from the sensor part through IIC communication, and the pressure sensor detects the air pressure to provide pressure data for the external equipment.

[0038] The corresponding electronic module is designed according to the above scheme, which is suitable for application scenarios of medium and low vacuum detection such as freeze drying, high temperature drying, and semiconductor equipment leak detection.

[0039] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

[0040] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0041] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", 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 this specification, the schematic representation 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.

[0042] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A full-range high-precision vacuum gauge main control circuit based on MEMS technology, characterized in that: Including power supply unit, main control unit, pressure sensor unit; The power supply unit supplies power to the main control unit and the pressure sensor unit; The main control unit includes a main control chip and a sensor unit, and acquires vacuum and pressure information by communicating with a pressure sensor and a thermocouple sensor; The pressure sensor unit enables an external device to obtain a more accurate pressure reading near atmospheric pressure by reading the pressure sensor.

2. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 1 is characterized in that: The power supply unit includes a power supply control chip, a power supply VDD terminal is connected in parallel with one end of a fourth capacitor and a first pin of the power supply control chip, and the other end of the fourth capacitor is connected in parallel with a second pin of the power supply control chip and grounded; an enable terminal of a third pin of the power supply control chip is connected with an LDOEN terminal; a fifth pin of the power supply control chip is connected with one end of a fifth capacitor, and an output working voltage of 1.2V is output; The other end of the fifth capacitor C5 is grounded.

3. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 1 is characterized in that: The thermocouple sensor includes a first heat source pin HEATER1, a second heat source pin HEATER2, a positive thermal resistor pin TH+ and a negative thermal resistor pin TH-, a thermopile is connected between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, when a specified voltage is applied between the first heat source pin HEATER1 and the second heat source pin HEATER2, a stable heat source is generated between the first heat source pin and the second heat source pin, and heat is transferred to the surface of the thermopile through gas molecules in the measured environment, when the target gas concentration in the measured environment changes, an electrical signal difference can be generated between the positive thermal resistor pin TH+ and the negative thermal resistor pin TH-, and a differential signal is detected; the positive electrode TH+ of the thermocouple sensor is connected in parallel with one end of the sixth capacitor and the fifteenth pin of the main control chip, and the other end of the sixth capacitor is connected in parallel with the fourteenth pin of the main control chip and one end of the first resistor The first resistor is connected to the second pin of the main control chip, the negative electrode TH- of the thermocouple sensor is connected in parallel with one end of the third capacitor and the sixteenth pin VCM of the main control chip; the other end of the third capacitor is grounded; one end of the power supply VDD is connected in parallel with the first capacitor and the nineteenth pin of the main control chip, and the other end of the first capacitor is connected in parallel with the twentieth pin of the main control chip; the 1.2V voltage end is connected to one end of the second resistor, the other end of the second resistor is connected in parallel with the eighteenth pin of the main control chip and one end of the second capacitor, and the other end of the second capacitor is connected in parallel with the seventeenth pin of the main control chip and the twentieth pin of the main control chip; the ninth pin of the main control chip U is connected to the SDA end; the eleventh pin of the main control chip is connected in parallel with the twelfth pin of the main control chip and the SCL end; the fifth pin of the main control chip is connected to the LDOEN end; the eighth pin of the main control chip is connected to the ICPCK end; the seventh pin of the main control chip is connected to the ICPDA end.

4. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 1 is characterized in that: The pressure sensor unit includes a pressure sensor chip, one end of the power supply VDD is connected in parallel with one end of the seventh capacitor, the first pin of the pressure sensor chip, and the third pin of the pressure sensor chip; the other end of the seventh capacitor is connected in parallel with the second pin of the pressure sensor chip and is grounded; the eighth pin of the pressure sensor chip is grounded; the sixth pin of the pressure sensor chip is connected to the SDA end; and the fifth pin of the pressure sensor chip is connected to the SCL end.

5. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 4 is characterized in that: The pressure sensor chip is CPS122.

6. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 1 is characterized in that: The main control chip is BH66F5242.

7. The full-range high-precision vacuum gauge main control circuit based on MEMS technology according to claim 2 is characterized in that: The power control chip is TPL730F12.

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