Device for measuring G-ohm-level large resistance and device for measuring internal resistance of G-ohm-level semiconductor type gas sensor

Abstract

The utility model discloses a device for measuring the internal resistance of a G-ohm-level semiconductor type gas sensor. The device comprises a direct-current power supply Ur, a controllable capacitor charging and discharging circuit, a microcontroller and an acquisition circuit, the direct-current power supply Ur is connected in series with the capacitor C through the semiconductor sensor to be detected; a collector electrode of the triode Q1 is connected to a series connection point of the semiconductor sensor to be detected and the capacitor C through a resistor R4, a base electrode is connected to an I / O output end of the microcontroller through a resistor R5, an emitter electrode is grounded, and a resistor R6 is further connected between the base electrode and the emitter electrode; one end of the sampling resistor R1 is connected to a series connection point of the semiconductor sensor to be tested and the capacitor C, and the other end is connected to a normal phase input end of the operational amplifier UT; one end of the resistor R2 is grounded, and the other end is connected to the inverting input end of the operational amplifier UT; the resistor R3 is connected between the inverting input end and the output end of the operational amplifier UT; and the output end of the operational amplifier UT is connected to the I / O input end of the microcontroller.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor device measurement, in particular to a device for measuring the internal resistance of a G-ohm level semiconductor gas sensor. Background Technique

[0002] Semiconductor resistive gas sensors have been widely used in the gas sensing field due to their low cost and easy preparation. However, the gas sensitive materials of current commercial sensors are still limited to the field of metal oxides. One of the major limiting factors is that the existing test technologies for integrated circuit sensors cannot meet the resistance test requirements of G-ohm level large resistance sensors. People often apply a relatively high working temperature to reduce the resistance of the metal oxide gas sensitive material to a measurable range, and at the same time improve the reaction activity of the material to achieve gas detection. Taking the leading gas sensor companies at home and abroad such as Figaro (Japan) and Winsensor Technology (China) as examples (refer to the official websites: www.figaro.co.jp; www.winsensor.com), no matter what gas the semiconductor gas sensors they produce are used to detect, the room temperature ultimate resistance of their gas sensitive materials is in the M-ohm level (<10 6 Ω) and requires a working temperature of one hundred or even several hundred degrees (the semiconductor resistance will further decrease at high temperatures). However, the high temperature leads to high power consumption of the sensor, so an external power supply is required during the actual use of the sensor, and the manufacturing cost and maintenance cost of the sensor are high, which greatly limits the development of gas sensors.

[0003] In recent years, the gas sensing performance of two-dimensional materials has received wide attention. Due to their large specific surface area and strong activity, they are an ideal choice for realizing room temperature and low power consumption sensing. At present, although two-dimensional materials have achieved very ideal gas sensing performance in laboratory research, the resistance of two-dimensional materials is generally in the G-ohm level (10 6 -10 9 Ω range) (refer to the relevant literature: J. Mater. Chem. A , 2023, 11, 35; J. Hazard. Mater. 2023, 455, 131591; ACS Appl. Mater. Interfaces, 2021, 13, 45). In laboratory research, an electrochemical workstation (a large-volume detection device with high precision but extremely high cost) is used for gas sensitive resistance performance testing, and the deviceization of the sensor cannot be realized. If the current commercial sensor test circuit board (a voltage dividing circuit for measuring resistance) is used to measure the resistance, when the sensor resistance is in the G-ohm level, the test circuit is equivalent to an open circuit, and when the sensor resistance changes, the circuit cannot generate a detectable response value. Therefore, although two-dimensional materials have excellent performance at present, the bottleneck of circuit board measurement must be overcome in the development of engineering applications. The current commercial integrated circuit board can only achieve 10 6Sensor tests below Ω have led to the inability to truly apply a large number of two-dimensional materials with excellent performance but slightly higher resistance in engineering practice. It can be seen that developing an integrated circuit test platform capable of detecting sensors with GΩ-level large resistances can not only meet the test requirements of existing two-dimensional materials but also be universal for all large-resistance semiconductor materials, with great practical value in engineering applications. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present utility model designs a device for measuring the internal resistance of a GΩ-level semiconductor gas sensor using an integrated circuit board based on the principle of capacitor charging and discharging.

[0005] The object of the present utility model is achieved by the following technical solutions:

[0006] In a first aspect, the present utility model provides a device for measuring GΩ-level large resistances, including: a DC power supply Ur, a controllable capacitor charging and discharging circuit, a microcontroller, and a sampling circuit;

[0007] The controllable capacitor charging and discharging circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6, and a triode Q1;

[0008] The DC power supply Ur is connected in series with the capacitor C through the large resistance to be measured, so as to charge and discharge the capacitor C through the large resistance to be measured;

[0009] The collector of the triode Q1 is connected to the series connection point of the large resistance to be measured and the capacitor C through the resistor R4, the base is connected to the I / O output end of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is also connected between the base and the emitter to control the charging and discharging process of the capacitor C;

[0010] The sampling circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2, and a resistor R3;

[0011] One end of the sampling resistor R1 is connected to the series connection point of the large resistance to be measured and the capacitor C, and the other end is connected to the positive input terminal of the operational amplifier UT;

[0012] One end of the resistor R2 is grounded, and the other end is connected to the negative input terminal of the operational amplifier UT;

[0013] The resistor R3 is connected between the negative input terminal and the output terminal of the operational amplifier UT;

[0014] The output terminal of the operational amplifier UT is connected to the I / O input terminal of the microcontroller;

[0015] The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

[0016] In a second aspect, the present utility model provides a device for measuring the internal resistance of a G-ohm-level semiconductor gas sensor, comprising: a DC power supply Ur, a controllable capacitor charging and discharging circuit, a microcontroller, and a acquisition circuit;

[0017] The controllable capacitor charging and discharging circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6, and a triode Q1;

[0018] The DC power supply Ur is connected in series with the capacitor C through the semiconductor sensor to be measured, so as to charge and discharge the capacitor C through the semiconductor sensor to be measured;

[0019] The collector of the triode Q1 is connected to the series connection point of the semiconductor sensor to be measured and the capacitor C through the resistor R4, the base is connected to the I / O output end of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is also connected between the base and the emitter to control the charging and discharging process of the capacitor C;

[0020] The acquisition circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2, and a resistor R3;

[0021] One end of the sampling resistor R1 is connected to the series connection point of the semiconductor sensor to be measured and the capacitor C, and the other end is connected to the positive-phase input end of the operational amplifier UT;

[0022] One end of the resistor R2 is grounded, and the other end is connected to the inverting input end of the operational amplifier UT;

[0023] The resistor R3 is connected between the inverting input end and the output end of the operational amplifier UT;

[0024] The output end of the operational amplifier UT is connected to the I / O input end of the microcontroller;

[0025] The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

[0026] The present utility model has substantial features and progress compared with the prior art. Specifically:

[0027] 1. The device of the present utility model uses a simple and low-cost controllable capacitor charging and discharging circuit, so that when measuring the resistance, the size of the resistance can be accurately and quickly measured, and the drawback that the input resistance of the voltage division circuit in the existing current-voltage method is too large to perform AD conversion is solved.

[0028] 2. The device of the present utility model has the characteristic of low power consumption;

[0029] The device of the present utility model realizes with extremely few components. Since the measured resistance is large, the power consumption during charging is extremely low; while during discharging, the consumed is the electric quantity of the capacitor. Therefore, during the operation process, the current is very small, achieving the purpose of low-power operation.

[0030] 3. The technical solution of the present utility model is cheap and easy to implement;

[0031] The device of the present utility model can realize the processing of semiconductor sensor signals by using only one capacitor, and has the advantages of fewer components used and good stability compared with the traditional signal conditioning circuit.

[0032] 4. The present utility model can charge the capacitor with a low voltage, replacing the existing high-voltage circuit for measuring large resistances, which is both simple and practical.

[0033] 5. The device for measuring the internal resistance of a GΩ-level semiconductor gas sensor based on the RC charge-discharge circuit on an integrated circuit board designed by the present utility model can fill the technical gap in the testing of large-resistance gas sensors, thereby effectively applying two-dimensional semiconductor materials with excellent gas-sensing performance to gas sensing and achieving high-performance and low-power gas sensing. This technical solution can be used as a universal testing platform in the future and extended to all large-resistance gas sensors, not limited to two-dimensional semiconductor gas-sensing materials. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the following will briefly introduce the drawings required to be used in the description of the embodiments or the related technologies. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is the circuit schematic diagram of the device in Embodiment 1.

[0036] Figure 2 It is the voltage change diagram at both ends of the capacitor C during charging.

[0037] Figure 3 It is the circuit schematic diagram of the device in Embodiment 2.

[0038] Figure 4 It is the circuit schematic diagram of the microcontroller in Embodiments 1 and 2.

[0039] Figure 5 It is the circuit schematic diagram of the power management circuit in Embodiments 1 and 2. Detailed Embodiments

[0040] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application.

[0041] Embodiment 1

[0042] This embodiment provides a device for measuring GΩ-level large resistors, as Figure 1 shown, including: a DC power supply Ur, a controllable capacitor charge and discharge circuit, a microcontroller, and a acquisition circuit;

[0043] The controllable capacitor charge and discharge circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6, and a triode Q1;

[0044] The DC power supply Ur is connected in series with the capacitor C through the large resistor to be measured, so as to charge and discharge the capacitor C through the large resistor to be measured;

[0045] The collector of the triode Q1 is connected to the series connection point of the large resistor to be measured and the capacitor C through the resistor R4, the base is connected to the I / O output end of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is also connected between the base and the emitter to control the charge and discharge process of the capacitor C;

[0046] The acquisition circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2, and a resistor R3;

[0047] One end of the sampling resistor R1 is connected to the series connection point of the large resistor to be measured and the capacitor C, and the other end is connected to the non-inverting input terminal of the operational amplifier UT;

[0048] One end of the resistor R2 is grounded, and the other end is connected to the inverting input terminal of the operational amplifier UT;

[0049] The resistor R3 is connected between the inverting input terminal and the output terminal of the operational amplifier UT;

[0050] The output terminal of the operational amplifier UT is connected to the I / O input terminal of the microcontroller;

[0051] The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

[0052] Technical principle of the device in this embodiment:

[0053] When the triode Q1 is turned off, the DC power supply Ur starts to charge the capacitor C through the internal resistance R of the semiconductor sensor to be measured. The voltage value across the capacitor C is amplified by the operational amplifier UT and then enters the microcontroller for AD conversion, converting the electrical analog quantity into a digital quantity, and thus the magnitude of the voltage U0 can be obtained. As the capacitor C is continuously charged, the voltage U0 across it rises rapidly. When the voltage charged across the capacitor C reaches a certain value, the charging stops, and the charging time t is recorded;

[0054] The resistance value of the large resistor to be measured can be obtained through the calculation formula (1):

[0055] (1)

[0056] In formula (1), U is the rated voltage of the capacitor C;

[0057] When the triode Q1 is turned on, the capacitor C can be quickly discharged.

[0058] When the device of this embodiment is used to measure the resistance value of the large resistor to be measured, the DC power supply Ur charges the capacitor C through the semiconductor sensor to be measured. A differential equation can be established according to Kirchhoff's circuit law, and the time constant can be calculated through this differential equation:

[0059] (2)

[0060] It can be known from formula (2) that the voltage change across the capacitor C is as Figure 2 shown. It can be seen from the figure that when the voltage across the capacitor C is relatively small, the linearity is relatively good, which is convenient for the calculation of the microcontroller. Therefore, the voltage U0 across the capacitor C is selected as U0 = (0.1 - 0.5)U, and taking U0 = 0.1U, formula (1) becomes:

[0061]

[0062] By collecting the time when the voltage across the capacitor C is 0.1U, the resistance value of the large resistor to be measured can be calculated.

[0063] Specifically, as Figure 4 and Figure 5 shown, the microcontroller uses the MSP430AFE253IPWR chip, and the operational amplifier UT uses the TP5552 - SR chip;

[0064] The device of this embodiment further includes a power management circuit; the power management circuit includes: a boost converter SGM6603 - 5 connected to the battery for providing a +5V voltage; a low dropout voltage regulator SGM2019 - 3YN5G connected to the battery for providing a +3V voltage;

[0065] The capacitor C used is a 100UF capacitor, the DC power supply Ur used is a 24V voltage, and the cut-off voltage for charging the capacitor C is 0.5V.

[0066] Embodiment 2

[0067] This embodiment provides a device for measuring the internal resistance of a G-ohm level semiconductor gas sensor, as Figure 3 shown, including: a DC power supply Ur, a controllable capacitor charge and discharge circuit, a microcontroller, and an acquisition circuit;

[0068] The controllable capacitor charge and discharge circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6, and a triode Q1;

[0069] The DC power supply Ur is connected in series with the capacitor C through the semiconductor sensor to be measured, so as to charge and discharge the capacitor C through the semiconductor sensor to be measured;

[0070] The collector of the triode Q1 is connected to the series connection point of the semiconductor sensor to be measured and the capacitor C through the resistor R4, the base is connected to the I / O output end of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is also connected between the base and the emitter to control the charge and discharge process of the capacitor C;

[0071] The acquisition circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2, and a resistor R3;

[0072] One end of the sampling resistor R1 is connected to the series connection point of the semiconductor sensor to be measured and the capacitor C, and the other end is connected to the positive input terminal of the operational amplifier UT;

[0073] One end of the resistor R2 is grounded, and the other end is connected to the negative input terminal of the operational amplifier UT;

[0074] The resistor R3 is connected between the negative input terminal and the output terminal of the operational amplifier UT;

[0075] The output terminal of the operational amplifier UT is connected to the I / O input terminal of the microcontroller;

[0076] The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

[0077] The technical principle of the device in this embodiment:

[0078] When the triode Q1 is turned off, the DC power supply Ur starts to charge the capacitor C through the internal resistance R of the semiconductor sensor to be measured. The voltage value across the capacitor C is amplified by the operational amplifier UT and then enters the microcontroller for AD conversion. The electrical analog quantity becomes a digital quantity, and thus the magnitude of the voltage U0 can be obtained. As the capacitor C is continuously charged, the voltage U0 across it rises rapidly. When the voltage charged across the capacitor C reaches a certain value, the charging stops, and the charging time t is recorded;

[0079] The resistance value of the semiconductor sensor to be measured can be obtained through the calculation formula (1):

[0080] (1)

[0081] In formula (1), U is the rated voltage of the capacitor C;

[0082] When the triode Q1 is turned on, the capacitor C can be quickly discharged.

[0083] When the device of this embodiment is used to measure the internal resistance value of the semiconductor sensor to be measured, the DC power supply Ur charges the capacitor C through the semiconductor sensor to be measured. A differential equation can be established according to Kirchhoff's circuit law, and the time constant can be calculated through this differential equation:

[0084] (2)

[0085] It can be known from formula (2) that the voltage change across the capacitor C is as Figure 2 shown. It can be seen from the figure that when the voltage across the capacitor C is relatively small, the linearity is relatively good, which is convenient for the calculation of the microcontroller. Therefore, the voltage U0 across the capacitor C is selected to be (0.1~0.5)U, and U0 = 0.1U is taken. Formula (1) becomes:

[0086]

[0087] By collecting the time when the voltage across the capacitor C is 0.1U, the resistance value of the semiconductor sensor to be measured can be calculated.

[0088] When using the device of the present utility model to measure the internal resistance value of the semiconductor sensor to be measured, since direct current is used, at the beginning of charging, the capacitor C is similar to a complete open circuit. There is no charge across the capacitor C, and the voltage is 0. The charging current I = Ur / R, and this current is very large. Therefore, the capacitor C is charged quickly. Since the charging time for one charge is very fast, for the semiconductor sensor, its response time may not be able to catch up with the charging time. Therefore, during measurement, the capacitor C needs to be repeatedly charged and discharged. Charge the capacitor C once to obtain an internal resistance value, and then quickly discharge the charge stored in the capacitor C. Repeat the charging and discharging process. When the obtained resistance value tends to be stable, this stable resistance value is the internal resistance value of the semiconductor sensor to be measured.

[0089] Specifically, as Figure 4 and Figure 5 shown, the microcontroller uses the MSP430AFE253IPWR chip, and the operational amplifier UT uses the TP5552-SR chip;

[0090] The device of this embodiment further includes a power management circuit; the power management circuit includes: a boost converter SGM6603-5 connected to the battery for providing a +5V voltage; a low-dropout voltage regulator SGM2019-3YN5G connected to the battery for providing a +3V voltage;

[0091] The capacitor C used is a 100UF capacitor, the DC power supply Ur used is a 24V voltage, and the cut-off voltage for charging the capacitor C is 0.5V.

[0092] As described above, the above are only the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A device for measuring G-ohm high resistance, characterized in that: include: DC power supply Ur, controllable capacitor charging and discharging circuit, microcontroller and acquisition circuit; The controllable capacitor charging and discharging circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6 and a transistor Q1; The DC power supply Ur is connected in series with the capacitor C through the large resistor to be measured, so as to charge and discharge the capacitor C through the large resistor to be measured; The collector of the transistor Q1 is connected to the series connection point of the large resistor to be measured and the capacitor C through the resistor R4, the base is connected to the I / O output terminal of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is further connected between the base and the emitter to control the charging and discharging process of the capacitor C; The acquisition circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2 and a resistor R3; One end of the sampling resistor R1 is connected to the series connection point of the large resistor to be measured and the capacitor C, and the other end is connected to the non-inverting input terminal of the operational amplifier UT; One end of the resistor R2 is grounded, and the other end is connected to the inverting input terminal of the operational amplifier UT; The resistor R3 is connected between the inverting input terminal and the output terminal of the operational amplifier UT; The output terminal of the operational amplifier UT is connected to the I / O input terminal of the microcontroller; The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

2. The device for measuring G-ohm high resistance according to claim 1, characterized in that: The capacitor C is a 100UF capacitor, the DC power supply Ur is a 24V voltage, and the charging cut-off voltage of the capacitor C is 0.5V.

3. The device for measuring G-ohm high resistance according to claim 1, characterized in that: The microcontroller adopts the MSP430AFE253IPWR chip, and the operational amplifier UT adopts the TP5552-SR chip.

4. The device for measuring G-ohm high resistance according to claim 1, characterized in that: Also included is a power management circuit; The power management circuit comprises: Connected to the battery, used to provide +5V voltage boost converter SGM6603-5; Connected to the battery, used to provide +3V power supply low dropout voltage regulator SGM2019-3YN5G.

5. A device for measuring the internal resistance of a G-ohm semiconductor gas sensor, characterized in that: include: DC power supply Ur, controllable capacitor charging and discharging circuit, microcontroller and acquisition circuit; The controllable capacitor charging and discharging circuit includes a capacitor C, a resistor R4, a resistor R5, a resistor R6 and a transistor Q1; The DC power supply Ur is connected in series with the capacitor C through the semiconductor sensor to be tested, so as to charge and discharge the capacitor C through the semiconductor sensor to be tested; The collector of the transistor Q1 is connected to the series connection point of the semiconductor sensor to be tested and the capacitor C through the resistor R4, the base is connected to the I / O output terminal of the microcontroller through the resistor R5, the emitter is grounded, and the resistor R6 is further connected between the base and the emitter to control the charging and discharging process of the capacitor C; The acquisition circuit includes a sampling resistor R1, an operational amplifier UT, a resistor R2 and a resistor R3; One end of the sampling resistor R1 is connected to the series connection point of the semiconductor sensor to be tested and the capacitor C, and the other end is connected to the non-inverting input terminal of the operational amplifier UT; One end of the resistor R2 is grounded, and the other end is connected to the inverting input terminal of the operational amplifier UT; The resistor R3 is connected between the inverting input terminal and the output terminal of the operational amplifier UT; The output terminal of the operational amplifier UT is connected to the I / O input terminal of the microcontroller; The microcontroller records the charging time when the capacitor C is charged to a certain voltage by collecting the voltage across the capacitor C during the charging process.

6. The device for measuring the internal resistance of a G-ohm semiconductor gas sensor according to claim 5, characterized in that: The capacitor C is a 100UF capacitor, the DC power supply Ur is a 24V voltage, and the charging cut-off voltage of the capacitor C is 0.5V.

7. The device for measuring the internal resistance of a G-ohm semiconductor gas sensor according to claim 5, characterized in that: The microcontroller adopts the MSP430AFE253IPWR chip, and the operational amplifier UT adopts the TP5552-SR chip.

8. The device for measuring the internal resistance of a G-ohm semiconductor gas sensor according to claim 5, characterized in that: Also included is a power management circuit; The power management circuit comprises: Connected to the battery, used to provide +5V voltage boost converter SGM6603-5; Connected to the battery, used to provide +3V power supply low dropout voltage regulator SGM2019-3YN5G.

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