CN116380180A - Gas flow sensor chip and gas flow sensor - Google Patents
Gas flow sensor chip and gas flow sensor Download PDFInfo
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- CN116380180A CN116380180A CN202310449604.3A CN202310449604A CN116380180A CN 116380180 A CN116380180 A CN 116380180A CN 202310449604 A CN202310449604 A CN 202310449604A CN 116380180 A CN116380180 A CN 116380180A
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- 238000010438 heat treatment Methods 0.000 claims abstract description 29
- 239000000758 substrate Substances 0.000 claims abstract description 4
- 230000005611 electricity Effects 0.000 claims description 5
- 238000005259 measurement Methods 0.000 abstract description 35
- 239000003344 environmental pollutant Substances 0.000 abstract description 21
- 231100000719 pollutant Toxicity 0.000 abstract description 21
- 238000000034 method Methods 0.000 abstract description 5
- 239000007789 gas Substances 0.000 description 96
- 239000000356 contaminant Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000008021 deposition Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
- G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
- G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
- G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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Abstract
The embodiment of the present specification relates to the technical field of flow sensors, and provides a gas flow sensor chip, including: a circuit substrate, a heating resistor and a temperature measuring resistor; the gas flow sensor chip has a first operating mode for measuring a gas flow; and a second working mode for electrifying the temperature measuring resistor and heating the temperature measuring resistor; and the working current of the temperature measuring resistor in the second working mode is larger than that of the temperature measuring resistor in the first working mode. By the technical method, the temperature measuring resistor is electrified to be in the second heating working mode, so that the pollution degree of pollutants in a flowing medium to the gas flow sensor chip is reduced to a certain extent, and the measurement accuracy of the gas flow sensor chip is improved.
Description
Technical Field
The embodiment of the specification relates to the technical field of flow sensors, in particular to a gas flow sensor chip and a gas flow sensor.
Background
With the development of technology, flow sensors are widely used in industrial production. The flow sensor can measure the flow of medium such as gas, liquid, steam and the like. With the development of the technology, the MEMS technology is developed, and the thermal type gas flow sensor based on the MEMS technology has the characteristics of quick response, low power consumption, small volume, high integration and the like, so that the thermal type gas flow sensor based on the MEMS technology is greatly developed. In the measurement process of the thermal type gas flow sensor, pollutants follow a flowing medium to reach the flow sensor chip, and after long-time deposition, the pollutants change the heat conduction value on the surface of the gas sensor chip and the micro-flow field of the upstream incoming flow direction of the gas sensor, so that the measurement signal is influenced. Therefore, contaminants deposited on the gas sensor chip may cause a decrease in measurement accuracy of the gas sensor chip.
Therefore, the gas sensor chip in the prior art may have a technical problem in that the measurement accuracy is lowered due to contaminants.
Disclosure of Invention
In view of this, various embodiments of the present disclosure are directed to providing a gas flow sensor chip and a gas flow sensor that solve the problem of contaminant precipitation in a flowing medium on the gas chip to some extent, thereby improving measurement accuracy of the new gas flow chip.
To achieve the above object, one embodiment of the present specification provides a gas flow sensor chip including: a circuit substrate, a heating resistor and a temperature measuring resistor; the gas flow sensor chip has a first operating mode for measuring a gas flow; and a second working mode for electrifying the temperature measuring resistor and heating the temperature measuring resistor; and the working current of the temperature measuring resistor in the second working mode is larger than that of the temperature measuring resistor in the first working mode.
One embodiment of the present disclosure provides a gas flow sensor that includes the gas flow sensor chip described above.
Compared with the prior art, the gas flow sensor chip provided by the specification has the beneficial effects that: the temperature measuring resistor is provided with a first working mode for measuring the gas flow and a second working mode for enabling the temperature measuring resistor to generate heat by passing electricity through the temperature measuring resistor, and pollutants in flowing media are blocked from being deposited on the gas flow sensor chip by the heat generation of the temperature measuring resistor, so that the measurement accuracy of the gas flow sensor chip is improved to a certain extent.
Drawings
Fig. 1 is a schematic structural diagram of a gas flow sensor chip according to an embodiment of the present disclosure.
Fig. 2 is a schematic structural diagram of a gas flow sensor chip according to an embodiment of the present disclosure.
Fig. 3 is a schematic structural diagram of a gas flow sensor chip according to an embodiment of the present disclosure.
Fig. 4 is a schematic structural diagram of a gas flow sensor chip according to an embodiment of the present disclosure.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present specification will be clearly and completely described in the following description with reference to the accompanying drawings in the embodiments of the present specification, and it is apparent that the described embodiments are only some embodiments of the present specification, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present application based on the embodiments herein.
Please refer to fig. 1. One embodiment of the present specification provides a gas flow sensor chip 100, the gas flow sensor chip 100 including: a circuit substrate 110, a heating resistor 120 and a temperature measuring resistor 130; the gas flow sensor chip 110 has a first operation mode for measuring a gas flow; and a second working mode for energizing the temperature measuring resistor 130 to heat the temperature measuring resistor 130; the working current of the temperature measuring resistor 130 in the second working mode is greater than the working current of the temperature measuring resistor 130 in the first working mode.
In the present embodiment, the temperature measuring resistors 130 in the gas flow sensor chip 100 are symmetrically disposed at both sides of the heating resistor 120. The temperature measured by the thermometric resistor 130 equidistant from the heating resistor 120 is the same when the flowing medium is stationary. The temperature measured by the temperature measuring resistor 130 is a temperature difference when the flowing medium flows on the surface of the gas flow sensor chip, and the gas flow sensor chip 100 measures the mass flow of the flowing medium through the temperature difference. The temperature measuring resistor 130 may have a first operation mode for measuring the gas flow, and the temperature measuring resistor 130 is powered on to make the temperature measuring resistor 130 be in a second operation mode, that is, the temperature measuring resistor 130 generates heat, so that the flowing medium has a temperature gradient. In the flowing medium with temperature gradient, the gas molecules in the higher temperature part collide with the particles with higher kinetic energy than the gas molecules in the lower temperature part, so that the particles move from the high temperature part to the low temperature part, the pollutants in the flowing medium move to the low temperature part, the pollution on the surface of the pollutant gas flow sensor chip in the flowing medium is reduced, and the measurement accuracy of the gas flow sensor chip is improved.
In this embodiment, the working current for energizing the temperature measuring resistor 130 is adjusted to control the working mode of the temperature measuring resistor 130, and when the working current reaches a certain value, the temperature measuring resistor 130 is in the first working mode, i.e. the working mode for measuring the gas flow. When the working current of the temperature measuring resistor 130 reaches a certain current value and is larger than the working current of the temperature measuring resistor 130 in the first working mode, the temperature measuring resistor 130 is in the second working mode, namely the anti-pollution working mode, and the heat generated by the heating of the temperature measuring resistor 130 prevents pollutants in the flowing medium from adhering to the surface of the gas sensor chip 100. The larger the operating current of the temperature measuring resistor 130, the larger the heat generated by the temperature measuring resistor 130.
In some embodiments, the temperature measuring resistor 130 may be a resistor with an adjustable resistance value. The working mode of the temperature measuring resistor 130 can be controlled by adjusting the resistance value of the temperature measuring resistor 130 by the controller, and when the resistance value of the temperature measuring resistor 130 reaches a certain value, the temperature measuring resistor 130 is in the first working mode. When the resistance value of the temperature measuring resistor reaches a certain resistance value and is larger than the resistance value of the temperature measuring resistor 130 in the first working mode, the temperature measuring resistor 130 is in the second working mode.
In some embodiments, the temperature sensing resistor 130 on the gas flow sensor chip 100 includes a first resistor and a second resistor, and the heat generating resistor 120 is in an inactive state when the temperature sensing resistor 130 is in the second operating mode. Of course, it is also possible that the first resistor in the main flow direction close to the flowing medium is in the second operation mode, and the heating resistor 120 and the second resistor in the main flow direction far from the flowing medium are in the inactive state. To a certain extent, power consumption is reduced.
Please refer to fig. 2. In some embodiments, when the gas flow sensor chip 100 includes at least the outer resistor pair 131 and the inner resistor pair 132, the inner resistor pair 132 is in the first operation mode and the heating resistor 120 is in the operation mode when the outer resistor pair 131 is in the second operation mode.
In some embodiments, the gas flow sensor 100 is an instrument that converts signals such as temperature and pressure of a fluid into flow. The gas flow sensor 100 is of a wide variety, and includes a throttle type, a volume type, a vortex street type, an electromagnetic type, a thermal type, an ultrasonic type, and the like. The thermal gas flow sensor 100 can detect the flow of the gas medium in the flow channel by utilizing the thermodynamic principle, and has good precision and repeatability.
In some embodiments, the first operation mode may refer to an operation mode in which the temperature measuring resistor 130 measures temperature in order to measure flow.
In some embodiments, the second mode of operation may refer to the mode of operation in which the thermometric resistor 130 is in order to resist deposition of contaminants in the flowing medium to the gas flow sensing chip 100. The heat generated by the thermometric resistor 130 when in the second mode of operation keeps contaminants in the flowing medium away to some extent.
In some embodiments, the operating current may be a current that causes the temperature sensing resistor 130 to operate. Specifically, for example, the operating current of the temperature measuring resistor 130 in the first operating mode is 5mA, the operating current of the second operating mode is 10mA, and when the current of the temperature measuring resistor 130 reaches 5mA, the temperature measuring resistor 130 is in the first operating mode, and in order to make the temperature measuring resistor 130 in the second operating mode, the operating current of 10mA needs to be passed through the temperature measuring resistor 130.
In some embodiments, the heating resistor 120 may be a resistor that generates heat having an isothermal gradient in order to form a sensing region of the gas sensor chip 100 with the temperature measuring resistor 130.
In some embodiments, the working current of the temperature measuring resistor 130 is controlled to be alternately switched between the working currents corresponding to the first working mode and the second working mode.
In the present embodiment, the gas flow sensor chip 100 is electrically connected to a controller, and the controller adjusts the magnitude of the operating current of the temperature measuring resistor 130, thereby achieving the mode of controlling the temperature measuring resistor 130. The controller controls the working current of the temperature measuring resistor 130 to be switched between the working current corresponding to the first working mode and the working current corresponding to the second working mode, so that the temperature measuring resistor 130 is switched between the first working mode and the second working mode, the gas flow sensor chip 100 can measure the flow of flowing media, and pollutants can be reduced to be attached to the gas flow sensor chip 100 through the heat generated by heating of the temperature measuring resistor 130, so that the measurement accuracy of the gas flow sensor chip 100 is improved.
Referring to fig. 2, in some embodiments, the temperature measuring resistor 130 on the gas flow sensor chip 100 includes at least an outer resistor pair 131 and an inner resistor pair 132, where the outer resistor pair 131 and the inner resistor pair 132 together measure the flow of the flowing medium, so as to improve the measurement accuracy of the gas flow sensor chip 100. By energizing the outer resistor pair 131, the outer resistor 131 is in the second operation mode, and the inner resistor pair 132 of the gas flow sensor chip 100 is in the first operation mode for measuring the flow rate of the flowing medium, the gas flow sensor chip 100 can emit heat through the outer resistor 131 while measuring the flow rate of the flowing medium, so that the adhesion of pollutants in the flowing medium on the surface of the gas flow sensor chip 100 is reduced, and the measurement accuracy of the gas sensor chip 100 is improved. Of course, the current may also be controlled by the controller to make the inner resistor pair 132 and the outer resistor pair 131 alternately in the operating state, that is, when the inner resistor pair 132 is in the first operating mode, the outer resistor pair 131 is in the inactive state, and when the outer resistor pair 131 is in the second operating mode, the inner resistor pair 132 is in the inactive state, and the inner resistor pair 132 and the outer resistor pair 131 are alternately in the operating state. When the controller controls the inner resistor pair 132 to work, the outer resistor pair 131 does not work, and heat generated by the outer resistor pair 131 when the outer resistor pair is in the second working mode is prevented from affecting the measurement of the flow of the flowing medium by the inner resistor pair 132, so that the measurement accuracy of the gas flow sensor chip 100 is improved.
In some embodiments, the time interval for the alternating transition is set; wherein, the value of the time interval does not influence the gas flow measured by the sensor chip.
In this embodiment, the controller sets the interval time value T1 between the first operation mode and the second operation mode of the temperature measuring resistor 130, and of course, the interval time value T2 between the second operation mode and the first operation mode set by the temperature measuring resistor 130 may also be set. The values T1 and T2 are switched between the first operation mode and the second operation mode according to the interval time, wherein T1 is the value of the time interval between the end of the first operation mode and the start of the second operation mode of the temperature measuring resistor 130, and T2 is the value of the time interval between the end of the second operation mode and the start of the first operation mode of the temperature measuring resistor 130. T1 and T2 may be fixed values, although the values of T1 and T2 do not affect the proper operation of the flow measurement circuit. After judging the pollution degree of the gas sensor chip, T1 can be set according to the pollution degree, the higher the pollution degree is, the smaller the set T1 is, the time that the temperature measuring resistor 130 is in the second working state is increased, and the pollutants in the flowing medium are effectively prevented from adhering to the gas sensor chip 100. The larger the T2 is set in a certain range, the effect of heat generated by the temperature measuring resistor 130 in the second working mode on the measurement of the first working mode is effectively reduced, and the normal operation of the flow measuring circuit cannot be influenced. The controller may calculate the pollution level of the gas sensor chip 100 according to the measured data, set T1 and T2 according to the pollution level of the gas sensor chip 100 and the flow rate of the flowing medium, and by adjusting T1 and T2, the frequency of the temperature measuring resistor 130 in the second working mode may be reduced in the early use period of the gas sensor chip 100, and the temperature measuring resistor 130 and the heating resistor 120 in the first mode may be in a non-working state without affecting the measurement, so that the operation power consumption of the gas flow sensor chip 100 may be reduced to some extent. The time interval T2 ensures measurement of the flowing medium, and also avoids heat generated by the temperature measuring resistor 130 in the heating second operation mode from affecting measurement of the flow, thereby improving measurement accuracy.
Referring to fig. 3, in some embodiments, the flowing medium has a main flow direction 140: the temperature resistor 131 in the second mode of operation is at least partially in front of the temperature resistor 132 in the first mode of operation in the main flow direction 140.
In this embodiment, there may be multiple flow directions of the flowing medium, where there is one main flow direction 140, and the temperature measuring resistor 130 includes at least a pair of inner resistor pairs 132 in the first operation mode and a pair of temperature measuring resistors 131 in the second operation mode. In the main flow direction, one temperature measuring resistor 133 of the temperature measuring resistor pair 131 is located in front of the temperature measuring resistor pair 132, which is located in the inner resistor pair 132 at a distance from the main flow direction, i.e. the flowing medium flows from the temperature measuring resistor 133 in the second operation mode first and then through one resistor of the inner resistor pair 132. The temperature measuring resistor 133 in the second working mode effectively blocks the pollutants in the flowing medium from adhering to the gas flow sensor chip 100 in the main flowing direction of the flowing medium, and reduces the degree of adhering the pollutants to the gas flow sensor chip 100 to a certain extent, so that the detection precision is improved.
In some embodiments, the flow medium may refer to a gas having multiple flow directions and having one main flow direction. Specifically, for example, oxygen.
Referring to fig. 3, in some embodiments, the distance between the temperature measuring resistor 133 in the second operation mode and the temperature measuring resistor 132 in the first operation mode is 1-2 mm.
In the present embodiment, the heat generated when the temperature measuring resistor 133 is in the second operation mode may be covered in a range of 1 to 2mm distance between the temperature measuring resistor 133 and the temperature measuring resistor 132 in the first operation mode. When the distance between the temperature measuring resistor 133 in the second operation mode and the temperature measuring resistor 132 in the first operation mode is 1-2 mm, the temperature measuring resistor 133 in the second operation mode can reduce the adhesion of pollutants in the flowing medium to the gas sensor chip 100 by heating, and certainly, the heat generated by the temperature measuring resistor 133 in the second operation mode is insufficient to influence the measurement value of the flow rate of the flowing medium. Specifically, for example, when the distance between the temperature measuring resistor 133 in the second operation mode and the temperature measuring resistor 132 in the first operation mode is smaller than 1mm, the heat generated by the temperature measuring resistor 133 in the second operation mode is included in the heat measured by the temperature measuring resistor 132 in addition to the heat generated by the heating resistor, so as to affect the measurement of the flow rate of the flowing medium. When the distance between the temperature measuring resistor 133 in the second operation mode and the temperature measuring resistor 132 in the first operation mode is greater than 2mm, the pollutants in the flowing medium cannot be effectively prevented from adhering to the gas sensor chip 100, so that the gas sensor chip 100 cannot be well prevented from being polluted by the pollutants in the flowing medium.
Referring to fig. 4, in some embodiments, at least a heating resistor 121, a heating resistor 122, and 6 temperature measuring resistors may be included on the gas flow sensor chip 100. The 6 temperature measuring resistors may be a temperature measuring resistor 134, a temperature measuring resistor 135, a temperature measuring resistor 136, a temperature measuring resistor 137, a temperature measuring resistor 138 and a temperature measuring resistor 139. The temperature measuring resistor 135 and the temperature measuring resistor 136, the temperature measuring resistor 134, the temperature measuring resistor 137 and the heating resistor 121 form a flow measuring working area 1, wherein the temperature measuring resistor 135 and the temperature measuring resistor 136 form a temperature measuring resistor pair in the flow measuring first working area 1, and the temperature measuring resistor 134 and the temperature measuring resistor 137 form a temperature measuring resistor pair outside the flow measuring first working area 141. The temperature measuring resistor 136 and the temperature measuring resistor 137, the temperature measuring resistor 138, the temperature measuring resistor 139 and the heating resistor 122 form a flow measuring second working area 142, wherein the temperature measuring resistor 137 and the temperature measuring resistor 138 form a temperature measuring resistor pair in the flow measuring second working area 142, and the temperature measuring resistor 136 and the temperature measuring resistor 139 form a temperature measuring resistor pair outside the flow measuring second working area 142.
In some embodiments, the flow measurement first working area 141 may be in the direction of the incoming flow of the flowing medium. The flow measurement of the first flow measurement working area 141 and the second flow measurement working area 142 have certain regular deviation, which indicates that the first flow measurement working area 141 has pollutants on the convection boundary of the cold and hot flowing body, and the flow measurement of the second flow measurement working area 142 is mainly used, so that the accuracy of measuring the flow is improved. In some embodiments, after serious pollution occurs after the first working area 141 for flow measurement is operated for a period of time, the controller may control the first working area 141 for flow measurement to be operated and the second working area 142 for flow measurement to be operated, so that the gas flow sensor chip 100 may be operated continuously, and the time for stable operation and verification cycle time of the gas flow sensor chip 100 are improved.
In some embodiments, at least a portion of the sensor chip is a suspended structure.
In the present embodiment, a portion of the gas flow sensor chip 100 is provided in a suspended structure. Specifically, for example, the suspended structure is a thin film suspended structure. By arranging the partial structure of the gas flow sensor chip 100 to be a suspended structure, the area of the sensor chip 100 in the main flow direction 140 of the flowing medium is reduced, and the area where pollutants in the flowing medium can adhere is reduced, so that the formation of pollutants on the gas sensor chip is avoided to a certain extent. Of course, the main flow direction of the flowing medium can be multiple selected directions, so that the applicability of the gas flow sensor chip 100 is improved. By reducing the structure of the gas flow sensor chip 100, the local micro-flow field on the surface of the gas flow sensor chip 100 is reduced, and the measurement accuracy of the gas flow sensor chip 100 is further improved.
Referring to fig. 2, in some embodiments, the temperature measuring resistor 130 includes at least an outer resistor pair 131 and an inner resistor pair 132; wherein the outer resistor pair 131 and the inner resistor pair 132 are respectively disposed at both sides of the heating resistor 120; and when the comparison value of the output signal of the outer resistor pair 131 and the output signal of the inner resistor pair 132 is greater than or equal to the pollution threshold, passing electricity through the outer resistor pair 131, so that the working mode of the outer resistor pair 131 is the second working mode.
In this embodiment, the temperature measuring resistors 130 are respectively disposed at two sides of the heating resistor 120, the outer resistor pair 131 and the inner resistor pair 132 alternately measure the flow of the flowing medium, the comparison value obtained by comparing the flow measuring signals of adjacent measuring periods of the outer resistor pair 131 and the inner resistor pair 132 is compared with the pollution threshold, when the comparison value is greater than or equal to the pollution threshold, the controller controls the outer resistor 131 to pass through electricity, so that the working current of the outer resistor 131 reaches the working current of the second working mode, and the outer resistor 131 is in the second working mode, so that the pollutants are blocked on the gas flow sensor chip 100 to a certain extent by the heat generated by the outer resistor 131, thereby improving the measuring accuracy. Specifically, for example, the flow measurement signals of adjacent measurement periods of the outer resistor pair 131 and the inner resistor pair 132 are U1 and U2, respectively, a comparison value a and a pollution threshold value B can be calculated through differential operation (U1-U2), and when a is greater than or equal to B, the controller controls the outer resistor pair 131 to pass through electricity, so that the outer resistor pair 131 is in a second working mode of heating. The comparison value can also be calculated by a division operation (U1/U2), and of course, the calculation method of the comparison value needs to be consistent with the method used when calibrating the pollution threshold.
In some embodiments, the temperature sensing resistor 130 includes at least an outer resistor pair 131 and an inner resistor pair 132; wherein the outer resistor pair 131 and the inner resistor pair 132 are symmetrical resistor pairs; when the differential voltage of the outer resistor pair 131 and the differential voltage of the inner resistor pair 132 are different, the outer resistor pair 131 is energized, and the operating current of the outer resistor pair 131 is increased, so that the operating mode of the outer resistor pair 131 is the second operating mode.
In this embodiment, the outer resistor pair 131 and the inner resistor pair 132 are symmetrical resistor pairs, and are distributed on two sides of the heating resistor 120, and the two pairs of temperature measuring resistors 130 are respectively measured and differential calculated to obtain two differential voltages, and when the differential voltages of the outer resistor pair 131 and the inner resistor pair 132 are different, it is determined that the gas flow sensor chip 100 is contaminated by the contaminant in the flowing medium, and a method for determining whether the gas flow sensor chip 100 is contaminated is provided. At this time, the controller controls the outer resistor pair 131 to be electrified, and increases the working current of the outer resistor pair 131, so that the working current of the outer resistor pair 131 reaches the working current of the second working mode, thereby enabling the outer resistor pair 131 to generate heat to block the pollutants in the flowing medium from continuously polluting the gas flow sensor chip 100, and improving the measurement accuracy of the gas flow sensor chip 100.
In some embodiments, the temperature sensing resistor 130 inputs a zero voltage; when the temperature measuring resistor 130 has an output voltage, the temperature measuring resistor 130 is electrified, so that the temperature measuring resistor 130 starts the second working mode.
In the present embodiment, the controller controls the temperature measuring resistor 130 to input the zero voltage, and determines that the gas flow sensor chip 100 is contaminated when the temperature measuring resistor 130 has an output voltage, and a method of determining whether the gas flow sensor chip 100 is contaminated is provided. At this time, the controller controls the energizing level of the temperature measuring resistor 130, so that the energizing working current of the temperature measuring resistor 130 reaches the working current corresponding to the second working mode, thereby heating the temperature measuring resistor 130 and further preventing the pollutants in the flowing medium from continuing to adhere to the gas flow sensor chip 100.
One embodiment of the present disclosure provides a gas flow sensor that includes any of the gas flow sensor chips 100 described above.
The technical features of the above embodiments may be combined in any manner, and for brevity, all of the possible combinations of the technical features of the above embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is to be construed as including any modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. A gas flow sensor chip, comprising: a circuit substrate, a heating resistor and a temperature measuring resistor; the gas flow sensor chip has a first operating mode for measuring a gas flow; and a second working mode for electrifying the temperature measuring resistor and heating the temperature measuring resistor; and the working current of the temperature measuring resistor in the second working mode is larger than that of the temperature measuring resistor in the first working mode.
2. The sensor chip of claim 1, wherein the operating current of the temperature sensing resistor is controlled to alternate between the operating currents corresponding to the first operating mode and the second operating mode.
3. The sensor chip of claim 2, wherein the time interval for alternating is set; wherein, the value of the time interval does not influence the gas flow measured by the sensor chip.
4. The sensor chip of claim 1, wherein the flow medium has a main flow direction; the temperature measuring resistor in the main flow direction at least partially in the second operation mode is in front of the temperature measuring resistor in the first operation mode.
5. The sensor chip of claim 4, wherein a distance between the temperature measuring resistor in the second operation mode and the temperature measuring resistor in the first operation mode is set to be 1-2 mm.
6. The sensor chip of claim 1, wherein at least a portion of the sensor chip is a suspended structure.
7. The sensor chip of claim 1, wherein the thermometric resistor comprises at least an outside resistor pair and an inside resistor pair; the outer resistor pair and the inner resistor pair are respectively arranged at two sides of the heating resistor; and when the comparison value of the output signal of the outer resistor pair and the output signal of the inner resistor pair is greater than or equal to a pollution threshold, passing electricity through the outer resistor pair, so that the working mode of the outer resistor pair is the second working mode.
8. The sensor chip of claim 1, wherein the thermometric resistor comprises at least an outside resistor pair and an inside resistor pair; wherein the outer resistance pair and the inner resistance pair are symmetrical resistance pairs; and when the differential voltage of the outer resistor pair is different from the differential voltage of the inner resistor pair, electrifying the outer resistor pair, and increasing the working current of the outer resistor pair to enable the working mode of the outer resistor pair to be the second working mode.
9. The sensor chip of claim 1, wherein the temperature sensing resistor inputs a zero voltage; and when the temperature measuring resistor has output voltage, electrifying the temperature measuring resistor to enable the temperature measuring resistor to start the second working mode.
10. A gas flow sensor comprising a gas flow sensor chip according to any one of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310449604.3A CN116380180A (en) | 2023-04-24 | 2023-04-24 | Gas flow sensor chip and gas flow sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310449604.3A CN116380180A (en) | 2023-04-24 | 2023-04-24 | Gas flow sensor chip and gas flow sensor |
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| CN116380180A true CN116380180A (en) | 2023-07-04 |
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| CN202310449604.3A Pending CN116380180A (en) | 2023-04-24 | 2023-04-24 | Gas flow sensor chip and gas flow sensor |
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- 2023-04-24 CN CN202310449604.3A patent/CN116380180A/en active Pending
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