Detection device and gas detector

Abstract

The invention discloses a detection device and a gas detector. The detection device comprises a detection module, a sampling processing module and a voltage regulation module, the voltage adjusting module comprises a signal adjusting unit and a voltage adjusting unit; the input end of the sampling processing module is electrically connected with the detection module; the output end of the sampling processing module is electrically connected with the input end of the signal adjusting unit; the output end of the signal adjusting unit is electrically connected with the voltage adjusting unit; one end of the detection module is electrically connected with the output end of the voltage adjusting unit, and the other end is electrically connected with the reference ground. The detection device can adjust the power supply voltage according to the working state, and facilitates the improvement of the detection precision of the detection module.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and more specifically, to a detection device and a gas detector. Background Art

[0002] In order to detect temperature or a certain gas, a thermal conductivity detection circuit can be used for detection. The core component of the thermal conductivity detection circuit is a temperature sensitive component, such as a temperature sensitive resistor NTC. The working state of the temperature sensitive component has a great influence on the detection accuracy. How to ensure that the temperature sensitive component works in a suitable working state is of great significance to the detection accuracy. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a detection device and a gas detector, wherein the detection device can adjust the working state to improve the detection accuracy.

[0004] A detection device comprises a detection module, a sampling processing module and a voltage regulation module; the voltage regulation module comprises a signal regulation unit and a voltage adjustment unit;

[0005] The input end of the sampling and processing module is electrically connected to the detection module; the output end of the sampling and processing module is electrically connected to the input end of the signal adjustment unit; the output end of the signal adjustment unit is electrically connected to the voltage adjustment unit; one end of the detection module is electrically connected to the output end of the voltage adjustment unit, and the other end is electrically connected to the reference ground.

[0006] The detection device is provided with a sampling and processing module, a voltage regulating module and a detection module. The sampling and processing module is electrically connected to the detection module and can detect the working state of the detection module. The voltage regulating module is electrically connected to the sampling and processing module and the detection module and can adjust the power supply voltage output to the detection module according to the working state of the detection module, so that the entire detection device works in a better working state, which is beneficial to improving the detection accuracy of the detection module.

[0007] An embodiment of the present application also provides a gas detector, including the above-mentioned detection device; the detection module of the detection device includes a thermistor, and the gas concentration is detected by detecting the voltage change of the thermistor; the sampling and processing module of the detection device is electrically connected to the thermistor.

[0008] The sampling and processing module of the gas detector detection device is electrically connected to the thermistor and can detect the working state of the thermistor. The voltage regulation module of the detection device can adjust the power supply voltage output to the detection module according to the working state of the thermistor, thereby enabling the gas detector to operate in a better working state, which is beneficial to improving the detection accuracy of the gas detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 It is a schematic diagram of a principle block diagram of a first detection device disclosed in an embodiment of the present invention;

[0011] Figure 2 It is a schematic diagram of a principle block diagram of a second detection device disclosed in an embodiment of the present invention;

[0012] Figure 3 A schematic diagram of the circuit principle of a third detection device disclosed in an embodiment of the present invention;

[0013] Figure 4 A schematic diagram of the circuit principle of a fourth detection device disclosed in an embodiment of the present invention;

[0014] Figure 5 A schematic diagram of the circuit principle of the fifth detection device disclosed in an embodiment of the present invention;

[0015] Figure 6 A schematic diagram of the circuit principle of the sixth detection device disclosed in an embodiment of the present invention;

[0016] Figure 7 It is a schematic diagram of a principle block diagram of a seventh detection device disclosed in an embodiment of the present invention;

[0017] Figure 8 A schematic diagram of the circuit principle of an eighth detection device disclosed in an embodiment of the present invention;

[0018] Fig. 9 A schematic diagram of the circuit principle of a ninth detection device disclosed in an embodiment of the present invention;

[0019] Fig.10 A schematic diagram of the circuit principle of the tenth detection device disclosed in an embodiment of the present invention;

[0020] Fig.11 A schematic diagram of the circuit principle of the eleventh detection device disclosed in an embodiment of the present invention;

[0021] Fig.12 This is a schematic diagram of the circuit principle of the twelfth detection device disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In this application, the terms "comprises", "comprising" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. "Electrically connected" includes direct electrical connection and indirect electrical connection.

[0024] In order to sense changes in substances (such as CO, CO2, refrigerants, etc.) or environments (temperature, humidity, etc.), detection devices are often set up. In order to ensure the detection concentration of the detection device, it is necessary to build a better working state for the detection device. The working state of the detection device includes ambient temperature, ambient humidity, working voltage, etc. The embodiment of the present application provides a detection device that can adjust the power supply voltage in real time according to the current working state so that the detection device works at a better power supply voltage, thereby improving the detection accuracy.

[0025] Specifically, Figure 1 As shown, the detection device includes a detection module 1, a sampling and processing module 2 and a voltage regulation module 3; the voltage regulation module 3 further includes a signal regulation unit 31 and a voltage adjustment unit 32;

[0026] The input end of the sampling processing module 2 is electrically connected to the detection module 1, and is used to detect the working state of the detection module 1; the output end of the sampling processing module 2 is electrically connected to the input end of the signal adjustment unit 31, and the sampling information representing the working state of the detection module 1 is sent to the signal adjustment unit 31; the output end of the signal adjustment unit 31 is electrically connected to the voltage adjustment unit 32. One end of the detection module 1 is electrically connected to the output end of the voltage adjustment unit 32, and the other end is electrically connected to the reference ground; wherein the power supply voltage of the detection module is the voltage at the output end of the voltage adjustment unit 32, and the voltage adjustment module adjusts the output voltage of its own output end according to the aforementioned sampling signal, thereby changing the power supply voltage of the detection module 1, so that the detection module 1 can work under a more suitable power supply voltage.

[0027] The first aspect of the present application provides a specific embodiment of the detection module, which can be referred to in the attached Figure 2 ,3 , 4 and 7-12 are schematic diagrams of the circuit principles of the detection module 1, the detection module 1 includes a bridge circuit. The bridge circuit includes at least one thermistor; the sensitivity of the electrical parameters of the thermistor to temperature can be used to detect changes in substances or the environment; generally, if the temperature of the thermistor changes or the thermal conductivity of the substance it contacts changes, its electrical parameters will change, and the detection function can be achieved by detecting the changes in the electrical parameters. The thermal conductivity type refrigerant detector can be implemented using the above-mentioned bridge circuit. In the present application, the thermistor is taken as an NTC resistor as an example. Furthermore, in the bridge circuit, the third second resistor and the third first resistor are taken as NTC resistors as an example to explain the scheme. The core of the thermal conductivity type refrigerant detector is the thermistor. The above-mentioned bridge circuit is required to detect the output of the thermistor, that is, the attached Figure 2 R31, R32, R1, R2. Figure 7 The third resistor R3 and the fourth resistor R4 on both sides of the bridge circuit are the current limiting resistors of the bridge circuit, and VCC is the power supply voltage of the detection module. In the detection device provided by the present application, the power supply voltage VCC of the detection module can be changed according to the change of the working state of the detection module, and the working state of the detection module mainly includes the ambient temperature and the temperature of the thermistor. Therefore, by detecting the ambient temperature and the temperature of the thermistor, and adjusting the power supply voltage VCC according to the ambient temperature and the temperature of the thermistor, the thermistor can be made to work in a more optimal working state, thereby improving the detection accuracy. At different temperatures, the temperature optimum point of the NTC resistor heating is different, and there is a corresponding relationship between the NTC resistor resistance and its temperature. Therefore, the temperature of the NTC resistor can be adjusted by adjusting the NTC resistor resistance, and the resistance value of the NTC can be achieved by adjusting the power supply voltage VCC. Therefore, the present application can achieve the better working temperature point of the NTC resistor by adjusting the power supply voltage VCC.

[0028] In the second aspect of the present application, in order to adjust the power supply voltage of the detection module (that is, the working voltage of the bridge circuit), a voltage regulation module 3 is provided. In one embodiment, Figure 2 As shown, the voltage regulating module 3 includes a signal regulating unit and a voltage regulating unit, and the voltage regulating unit 32 includes a switching regulator 321; the switching regulator 321 has a voltage reference terminal Vref and a voltage output terminal Vout, and the output terminal of the voltage regulating unit 32 is the voltage output terminal Vout; the voltage value of the voltage output terminal is adjusted by changing the regulating current input to the voltage reference terminal.

[0029] In specific application, the sampling processing module 2 is electrically connected to the bridge circuit, and the sampling processing module 2 can sample at least one node voltage of the bridge circuit to obtain a voltage sampling signal, and generate a PWM signal or an analog signal at least according to the voltage sampling signal;

[0030] The output end of the sampling and processing module 2 is electrically connected to the input end of the signal conditioning unit 31, and the above-mentioned PWM signal or analog signal is sent to the signal conditioning unit 31; the output end of the signal conditioning unit 31 is electrically connected to the voltage reference end Vref, and the signal conditioning unit 31 can adjust the regulating current flowing into the voltage reference end Vref according to the PWM signal or analog signal, and the switching regulator 321 then controls the voltage VCC of the voltage output end Vout according to the regulating current.

[0031] Further, in one embodiment, the signal conditioning unit is as follows Figure 3 As shown in the diagram 311, it includes a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7: the first end of the seventh resistor R7 is electrically connected to the sampling and processing module 2, and the second end of the seventh resistor R7 is electrically connected to the first end of the sixth resistor R6; the second end of the sixth resistor R6 is electrically connected to the reference ground, and the first end of the sixth resistor R6 is electrically connected to the voltage reference end Vref; the first end of the fifth resistor R5 is electrically connected to the voltage output end Vout, and the second end of the fifth resistor R5 is electrically connected to the first end of the sixth resistor R6; the voltage output end Vout is electrically connected to the first end of the fifth resistor R5. In this embodiment, when the sampling and processing module 2 outputs an analog signal, the analog signal represents a certain analog voltage value Va. According to Kirchhoff's current law (KCL), it can be known that:

[0032] (VCC-Vref) / R5+(Va-Vref) / R7=Vref / R6;

[0033] The voltage Vref at the voltage reference terminal of the switching regulator 321 is a certain value, so the value of the power supply voltage VCC can be changed by adjusting the value of Va. Specifically, Va can be determined by the working state of the bridge circuit.

[0034] When the sampling and processing module 2 outputs a PWM signal, I1 is different when the PWM signal is at a high level and a low level, so the value of the power supply voltage VCC can be changed by changing the duty cycle or frequency of the PWM signal, and VCC can be set to at least two different values. Specifically, the PWM signal can be determined by the working state of the bridge circuit.

[0035] Furthermore, if the sampling processing module 2 outputs a PWM signal, the signal adjustment unit may further set a switch tube Q1, specifically, Figure 4As shown in the signal conditioning unit 312, the switch tube is used to increase the driving capability of the PWM signal to generate sufficient regulating current. Specifically, the control end of the controllable switch tube Q1 is electrically connected to the output end of the sampling and processing module 2 to receive the PWM signal, the first end of the controllable switch tube is electrically connected to the power supply end VDD, and the second end of the controllable switch tube is electrically connected to the first end of the seventh resistor R7. When the PWM signal is at a high level and a low level, the working state (on or off) of the controllable switch tube Q1 is different, so the voltage at the first end of R7 is also different, so the current I1 is also different, so the value of VCC can be changed, and VCC can be set to at least 2 different values. Specifically, the controllable switch tube can be a PNP transistor, an NPN transistor, a P-MOS, an N-MOS, a relay, an optocoupler, etc.

[0036] Furthermore, in order to achieve stepless voltage regulation of VCC, the signal adjustment unit is configured to further include an eighth resistor R8 and a first capacitor C1, such as Figure 5 As shown in the figure 313, the second end of the controllable switch tube Q1 is electrically connected to the first end of the seventh resistor R7 through the eighth resistor R8, the first end of the first capacitor is electrically connected to the first end of the seventh resistor R7, and the second end of the first capacitor is electrically connected to the reference ground. In this embodiment, due to the existence of the capacitor C1, when a suitable capacitance value is selected, the voltage V7 at the first end of the seventh resistor is a stable voltage. When the duty cycle of the PWM signal changes, the average value of the voltage at the second end of Q1 changes within a cycle, so that I1 will also change. Therefore, the VCC voltage value can be adjusted by adjusting the duty cycle or frequency of the PWM signal.

[0037] Further, such as Figure 6 As shown, the signal adjustment unit 314 also includes a first diode D1, the anode of the first diode D1 is electrically connected to the second end of the seventh resistor R7, and the cathode of the first diode D1 is electrically connected to the voltage reference end Vref. The first diode is used to ensure that the current on R7 flows from the V7 end to the Vref end, so when the V7 voltage is less than Vref, the voltage of VCC is only controlled by the resistors R5 and R6. In this embodiment, the controllable switch tube Q1 is a PNP transistor Q12 as an example to illustrate the adjustment principle of the VCC voltage value:

[0038] The calculation process of VCC voltage in steady state is as follows:

[0039] When the PWM signal output by the sampling and processing module 2 is at a high level, Q12 is turned off, and Veq_in = V7;

[0040] When the PWM signal output by the sampling and processing module 2 is at a low level, Q12 is turned on, and Veq_in = VDD-VCE(sat).

[0041] Due to the presence of capacitor C1, when a suitable capacitance value is selected, voltage V7 is a stable voltage, so in one PWM cycle, the average voltage of Veq_in is:

[0042] Veq_in=V7·D+(V DD -V CE(sat) )·(1-D);

[0043] In the above formula, VCE(sat) is the saturation voltage drop between C (collector) and E (emitter) of transistor Q1, and D is the duty cycle of the PWM signal.

[0044] In steady state, the current flowing through R7 is equal to the current flowing through R8, so the voltage of V7 is derived,

[0045]

[0046] In the above formula, Vref is the reference voltage of the switching regulator, and Vd is the forward conduction voltage of the first diode D1.

[0047] Since I1+I2=I3,

[0048] Therefore, the value of Vcc can be derived,

[0049]

[0050] Substituting the equation of V7 into the equation, we can get the relationship with the PWM signal duty cycle D,

[0051]

[0052] Based on the above principle description, it can be known that the power supply voltage VCC can be controlled by adjusting the duty cycle of the PWM signal.

[0053] The temperature of the NTC resistor has a one-to-one correspondence with its resistance value, and the temperature of the NTC resistor can be calculated by detecting the resistance of the NTC. Therefore, the third aspect of the present application provides a temperature detection method for a thermistor, which can be implemented by the sampling processing module 2.

[0054] In one embodiment, the circuit schematic diagram of the detection module 1 is as follows Figure 7As shown in FIG. 8, the first bridge arm of the bridge circuit of the detection module 1 includes a third-first resistor R31 and a third-second resistor R32 connected in series; the second bridge arm of the bridge circuit includes a first resistor R1 and a first resistor R2 connected in series; one end of the bridge circuit is electrically connected to the voltage output terminal Vout through the third resistor R3, and the other end of the bridge circuit is electrically connected to the reference ground through the fourth resistor R4; the third-first resistor and the third-second resistor are NTC resistors. In this embodiment, the calculation of the values ​​of R31 and R32 can be realized by detecting the voltage VR4 of the resistor R4 and the voltage V1 and the voltage VCC of the midpoint of the thermistors R31 and R32, and the principle is as follows:

[0055] Assume that the current flowing through the thermistor is Isen,

[0056]

[0057] Therefore, the resistance of the third resistor R32 is:

[0058]

[0059] The resistance of the third resistor R31 is:

[0060]

[0061] In this embodiment, the resistance of the thermistor can be calculated by sampling the voltage of at least one node of the bridge circuit, so that the working state of the thermistor can be obtained, and the supply voltage can be further adjusted according to the working state, so as to change the working state of the thermistor and make it work in a more suitable working state. In addition, the sampling processing module 2 provided in the present application can calculate the resistance of the thermistor through voltage detection, so as to determine the temperature of the thermistor. In addition to changing the supply voltage according to the temperature provided in the present application, other controls can also be performed according to the temperature.

[0062] In one embodiment, in order to adjust the power supply voltage according to the working state of the detection module, the sampling processing module 2 is used to sample the power supply voltage VCC and the ambient temperature of the detection module; and the sampling processing module 2 is preset with a first mapping relationship between the ambient temperature and the suitable power supply voltage. Under different ambient temperatures, its suitable power supply voltage will also change; the ambient temperature obtained by sampling and the first mapping relationship can determine the optimal power supply voltage, and detect VCC at the same time. The sampling processing module 2 can generate an adjustment signal output to the signal adjustment unit based on at least the sampled ambient temperature, the power supply voltage and the first mapping relationship; the voltage adjustment module then adjusts the voltage at the output end of the voltage adjustment unit according to the adjustment signal. For example, the adjustment signal is a PWM signal including duty cycle information. If the detected VCC is too low, the PWM signal duty cycle D is increased to increase VCC; if the detected VCC is too large, the PWM signal duty cycle D is reduced to reduce VCC, and D is adjusted repeatedly so that the detected VCC reaches a suitable power supply voltage value.

[0063] In one embodiment, the thermistor is an NTC resistor, and the bridge circuit is used to detect the gas concentration, such as the A2L refrigerant concentration; the output voltage of the bridge circuit is measured to determine whether the refrigerant leaks or the refrigerant concentration. Figure 7 As shown, the sampling processing module 2 includes a sampling unit 21 and a processing unit 22; the sampling unit 21 is used to sample the voltage sampling signal Vs of at least one node in the bridge circuit; the processing unit 22 is used to calculate the resistance value of the NTC resistor at least according to the voltage sampling signal Vs; specifically, the sampling nodes and the voltage sampling signals can refer to other embodiments, and can be V1, V2, V R4 Etc. The processing unit is used to determine the PWM signal or analog signal output to the voltage regulation module at least according to the resistance value of the NTC resistor and / or the power supply voltage of the voltage output terminal. The bridge circuit provided in the drawings of the present application includes two NTC resistors: R32 and R31; one of which is a reference NTC and the other is a detection NTC. The reference NTC is arranged in a standard gas chamber, and the detection NTC is connected to the external environment. When the A2L refrigerant leaks, it can contact the A2L refrigerant gas. Whether a refrigerant leak occurs can be determined by detecting the voltage of the bridge circuit node. In order to improve the detection accuracy, R32 and R31 can be kept at a preferred operating temperature, and the resistance values ​​of R32 and R31 can be changed by adjusting their electrical parameters (such as voltage or current), so that they are at a preferred operating temperature. In one embodiment, the processing unit 22 includes a storage unit, which stores a second mapping relationship between the resistance value of the NTC resistor and the temperature. The processing unit 22 is used to determine the PWM signal or analog signal at least according to the resistance value of the NTC resistor, the second mapping relationship, and the power supply voltage of the voltage output terminal, thereby changing the resistance value of the NTC resistor so that it is at a preferred operating temperature.

[0064] The circuit schematic diagram of the detection module 1 can be shown as follows: Figure 8 Or as shown in 9, the first bridge arm of the bridge circuit includes a third-first resistor R32 and a third-second resistor R31 connected in series; the second bridge arm of the bridge circuit includes a first resistor R1 and a first resistor R2 connected in series; one end of the bridge circuit is electrically connected to the voltage output terminal Vout through the third resistor R3, and the other end of the bridge circuit is electrically connected to the reference ground through the fourth resistor R4; the third-first resistor and the third-second resistor are NTC resistors.

[0065] To achieve Figure 8 and Fig. 9 The resistance value detection of the NTC resistor in the detection module shown is as follows: Figure 8 As shown, the sampling unit 21 is provided to include a first voltage detection circuit 211, a second voltage detection circuit 212, and a third voltage detection circuit 213; one end of the first voltage detection circuit 211 is electrically connected to the voltage output terminal Vout, and one end of the second voltage detection circuit 212 is electrically connected to the common point of the third resistor R31 and the third resistor R32; one end of the third voltage detection circuit 213 is electrically connected to the high potential of the fourth resistor R4; the processing unit includes a signal end, and the output ends of the first voltage detection circuit 211, the second voltage detection circuit 212, and the third voltage detection circuit 213 are electrically connected to the signal end; specifically, the processing unit may include an MCU chip, and the signal end of the processing unit is the data port of the MCU chip. Specifically, the processing unit may include multiple signal ends, and the first, second, and third voltage detection circuits are electrically connected to different signal ends respectively. In the present application, the sampling unit 21 performs a control operation by controlling VCC, V1, V R4 The sampling unit 21 obtains the sampling signal, and the processing unit can calculate the resistance values ​​of R32 and R31 according to the sampling signal. The specific calculation method and formula can refer to the calculation method of R32 and R31 mentioned above. Further, in order to realize the change of VCC voltage, the sampling signal is further processed to obtain a PWM signal or an analog signal. In order to obtain the PWM signal or the analog signal, the R (resistance)-T (temperature) table of the NTC resistor can be preset, and the NTC resistor temperature can be determined according to the resistance value, and then the duty cycle of the PWM signal or the size of the analog signal can be determined according to the ambient temperature, the reference NTC temperature, and the detected NTC temperature. In one embodiment, the sampling unit 21 also includes an ambient temperature detection circuit, which is electrically connected to the processing unit 22, and the processing unit 22 is used to determine the PWM signal or the analog signal according to at least the resistance value of the NTC resistor, the second mapping relationship, the power supply voltage of the voltage output terminal, and the ambient temperature.

[0066] like Fig. 9As shown, the sampling unit 21 includes a first voltage detection circuit 211, a differential amplifier circuit 214 and a third voltage detection circuit 213; one end of the first voltage detection circuit 211 is electrically connected to the voltage output terminal Vout for sampling the VCC value; the two input ends of the differential amplifier circuit 214 are electrically connected to the middle point of the first bridge arm and the second bridge arm respectively, and are used to detect the output voltage of the bridge circuit on the one hand to detect the concentration of the refrigerant, and the output voltage is different for different refrigerant concentrations; one end of the third voltage detection circuit 213 is electrically connected to the high potential of the fourth resistor R4; the processing unit includes a signal end, and the output ends of the first voltage detection circuit 211, the differential amplifier circuit 214 and the third voltage detection circuit 213 are electrically connected to the signal end. In the present application, the output voltage Vo detected by the differential amplifier circuit or the input voltage value (V1 / V2) of the differential amplifier circuit can also be used to calculate the resistance value of the NTC resistor.

[0067] In this embodiment, the voltage value of V1 is not detected, and V1 can be inferred from the output voltage value Vo of the differential amplifier circuit, where Vo = (V1-V2)*α. The principle is as follows: since R1 and R2 are fixed resistors with known resistance values, it can be considered that they do not change with temperature, so the voltage of V2 is:

[0068]

[0069] V1 can be calculated from V2 and Vo.

[0070]

[0071] The calculation of the resistance values ​​of R32 and R31 can refer to the calculation formula and process of R32 and R31 mentioned above.

[0072] Furthermore, because the voltage at the voltage output terminal is determined by the PWM signal or the analog signal; therefore, Figure 8 and Fig. 9 In the provided sampling unit, the supply voltage value can be determined by a PWM signal or an analog signal. Therefore, the first voltage detection circuit may not be provided, and the supply voltage VCC can be calculated by the processing unit according to the PWM signal or the analog signal.

[0073] At this time, the sampling unit 21 includes a second voltage detection circuit 212 and a third voltage detection circuit 213; one end of the second voltage detection circuit 212 is electrically connected to the common point of the third first resistor and the third second resistor; one end of the third voltage detection circuit 213 is electrically connected to the high potential of the fourth resistor R4; the processing unit 22 includes a signal end, and the output ends of the second voltage detection circuit 212 and the third voltage detection circuit 213 are electrically connected to the signal end. In this embodiment, the processing unit 22 calculates the VCC obtained by calculation and the V1 and V R4 The NTC resistance can be calculated.

[0074] Alternatively, the sampling unit 21 includes a differential amplifier circuit 214 and a third voltage detection circuit 213; two input terminals of the differential amplifier circuit 214 are electrically connected to the middle point of the first bridge arm and the second bridge arm respectively, and one terminal of the third voltage detection circuit 213 is electrically connected to the high potential of the fourth resistor R4; the processing unit includes a signal terminal, and the output terminals of the first voltage detection circuit 211, the differential amplifier circuit 214 and the third voltage detection circuit 213 are electrically connected to the signal terminal. In this embodiment, the processing unit 22 obtains the VCC obtained by calculation and the Vo and V R4 The NTC resistance can be calculated.

[0075] In one embodiment, if the third resistor R31 and the third resistor R32 have the same nominal resistance, the sampling unit may only include the third voltage detection circuit, and it is not necessary to sample V1 / V2 to obtain the NTC resistance. One end of the third voltage detection circuit 213 is electrically connected to the high potential of the fourth resistor R4. The processing unit 22 includes a signal end, and the output end of the third voltage detection circuit 213 is electrically connected to the signal end. In this embodiment, V1 can be calculated by the following formula, and VCC can be obtained by the processing unit calculation method, or as follows: Fig.10 As shown, the first voltage detection circuit is used. Of course, Fig.10 In order to detect gas concentration, you can also set Fig. 9 The differential amplifier circuit shown in FIG. 1 is a differential amplifier circuit, but the differential amplifier circuit in this embodiment does not participate in the calculation of the resistance value of the NTC resistor.

[0076]

[0077] The calculation of the resistance values ​​of R32 and R31 can refer to the calculation formula and process of R32 and R31 mentioned above.

[0078] There are various forms of bridge circuits. The detection module 1 disclosed in one embodiment of the present application is as follows: Fig.11As shown, the first bridge arm of the bridge circuit includes a first resistor R2 and a third resistor R32 connected in series; the second bridge arm of the bridge circuit includes a first resistor R1 and a third resistor R31 connected in series; the third resistor and the third resistor are NTC resistors; the sampling unit 21 includes a first voltage detection circuit 211, a differential amplifier circuit 214 and a fourth voltage detection circuit 215; one end of the first voltage detection circuit 211 is electrically connected to the voltage output end; the two input ends of the differential amplifier circuit 214 are electrically connected to the middle point of the first bridge arm and the second bridge arm respectively; the fourth voltage detection circuit 215 is electrically connected to the middle point of the first bridge arm and / or the middle point of the second bridge arm; the processing unit includes a signal end, and the output ends of the first voltage detection circuit 211, the differential amplifier circuit 214 and the fourth voltage detection circuit 215 are electrically connected to the signal end. In this embodiment, the differential amplifier circuit is used for gas detection, and the fourth voltage detection circuit is used for voltage detection of V1 and V2, the first voltage detection circuit is used to detect VCC, and the processing unit 22 calculates the resistance value of the NTC resistor according to VCC, V1, and V2.

[0079] Specifically, the third-second resistor R32 is located at the high potential side of the first bridge arm and the third-first resistor R31 is located at the high potential side of the second bridge arm, that is, the NTC resistor potential is higher than the potential of R1 or R2. Of course, the third-second resistor R32 can also be set to be located at the low potential side of the first bridge arm and the third-first resistor R31 is located at the low potential side of the second bridge arm.

[0080] The detection module 1 disclosed in the embodiment of the present application is as follows Fig.12 As shown, the first bridge arm of the bridge circuit includes a first resistor R2, a third resistor and a second resistor connected in series; the second bridge arm of the bridge circuit includes a first resistor R1, a third resistor and a second resistor connected in series; the third resistor and the third resistor are NTC resistors;

[0081] In this embodiment, the sampling unit 21 includes a first voltage detection circuit 211, a differential amplifier circuit 214 and a fifth voltage detection circuit 216; one end of the first voltage detection circuit 211 is electrically connected to the voltage output end Vout; one input end of the differential amplifier circuit 214 is electrically connected to the common end of the first resistor R2 and the third resistor, and the other input end of the differential amplifier circuit 214 is electrically connected to the common end of the first resistor R1 and the third resistor; the fifth voltage detection circuit 216 is electrically connected to the second resistor and the second resistor, and is used to sample the voltage on the second resistor and the second resistor, wherein the second resistor and the second resistor are sampling resistors. The processing unit calculates the resistance value of the NTC resistor according to the voltage value detected by the sampling unit.

[0082] The above detection device can be applied to a gas detector, that is, based on the above detection device, the embodiment of the present application also provides a gas detector, including the above detection device; the detection module 1 of the detection device includes a thermistor, and the gas concentration is detected by detecting the voltage change of the thermistor; the sampling and processing module 2 of the detection device is electrically connected to the thermistor. The gas detector also has the advantages and working principles of the above detection device, which will not be repeated here.

[0083] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0084] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present invention. Therefore, the embodiments of the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A detection device, characterized in that: It includes a detection module, a sampling and processing module and a voltage regulation module; the voltage regulation module includes a signal regulation unit and a voltage adjustment unit; The input end of the sampling and processing module is electrically connected to the detection module; the output end of the sampling and processing module is electrically connected to the input end of the signal adjustment unit; the output end of the signal adjustment unit is electrically connected to the voltage adjustment unit; one end of the detection module is electrically connected to the output end of the voltage adjustment unit, and the other end is electrically connected to the reference ground.

2. The detection device according to claim 1, characterized in that: The detection module includes a bridge circuit, and the bridge circuit includes at least one thermistor; the voltage adjustment unit includes a switching regulator; the switching regulator has a voltage reference terminal and a voltage output terminal, and the output terminal of the voltage adjustment unit is the voltage output terminal; the sampling processing module is electrically connected to the bridge circuit, and the sampling processing module can sample at least one node voltage of the bridge circuit to obtain a voltage sampling signal, and generate a PWM signal or an analog signal at least according to the voltage sampling signal; The output end of the sampling and processing module is electrically connected to the input end of the signal adjustment unit, and can send the PWM signal or the analog signal to the signal adjustment unit; the output end of the signal adjustment unit is electrically connected to the voltage reference end, and the signal adjustment unit can adjust the adjustment current flowing into the voltage reference end according to the PWM signal or the analog signal, and the switching regulator can control the voltage of the voltage output end according to the adjustment current.

3. The detection device according to claim 2, characterized in that: The signal adjustment unit 311 includes a fifth resistor, a sixth resistor and a seventh resistor: the first end of the seventh resistor is electrically connected to the sampling processing module, and the second end of the seventh resistor is electrically connected to the first end of the sixth resistor; the second end of the sixth resistor is electrically connected to the reference ground, and the first end of the sixth resistor is electrically connected to the voltage reference end; the first end of the fifth resistor is electrically connected to the voltage output end, and the second end of the fifth resistor is electrically connected to the first end of the sixth resistor; the voltage output end is electrically connected to the first end of the fifth resistor.

4. The detection device according to claim 3, characterized in that: The sampling and processing module can output a PWM signal, and the signal adjustment unit 312 also includes a controllable switch tube; the control end of the controllable switch tube is electrically connected to the output end of the sampling and processing module, the first end of the controllable switch tube is electrically connected to the power supply end, and the second end of the controllable switch tube is electrically connected to the first end of the seventh resistor.

5. The detection device according to claim 4, characterized in that: The signal adjustment unit 313 also includes an eighth resistor and a first capacitor. The second end of the controllable switch tube is electrically connected to the first end of the seventh resistor through the eighth resistor, the first end of the first capacitor is electrically connected to the first end of the seventh resistor, and the second end of the first capacitor is electrically connected to the reference ground.

6. The detection device according to claim 5, characterized in that: The signal conditioning unit 314 further includes a first diode, wherein an anode of the first diode is electrically connected to the second end of the seventh resistor, and a cathode of the first diode is electrically connected to the voltage reference end.

7. The detection device according to any one of claims 1 to 6, characterized in that: The sampling and processing module is used to sample the power supply voltage and ambient temperature of the detection module; the sampling and processing module is preset with a first mapping relationship between the ambient temperature and the suitable power supply voltage, and the sampling and processing module can generate an adjustment signal output to the signal adjustment unit based on at least the ambient temperature, the power supply voltage and the first mapping relationship; the voltage adjustment module adjusts the voltage at the output end of the voltage adjustment unit according to the adjustment signal.

8. The detection device according to any one of claims 2 to 6, characterized in that: The thermistor is an NTC resistor, and the bridge circuit is used to detect gas concentration; the sampling and processing module includes a sampling unit and a processing unit; the sampling unit is used to sample the voltage sampling signal; the processing unit is used to calculate the resistance value of the NTC resistor at least based on the voltage sampling signal; the processing unit is used to determine the PWM signal or analog signal at least based on the resistance value of the NTC resistor and / or the power supply voltage of the voltage output end.

9. The detection device according to claim 8, characterized in that: The first bridge arm of the bridge circuit includes a third-first resistor and a third-second resistor connected in series; the second bridge arm of the bridge circuit includes a first resistor and a second resistor connected in series; one end of the bridge circuit is electrically connected to the voltage output end through the third resistor, and the other end of the bridge circuit is electrically connected to the reference ground through the fourth resistor; the third-first resistor and the third-second resistor are NTC resistors.

10. The detection device according to claim 9, characterized in that: The sampling unit includes a first voltage detection circuit, a second voltage detection circuit, and a third voltage detection circuit; one end of the first voltage detection circuit is electrically connected to the voltage output end, and one end of the second voltage detection circuit is electrically connected to a common point of the third first resistor and the third second resistor; one end of the third voltage detection circuit is electrically connected to a high potential of the fourth resistor; the processing unit includes a signal end, and the output ends of the first voltage detection circuit, the second voltage detection circuit, and the third voltage detection circuit are electrically connected to the signal end; Alternatively, the sampling unit includes a first voltage detection circuit, a differential amplifier circuit and a third voltage detection circuit; one end of the first voltage detection circuit is electrically connected to the voltage output end, the two input ends of the differential amplifier circuit are electrically connected to the midpoints of the first bridge arm and the second bridge arm respectively, and one end of the third voltage detection circuit is electrically connected to the high potential of the fourth resistor; the processing unit includes a signal end, and the output ends of the first voltage detection circuit, the differential amplifier circuit and the third voltage detection circuit are electrically connected to the signal end.

11. The detection device according to claim 9, characterized in that: The voltage at the voltage output terminal is determined by the PWM signal or the analog signal; The sampling unit includes a second voltage detection circuit and a third voltage detection circuit; one end of the second voltage detection circuit is electrically connected to a common point of the third-first resistor and the third-second resistor; one end of the third voltage detection circuit is electrically connected to a high potential of the fourth resistor; the processing unit includes a signal end, and the output ends of the second voltage detection circuit and the third voltage detection circuit are electrically connected to the signal end; Alternatively, the sampling unit includes a differential amplifier circuit and a third voltage detection circuit; the two input terminals of the differential amplifier circuit are electrically connected to the midpoints of the first bridge arm and the second bridge arm respectively, and one end of the third voltage detection circuit is electrically connected to the high potential of the fourth resistor; the processing unit includes a signal terminal, and the output terminals of the first voltage detection circuit, the differential amplifier circuit and the third voltage detection circuit are electrically connected to the signal terminal.

12. The detection device according to claim 9, characterized in that: The nominal resistance values ​​of the third-first resistor and the third-second resistor are the same; the sampling unit includes a third voltage detection circuit; one end of the third voltage detection circuit is electrically connected to the high potential of the fourth resistor; the processing unit includes a signal end, and the output end of the third voltage detection circuit is electrically connected to the signal end.

13. The detection device according to claim 8, characterized in that: The first bridge arm of the bridge circuit includes a second resistor and a third resistor connected in series; the second bridge arm of the bridge circuit includes a first resistor and a third resistor connected in series; the third resistor and the third resistor are NTC resistors; the sampling unit includes a first voltage detection circuit, a differential amplifier circuit and a fourth voltage detection circuit; one end of the first voltage detection circuit is electrically connected to the voltage output end; the two input ends of the differential amplifier circuit are electrically connected to the midpoints of the first bridge arm and the second bridge arm respectively; the fourth voltage detection circuit is electrically connected to the midpoint of the first bridge arm and / or the midpoint of the second bridge arm; the processing unit includes a signal end, and the output ends of the first voltage detection circuit, the differential amplifier circuit and the fourth voltage detection circuit are electrically connected to the signal end.

14. The detection device according to claim 13, characterized in that: The third second resistor is located at the high potential side of the first bridge arm and the third first resistor is located at the high potential side of the second bridge arm; Alternatively, the third-second resistor is located at the low potential side of the first bridge arm and the third-first resistor is located at the low potential side of the second bridge arm.

15. The detection device according to claim 8, characterized in that: The first bridge arm of the bridge circuit comprises a second resistor, a third resistor and a second resistor connected in series; the second bridge arm of the bridge circuit comprises a first resistor, a third resistor and a second resistor connected in series; the third resistor and the third resistor are NTC resistors; The sampling unit includes a first voltage detection circuit, a differential amplifier circuit and a fifth voltage detection circuit; one end of the first voltage detection circuit is electrically connected to the voltage output end; one input end of the differential amplifier circuit is electrically connected to the common end of the second resistor and the third resistor, and the other input end of the differential amplifier circuit is electrically connected to the common end of the first resistor and the third resistor; the fifth voltage detection circuit is electrically connected to the second resistor and the second resistor, and is used to sample the voltage on the second resistor and the second resistor.

16. The detection device according to claim 8, characterized in that: The sampling unit also includes an ambient temperature detection circuit, which is electrically connected to the processing unit. The processing unit is used to determine the PWM signal or the analog signal based on at least the resistance value of the NTC resistor, the second mapping relationship between the resistance value of the NTC resistor and the temperature, the supply voltage of the voltage output end, and the ambient temperature.

17. A gas detector, characterized in that: It comprises a detection device as described in any one of claims 1 to 16; the detection module of the detection device comprises a thermistor, and the gas concentration is detected by detecting the voltage change of the thermistor; the sampling and processing module of the detection device is electrically connected to the thermistor.

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