Smoke detector calibration method and device

Abstract

The present invention provides a smoke detector calibration method and device. The method comprises: providing a smoke detector; powering on a first arithmetic unit, a second arithmetic unit, and an analog-to-digital converter; sampling the output of the second arithmetic unit for a first time via the analog-to-digital converter after a first preset duration to obtain a first sampling result; adjusting the first arithmetic unit to an integration mode, and disabling the integration mode of the first arithmetic unit after a second preset duration; waiting for a third preset duration, sampling the output of the second arithmetic unit for a second time via the analog-to-digital converter to obtain a second sampling result; obtaining a dark current error based on the second sampling result and the first sampling result; and calibrating the output of the smoke detector based on the dark current error. The present invention eliminates the influence of dark current on the detection accuracy of smoke detectors with corresponding structures.

Description

Technical Field

[0001] The present invention relates to the technical field of smoke detectors, and in particular to a calibration method and device for a smoke detector. Background Art

[0002] Traditional calibration methods for smoke detectors (also known as smoke sensors) often overlook the effects of dark current. Dark current varies with temperature, affecting the detector's accuracy and potentially causing false alarms.

[0003] A Chinese authorized patent with publication number CN115063943A discloses a smoke sensor and smoke detection device based on a low-power analog-to-digital converter. During the smoke detection process, although the smoke detection stability is high and the application cost of the smoke detection module is greatly reduced, it is inevitably affected by dark current.

[0004] Therefore, the present invention proposes a smoke detector calibration method and device to reduce the influence of dark current on the detection accuracy of the smoke detector. Summary of the Invention

[0005] The present invention provides a smoke detector calibration method and device to solve the technical problem in the prior art that the detection accuracy of the smoke detector is reduced due to the influence of dark current.

[0006] In a first aspect, the present invention provides a method for calibrating a smoke detector, comprising: providing a smoke detector, the smoke detector comprising: a current sink generator, a smoke sensing module, a first operation unit, a second operation unit, and an analog-to-digital converter; the current sink generator is used to provide current to the smoke sensing module; the smoke sensing module is used to detect smoke and output a sensed current after detecting smoke; the first operation unit is connected to the output end of the smoke sensing module and is used to integrate the sensed current to obtain an integrated voltage signal; the second operation unit is connected to the output end of the first operation unit and is used to buffer the integrated voltage signal to obtain a buffered voltage signal; the analog-to-digital converter converts the buffered voltage signal into a digital signal ; Power on the first operation unit, the second operation unit and the analog-to-digital converter, and the first operation unit and the second operation unit are both in gain buffer mode; after a first preset time, sample the output of the second operation unit for the first time through the analog-to-digital converter to obtain a first sampling result; adjust the first operation unit to an integration mode, and after a second preset time, turn off the integration mode of the first operation unit; wait for a third preset time, sample the output of the second operation unit for a second time through the analog-to-digital converter to obtain a second sampling result; obtain a dark current error based on the second sampling result and the first sampling result; calibrate the output of the smoke detector based on the dark current error.

[0007] The smoke detector calibration method provided by the present invention has the beneficial effect of being applicable to smoke detectors with corresponding structures. The present invention obtains a dark current error based on the second sampling result and the first sampling result, and calibrates the output of the smoke detector based on the obtained dark current error. This eliminates the influence of dark current on the detection accuracy of smoke detectors with corresponding structures, thus resolving the technical problem in the prior art of reduced detection accuracy of smoke detectors due to the influence of dark current.

[0008] Optionally, obtaining a dark current error based on the second sampling result and the first sampling result includes obtaining the dark current error based on a difference between the second sampling result and the first sampling result. This advantageously provides a simple and easy-to-operate solution for obtaining the dark current error based on the difference between the second sampling result and the first sampling result.

[0009] Optionally, calibrating the output of the smoke detector based on the dark current error includes: resetting the first operation unit, sampling the output of the second operation unit for a third time via the analog-to-digital converter to obtain a third sampling result; powering on the current generator and causing the smoke sensing module to generate the induced current under preset conditions; adjusting the first operation unit to an integration mode again, and disabling the integration mode of the first operation unit after a fourth preset time; waiting for a fifth preset time, sampling the output of the second operation unit for a fourth time via the analog-to-digital converter to obtain a fourth sampling result; and obtaining the calibrated output of the smoke detector by calculating the difference between a first difference and a second difference, wherein the first difference is the dark current error, and the second difference is the difference between the fourth sampling result and the third sampling result. The beneficial effect of this method is that the calibrated output of the smoke detector is obtained by calculating the difference between the first difference and the second difference.

[0010] Optionally, the smoke detector calibration method further includes: obtaining a comparison result by comparing the output of the calibrated smoke detector with an alarm threshold of the smoke detector; and determining whether the smoke detector needs to alarm based on the comparison result.

[0011] Optionally, the smoke detector calibration method further includes: calibrating the analog-to-digital converter before obtaining the first sampling result.

[0012] Optionally, calibrating the analog-to-digital converter includes: S1, obtaining a first digital code generated by the analog-to-digital converter based on a first analog signal and a second digital code generated by the analog-to-digital converter based on a second analog signal at a normal operating temperature; S2, converting the first analog signal into a third digital code and converting the second analog signal into a fourth digital code according to a first conversion coefficient; S3, obtaining a first slope by calculating a ratio of a first difference to a second difference, wherein the first difference is the difference between the first digital code and the second digital code, and the second difference is the difference between the third digital code and the fourth digital code; S4, obtaining a first constant by calculating a first product and a difference between the first digital code and the first product, wherein the first product is the product of the second digital code and the first slope; S5, adjusting a parameter of the digital code generated by the analog signal in the analog-to-digital converter based on the first slope and the first constant to complete parameter calibration. The beneficial effect of the present invention is that the conversion accuracy of the analog-to-digital converter is improved by correcting the linear relationship between the input and output of the analog-to-digital converter.

[0013] Optionally, the first conversion coefficient is the second product and 2N The second product is the product of the reference voltage of the device constituting the analog-to-digital converter and a first coefficient T1, the first coefficient T1 being obtained based on the operating temperature of the analog-to-digital converter, and N being the number of counting bits of the analog-to-digital converter. The advantageous effect is that the first conversion coefficient is obtained.

[0014] Alternatively, by the formula The first coefficient T1 is obtained, where Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of i is -1 to 1.

[0015] Optionally, in S2, converting the first analog signal into a third digital code and converting the second analog signal into a fourth digital code according to a first conversion coefficient includes: obtaining the third digital code by calculating the quotient of the first analog signal and the first conversion coefficient; and obtaining the fourth digital code by calculating the quotient of the second analog signal and the first conversion coefficient. This advantageously enables the first analog signal and the second analog signal to be converted into data of the same type as the output of the analog-to-digital converter using the first conversion coefficient, thereby facilitating comparison and analysis.

[0016] Optionally, after completing S5, the method further includes: obtaining a first operating temperature, the first operating temperature being the actual operating temperature of the analog-to-digital converter after parameter calibration is completed; determining whether the first operating temperature is room temperature, and if so, converting the analog signal into a digital code according to the first slope, the first constant, and the first conversion coefficient by the analog-to-digital converter; otherwise, obtaining the first coefficient T; obtaining a second slope by calculating the product of the first slope and the first coefficient T; and adjusting the parameters of the digital code generated according to the analog signal in the analog-to-digital converter again based on the second slope and the first constant to complete parameter calibration. The beneficial effect is that by calculating the product of the first slope and the first temperature coefficient to obtain the second slope, the conversion accuracy of the analog-to-digital converter can be guaranteed to be consistent at different temperatures.

[0017] Optionally, before obtaining the first operating temperature, the method further includes: the analog-to-digital converter converting the third analog signal into a fifth digital code under the first temperature signal, wherein the first temperature signal corresponds to the operating temperature of the analog-to-digital converter being room temperature; the analog-to-digital converter converting the fourth analog signal into a sixth digital code under the second temperature signal, wherein the operating temperature corresponding to the second temperature signal is the first operating temperature; converting the first temperature signal of the analog-to-digital converter when generating the fifth digital code into a seventh digital code, and converting the second temperature signal of the analog-to-digital converter when generating the sixth digital code according to a second conversion coefficient; and calculating the sum of a third product and the room temperature to calibrate the second temperature signal, wherein the third product is the product of a third difference and a second temperature coefficient, and the third difference is the difference between the second temperature signal and the first temperature signal. The advantageous effect is that, because the temperature signal obtained by the analog-to-digital converter may not necessarily match the actual temperature, the temperature signal received by the analog-to-digital converter is calibrated through the above operations.

[0018] Optionally, the second temperature coefficient has a value range of -1 to 1. The beneficial effect is that the operating temperature obtained within this range is more practical.

[0019] Optionally, the second conversion coefficient is the fourth product and 2 N The fourth product is the product of the reference voltage of the device formed by the analog-to-digital converter and the second coefficient, and N is the number of counting bits of the analog-to-digital converter. Its beneficial effect is: to obtain the second conversion coefficient.

[0020] Optionally, according to the formula The second coefficient T2 is obtained, where Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of j is -1 to 1.

[0021] Optionally, according to the second conversion coefficient, the first temperature signal of the analog-to-digital converter when generating the fifth digital code is converted into a seventh digital code, and the second temperature signal of the analog-to-digital converter when generating the sixth digital code is converted into an eighth digital code, including: obtaining the seventh digital code by calculating the quotient of the first temperature signal and the second coefficient; obtaining the eighth digital code by calculating the quotient of the second temperature signal and the second coefficient.

[0022] Optionally, the smoke detector calibration method further includes: calibrating a current injection generator. The beneficial effect of this method is that the detection accuracy of the smoke detector is further improved.

[0023] Optionally, calibrating the current sink generator includes: obtaining an ideal current corresponding to an initial default configuration of the current sink generator by using the initial default configuration; obtaining an actual current generated by the current sink generator for the smoke sensing module; obtaining a register deviation in the analog-to-digital converter by calculating a quotient of a difference between the ideal current and the actual current and a current value corresponding to each digital code in the analog-to-digital converter; and calibrating the initial default configuration of the current sink generator according to the register deviation.

[0024] In a second aspect, the present invention provides a calibration device for a smoke detector, which is used to perform the calibration method for a smoke detector as described in any one of the first aspects, comprising: a smoke detector, a power-on module, a first sampling unit, an integral adjustment unit, a second sampling unit, an error acquisition unit, and a calibration unit; the smoke detector comprises: a current generator, a smoke sensing module, a first operation unit, a second operation unit, and an analog-to-digital converter; the current generator is used to provide current to the smoke sensing module; the smoke sensing module is used to detect smoke and output an induced current after detecting smoke; the first operation unit is connected to the output end of the smoke sensing module, and is used to integrate the induced current to obtain an integrated voltage signal; the second operation unit is connected to the output end of the first operation unit, and is used to buffer the integrated voltage signal to obtain a buffered voltage signal; the analog-to-digital converter converts the buffered voltage signal into a digital signal word signal; the power-on module is used to power on the first operation unit, the second operation unit and the analog-to-digital converter, and the first operation unit and the second operation unit are both in gain buffer mode; the first sampling unit is used to sample the output of the second operation unit for the first time through the analog-to-digital converter after a first preset time length to obtain a first sampling result; the integral adjustment unit is used to adjust the first operation unit to the integration mode, and turn off the integration mode of the first operation unit after a second preset time length; the second sampling unit is used to wait for a third preset time length, and sample the output of the second operation unit for the second time through the analog-to-digital converter to obtain a second sampling result; the error acquisition unit is used to obtain a dark current error according to the second sampling result and the first sampling result; the calibration unit is used to calibrate the output of the smoke detector according to the dark current error.

[0025] The smoke detector calibration device provided by the present invention has the beneficial effect of being suitable for calibrating smoke detectors with corresponding structures. The present invention obtains a dark current error based on the second sampling result and the first sampling result, and calibrates the output of the smoke detector based on the obtained dark current error. This eliminates the influence of dark current on the detection accuracy of smoke detectors with corresponding structures, thereby resolving the technical problem in the prior art of reduced detection accuracy of smoke detectors due to the influence of dark current. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of an embodiment of a smoke detector calibration method provided by the present invention;

[0027] Figure 2 A schematic structural diagram of a smoke detector embodiment provided by the present invention;

[0028] Figure 3 A flow chart of an analog-to-digital converter calibration embodiment provided by the present invention;

[0029] Figure 4 A schematic diagram of an embodiment of potential changes of related components in a smoke detector provided by the present invention;

[0030] Figure 5 This is a schematic structural diagram of an embodiment of a smoke detector calibration device provided by the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. Among them, in the description of the embodiments of the present application, the terms used in the following embodiments are only for the purpose of describing specific embodiments, and are not intended to be used as limitations on the present application. As used in the specification and claims of the present application, the singular expressions "a", "the", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context. It should also be understood that in the following embodiments of the present application, "at least one", "one or more" refer to one or more (including two). The term "and / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist; for example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0032] References to "one embodiment" or "some embodiments" etc. described in this specification mean that the specific features, structures or characteristics described in conjunction with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in another way. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in another way. The term "connected" includes direct and indirect connections, unless otherwise stated. "First" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0033] In the embodiments of this application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplarily" or "for example" is intended to present the relevant concepts in a concrete manner.

[0034] The present invention provides a smoke detector calibration method and device to solve the technical problem in the prior art that the detection accuracy of the smoke detector is reduced due to the influence of dark current.

[0035] The present invention provides a smoke detector calibration method, the process of which is as follows: Figure 1 Shown, including:

[0036] S101, providing a smoke detector, the structure of which is as follows Figure 2 As shown, the smoke detector includes: a current sink generator 201, a smoke sensing module 202, a first operation unit 203, a second operation unit 204 and an analog-to-digital converter 205; the current sink generator 201 is used to provide current to the smoke sensing module 202; the smoke sensing module 202 is used to detect smoke and output a sensed current after detecting smoke; the first operation unit 203 is connected to the output end of the smoke sensing module 202, and is used to integrate the sensed current to obtain an integrated voltage signal; the second operation unit 204 is connected to the output end of the first operation unit 203, and is used to buffer the integrated voltage signal to obtain a buffered voltage signal; the analog-to-digital converter 205 converts the buffered voltage signal into a digital signal;

[0037] S102, powering on the first arithmetic unit, the second arithmetic unit, and the analog-to-digital converter, with the first arithmetic unit and the second arithmetic unit all being in a gain buffer mode;

[0038] S103: After a first preset time period, sampling the output of the second operation unit for the first time through the analog-to-digital converter to obtain a first sampling result;

[0039] In this step, the first preset time duration is 3 to 100 microseconds, and is set to ensure that the first operation unit, the second operation unit, and the analog-to-digital converter are all powered on without wasting time.

[0040] S104, adjusting the first operation unit to an integration mode, and turning off the integration mode of the first operation unit after a second preset time period;

[0041] In this step, the second preset time is of any length and can be flexibly set according to actual conditions.

[0042] S105: Wait for a third preset time period, and perform a second sampling on the output of the second operation unit through the analog-to-digital converter to obtain a second sampling result;

[0043] In this step, the third preset time length is 1 to 100 microseconds, and the third preset time length is set to ensure the stability of the integration mode of the first operation unit without wasting time.

[0044] S106 . Obtain a dark current error according to the second sampling result and the first sampling result; and calibrate the output of the smoke detector according to the dark current error.

[0045] The smoke detector calibration method provided by the present invention has the beneficial effect of being applicable to smoke detectors with corresponding structures. The present invention obtains a dark current error based on the second sampling result and the first sampling result, and calibrates the output of the smoke detector based on the obtained dark current error. This eliminates the influence of dark current on the detection accuracy of smoke detectors with corresponding structures, thus resolving the technical problem in the prior art of reduced detection accuracy of smoke detectors due to the influence of dark current.

[0046] The smoke detector provided by the present invention only lists the more critical components, and of course covers smoke detectors based on the structure listed by the present invention. The smoke sensing module and current injection generator provided by the present invention are both existing technologies. In some embodiments, the smoke sensing module includes a first light-emitting diode, a second light-emitting diode, and a photosensitive diode arranged in a smoke detection cavity; the positive electrode of the first light-emitting diode and the positive electrode of the second light-emitting diode are connected to a power supply module, and the power supply module is used to supply power to the positive electrode of the first light-emitting diode and the second light-emitting diode; the positive electrode of the photosensitive diode is connected to the negative input terminal of the first operation unit through a ninth switch, the negative electrode of the photosensitive diode is connected to the first input terminal of the first data selector, and the second input terminal of the first data selector is connected to the output terminal of the digital-to-analog converter. Optionally, when there is smoke in the smoke detection cavity, the photosensitive diode receives the light signal emitted by the first light-emitting diode and the second light-emitting diode, and outputs the induced current. In some embodiments, the current injection generator includes: a first transistor, a second transistor, a third transistor, a current source, a tenth switch and an eleventh switch; the first end of the first transistor is connected to the cathode of the first light-emitting diode, the second end of the first transistor is grounded, and the control end of the first transistor is connected to the first end of the tenth switch; the first end of the second transistor is connected to the cathode of the second light-emitting diode, the second end of the second transistor is grounded, and the control end of the second transistor is connected to the second end of the tenth switch through the eleventh switch; the positive electrode of the current source is connected to the first end of the third transistor, the control end of the third transistor is connected to the second end of the tenth switch, and the second end of the third transistor is grounded.

[0047] In some further embodiments, the smoke detector further includes a microcontroller unit (MCU), which is used to control the switching of the working states of the remaining modules in the smoke detector, and the working states include: power on, power off, on, off, on and off of the integration mode, and on and off of the gain buffer mode.

[0048] Optionally, the first operation unit may be an integrator or a transimpedance amplifier (TIA) based on an operational amplifier. The second operation unit may be a buffer based on an operational amplifier. The operational amplifier-based integrator, transimpedance amplifier, and operational amplifier-based buffer are all prior art and are not described in detail here.

[0049] In some embodiments, obtaining a dark current error based on the second sampling result and the first sampling result includes obtaining the dark current error based on a difference between the second sampling result and the first sampling result. This advantageously provides a simple and easy-to-operate solution for obtaining the dark current error based on the difference between the second sampling result and the first sampling result.

[0050] In some embodiments, calibrating the output of a smoke detector based on the dark current error includes: resetting the first arithmetic unit, sampling the output of the second arithmetic unit for a third time via the analog-to-digital converter to obtain a third sampling result; powering on the current sink generator and causing the smoke sensing module to generate the induced current under preset conditions; adjusting the first arithmetic unit to an integration mode again, and disabling the integration mode of the first arithmetic unit after a fourth preset time; waiting for a fifth preset time, sampling the output of the second arithmetic unit for a fourth time via the analog-to-digital converter to obtain a fourth sampling result; and obtaining the calibrated output of the smoke detector by calculating the difference between a first difference and a second difference, wherein the first difference is the dark current error, and the second difference is the difference between the fourth sampling result and the third sampling result. The advantageous effect is that the calibrated output of the smoke detector is obtained by calculating the difference between the first difference and the second difference. Optionally, the fourth preset time may be equal to or unequal to the second preset time; and the third preset time may be equal to or unequal to the fifth preset time.

[0051] In some embodiments, the smoke detector calibration method further includes: obtaining a comparison result by comparing the output of the calibrated smoke detector with an alarm threshold of the smoke detector; and determining whether the smoke detector needs to alarm based on the comparison result.

[0052] In some embodiments, the smoke detector calibration method further includes: calibrating the analog-to-digital converter before obtaining the first sampling result.

[0053] In some embodiments, the analog-to-digital converter is calibrated as follows: Figure 3 Shown, including:

[0054] S1. Under normal operating temperature, obtaining a first digital code generated by an analog-to-digital converter according to a first analog signal and a second digital code generated by the analog-to-digital converter according to a second analog signal;

[0055] S2, converting the first analog signal into a third digital code according to a first conversion coefficient, and converting the second analog signal into a fourth digital code;

[0056] S3. Obtain a first slope by calculating a ratio of a first difference to a second difference, where the first difference is a difference between the first digital code and the second digital code, and the second difference is a difference between the third digital code and the fourth digital code;

[0057] S4. Obtain a first constant by calculating a first product and a difference between the first digital code and the first product, where the first product is the product of the second digital code and the first slope;

[0058] S5. Adjust the parameters of the digital code generated according to the analog signal in the analog-to-digital converter based on the first slope and the first constant to complete parameter calibration.

[0059] The present invention improves the conversion accuracy of the analog-to-digital converter by correcting the linear relationship between the input and output of the analog-to-digital converter. The normal temperature is 23-27 degrees Celsius. Optionally, the normal temperature is 23, 25 or 27 degrees Celsius.

[0060] In some embodiments, the first conversion factor is the second product and 2 N The second product is the product of the reference voltage of the device constituting the analog-to-digital converter and a first coefficient T1, the first coefficient T1 being obtained based on the operating temperature of the analog-to-digital converter, and N being the number of counting bits of the analog-to-digital converter. The advantageous effect is that the first conversion coefficient is obtained.

[0061] In some embodiments, the formula The first coefficient T1 is obtained, Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of i is between -1 and 1. The value of i is specifically set between -1 and 1 according to actual conditions and is not limited here.

[0062] In some embodiments, in S2, converting the first analog signal into a third digital code and converting the second analog signal into a fourth digital code according to a first conversion coefficient includes: obtaining the third digital code by calculating the quotient of the first analog signal and the first conversion coefficient; and obtaining the fourth digital code by calculating the quotient of the second analog signal and the first conversion coefficient. This advantageously converts the first analog signal and the second analog signal into data of the same type as the output of the analog-to-digital converter using the first conversion coefficient, facilitating comparison and analysis.

[0063] In some embodiments, after completing S5, the process further includes: obtaining a first operating temperature, the first operating temperature being the actual operating temperature of the analog-to-digital converter after parameter calibration is completed; determining whether the first operating temperature is room temperature; if so, the analog-to-digital converter converts the analog signal into a digital code according to the first slope, the first constant, and the first conversion coefficient; otherwise, obtaining the first coefficient T; obtaining a second slope by calculating the product of the first slope and the first coefficient T; and adjusting the parameters of the digital code generated according to the analog signal in the analog-to-digital converter again based on the second slope and the first constant to complete parameter calibration. The beneficial effect is that by calculating the product of the first slope and the first temperature coefficient to obtain the second slope, the conversion accuracy of the analog-to-digital converter can be guaranteed to be consistent at different temperatures.

[0064] In some embodiments, before obtaining the first operating temperature, the method further includes: converting the third analog signal by the analog-to-digital converter into a fifth digital code under a first temperature signal, wherein the first temperature signal corresponds to the operating temperature of the analog-to-digital converter being room temperature; converting the fourth analog signal by the analog-to-digital converter into a sixth digital code under a second temperature signal, wherein the operating temperature corresponding to the second temperature signal is the first operating temperature; converting the first temperature signal by the analog-to-digital converter when generating the fifth digital code into a seventh digital code, and converting the second temperature signal by the analog-to-digital converter when generating the sixth digital code according to a second conversion coefficient; and calculating a sum of a third product and the room temperature to calibrate the second temperature signal, wherein the third product is the product of a third difference and a second temperature coefficient, wherein the third difference is the difference between the second temperature signal and the first temperature signal. The advantageous effect is that, because the temperature signal obtained by the analog-to-digital converter may not necessarily match the actual temperature, the temperature signal received by the analog-to-digital converter is calibrated through the above operations.

[0065] In some embodiments, the second temperature coefficient has a value range of -1 to 1. This advantageously provides a more realistic operating temperature. Optionally, the second temperature coefficient is -1, -0.5, -0.3, -0.1, 0.12, 0.15, 0.18, 0.2, 0.5, 0.7, or 1.

[0066] In some embodiments, the second conversion factor is the fourth product and 2 N The fourth product is the product of the reference voltage of the device formed by the analog-to-digital converter and the second coefficient, and N is the number of counting bits of the analog-to-digital converter. Its beneficial effect is: to obtain the second conversion coefficient.

[0067] In some embodiments, according to the formula The second coefficient T2 is obtained, wherein Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of j is between -1 and 1. The value of j is specifically set between -1 and 1 according to actual conditions and is not limited here.

[0068] In some embodiments, according to a second conversion coefficient, the first temperature signal of the analog-to-digital converter when generating the fifth digital code is converted into a seventh digital code, and the second temperature signal of the analog-to-digital converter when generating the sixth digital code is converted into an eighth digital code, including: obtaining the seventh digital code by calculating the quotient of the first temperature signal and the second coefficient; obtaining the eighth digital code by calculating the quotient of the second temperature signal and the second coefficient.

[0069] In some embodiments, the smoke detector calibration method further includes: calibrating the current sink generator. The beneficial effect of this is: further improving the detection accuracy of the smoke detector.

[0070] In some embodiments, calibration of the current sink generator includes: obtaining an ideal current corresponding to an initial default configuration of the current sink generator by using the initial default configuration; obtaining an actual current generated by the current sink generator for the smoke sensing module; obtaining a register deviation in the analog-to-digital converter by calculating a quotient of a difference between the ideal current and the actual current and a current value corresponding to each digital code in the analog-to-digital converter; and calibrating the initial default configuration of the current sink generator based on the register deviation.

[0071] To further illustrate the calibration method of the smoke detector provided by the present invention, an example is given here:

[0072] Example 1:

[0073] At room temperature, the analog-to-digital converter (ADC) is calibrated using the above method. For example, the ADC reference voltage vref is 1.5V. The mathematical relationship between the ADC input signal Vi and the ADC count result code is: code = Vi / m, where m = 1.5V*Tc / 4096, where Tc is a temperature-dependent coefficient. Input signals Vi1 and Vi2 are selected as 0.375V and 1.125V, respectively. The ADC count results based on Vi1 and Vi2 are Co1 and Co2, respectively. Based on the above input signals and the above mathematical relationship, the input signals Vi1 and Vi2 correspond to Co3 and Co4, respectively. The first slope K is obtained using the formula K = (Co1-Co2) / (Co3-Co4), and the first constant B is obtained using the formula B = Co1-K*Co2. The parameters used in the ADC to generate digital codes from analog signals are adjusted based on the first slope K and the first constant B.

[0074] When the analog-to-digital converter is not operating at room temperature, k=aK, where k is the actual operating temperature and a is the first coefficient. The first slope at the corresponding temperature is obtained.

[0075] Example 2:

[0076] Using the results of the analog-to-digital converter calibration, the temperature sensor is calibrated (Tsensor calibration). The second temperature signal Ti2 is obtained using the formula Ti2 = (Co2_cali - Co1_cali) * 0.16 + Ti1, where Co2_cali is the digital code corresponding to the second temperature signal, Co1_cali is the first temperature signal, i.e., room temperature, and 0.16 is the second temperature coefficient. This method is applicable to operating temperatures between -40°C and 125°C, and Ti1 can be set to 25°C.

[0077] Example 3:

[0078] The calibration of the voltage sensor is done in the same way as in the example:

[0079] At room temperature, assuming the power supply voltage of the voltage sensor ranges from 2.2 to 5.5 V, two input signals, Vi1 = 3.025 V and Vi2 = 4.675 V, are obtained for the analog-to-digital converter in the voltage sensor. The mathematical relationship between the input signal Vi of the analog-to-digital converter in the voltage sensor and the count result code of the analog-to-digital converter is: code = Vi / m, where m = 1.5 V * Tc / 4096, where Tc is a temperature-dependent coefficient. The count results of Vi1 and Vi2 are respectively Co1 and Co2, respectively, obtained from the analog-to-digital converter. Based on the above input signals and the above mathematical relationship, the input signals Vi1 and Vi2 correspond to Co3 and Co4, respectively. The first slope K is obtained according to the formula K = (Co1 - Co2) / (Co3 - Co4), and the first constant B is obtained according to the formula B = Co1 - K * Co2. The parameters of the analog-to-digital converter used to generate digital codes from analog signals are adjusted based on the first slope K and the first constant B.

[0080] When the analog-to-digital converter is not operating at room temperature, k=aK, where k is the actual operating temperature and a is the first coefficient. The first slope at the corresponding temperature is obtained.

[0081] The voltage sensor in this example may be a power supply voltage sensor.

[0082] Example 4:

[0083] The calibration of the operational amplifiers in the first operation unit and the second operation unit is similar to the calibration method in Example 1 and Example 3, and will not be repeated here.

[0084] Example 5:

[0085] At room temperature, the current sink generator is calibrated. When using the current sink generator, the initial default configuration of the current sink generator is used. Assuming that the initial default configuration is 10000, the ideal current I0_I corresponding to the initial default configuration is obtained. Assuming that the ideal current I0_I is 50 mA, the actual current I0_A of the current sink generator is obtained. Assuming that the actual current I0_A is 55 mA, the difference between the ideal current I0_I and the actual current I0_A and the current value Itune_step corresponding to each digital code in the analog-to-digital converter are calculated using the formula code shift = (55-50) / Itune_step to obtain the register deviation code shift that needs to be calibrated. For example, taking itune step = 1 mA, it is calculated that an initial offset of 5 digital codes is required to match the actual measured current value with the ideal current value. Therefore, the decimal value minus 5 is configured to the initial default configuration, that is, the initial default configuration 10000 is converted to 01011.

[0086] Before each sampling operation, the internal temperature sensor is awakened to read the current temperature. This temperature reading is then used to perform a secondary calibration of the current sink generator, ensuring that the current sink generator maintains the same accuracy at all temperatures, from -40°C to 125°C, as at room temperature. This improves the accuracy of the smoke detector's emitter diode current. This secondary calibration is similar to the temperature calibration of the analog-to-digital converter, except that the coefficient differs by 0.1%.

[0087] After completing the above calibration, calibrate the smoke detector.

[0088] Example 6:

[0089] Provide Figure 2The smoke detector shown in the figure powers on the first operation unit, the second operation unit, and the analog-to-digital converter at the same time, and the first operation unit and the second operation unit are all in the gain buffer mode; wait for 5us, that is, wait for all three to be powered on, and sample the output of the second operation unit once through the analog-to-digital converter to obtain a first sampling result V0; turn on the integration mode of the first operation unit for the first time, and turn off the integration mode after T1us; the T is an arbitrarily set value and the present invention does not impose any limitation on this; wait for about 2us, and the analog-to-digital converter ADC samples the output of the second operation unit for the second time to obtain a second sampling result V1; reset the first operation unit, and after it stabilizes, the analog-to-digital converter samples the output of the second operation unit The output of the calculation unit is sampled for the third time to obtain the third sampling result V2; the current injection generator is powered on to make the smoke sensing module generate the induced current under the preset conditions, and the preset conditions refer to the presence of smoke in the surrounding environment of the smoke sensor; after waiting for the induced current to stabilize, the integration mode of the first calculation unit is turned on for the second time, and after integrating for T2us, the integration mode is turned off; after waiting for about 2us, the analog-to-digital converter samples the output of the second calculation unit for the fourth time to obtain the fourth sampling result V3; smoke detection is completed, and all devices in the smoke detector are powered off at the same time; the photocurrent integration result is calculated by the formula (V3-V2)-(V1-V0) to determine whether it reaches the alarm threshold. During the process of this example, the potential changes of the relevant devices in the smoke detector are as follows: Figure 4 shown.

[0090] Based on the smoke detector calibration method described in any one of the above embodiments, the present invention provides a smoke detector calibration device for performing the smoke detector calibration method described in any one of the above embodiments. Figure 5 As shown, it includes: a smoke detector 501, a power-on module 502, a first sampling unit 503, an integral adjustment unit 504, a second sampling unit 505, an error acquisition unit 506, and a calibration unit 507; the smoke detector 501 includes: a current generator, a smoke sensing module, a first operation unit, a second operation unit and an analog-to-digital converter; the current generator is used to provide current to the smoke sensing module; the smoke sensing module is used to detect smoke and output a sensed current after detecting smoke; the first operation unit is connected to the output end of the smoke sensing module and is used to integrate the sensed current to obtain an integrated voltage signal; the second operation unit is connected to the output end of the first operation unit and is used to buffer the integrated voltage signal to obtain a buffered voltage signal; the analog-to-digital converter converts the buffered voltage signal into a digital signal ( Figure 5(not shown); the power-on module 502 is used to power on the first operation unit, the second operation unit and the analog-to-digital converter, and the first operation unit and the second operation unit are both in gain buffer mode; the first sampling unit 503 is used to sample the output of the second operation unit for the first time through the analog-to-digital converter after a first preset time length to obtain a first sampling result; the integral adjustment unit 504 is used to adjust the first operation unit to the integration mode, and turn off the integration mode of the first operation unit after a second preset time length; the second sampling unit 505 is used to wait for a third preset time length, and sample the output of the second operation unit for the second time through the analog-to-digital converter to obtain a second sampling result; the error acquisition unit 506 is used to obtain a dark current error based on the second sampling result and the first sampling result; the calibration unit 507 is used to calibrate the output of the smoke detector based on the dark current error.

[0091] The smoke detector calibration device provided by the present invention has the beneficial effect of being suitable for calibrating smoke detectors with corresponding structures. The present invention obtains a dark current error based on the second sampling result and the first sampling result, and calibrates the output of the smoke detector based on the obtained dark current error. This eliminates the influence of dark current on the detection accuracy of smoke detectors with corresponding structures, thereby resolving the technical problem in the prior art of reduced detection accuracy of smoke detectors due to the influence of dark current.

[0092] All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding unit module and will not be repeated here.

[0093] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A smoke detector calibration method, characterized in that: include: A smoke detector is provided, comprising: a current sink generator, a smoke sensing module, a first operation unit, a second operation unit, and an analog-to-digital converter; the current sink generator is configured to provide current to the smoke sensing module; the smoke sensing module is configured to detect smoke and output a sensed current upon detecting smoke; the first operation unit is connected to an output end of the smoke sensing module and is configured to integrate the sensed current to obtain an integrated voltage signal; the second operation unit is connected to the output end of the first operation unit and is configured to buffer the integrated voltage signal to obtain a buffered voltage signal; and the analog-to-digital converter converts the buffered voltage signal into a digital signal; Powering on the first arithmetic unit, the second arithmetic unit, and the analog-to-digital converter, wherein the first arithmetic unit and the second arithmetic unit are both in a gain buffer mode; After a first preset time period, sampling the output of the second operation unit for the first time through the analog-to-digital converter to obtain a first sampling result; Adjusting the first operation unit to an integration mode, and turning off the integration mode of the first operation unit after a second preset time period; Waiting for a third preset time period, and sampling the output of the second operation unit for a second time through the analog-to-digital converter to obtain a second sampling result; Obtaining a dark current error according to the second sampling result and the first sampling result; The output of the smoke detector is calibrated according to the dark current error.

2. The smoke detector calibration method according to claim 1, characterized in that: Obtaining a dark current error according to the second sampling result and the first sampling result includes: obtaining the dark current error according to a difference between the second sampling result and the first sampling result.

3. The smoke detector calibration method according to claim 2, characterized in that: The output of the smoke detector is calibrated according to the dark current error, including: Resetting the first operation unit, and sampling the output of the second operation unit for a third time through the analog-to-digital converter to obtain a third sampling result; Powering on the current injection generator and causing the smoke sensing module to generate the induced current under preset conditions; adjusting the first operation unit to the integration mode again, and turning off the integration mode of the first operation unit after a fourth preset time period; Waiting for a fifth preset time period, and sampling the output of the second operation unit for a fourth time through the analog-to-digital converter to obtain a fourth sampling result; The calibrated output of the smoke detector is obtained by calculating the difference between a first difference and a second difference, where the first difference is the dark current error and the second difference is the difference between the fourth sampling result and the third sampling result.

4. The smoke detector calibration method according to claim 3, characterized in that: Also includes: obtaining a comparison result by comparing the calibrated output of the smoke detector with an alarm threshold of the smoke detector; According to the comparison result, it is determined whether the smoke detector needs to sound an alarm.

5. The smoke detector calibration method according to claim 4, characterized in that: Also includes: Before obtaining the first sampling result, the analog-to-digital converter is calibrated.

6. The smoke detector calibration method according to claim 5, characterized in that: Calibrating the analog-to-digital converter includes: S1. Under normal operating temperature, obtaining a first digital code generated by an analog-to-digital converter according to a first analog signal and a second digital code generated by the analog-to-digital converter according to a second analog signal; S2, converting the first analog signal into a third digital code according to a first conversion coefficient, and converting the second analog signal into a fourth digital code; S3. Obtain a first slope by calculating a ratio of a first difference to a second difference, where the first difference is a difference between the first digital code and the second digital code, and the second difference is a difference between the third digital code and the fourth digital code; S4. Obtain a first constant by calculating a first product and a difference between the first digital code and the first product, where the first product is the product of the second digital code and the first slope; S5. Adjust the parameters of the digital code generated according to the analog signal in the analog-to-digital converter based on the first slope and the first constant to complete parameter calibration.

7. The smoke detector calibration method according to claim 6, characterized in that: The first conversion factor is the second product and 2 N The second product is the product of the reference voltage of the device constituted by the analog-to-digital converter and the first coefficient T1, the first coefficient T1 is obtained according to the operating temperature of the analog-to-digital converter, and N is the number of counting bits of the analog-to-digital converter.

8. The smoke detector calibration method according to claim 7, characterized in that: By formula The first coefficient T1 is obtained, where Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of i is -1 to 1.

9. The smoke detector calibration method according to claim 6, characterized in that: In S2, converting the first analog signal into a third digital code and converting the second analog signal into a fourth digital code according to a first conversion coefficient includes: Obtaining the third digital code by calculating a quotient of the first analog signal and the first conversion coefficient; The fourth digital code is obtained by calculating a quotient of the second analog signal and the first conversion coefficient.

10. The smoke detector calibration method according to claim 9, characterized in that: After completing S5, the method further includes: Acquiring a first operating temperature, where the first operating temperature is an actual operating temperature of the analog-to-digital converter after parameter calibration is completed; determining whether the first operating temperature is room temperature; if so, converting the analog signal into a digital code by the analog-to-digital converter according to the first slope, the first constant, and the first conversion coefficient; otherwise, obtaining the first coefficient T1; Obtaining a second slope by calculating a product of the first slope and the first coefficient T1; The parameters of the digital code generated according to the analog signal in the analog-to-digital converter are adjusted again based on the second slope and the first constant to complete parameter calibration.

11. The smoke detector calibration method according to claim 10, characterized in that: Before obtaining the first operating temperature, the method further includes: The analog-to-digital converter converts the third analog signal into a fifth digital code under a first temperature signal, wherein the first temperature signal corresponds to a normal operating temperature of the analog-to-digital converter; The analog-to-digital converter converts the fourth analog signal into a sixth digital code under a second temperature signal, wherein the operating temperature corresponding to the second temperature signal is the first operating temperature; converting, according to a second conversion coefficient, a first temperature signal generated by the analog-to-digital converter when generating the fifth digital code into a seventh digital code, and converting a second temperature signal generated by the analog-to-digital converter when generating the sixth digital code into an eighth digital code; A sum of a third product and the normal temperature is calculated to calibrate the second temperature signal, the third product being the product of a third difference and a second temperature coefficient, and the third difference being the difference between the second temperature signal and the first temperature signal.

12. The smoke detector calibration method according to claim 11, characterized in that: The second temperature coefficient has a value range of -1 to 1.

13. The smoke detector calibration method according to claim 12, characterized in that: The second conversion factor is the product of the fourth and 2 N The fourth product is the product of the reference voltage of the device constituted by the analog-to-digital converter and the second coefficient, and N is the number of counting bits of the analog-to-digital converter.

14. The smoke detector calibration method according to claim 13, characterized in that: According to the formula The second coefficient T2 is obtained, where Ts is the actual operating temperature of the analog-to-digital converter, Tc is the normal temperature, and the value of j is -1 to 1.

15. The smoke detector calibration method according to claim 14, characterized in that: Converting, according to a second conversion coefficient, the first temperature signal of the analog-to-digital converter when generating the fifth digital code into a seventh digital code, and converting the second temperature signal of the analog-to-digital converter when generating the sixth digital code into an eighth digital code, comprises: Obtaining the seventh digital code by calculating a quotient of the first temperature signal and the second coefficient; The eighth digital code is obtained by calculating the quotient of the second temperature signal and the second coefficient.

16. The smoke detector calibration method according to claim 4, characterized in that: Also includes: Calibration of the current sink generator.

17. The smoke detector calibration method according to claim 16, characterized in that: Calibration of the current sink generator, including: By using an initial default configuration of the current sink generator, obtaining an ideal current corresponding to the initial default configuration; Obtaining an actual current generated by the current injection generator to the smoke sensing module; Obtaining a register deviation in the analog-to-digital converter by calculating a quotient of a difference between an ideal current and an actual current and a current value corresponding to each digital code in the analog-to-digital converter; An initial default configuration of the current sink generator is calibrated according to the register offset.

18. A smoke detector calibration device, characterized in that: The method for calibrating a smoke detector according to any one of claims 1 to 17 comprises: a smoke detector, a power-on module, a first sampling unit, an integral adjustment unit, a second sampling unit, an error acquisition unit, and a calibration unit; The smoke detector includes: a current sink generator, a smoke sensing module, a first operation unit, a second operation unit, and an analog-to-digital converter; the current sink generator is used to provide current to the smoke sensing module; the smoke sensing module is used to detect smoke and output a sensed current after detecting smoke; the first operation unit is connected to the output end of the smoke sensing module, and is used to integrate the sensed current to obtain an integrated voltage signal; the second operation unit is connected to the output end of the first operation unit, and is used to buffer the integrated voltage signal to obtain a buffered voltage signal; the analog-to-digital converter converts the buffered voltage signal into a digital signal; The power-on module is used to power on the first operation unit, the second operation unit and the analog-to-digital converter, and the first operation unit and the second operation unit are both in a gain buffer mode; The first sampling unit is configured to perform a first sampling on the output of the second operation unit through the analog-to-digital converter after a first preset time period to obtain a first sampling result; The integral adjustment unit is used to adjust the first operation unit to an integral mode and turn off the integral mode of the first operation unit after a second preset time period; The second sampling unit is configured to wait for a third preset time period and perform a second sampling on the output of the second operation unit through the analog-to-digital converter to obtain a second sampling result; The error acquisition unit is used to acquire a dark current error according to the second sampling result and the first sampling result; The calibration unit is used to calibrate the output of the smoke detector according to the dark current error.

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