CN107884095B

CN107884095B - Automatic calibration circuit structure in temperature measuring device and automatic calibration method

Info

Publication number: CN107884095B
Application number: CN201711095982.7A
Authority: CN
Inventors: 王磊
Original assignee: Wuxi China Resources Semico Co Ltd
Current assignee: CRM ICBG Wuxi Co Ltd
Priority date: 2017-11-09
Filing date: 2017-11-09
Publication date: 2019-12-10
Anticipated expiration: 2037-11-09
Also published as: CN107884095A

Abstract

the invention relates to an automatic calibration circuit structure and an automatic calibration method in a temperature measuring device, wherein the temperature measuring device further comprises an external reference resistor and an external measuring resistor, the automatic calibration circuit structure in the temperature measuring device comprises an automatic calibration main control module, a measuring module, an internal data registering module, a comparator module, a shift registering module and a selector module, the modules are mutually connected, and the temperature measuring device is calibrated by adopting a method for realizing the automatic calibration of the temperature measuring device. By adopting the automatic calibration circuit structure and the automatic calibration method in the temperature measuring device, the calibration of the temperature measuring device can be satisfied on the basis of not replacing the reference resistor by adjusting the reference oscillation frequency, so that the measurement precision reaches the manufacturing standard, the efficiency is effectively improved, and the production cost is reduced.

Description

automatic calibration circuit structure in temperature measuring device and automatic calibration method

Technical Field

The invention relates to the field of detection, in particular to the field of temperature detection and calibration; in particular to an automatic calibration circuit structure and an automatic calibration method in a temperature measuring device.

Background

Electronic temperature measuring equipment is widely applied in daily life, such as electronic thermometers, most of the temperature measuring equipment adopts a reference resistor and a thermistor for comparison to test the temperature of a human body, since the reference resistor and the thermistor have errors, even if the high-precision resistor has errors due to process reasons and materials, the errors can cause test errors, and the manufacturing standard of the thermometer is that the precision is +/-0.1 ℃, for example, the body temperature of a person is 36.7 ℃, but the actual test is 36.9 ℃ or 36.5 ℃, the manufacturing standard is exceeded, and the electronic thermometer is unqualified. At present, all electronic thermometer manufacturers produce electronic thermometers, when the precision of the electronic thermometers exceeds the manufacturing standard, the adopted method is to replace a reference resistor or a thermistor for adjustment, and after the resistors are replaced for many times, the measurement precision meets the manufacturing standard, the method is effective and feasible, but the existing technology invisibly increases the production cost, reduces the production efficiency and the daily yield, even if the proper resistor cannot be replaced by one replacement, and the replacement is required to be carried out for more than two times.

Disclosure of Invention

the invention aims to overcome the defects of the prior art and provide an automatic calibration circuit structure and an automatic calibration method in a temperature measuring device, which are low in cost and high in efficiency.

in order to achieve the above object, the automatic calibration circuit structure and the automatic calibration method in the temperature measuring device of the present invention are specifically as follows:

the automatic calibration circuit structure in the temperature measuring device also comprises an external reference resistor and an external measuring resistor, and is characterized in that,

The automatic calibration circuit structure comprises an automatic calibration main control module, a measurement module, an internal data registering module, a comparator module, a shift registering module and a selector module:

The automatic calibration main control module is respectively connected with an external power supply, the comparator module and the shift register module, outputs a starting automatic detection signal to the comparator module and the shift register module, receives a stopping detection signal output by the shift register module and is used for setting whether the automatic calibration circuit structure enters a calibration mode or not;

The measuring module is connected with the external reference resistor, the external measuring resistor and the internal data registering module, and is used for storing preset reference oscillation times X corresponding to the external reference resistor according to a corresponding table of preset oscillation times and temperature of a system during a preset test environment temperature experiment of the system_RFAnd measuring the oscillation times X of the external measuring resistor corresponding to the external measuring resistor_RSThe oscillation times X of the external measuring resistor_RSoutputting the data to the internal data register module;

The internal data register module is connected with the comparator module and used for storing a corresponding table of preset oscillation times and temperature of the system and taking the corresponding table of the preset oscillation times and temperature of the system as a basis to measure the oscillation times X of the external measuring resistor_RSconverting the current measured temperature value into a corresponding current measured temperature value, and outputting the current measured temperature value to the comparator module;

the comparator module is connected with the internal data register module and the shift register module and is used for comparing the current measured temperature value with an actual temperature value at a test environment temperature preset by the system, the actual temperature value is preset in the comparator module, the actual temperature value and the current measured temperature value are compared in a binary mode, and a comparison result of the current measured temperature value and the actual temperature value is output to the shift register module;

the shift register module is connected with the comparator module and the selector module, and sends a shift signal according to the comparison result of the current measured temperature value and the actual temperature value to control the selector module to select one preset temperature value;

The selector module is connected with the shift register module and the test module, N different preset temperature values and N reference oscillation times corresponding to the preset temperature values are arranged in the selector module, the higher the preset temperature value is, the more the reference oscillation times are, and a new reference oscillation time X 'is correspondingly determined by the selected preset temperature value'_RFAnd the obtained X'_RFand outputting the temperature values to a test module, wherein the N different preset temperature values are arranged according to the size sequence.

the method for realizing the automatic calibration of the temperature measuring device based on the automatic calibration circuit structure is mainly characterized in that the method specifically comprises the following steps:

(1) The measuring module uses the preset reference oscillation times X currently stored in the measuring module_RFDetermining the oscillation times X of the external measuring resistor for temperature measurement standard_RS；

(2) The internal data register module determines the oscillation times X of the external measuring resistor according to the preset oscillation times and temperature correspondence table of the system_RSThe corresponding current measured temperature value;

(3) The comparator module judges whether the current measured temperature value is equal to the actual temperature value;

(4) if the current measured temperature value is equal to the actual temperature value, continuing the subsequent step (12), otherwise continuing the subsequent step (5);

(5) the comparator module judges whether the current measured temperature value is greater than the actual temperature value;

(6) if the current measured temperature value is larger than the actual temperature value, continuing the subsequent step (7), otherwise continuing the subsequent step (8);

(7) The shift register module drives the selector module to select the preset reference oscillation times X_RFfirst preset reference oscillation frequency X 'of difference value of phase difference system preset number'_RF1Replacing the current preset reference oscillation times X_RFstoring the number of the first preset reference oscillation times X 'into the measuring module'_RF1as new current preset reference oscillation times X_RFstoring the data into the measurement module as a temperature measurement standard, and continuing to the subsequent step (9), wherein the first preset reference oscillation frequency X'_RF1Is equal to the preset reference oscillation times X_RFThe number of the system is reduced by the difference of the preset number of the system;

(8) The shift register module drives the selector module to select the preset reference oscillation times X_RFAnd a second preset reference oscillation frequency X 'of the difference value of the preset number of the system phase difference'_RF2Replacing the current preset reference oscillation times X_RFstoring the number of second preset reference oscillation times X 'into the measuring module'_RF2As new current preset reference oscillation times X_RFStoring the measured data into the measuring module as a temperature measurement standard, and continuing to a subsequent step (9), wherein the second preset reference oscillation frequency X'_RF2is equal to the preset reference oscillation times X_RFThe number of the system is increased by the difference value of the preset number of the system;

(9) The shift register module judges whether the current judgment frequency exceeds a preset judgment frequency threshold value;

(10) if the current judgment frequency exceeds a preset judgment frequency threshold value, continuing the subsequent step (11), otherwise, returning to the step (2);

(11) The automatic calibration main control module increases the preset judgment frequency threshold according to a preset threshold increasing strategy and returns to the step (2);

(12) And finishing the automatic calibration, and outputting the current measured temperature value by the internal data registering module.

by adopting the automatic calibration circuit structure and the automatic calibration method in the temperature measuring device, the effect of replacing the external reference resistor can be realized under the condition of not replacing the external reference resistor by changing the parameter value of the reference oscillation frequency, the cost of replacing the external reference resistor or replacing the external measuring resistor in the production process in the prior art is saved, the calibration efficiency of the temperature measuring device is improved, manual operation is not needed, and the measuring precision reaches the manufacturing standard.

Drawings

Fig. 1 is a flowchart of an automatic calibration circuit structure in a temperature measuring device and a method for implementing automatic calibration of the temperature measuring device in an automatic calibration method according to an embodiment of the present invention.

fig. 2 is a schematic circuit diagram of an auto-calibration circuit structure in a temperature measuring device and an auto-calibration method according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an auto-calibration main control module of an auto-calibration circuit structure in a temperature measuring device and an auto-calibration method of the auto-calibration circuit structure in the temperature measuring device according to an embodiment of the present invention.

Fig. 4 is a display screen diagram of an external display module connected to an auto-calibration circuit structure in a temperature measuring device and an auto-calibration circuit structure in a temperature measuring device in an auto-calibration method according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of an external display driving module connected to an auto-calibration circuit structure of a temperature measuring device and an auto-calibration circuit structure of a temperature measuring device in an auto-calibration method according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of a comparator unit in an auto-calibration circuit structure of a temperature measuring device and an auto-calibration method according to an embodiment of the present invention.

FIG. 7 is a logic diagram of a comparator module in an auto-calibration circuit structure of a temperature measuring device and an auto-calibration method according to an embodiment of the present invention.

FIG. 8 is a logic diagram of a selector module in an auto-calibration circuit structure of a temperature measuring device and an auto-calibration method according to an embodiment of the present invention.

FIG. 9 is a logic diagram of a shift register module in an auto-calibration circuit structure of a temperature measuring device and an auto-calibration method according to an embodiment of the present invention.

Detailed Description

In order to more clearly describe the technical contents of the present invention, the following further description is given in conjunction with specific embodiments.

the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Embodiments of the present invention are described in detail below with reference to the accompanying drawings.

in the automatic calibration circuit structure and the automatic calibration method in the temperature measuring device of the present invention, the automatic calibration circuit structure in the temperature measuring device further comprises an external reference resistor and an external measuring resistor, wherein the automatic calibration circuit structure comprises an automatic calibration main control module, a measuring module, an internal data registering module, a comparator module, a shift registering module and a selector module:

The selector module is connected with the shift register module and the test module, N different preset temperature values and N reference oscillation times corresponding to the preset temperature values are arranged in the selector module, the higher the preset temperature value is, the more the reference oscillation times are, and a new reference oscillation time X 'is correspondingly determined by the selected preset temperature value'_RFand the obtained X'_RFAnd outputting the temperature values to a test module, wherein the N different preset temperature values are arranged according to the size sequence, and N is a preset value.

In an embodiment of the present invention, the auto-calibration main control module may further include:

The external power supply access end is connected with the external power supply through the starting button and outputs a starting signal and a working mode selection signal;

the clock timing unit is connected with the starting button and is used for timing the on-time of the starting button;

And the reset signal port is connected with the external power supply and is used for initializing the automatic calibration main control module.

In an embodiment of the present invention, the comparator module may include a highest comparator unit and M-1 comparator units, where M is equal to the number of bits after the current measured temperature value is converted into a binary number, the highest comparator unit and the M-1 comparator units are connected in an order from high to low of the binary number bits, and both the highest comparator unit and the comparator unit at least include:

The exclusive nor subunit is used for comparing whether the corresponding bit of the current measured temperature value converted into the binary system is equal to the corresponding bit of the actual temperature value converted into the binary system;

the negation subunit is used for converting the actual temperature value into a binary system and negating the corresponding bit to obtain a negation value of the binary system corresponding bit converted from the actual temperature value;

the and subunit is used for judging and outputting a higher value of the corresponding bit after the current measured temperature value is converted into the binary system and the negation value of the corresponding bit after the actual temperature value is converted into the binary system;

The input end of the abnormal or non-abnormal subunit and the input end of the sub-unit are both correspondingly connected with the first input end of the comparator module, and the output end of the abnormal or non-abnormal subunit and the output end of the sub-unit are both correspondingly connected with the feedback output end of the comparator module;

wherein, M is equal to the number of the digits after the current measured temperature value is converted into the binary digits, and the highest bit comparator unit and the M-1 comparator units are connected in a cascade way in an order from high to low of the binary digits.

In a specific embodiment of the present invention, the shift signal is an N-bit signal, each bit of the shift signal corresponds to a preset temperature value, each time the shift register module sends out the shift signal, only one bit of the shift signal is at a high level, which corresponds to the selected preset temperature value, and the remaining N-1 bits are at a low level; determining which bit in the shift signal is a high level according to a comparison result of the current measured temperature value and the actual temperature value output by the comparator module, wherein N is more than or equal to 2;

when the current measured temperature value is equal to the actual temperature value, the shift signal is kept unchanged, and the shift register module outputs a detection stop signal to the automatic calibration main control module, so that the automatic calibration circuit structure finishes calibration and outputs the current measured temperature value;

when the current measured temperature value is greater than the actual temperature value, the high-level signal bit in the shift signal moves in the direction of other preset temperature values with temperature values lower than the current preset temperature value, and the high-level signal bit in the shift signal only moves by one bit each time to select the preset temperature value adjacent to the current preset temperature value as a new preset temperature value, until the comparator module sends a signal that the current measured temperature value is equal to the actual temperature value to the shift register module, the high-level signal bit in the shift signal stops moving, that is, the shift signal remains unchanged;

when the current measured temperature value is smaller than the actual temperature value, the high-level signal bit in the shift signal moves in the direction of other preset temperature values with temperature values higher than the current preset temperature value, and the high-level signal bit in the shift signal only moves by one bit each time to select the preset temperature value adjacent to the current preset temperature value as a new preset temperature value, until the comparator module sends a signal that the current measured temperature value is equal to the actual temperature value to the shift register module, the high-level signal bit in the shift signal stops moving, that is, the shift signal remains unchanged.

in one embodiment of the present invention, the internal connection relationship between the highest bit comparator unit and the M-1 comparator units may be specifically as follows, in order to distinguish the sub-unit in the highest bit comparator unit from the following connection relationship between the sub-unit in the comparator unit, the sub-unit in the highest bit comparator unit and the input/output terminals are named with "highest bit" three words added to distinguish the highest bit comparator unit from the comparator unit, and the corresponding bit in the highest bit comparator is the highest bit in the binary number, so the "corresponding bit" in the highest bit comparator is named directly with "highest bit":

(1) the highest bit comparator unit includes:

(a) The highest-order hetero or non-sub unit comprises a first highest-order hetero or non-sub unit input end, a second highest-order hetero or non-sub unit input end and a first highest-order hetero or non-sub unit output end, wherein the first highest-order hetero or non-sub unit input end inputs the current measured temperature value and converts the current measured temperature value into the highest order after the binary system, the second highest-order hetero or non-sub unit input end is used for inputting the actual temperature value and converts the actual temperature value into the highest order after the binary system, and the highest-order hetero or non-sub unit is used for comparing whether the highest order of the current measured temperature value converted into the binary system is equal to the highest order of the actual temperature value converted into the binary system or not;

(b) the highest-order negation sub-unit comprises a third input end of the highest-order negation sub-unit and a second output end of the highest-order negation sub-unit, the third input end of the highest-order negation sub-unit is used for inputting the actual temperature value and converting the actual temperature value into a highest order after the binary system is obtained, and the highest-order negation sub-unit converts the actual temperature value into a highest order after the binary system is obtained;

(c) the highest-order first sub-unit comprises a highest-order first sub-unit fourth input end, a highest-order first sub-unit fifth input end and a highest-order first sub-unit third output end; the fourth input end of the highest-order first sub-unit and the fourth input end of the highest-order sub-unit are connected with the second output end of the highest-order hetero or non-sub-unit, the fifth input end of the highest-order first sub-unit and the fifth input end of the sub-unit input the current measured temperature value and convert the current measured temperature value into the highest-order bit after binary conversion, the third output end of the highest-order first sub-unit and the third output end of the sub-unit output the comparison result of the negation value of the highest-order bit after the actual temperature value is converted into the binary conversion and the highest-order bit after the current measured temperature value is converted into the binary conversion, and the first sub-unit and the third output end of the highest-order sub-unit judge whether the highest-order bit after the current; the highest bit first and the third output ends of the sub-unit output the signal which is the highest bit after the current measured temperature value is converted into the binary system and which is the highest bit after the actual temperature value is converted into the binary system;

(d) The highest-order second sub-unit comprises a highest-order second input end and a highest-order second output end, wherein the highest-order second input end is connected with the first output end of the highest-order hetero or hetero sub-unit;

(e) The highest-order third and subunit comprises a highest-order third and subunit seventh input end, a highest-order third and subunit eighth input end and a highest-order third and subunit fifth output end, wherein the highest-order third and subunit seventh input end is connected with the highest-order first and subunit third output end, and the highest-order third and subunit eighth input end is connected with the highest-order second and subunit fourth output end;

the first input end of the highest-order hetero or non-subunit and the fifth input end of the highest-order first and subunit are correspondingly connected with the internal data register module, and the first output end of the highest-order hetero or non-subunit, the third output end of the highest-order first and subunit and the fifth output end of the highest-order third and subunit are correspondingly connected with the shift register module.

(2) each of said comparator units comprising:

(a) the exclusive nor subunit comprises a ninth input end of the exclusive nor subunit, a tenth input end of the exclusive nor subunit and a sixth output end of the exclusive nor subunit, wherein the ninth input end of the exclusive nor subunit inputs the current measured temperature value and converts the current measured temperature value into a binary corresponding bit, the tenth input end of the exclusive nor subunit is used for inputting the actual temperature value and converts the actual temperature value into a binary corresponding bit, and the exclusive nor subunit is used for comparing whether the actual temperature value converted into the binary corresponding bit is equal to the actual temperature value or not;

(b) the negation subunit comprises an eleventh input end of the negation subunit and a seventh output end of the negation subunit, wherein the eleventh input end of the negation subunit is used for inputting the actual temperature value and converting the actual temperature value into a binary corresponding bit, and the negation subunit converts the actual temperature value into the binary corresponding bit to negate so as to obtain a negated value of the binary corresponding bit converted from the actual temperature value;

(c) The first and subunit comprises a twelfth input end of the first and subunit, a thirteenth input end of the first and subunit and an eighth output end of the first and subunit; the twelfth input end of the first and the subunit is connected with the seventh output end of the negating subunit, the thirteenth input end of the first and the subunit inputs the current measured temperature value converted into the corresponding bit after the binary system, the eighth output end of the first and the subunit outputs a comparison result of the negating value of the corresponding bit after the actual temperature value is converted into the binary system and the corresponding bit after the current measured temperature value is converted into the binary system, and the first and the subunit judges whether the corresponding bit after the current measured temperature value is converted into the binary system is higher than the corresponding bit after the actual temperature value is converted into the binary system or not according to the comparison result; the eighth output end of the first and the subunit outputs a signal indicating which of the corresponding bit after the current measured temperature value is converted into the binary system and the corresponding bit after the actual temperature value is converted into the binary system is large;

(d) The second and subunit comprises a fourteenth input end of the second and subunit, a fifteenth input end of the second and subunit and a ninth output end of the second and subunit, wherein the fourteenth input end of the second and subunit is connected with the sixth output end of the exclusive-nor subunit, and the fifteenth input end of the second and subunit is used for inputting the comparison result of the comparator unit corresponding to the comparator unit and higher than one bit;

(e) a third and subunit including a sixteenth input terminal of the third and subunit, a seventeenth input terminal of the third and subunit, and a tenth output terminal of the third and subunit, the sixteenth input terminal of the third and subunit being connected to the eighth output terminal of the first and subunit, the seventeenth input terminal of the third and subunit being connected to the ninth output terminal of the second and subunit;

The ninth input end of the exclusive or non-subunit and the thirteenth input end of the first and the subunit are correspondingly connected with the internal data register module, and the sixth output end of the exclusive or non-subunit, the eighth output end of the first and the subunit and the tenth output end of the third and the subunit are correspondingly connected with the shift register module.

furthermore, in the M-1 comparator units of the present invention, the fifteenth input terminal of the second and subunit in the comparator unit adjacent to the highest comparator unit is connected to the fifth output terminal of the highest comparator unit; the fifteenth input ends of the second and subunit in the rest M-2 comparator units are connected to the tenth output ends of the third and subunit in the comparator unit that is one bit higher than the corresponding comparator unit, and since the actual temperature value is a value preset in the comparator module, the third output end of the highest inverting subunit and the eleventh output end of the inverting subunit have no connection relationship with other modules.

in an embodiment of the present invention, the selector module may include a preset number N of selector units, where each selector unit is provided with one preset temperature value and the reference oscillation frequency corresponding to the preset temperature value, and each selector unit includes a selector unit input end and a selector unit output end; the N selector units are arranged in the order of the preset temperature value built in the selector unit, wherein the input end of the selector unit of each selector unit is connected with the input end of the corresponding selector module, the output end of the selector unit of each selector unit is correspondingly connected with the output end of the selector module, and the output end of the selector unit of each selector unit is used for outputting the corresponding reference oscillation frequency.

As a specific embodiment of the present invention, the comparator module may be a bit-by-bit comparator module, in which an internal logic gate unit performs bit-by-bit comparison on a preset temperature value converted into a binary value, the comparison process is performed from a high bit to a low bit, if the high bit has determined the comparison result, the low bit does not need to be compared (the binary value only includes two numbers, i.e. 0 and 1, and the two numbers are used to represent the number), only when the high bit has not determined the comparison result, the low bit needs to continue the comparison, since the highest bit comparator unit is the highest bit (i.e. the first bit), the highest second and sub-units only include one input terminal, i.e. the sixth input terminal of the highest second and sub-units, and the rest of bits are connected to the comparison result terminal of the previous bit, so that the second and sub-units in the rest of the comparator units are provided with two input terminals, a fourteenth input terminal of the second and subunit, and a fifteenth input terminal of the second and subunit, wherein one of the input terminals is used for connecting the comparison result output terminal of the corresponding previous bit, that is, the fifteenth input terminal of the second and subunit in the comparator unit is connected to the fifth output terminal of the highest bit first and subunit in the highest bit comparator unit; and the second and subunit fifteenth input ends of the remaining M-2 comparator units are connected to the tenth output end of the third and subunit of the comparator unit corresponding to the comparator unit and one higher bit.

In a specific embodiment of the present invention, the shift register module includes N shift signal output ends, each of the shift signal output ends is configured to output a one-bit signal of the shift signal, the selector module includes N selector module input ends, each of the selector module input ends corresponds to one of the preset temperature values, the N selector module input ends are arranged in a size sequence according to the size of the corresponding preset temperature value, and the N shift signal output ends are connected to the N selector module input ends in a one-to-one correspondence.

in a specific embodiment of the present invention, the N different preset temperature values may be in an equal difference relationship, and the difference value is an equal difference value preset by the system, but other preset relationships that can be implemented may also be adopted.

In an embodiment of the present invention, the selector module includes a preset number N of selector units, where each selector unit has a preset temperature value and a reference oscillation frequency corresponding to the preset temperature value, and each selector unit includes a selector unit input end and a selector unit output end; the N selector units are arranged in the order of the preset temperature value built in the selector unit, wherein the input end of each selector unit is connected with the shift register module and used for receiving a shift signal, and the output end of each selector unit is used for outputting the reference oscillation frequency built in the selector unit.

in one embodiment of the present invention, the output terminal of the selector module is used for outputting a new selected reference oscillation number X'_RFTo said measurement module, the new reference oscillation number X'_RFafter the shift register module controls the selector module to select one preset temperature value, the selected preset temperature value is correspondingly determined;

the shift register module outputs an output shift signal with N bits each time, and each signal bit of the output shift signal with N bits is output by a corresponding shift signal output end; each time, only one bit of the N bits of shift signals is a high level, the rest N-1 bits are low levels, the signal bits of the N bits of shift signals are in one-to-one correspondence with the N shift signal output ends, the comparator module determines the shift signals output by the shift register module according to the comparison result of the current measured temperature value and the actual temperature value, when the current measured temperature value is equal to the actual temperature value, the output signals of the shift register module are kept unchanged, the shift register module of the shift register module stops the automatic detection signal output end from outputting a stop detection signal to the automatic calibration main control module, so that the automatic calibration circuit structure finishes calibration, and outputs the current measured temperature value; when the current measured temperature value is not equal to the actual temperature value, the comparator module determines the moving direction of the high-level signal bit in the N-bit output shift signal according to the magnitude of the current measured temperature value and the actual temperature value, after the moving direction is determined, each subsequent moving is performed towards the determined moving direction, and each comparison result only enables the high-level signal bit to move by one bit, and the high-level signal bit of the output shift signal does not move any more until the comparison values are equal.

the shift register module determines which preset temperature value is selected by the selector module, namely the input end of the selector module, which is connected with the shift signal output end of the N-bit shift signal output end and outputs a high level signal, of the input ends of the N selector modules is the selected input end, the preset temperature value corresponding to the selected input end is the selected preset temperature value, and the reference oscillation times X 'corresponding to the preset temperature value'_RFoutputting the frequency to the measuring module as a new preset reference oscillation frequency X_RF。

In one embodiment of the present invention, the temperature measuring device further includes: the display device comprises a display conversion module, a display driving module and a display module;

The display conversion module is respectively and correspondingly connected with the internal data registering module and the input end of the display driving module, and is used for converting the current measured temperature value output by the internal data registering module into an on-off signal which can be displayed by the display module and correspondingly outputting the on-off signal which can be displayed by the display module to the input end of the display driving module;

the output end of the display driving module is connected with the display module, and the display driving module drives the display module to display the current measured temperature value according to on-off signals which can be displayed by the display module;

The display module is also connected with the automatic calibration main control module and is also used for displaying prompt characters preset by the system.

as a specific embodiment of the present invention, the display conversion module may adopt an LCD display conversion module; the display driving module is the LCD display driving module; the display module is the LCD display module.

In an embodiment of the present invention, in the method for implementing automatic calibration of a temperature measuring device based on the above automatic calibration circuit structure, the preset test environment temperature of the system is the actual temperature value, wherein the method specifically includes the following steps:

(2) The internal data register module determines the oscillation times X of the external measuring resistor according to the preset oscillation times and temperature correspondence table of the system_RSThe corresponding current measured temperature value specifically comprises the following steps:

(21) The internal data register module obtains the oscillation times X of the external measuring resistor_RS；

(22) Determining the oscillation times X of the external measuring resistor based on the preset oscillation times and temperature table_RSthe corresponding oscillation frequency interval;

(23) determining the oscillation times X of the external measuring resistor according to the oscillation time interval_RSthe corresponding current measured temperature value;

(7) The shift register moduleThe selector module is driven by the block to select the preset reference oscillation times X_RFFirst preset reference oscillation frequency X 'of difference value of phase difference system preset number'_RF1Replacing the current preset reference oscillation times X_RFStoring the number of the first preset reference oscillation times X 'into the measuring module'_RF1as new current preset reference oscillation times X_RFstoring the data into the measurement module as a temperature measurement standard, and continuing to the subsequent step (9), wherein the first preset reference oscillation frequency X'_RF1is equal to the preset reference oscillation times X_RFthe number of the system is reduced by the difference of the preset number of the system;

(9) The shift register module judges whether the current judgment frequency exceeds a preset threshold value of the judgment frequency;

(10) If the current judgment frequency exceeds the preset judgment frequency threshold value, continuing the subsequent step (11), otherwise, returning to the step (2);

(12) Ending the automatic calibration, and outputting the current measured temperature value by the internal data registering module, wherein the step specifically comprises the following steps:

(121) finishing automatic calibration, wherein the internal data register module outputs the current measured temperature value to the display conversion module;

(122) The display conversion module converts the current measured temperature value into a corresponding temperature driving signal and outputs the temperature driving signal to the display driving module;

(123) And the display driving module drives the display module to display the current measured temperature value.

It should be noted that, if the preset threshold for the number of times of determination is increased in the step (11) of the present invention, the effect of successful and accurate calibration still cannot be achieved, the external measuring resistor needs to be manually replaced, and the calibration operation needs to be performed again, so as to further ensure accurate calibration of the temperature measuring device.

as another more complete embodiment of the present invention, before the step (1), the following steps may be further included:

(a0) Starting the reset signal port and initializing the automatic calibration main control module;

(a1) Starting a starting button in the automatic calibration main control module;

(a2) A clock timing unit in the automatic calibration main control module starts timing and judges whether the connection time of the start button reaches the preset duration of the system;

(a3) if the on time of the starting button reaches the preset duration of the system, entering an automatic calibration mode, and entering the subsequent step (a4), otherwise, entering a temperature measurement mode;

(a4) And the external display module displays prompt characters preset by the system, and the prompt characters are used for prompting that the current mode is the automatic calibration mode.

In an embodiment of the present invention, the temperature measuring device may be an electronic thermometer.

The display conversion module is an LCD display conversion module, the display drive module is an LCD display drive module, and the display module is an LCD display module.

The IC chip principle of the traditional electronic thermometer is as follows:

the IC chip detection principle of the traditional electronic thermometer is realized by a formula as follows

R_RF×X_RF＝R_RS×X_RS；

Wherein R is_RFis the resistance value of an external reference resistor, X_RFIs a reaction with R_RFCorresponding preset reference oscillation times, R_RSResistance value of external measuring resistor, X_RSIs a reaction with R_RSOscillation times X of corresponding external measuring resistor_RS。

In an embodiment of the present invention, a 503ET type thermistor is selected as the measuring resistor, and the preset test environment temperature of the system is set to be 37 degrees of constant temperature, wherein X_RF6455, so the formula changes towherein R is_RF＝30K，R_RSAccording to the change in temperature, at a certain temperature, X_RSCalculated by the formula, the principle is that the X is finally obtained_RSJudging the current temperature, checking the preset oscillating times and temperature corresponding table, and obtaining the oscillating result X_RSIn which section, which temperature is determined, the specific results are shown in the following table:

X_RS	Temperature of	X_RS	Temperature of	X_RS	temperature of	X_RS	Temperature of
								5247-5269	32	5874-5897	34.7	6559-6583	37.4	7344-7373	40.2
5270-5291	32.1	5898-5922	34.8	6584-6609	37.5	7374-7403	40.3
								5292-5313	32.2	5923-5946	34.9	6610-6637	37.6	7404-7433	40.4
5314-5335	32.3	5947-5971	35	6638-6665	37.7	7434-7463	40.5
								5336-5357	32.4	5972-5997	35.1	6666-6693	37.8	7464-7493	40.6
5358-5380	32.5	5998-6022	35.2	6694-6720	37.9	7494-7524	40.7
								5381-5403	32.6	6023-6047	35.3	6721-6747	38	7525-7553	40.8
5404-5425	32.7	6048-6071	35.4	6748-6775	38.1	7554-7583	40.9
								5426-5446	32.8	6072-6096	35.5	6776-6801	38.2	7584-7613	41
5447-5469	32.9	6097-6121	35.6	6802-6829	38.3	7614-7644	41.1
								5470-5491	33	6122-6146	35.7	6830-6856	38.4	7645-7675	41.2
5492-5515	33.1	6147-6171	35.8	6857-6884	38.5	7676-7707	41.3
								5516-5538	33.2	6172-6195	35.9	6885-6911	38.6	7708-7737	41.4
5539-5561	33.3	6196-6221	36	6912-6939	38.7	7738-7769	41.5
								5562-5585	33.4	6222-6246	36.1	6940-6967	38.8	7770-7799	41.6
5586-5608	33.5	6247-6271	36.2	6968-6995	38.9	7800-7829	41.7
								5609-5631	33.6	6272-6297	36.3	6996-7023	39	7830-7860	41.8
5632-5655	33.7	6298-6322	36.4	7024-7052	39.1	7861-7892	41.9
								5656-5678	33.8	6323-6347	36.5	7053-7081	39.2	7893-7923	42
5679-5702	33.9	6348-6374	36.6	7082-7109	39.3	7924-7955	42.1
								5703-5726	34	6375-6401	36.7	7110-7139	39.4	7956-7985	42.2
5727-5751	34.1	6402-6427	36.8	7140-7167	39.5	7986-8017	42.3
								5752-5774	34.2	6428-6454	36.9	7168-7196	39.6	8018-8047	42.4
5775-5799	34.3	6455-6481	37	7197-7225	39.7	8048-8079	42.5
								5800-5823	34.4	6482-6506	37.1	7226-7255	39.8	8080-8111	42.6
5824-5848	34.5	6507-6531	37.2	7256-7284	39.9	8112-8144	42.7
								5849-5873	34.6	6532-6558	37.3	7285-7313	40	8145-8176	42.8
				7314-7343	40.1	8177-8209	42.9

but due to process or manufacturing process effects, the external reference resistance R_RFexternal measuring of the resistance R_RSthere is an error. In the present invention, the existence of such an error is considered, so the preset temperature point in the above table generally corresponds to a reference oscillation frequency interval, such as: the reference oscillation frequency interval corresponding to the temperature of 37 ℃ is 6455-6481, the reference oscillation frequency interval corresponding to the temperature of 36.9 ℃ is 6428-6454, and the reference oscillation frequency interval corresponding to the temperature of 37.1 ℃ is 6482-6506. Thus, in the case of determining the reference oscillation number interval, if the oscillation result X is obtained_RSThe boundary value or any value within the boundary value of the interval is selected to correspond to the corresponding temperature point.

The basic principle of the calibration method according to the invention is that, because the actual temperature value is determined, if the current measured temperature value measured by the thermometer is the measured temperature>37.0, then X is added_RFby replacement with<6455, if the measured temperature is reversed<37.0, then X is added_RFBy replacement with>6455 the value corresponds to the number X of preset reference oscillations in the detection module_RFUsing a new first preset reference oscillation time number X'_RF1or a second preset reference oscillation time number X'_RF2The replacement is performed, according to the values in the look-up table,<The value of 6455 may be 6428, 6402, 6375, 6348,>6455 the value may be 6482, 6507, 6532, 6559, since at body temperatureThe temperature corresponding to the oscillation times in the thermometer is more consistent with the temperature of the human body, so that the oscillation times are only replaced in the calibration of the thermometer.

In the hardware circuit, the aim of calibration is realized by adopting bit-by-bit replacement, namely, the 9 selected oscillation times are replaced one by one, and successive calibration comparison is carried out. The bit-by-bit replacement method adopts the following process design, wherein the process is shown as fig. 1, the schematic diagram of the hardware structure is shown as fig. 2, and each module is respectively as follows:

1.1, the way to enter the auto-calibration mode in the flowchart is as follows:

wherein, ARR in the figure means auto-calibration, "ARR" is a preset on-screen display character:

The following logic design is adopted, as shown in fig. 3, where PSW is a switch button (i.e. start button), CLK is a clock timing unit with a period of 4s, (the time is preset by the system, if the start button is not on for 4s, the thermometer enters the calibration mode, otherwise the thermometer enters the normal temperature measurement mode).

The automatic calibration main control module automatically detects that a signal output end outputs an ARR2 signal, an ARR2 is a signal capable of controlling display, an ARR2 is equal to 1, an Arr is displayed on a screen, and when the ARR2 is equal to 0, the screen does not display the Arr (the Arr is a prompt character prompting to enter an automatic calibration mode, and other characters can be selected as the prompt character).

1.2 Display "Arr" in the flow sheet (Display "Arr")

The display driver 'Arr' is controlled by an automatic detection signal output end ARR2 of an automatic calibration main control module, an external display module is controlled by an external display conversion module and an external display driving module to display corresponding characters, and the corresponding relation of specific display contents is shown as the following table:

Port(s)

S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

COM1

F1

A1

B1

F2

A2

B2

F3

A3

B3

A5

COM2

E1

G1

C1

E2

G2

C2

E3

G3

C3

B5

COM3

H1

D1

D2

H2

H4

D3

I4

C5

the LCD conversion module converts the temperature measured by the thermometer into an on-off signal which can be displayed by an LCD, the on-off signal is input to the LCD driving module, the LCD driving module drives the LCD display screen to display, the external display module can display prompt characters and a test temperature value, the LCD display screen is as shown in figure 4, and the LCD driving module is as shown in figure 5.

when ARR2 is equal to 1, the screen displays ARR, and when the auto-calibration is completed, ARR2 is equal to 0, and the display screen returns to normal.

1.3, the following digital comparator is used as a temperature determination method in the flow chart, namely three conditions of temperature <37, temperature equal to 37 and temperature > 37.

the schematic diagram of the comparator module is shown in fig. 6, because the second and sub-units of the highest bit in the highest bit comparator unit have only one input end next to the previous bit less than the second and sub-units in the subsequent cascaded comparator unit, the schematic diagram is not illustrated, and the comparison principle is as follows:

Wherein, A is the corresponding bit after the current measured temperature value is converted into binary system;

b is the corresponding bit after the actual temperature value is converted into the binary system;

the nxor is a comparison output result of comparison results of a corresponding bit after the current measured temperature value is converted into the binary system and a corresponding bit after the actual temperature value is converted into the binary system;

bigger _ n is the output signal of the result with the larger value than the larger value in the results of A and B ;

alarm is the result of this comparison;

alarm < i-1> is the comparison result one bit lower;

the specific value of i is determined by the position of the specific bit in the compared decimal place.

1) Taking an exclusive or non-xor of two bits (B and A ), if equal, outputting 1, and if not equal, outputting 0, wherein A is the current measured temperature value, and B is the actual temperature value;

2) Inverting B , and then performing AND operation on the inverted B and A to obtain bigger _ n , wherein if nxor -0 (indicating two unequal bits): b, when bigger _ n is 0, it represents that A is larger than B , and alarm is 1; bigger _ n -1 means that a is less than or equal to B , and alarm -0.

3) alarm < i-1> is the comparison result of the lower bit (no other bit before the most significant bit, so the most significant bit second and subunit has no end), if nxor is 0, the comparison result of the lower bit is not used, and if nxor is 1, the comparison result of the lower bit is used.

4) according to this principle, the logic diagram of the whole comparator is shown in fig. 7, the truth table of which is shown in the following table, by comparing from high to low bit by bit:

	OUT<0>	OUT<1>	OUT<2>
				A＝B	1	0	0
A>B	0	1	0
				A<B	0	0	1

1.4, when the temperature is <37 and the temperature is >37 in the flow chart, adopting a bit-by-bit approximation method to approximate the numerical values in the table bit by bit:

as a typical example of the actual corrected temperature, 37 may correspond to 6455, 37.1 may correspond to 6482, 37.2 may correspond to 6507, 37.3 may correspond to 6532, 37.4 may correspond to 6559, 36.9 may correspond to 6428, 36.8 may correspond to 6402, 36.7 may correspond to 6375, 36.6 may correspond to 6348, when the temperature is less than 37 degrees, the oscillation frequency of the reference is changed from 6455 to 6482, where 6482 corresponds to 37.1 degrees, the principle is that when 37 is improper, the cutoff bit is changed from 37 to 37.1, if the temperature is less than 37 degrees, the cutoff bit is continuously changed from 37.1 to 37.2, the oscillation frequency is changed from 6482 to 6507, and so on, but when the oscillation frequency is changed to 6559, the temperature is still less than 37 degrees, the circuit is considered to be unable to be calibrated.

on the contrary, when the temperature is greater than 37 degrees, the oscillation frequency of the reference is firstly changed from 6455 to 6428, wherein 6428 corresponds to 36.9 degrees, the principle is that when 37 is improper, the cut-off bit is changed from 37 to 36.9, and the like, when the oscillation frequency is changed to 6348, the temperature is still greater than 37 degrees, and the circuit is considered to be incapable of being calibrated.

whether the temperature is <37 degrees or >37 degrees, a bit-by-bit approximation method is adopted, a shift register is needed, and a signal is driven by the shift register module to a selector module to determine which corresponding preset temperature value is selected by the selector module and the reference oscillation frequency corresponding to the temperature.

in an embodiment, nine selectors are required, which may correspond to 37, 37.1, 37.2, 37.3, 37.4, 36.9, 36.8, 36.7, and 36.6, respectively, the logic design is as shown in fig. 8, the logic design of the shift register module is as shown in fig. 9, and the selectors correspond to the following selections: 37. the number of the signals is nine, namely 37.1, 37.2, 37.3, 37.4, 36.9, 36.8, 36.7 and 36.6, OUT <0:2> signals output by the feedback output end of the comparator module judge the direction of bit-by-bit approximation, each CLK clock set time approximates to one time, and after the calibration is successful, a STOP signal is generated to indicate that the calibration is finished.

In summary, the present invention achieves the purpose of automatic calibration by using circuit logic, and can be implemented in a hardware circuit, so as to save cost for manufacturers, improve efficiency, and increase yield by using a hardware method.

Those skilled in the art will appreciate that the drawings are merely schematic representations of one preferred embodiment and that the blocks or flow diagrams in the drawings are not necessarily required to practice the present invention. The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the present invention shall be covered thereby. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. the utility model provides an automatic calibration circuit structure among temperature measuring device, temperature measuring device still include outside reference resistance and outside measuring resistor, its characterized in that, automatic calibration circuit structure including automatic calibration host system, measuring module, inside data register module, comparator module, shift register module and selector module:

The automatic calibration main control module is respectively connected with an external power supply, the comparator module and the shift register module, outputs a starting automatic detection signal to the comparator module and the shift register module, receives a stopping detection signal output by the shift register module, and is used for setting whether the automatic calibration circuit structure enters a calibration mode or not;

the shift register module is connected with the comparator module and the selector module, and sends a shift signal according to the comparison result of the current measured temperature value and the actual temperature value to control a preset temperature value selected by the selector module;

the selector module is connected with the shift register module and the test module, and correspondingly determines a new reference oscillation frequency X 'according to the selected preset temperature value'_RFAnd the obtained X'_RFAnd outputting the data to a test module.

2. The automatic calibration circuit structure of temperature measuring device of claim 1, wherein said automatic calibration main control module further comprises:

3. The automatic calibration circuit structure of temperature measuring device of claim 1, wherein said comparator module comprises a highest comparator unit and M-1 comparator units, said highest comparator unit and said comparator units each comprising at least:

4. The automatic calibration circuit structure of claim 1, wherein said shift register module comprises N shift signal output terminals, each of said shift signal output terminals is configured to output a bit of said shift signal, each bit of said shift signal uniquely corresponds to one of said preset temperature values;

The selector module comprises N selector module input ends, each selector module input end corresponds to one preset temperature value, and the N selector module input ends are arranged according to the size sequence by taking the size of the corresponding preset temperature value as the basis;

The N shift signal output ends are correspondingly connected with the input ends of the N selector modules one by one;

in case the current measured temperature value is equal to the actual temperature value, the shift signal remains unchanged;

Under the condition that the current measured temperature value is larger than the actual temperature value, the high-level signal bit in the shift signal is shifted by one bit towards the direction of other preset temperature values lower than the current preset temperature value;

in the case that the current measured temperature value is smaller than the actual temperature value, the high level signal bit in the shift signal is shifted by one bit toward other preset temperature values higher than the current preset temperature value.

5. the automatic calibration circuit structure of temperature measuring device of claim 1, wherein the different preset temperature values are in an equal difference relationship, and the difference is an equal difference preset by the system.

6. The automatic calibration circuit structure of temperature measuring device according to any one of claims 1 to 5, wherein said temperature measuring device further comprises: the display device comprises a display conversion module, a display driving module and a display module;

the display conversion module is correspondingly connected with the internal data registering module and the input end of the display driving module respectively, converts the current measured temperature value output by the internal data registering module into an on-off signal which can be displayed by the display module, and outputs the on-off signal which can be displayed by the display module to the input end of the display driving module;

The output end of the display driving module is connected with the display module, and the display module is driven to display the current measured temperature value according to the on-off signal which can be displayed by the display module;

The display module is also connected with the automatic calibration main control module and is used for displaying prompt characters preset by the system.

7. The method for automatically calibrating the temperature measuring device based on the automatic calibration circuit structure of claim 6, wherein the preset test environment temperature of the system is the actual temperature value, and the method comprises the following steps:

(2) The internal data register module is based on the systemintegrating the preset corresponding table of the oscillation times and the temperature to determine the oscillation times X of the external measuring resistor_RSthe corresponding current measured temperature value;

(8) The shift register module drives the selector module to select the preset reference oscillation times X_RFAnd a second preset reference oscillation frequency X 'of the difference value of the preset number of the system phase difference'_RF2Replacing the current preset reference oscillation times X_RFstoring the number of second preset reference oscillation times X 'into the measuring module'_RF2As new current preset reference oscillation times X_RFStoring the measured data in the measuring module as a temperature measuring standard, and continuing to the subsequent step (9), wherein the second preset reference oscillation frequencyX’_RF2is equal to the preset reference oscillation times X_RFThe number of the system is increased by the difference value of the preset number of the system;

8. the method as claimed in claim 7, wherein the auto-calibration main control module further comprises a start button and a clock timing unit,

the method also comprises the following steps before the step (1):

(a3) And (3) if the on time of the starting button reaches the preset time of the system, entering an automatic calibration mode, and entering the subsequent step (1), otherwise, entering a temperature measurement mode.

9. The method of claim 8, wherein the auto-calibration master module further comprises a reset signal port, and the step (a1) further comprises the following steps:

(a0) And starting the reset signal port to initialize the automatic calibration main control module.

10. the method for realizing automatic calibration of a temperature measuring device according to claim 7, wherein the step (11) comprises the following steps:

(111) Finishing the automatic calibration, wherein the automatic calibration main control module outputs a signal for finishing the automatic calibration and failing to calibrate to the display driving module;

(112) The display driving module drives the display module to display prompt characters preset by the system.

11. The method for realizing automatic calibration of a temperature measuring device according to claim 7, wherein the step (12) comprises the following steps: