A temperature detection circuit

Abstract

The application relates to the electronic technical field and provides a temperature detection circuit, which comprises a temperature collection unit and a signal processing module; the signal processing module comprises a signal amplification circuit, an analog-digital conversion unit, a self-calibration module, a feedback control unit, a temperature inverse calculation unit and a temperature-sensitive resistance aging monitoring module; the temperature collection unit provides an input signal to the signal amplification circuit; the signal amplification circuit, the analog-digital conversion unit, the self-calibration module and the temperature inverse calculation unit are sequentially connected; the output of the self-calibration module is connected to the feedback control unit; the output of the feedback control unit is connected to the signal amplification circuit to adjust the amplification multiple of the signal amplification circuit; and the temperature-sensitive resistance aging monitoring module is connected to the self-calibration module.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and more particularly to a temperature detection circuit. Background Art

[0002] Figure 1 This is a traditional thermistor-type temperature sensor. It consists of a temperature acquisition unit and a signal processing module. The temperature acquisition unit converts the temperature into a voltage signal by dividing the voltage between the thermistor Rtemp and the voltage divider resistor Rv. The voltage signal then passes through the signal processing module, where it is reverse-calculated to obtain the temperature value, ultimately determining the temperature detected by the thermistor.

[0003] This conventional solution has the following advantages and disadvantages.

[0004] Advantages: Simple structure, temperature detection effect can be achieved through peripherals and ADC.

[0005] Disadvantages: Due to the influence of the manufacturing process, the power supply VCC and the voltage divider resistor Rv have a certain degree of dispersion and error. Traditional solutions cannot correct for errors caused by the manufacturing process, which will introduce deviations when the voltage is calculated back to the temperature value. In addition, the input signal range of this architecture is limited by the input signal range of the chip's internal PGA, and it cannot achieve a wide input signal range of 0 to VCC. In addition, since the resistance of thermistors generally ranges from ohms to megohms, the PGA's amplification factor needs to be adjusted according to the input signal range. Traditional temperature sensors use a manual switching mode, which is relatively complicated to operate. Summary of the Invention

[0006] In one embodiment of the present application, a temperature detection circuit is provided, comprising: a temperature acquisition unit and a signal processing module, the signal processing module comprising a signal amplification circuit, an analog-to-digital conversion unit, a self-calibration module, a feedback control unit, a temperature inversion unit and a temperature-sensitive resistor aging monitoring module, the temperature acquisition unit provides an input signal to the signal amplification circuit, the signal amplification circuit, the analog-to-digital conversion unit, the self-calibration module and the temperature inversion unit are connected in sequence, the output of the self-calibration module is connected to the feedback control unit, the output of the feedback control unit is connected to the signal amplification circuit to adjust the amplification factor of the signal amplification circuit, and the temperature-sensitive resistor aging monitoring module is connected to the self-calibration module.

[0007] In a preferred embodiment, the temperature acquisition unit comprises a temperature sensitive resistor and a voltage dividing resistor, wherein one end of the temperature sensitive resistor is connected to a voltage source, the other end of the temperature sensitive resistor is connected to the voltage dividing resistor, and the other end of the voltage dividing resistor is connected to a ground terminal; wherein the voltage source is connected to a signal input node through a first control switch, a node between the temperature sensitive resistor and the voltage dividing resistor, a node between the voltage dividing resistor and the ground terminal through a second control switch and a third control switch in parallel, and the ground terminal through a fourth control switch.

[0008] In a preferred embodiment, the signal amplification circuit comprises an amplifier, a first voltage dividing resistor string and a second voltage dividing resistor string, the first voltage dividing resistor string comprises a plurality of first resistors, one end of the first voltage dividing resistor string is connected to the signal input node and connected to the non-inverting input terminal of the amplifier through a fifth control switch, the other end of the first voltage dividing resistor string is connected to the ground terminal, the other end of one first resistor connected to the ground terminal is connected to the non-inverting input terminal of the amplifier through a sixth control switch, the second voltage dividing resistor string comprises a plurality of second resistors, one end of the second voltage dividing resistor string is connected to the output terminal of the amplifier, the other end of the second voltage dividing resistor string is connected to the ground terminal, and the nodes between adjacent second resistors are connected to the inverting input terminal of the amplifier through control switches respectively, and the output terminal of the signal amplification circuit is connected to the analog-digital conversion unit.

[0009] In a preferred embodiment, the second voltage dividing resistor string comprises five second resistors, and the nodes between adjacent second resistors are connected to the inverting input terminal of the amplifier through seventh to tenth control switches respectively.

[0010] In a preferred embodiment, when the output of the self-calibration module is between 0 and VCC / 32, the fifth control switch and the tenth control switch are closed, when the output of the self-calibration module is between VCC / 32 and VCC / 16, the fifth control switch and the ninth control switch are closed, when the output of the self-calibration module is between VCC / 16 and VCC / 8, the fifth control switch and the eighth control switch are closed, when the output of the self-calibration module is between VCC / 8 and VCC / 4, the fifth control switch and the seventh control switch are closed, when the output of the self-calibration module is between VCC / 4 and VCC / 2, the sixth control switch and the eighth control switch are closed, and when the output of the self-calibration module is between VCC / 2 and VCC, the sixth control switch and the seventh control switch are closed, wherein Regout is the output of the self-calibration module, and VCC is the voltage value of the voltage source.

[0011] In a preferred embodiment, the self-calibration module comprises first to fourth registers, the first register is connected to the analog-digital conversion unit through an eleventh control switch and connected to the temperature inverse calculation unit through a twelfth control switch, the second register is connected to the analog-digital conversion unit through a thirteenth control switch and connected to the temperature inverse calculation unit through a fourteenth control switch, the third register is connected to the analog-digital conversion unit through a fifteenth control switch and connected to the temperature inverse calculation unit through a sixteenth control switch, and the fourth register is connected to the analog-digital conversion unit through a seventeenth control switch and connected to the temperature inverse calculation unit through an eighteenth control switch.

[0012] In a preferred embodiment, when the eleventh control switch is closed, the voltage source is sampled and the voltage value of the voltage source is saved to the first register; when the thirteenth control switch is closed, the voltage dividing resistor is sampled and the value of the voltage dividing resistor is saved to the second register, wherein the voltage dividing resistor is wherein Rtemp0 is the resistance value of the temperature-sensitive resistor looked up at temperature T0, Vout is the output of the analog-digital conversion unit, PGA is the amplification multiple of the signal amplification circuit, VCC is the voltage value of the voltage source saved in the first register; when the fourth control switch and the seventeenth control switch are closed, the signal input node is set to 0 and the output of the analog-digital conversion unit is stored in the fourth register as the offset voltage.

[0013] In a preferred embodiment, the temperature inverse calculation unit comprises a voltage-resistance conversion module and a resistance-temperature lookup index; when the fifteenth control switch is closed, the voltage-resistance conversion module calculates the resistance value of the temperature-sensitive resistor wherein Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification multiple of the signal amplification circuit, VCC is the voltage value of the voltage source saved in the first register, Rv is the resistance value of the voltage dividing resistor saved in the second register, Voso is the offset voltage saved in the fourth register; the resistance-temperature lookup index looks up the corresponding temperature value according to Rtemp.

[0014] In a preferred embodiment, further comprising a temperature-sensitive resistor aging monitoring module connected to the self-calibration module through a nineteenth control switch, the temperature-sensitive resistor aging monitoring module comprises a resistance inverse calculation module, a fifth register and a logic control module, the fifth register saves the resistance value Rtempn looked up at temperature Tn, the nineteenth control switch is closed at temperature Tn, and the resistance inverse calculation module calculates the resistance value of the temperature-sensitive resistor Wherein, Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification multiple of the signal amplification circuit, VCC is the voltage value of the voltage source registered in the first register, Rv is the resistance value of the voltage dividing resistor registered in the second register, Voso is the offset voltage registered in the fourth register; the logic control module judges whether Rtemp is in the interval [(1-a)*Rtempn, (1+a)*Rtempn], and if not, the logic control module alarms, wherein, 0

[0015] Compared with the prior art, the application has at least the following beneficial effects:

[0016] 1) On the basis of the temperature sensor of the temperature-sensitive resistor detection type, the self-calibration power supply voltage and resistance value function is provided, and the demand for the precision of the power supply voltage and the voltage dividing resistor is reduced.

[0017] 2) The feedback control function is adopted, the amplification multiple of PGA is adjustable through the digital algorithm, and the PGA is compatible with the full-range input signal of 0-VCC, the amplification multiple of PGA is controlled by the internal feedback control unit, and the function of high-precision small signal input signal detection is realized.

[0018] 3) The offset voltage calibration function and the temperature-sensitive resistor aging monitoring function are introduced.

[0019] A large number of technical features are described in the specification and distributed in various technical solutions. If all possible combinations of technical features (i.e. technical solutions) of the application are listed, the specification will be too long. In order to avoid this problem, each technical feature disclosed in the above summary of the application, each technical feature disclosed in the following embodiments and examples, and each technical feature disclosed in the drawings can be freely combined to form various new technical solutions (these technical solutions should be regarded as having been described in the specification), unless such combination of technical features is technically infeasible. For example, features A+B+C are disclosed in one example, features A+B+D+E are disclosed in another example, features C and D are equivalent technical means that play the same role, and only one of them can be used technically, and feature E can be combined with feature C technically. Therefore, the scheme of A+B+C+D should not be regarded as having been described because it is technically infeasible, and the scheme of A+B+C+E should be regarded as having been described. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A schematic diagram of a temperature detection circuit in a conventional scheme is shown.

[0021] Figure 2A schematic diagram of a temperature detection circuit in one embodiment of the present application is shown.

[0022] Figure 3 A schematic diagram of a temperature acquisition unit in one embodiment of the present application is shown.

[0023] Figure 4 A schematic diagram of a signal amplification circuit in one embodiment of the present application is shown.

[0024] Figure 5 A schematic diagram of a self-calibration module in one embodiment of the present application is shown.

[0025] Figure 6 A schematic diagram of a feedback control unit in one embodiment of the present application is shown.

[0026] Figure 7 A schematic diagram of a temperature-sensitive resistor aging monitoring module in one embodiment of the present application is shown.

[0027] Figure 8 A schematic diagram of a temperature inversion unit in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present application.

[0029] In order to make the purposes, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0030] One embodiment of the present application provides a temperature detection circuit, Figure 2 A schematic diagram of a temperature detection circuit in one embodiment is shown. The temperature detection circuit includes a temperature acquisition unit 11 and a signal processing module 12. The signal processing module 12 includes a signal amplification circuit 21, an analog-to-digital conversion unit 22, a self-calibration module 23, a feedback control unit 25, a temperature inversion unit 24, and a temperature-sensitive resistor aging monitoring module 26. The temperature acquisition unit 11 provides an input signal Vin to the signal amplification circuit 21. The signal amplification circuit 21, the analog-to-digital conversion unit 22, the self-calibration module 23, and the temperature inversion unit 24 are connected in sequence. The output of the self-calibration module 24 is connected to the feedback control unit 25. The output of the feedback control unit 25 is connected to the signal amplification circuit 21 to adjust the amplification factor of the signal amplification circuit 21. The temperature-sensitive resistor aging monitoring module 26 is connected to the self-calibration module 23.

[0031] Figure 3 A schematic diagram of the temperature acquisition unit 11 in one embodiment is shown. The temperature acquisition unit includes a temperature-sensitive resistor Rtemp and a voltage dividing resistor Rv. One end of the temperature-sensitive resistor Rtemp is connected to a voltage source VCC, the other end is connected to the voltage dividing resistor Rv, and the other end of the voltage dividing resistor Rv is connected to a ground terminal. Among them, the voltage source VCC is connected to a signal input node through a first control switch swa<1>, a node between the temperature-sensitive resistor Rtemp and the voltage dividing resistor Rv, a second control switch swa<2> and a third control switch swa<3> in parallel, and a fourth control switch swa<4> through the ground terminal, and provides an input signal Vin to the signal amplification circuit.

[0032] In practical applications, the temperature-sensitive resistor Rtemp is placed close to the heat source, converts the temperature signal into a resistance signal, and then divides the voltage through the voltage dividing resistor Rv, finally realizing the function of converting the temperature signal into a voltage signal.

[0033]

[0034] Among them, swa<1>, swa<2> and swa<3> are switches used to sample the power supply voltage VCC and the voltage dividing signal Vin, and swa<4> is used to sample the potential relative to the ground. swa<1>, swa<2>, swa<3> and swa<4> are not turned on at the same time.

[0035] When swa<1> is turned on, the system enters VCC correction mode, and the VCC voltage is sampled.

[0036] When swa<2> is turned on, the system enters voltage dividing resistor Rv correction mode, and the voltage dividing signal of Rtemp and Rv is sampled.

[0037] When swa<3> is turned on, the system enters normal temperature measurement mode.

[0038] When swa<4> is turned on, the system enters the offset voltage calibration mode.

[0039] Figure 4A schematic diagram of the signal amplification circuit 21 in one embodiment is shown. The signal amplification circuit 22 includes an amplifier 33, a first voltage dividing resistor string 31 and a second voltage dividing resistor string 32. The first voltage dividing resistor string 31 includes a plurality of first resistors Rh, one end of the first voltage dividing resistor string 31 is connected to the signal input node Vin and connected to the non-inverting input of the amplifier 33 through a fifth control switch swb<1>, the other end of the first voltage dividing resistor string Rh is connected to the ground, and the other end of one first resistor connected to the ground is connected to the non-inverting input of the amplifier 33 through a sixth control switch swb<2>. The second voltage dividing resistor string 32 includes a plurality of second resistors (e.g., resistors Rp1, Rp2, Rp3, Rp4, Rp5), one end of the second voltage dividing resistor string 32 is connected to the output of the amplifier 33, and the other end of the second voltage dividing resistor string 32 is connected to the ground. The nodes between adjacent second resistors are connected to the inverting input of the amplifier 33 through control switches swc<1:4>, respectively. The output of the signal amplification circuit is connected to the analog-to-digital conversion unit.

[0040] In one embodiment, the first voltage dividing resistor string 31 includes four first resistors Rh. In one embodiment, the second voltage dividing resistor string 32 includes five second resistors, and the nodes between adjacent second resistors are connected to the inverting input of the amplifier 33 through seventh to tenth control switches swc<1>~swc<4>, respectively.

[0041] By controlling the conduction and blocking of the control switches swb<1>, swb<2> and swc<1>~swc<4>, the signal amplification circuit can realize 0.5 times, 1 times, 2 times, 4 times, 8 times and 16 times amplification functions of the input signal Vin. Among them, swb<1> and swb<2> switches can only be turned on one at a time, and similarly, swc<1>~swc<4> switches can only be turned on one at a time. For example, when swb<2> and swc<1> are turned on, the amplification circuit can realize 0.5 times amplification.

[0042] The signal amplification circuit is composed of two parts. The first part is the Rh resistance voltage dividing circuit integrated in the chip. Because of the large discrete degree of discrete components, the Rh resistance voltage dividing circuit of the input signal Vin is integrated in the chip. When swb<1> is turned on, Vp=Vin. When swb<2> is turned on, Vp=0.25*Vin. The input signal resistance voltage dividing circuit realizes the functions of 1 times amplification and 0.25 times amplification. The second part is composed of the in-phase amplifier with selectable amplification. By changing the conduction order of swc<1>~swc<4>, the in-phase amplifier can realize the functions of 2 times, 4 times, 8 times and 16 times amplification. Combined with the voltage dividing resistance Rh and the in-phase amplifier, the PGA amplification circuit can realize the functions of 0.5 times, 1 times, 2 times, 4 times, 8 times and 16 times amplification of the input signal. The output of the PGA amplification circuit is processed by the analog-to-digital converter (ADC), and the processed signal is transmitted to the next stage.

[0043] Figure 5 A schematic diagram of the self-calibration module 23 in one embodiment is shown. The self-calibration module includes a first register reg1, a second register reg2, a third register reg3 and a fourth register reg4. The first register reg1 is connected to the analog-to-digital conversion unit through an eleventh control switch swd<1> and connected to the temperature inverse calculation unit through a twelfth control switch swe<1>. The second register reg2 is connected to the analog-to-digital conversion unit through a thirteenth control switch swd<2> and connected to the temperature inverse calculation unit through a fourteenth control switch swe<2>. The third register reg3 is connected to the analog-to-digital conversion unit through a fifteenth control switch swd<3> and connected to the temperature inverse calculation unit through a sixteenth control switch swe<4>. The fourth register reg4 is connected to the analog-to-digital conversion unit through a seventeenth control switch swd<4> and connected to the temperature inverse calculation unit through an eighteenth control switch swe<4>.

[0044] In one embodiment, when the eleventh control switch swd<1> is closed, the voltage source is sampled and the voltage value of the voltage source VCC is saved to the first register reg1. When the thirteenth control switch swd<2> is closed, the voltage dividing resistance Rv is sampled and the value of the voltage dividing resistance is saved to the second register reg2. The voltage dividing resistance is Wherein, Rtemp0 is the resistance value of the temperature-sensitive resistor at temperature T0, Vout is the output of the analog-digital conversion unit, PGA is the amplification multiple of the signal amplification circuit, VCC is the voltage value of the voltage source stored in the first register reg1. When the fourth control switch swa<4> and the seventeenth control switch swd<4> are closed, the signal input node is set to 0 and the output of the analog-digital conversion unit is stored in the fourth register reg4 as the offset voltage.

[0045] Due to the deviation of the supply voltage VCC and the voltage dividing resistor Rv, the temperature calculated by the voltage will be deviated, so the supply voltage VCC and the voltage dividing resistor Rv need to be self-calibrated. The following is the working process of the self-calibration module:

[0046] When the switches swa<1> and swd<1> are turned on, the supply voltage VCC enters the calibration mode. By sampling the supply voltage VCC signal and then processing it through the ADC, the accurate VCC signal is stored in the register reg1 for use by the following voltage dividing resistor correction module and the subsequent temperature calculation circuit.

[0047] When the switches swa<2> and swd<2> are turned on, the voltage dividing resistor Rv enters the calibration mode. By sampling the input signal Vin of the voltage dividing circuit at the temperature-sensitive resistor Rtemp at a certain temperature T0 and processing it through the ADC, the accurate value of Rv can be calculated. The accurate Rv is stored in the register reg2 for use by the subsequent temperature calculation circuit.

[0048]

[0049] Wherein, Rtemp0 is the resistance value of the temperature-sensitive resistor at temperature T0 obtained by looking up the temperature-sensitive resistor R-Temp table first, Vout is the output of the ADC when swd<2> is turned on, PGA is the amplification multiple, and VCC is the self-calibrated power supply voltage value stored in reg1.

[0050] When the switches swa<4> and swd<4> are turned on, the offset voltage calibration mode is entered. By setting Vin to 0, the output offset voltage Voso of the ADC system can be obtained, and Voso is stored in the register reg4. The next time the temperature is calculated, Voso can be subtracted to realize the offset voltage calibration function.

[0051] When the switches swa<3> and swd<3> are turned on, the normal temperature sensor working process is entered. By updating the values of the supply voltage VCC, the voltage dividing resistor Rv, and the offset voltage Voso through the self-calibration module, real-time and accurate temperature detection can be realized.

[0052] Figure 6A schematic diagram of the feedback control unit in one embodiment is shown. The supply voltage VCC is divided into 6 segments by a binary divider, and then the on / off of the swb and swc switches is controlled by the feedback control unit logic, thereby realizing the functions of wide input signal range and small signal amplification of the temperature sensor 0~VCC. The specific control logic is as follows:

[0053] Regout is the output of the self-calibration module, and the switches of the signal amplification circuit are adjusted according to the output Regout of the self-calibration module to obtain different amplification multiples. When the output of the self-calibration module is between 0≤Regout

[0054] Reference is made to Figure 7 As shown, the temperature-sensitive resistor aging monitoring module is connected to the self-calibration module through the nineteenth control switch swf. The temperature-sensitive resistor aging monitoring module includes a resistance inverse calculation module 41, a fifth register (not shown in the figure) and a logic control module 42. The fifth register stores the resistance value Rtempn looked up at temperature Tn, and when the nineteenth control switch swf is closed at temperature Tn, the resistance inverse calculation module 41 calculates the resistance value of the temperature-sensitive resistor Wherein, Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification of the signal amplification circuit, VCC is the voltage value of the voltage source stored in the first register, Rv is the resistance value of the voltage dividing resistor stored in the second register, and Voso is the offset voltage stored in the fourth register. The logic control module 42 judges whether Rtemp is in the interval [(1-a)*Rtempn, (1+a)*Rtempn], and if yes, no processing is performed, and if not, the logic control module alarms, wherein 0 < a < 1.

[0055] Specifically, if (1-a)*Rtempn < Rtemp < (1+a)*Rtempn, the temperature-sensitive resistor aging monitoring module outputs Rutout = 0, the temperature-sensitive resistor resistance is normal, and the module does not alarm. In other cases, the temperature-sensitive resistor aging monitoring module outputs Rutout = 1, the temperature-sensitive resistor resistance is abnormal, and the module alarms.

[0056] Figure 8 A schematic diagram of the temperature inverse calculation unit 24 in an embodiment is shown. The temperature inverse calculation unit includes a voltage-resistance conversion module 51 and a resistance-temperature lookup index 52. When the fifteenth control switch swd<3> is closed, the voltage-resistance conversion module calculates the resistance value of the temperature-sensitive resistor Wherein, Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification of the signal amplification circuit, VCC is the voltage value of the voltage source stored in the first register, Rv is the resistance value of the voltage dividing resistor stored in the second register, and Voso is the offset voltage stored in the fourth register. The resistance-temperature lookup index looks up the corresponding temperature value according to Rtemp. Because the temperature-sensitive resistor manufacturer will provide the Rtemp-Temp lookup table of the temperature-sensitive resistor, the lookup table is stored in the register, and the corresponding Temp of Rtemp can be found through the index, so that the temperature value detected by the temperature-sensitive resistor is obtained.

[0057] The patent utilizes the temperature-sensitive resistor and the voltage dividing resistor to constitute a temperature acquisition unit, converts the temperature signal into a voltage signal to be collected into an ADC system, and realizes self-calibration of the power supply voltage and the voltage dividing resistor through a digital algorithm. The feedback control unit adjusts the amplitude of the input signal by controlling the amplification of PGA, and has the functions of compatible large signal input and small signal amplification. Finally, the temperature detected by the temperature-sensitive resistor is calculated in real time through the V-T inverse calculation module. In addition, the offset voltage calibration and the temperature-sensitive resistor aging monitoring function are added.

[0058] It should be noted that in this patent application, relational terms such as first and second, etc., are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. Without further limitation, an element specified by the phrase "comprising a" does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element. In this patent application, reference to performing an action in accordance with an element means performing the action in accordance with at least that element, including two situations: performing the action in accordance with that element alone, and performing the action in accordance with that element and other elements. Expressions such as "plurality," "multiple times," and "many" include "two," "twice," "two kinds," and "more than two," "more than two times," and "more than two kinds."

[0059] This specification includes combinations of the various embodiments described herein. Separate references to an embodiment (e.g., "one embodiment" or "some embodiments" or "preferred embodiments") do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive unless indicated as such or clear to one skilled in the art. It should be noted that the word "or" is used in this specification in a non-exclusive sense unless the context clearly indicates or requires otherwise.

[0060] All documents mentioned in this specification are considered to be included in their entirety in the disclosure of this specification so that they can be used as a basis for modification when necessary. In addition, it should be understood that the above are only preferred embodiments of this specification and are not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of one or more embodiments of this specification.

Claims

1. A temperature detection circuit, characterized in that: include: A temperature acquisition unit and a signal processing module, wherein the signal processing module includes a signal amplification circuit, an analog-to-digital conversion unit, a self-calibration module, a feedback control unit, a temperature inversion unit, and a temperature-sensitive resistor aging monitoring module. The temperature acquisition unit provides an input signal to the signal amplification circuit. The signal amplification circuit, the analog-to-digital conversion unit, the self-calibration module, and the temperature inversion unit are connected in sequence. The output of the self-calibration module is connected to the feedback control unit. The output of the feedback control unit is connected to the signal amplification circuit to adjust the amplification factor of the signal amplification circuit. The temperature-sensitive resistor aging monitoring module is connected to the self-calibration module. The temperature acquisition unit includes a temperature-sensitive resistor and a voltage-dividing resistor, wherein one end of the temperature-sensitive resistor is connected to a voltage source, the other end is connected to the voltage-dividing resistor, and the other end of the voltage-dividing resistor is connected to a ground terminal; wherein the voltage source is connected to a signal input node through a first control switch, a node between the temperature-sensitive resistor and the voltage-dividing resistor through a second control switch and a third control switch connected in parallel, and the ground terminal is connected through a fourth control switch; wherein when the first control switch is turned on, the system enters a voltage source calibration mode; when the second control switch is turned on, the system enters a voltage-dividing resistor calibration mode; when the third control switch is turned on, the system enters a normal temperature measurement mode; and when the fourth control switch is turned on, the system enters an offset voltage calibration mode; The signal amplification circuit includes an amplifier, a first voltage-dividing resistor string and a second voltage-dividing resistor string, the first voltage-dividing resistor string includes a plurality of first resistors, one end of the first voltage-dividing resistor string is connected to the signal input node and is connected to the non-inverting input terminal of the amplifier through a fifth control switch, the other end of the first voltage-dividing resistor string is connected to the ground terminal, and the other end of a first resistor connected to the ground terminal is connected to the non-inverting input terminal of the amplifier through a sixth control switch, the second voltage-dividing resistor string includes a plurality of second resistors, one end of the second voltage-dividing resistor string is connected to the output terminal of the amplifier, the other end of the second voltage-dividing resistor string is connected to the ground terminal, and the nodes between adjacent second resistors are respectively connected to the inverting input terminal of the amplifier through a control switch, and the output terminal of the signal amplification circuit is connected to the analog-to-digital conversion unit; wherein the fifth and sixth control switches connected to the first voltage-dividing resistor string and the control switches connected to the plurality of second resistors are controlled according to the output of the self-calibration module, thereby adjusting the amplification factor of the signal amplification circuit.

2. The temperature detection circuit according to claim 1, wherein: The second voltage-dividing resistor string includes five second resistors, and nodes between adjacent second resistors are connected to the inverting input terminal of the amplifier through seventh to tenth control switches, respectively.

3. The temperature detection circuit according to claim 2, wherein: When the output of the self - calibration module is between 0 ≤ Regout < VCC / 32, the fifth control switch and the tenth control switch are closed; when the output of the self - calibration module is between VCC / 32 ≤ Regout < VCC / 16, the fifth control switch and the ninth control switch are closed; when the output of the self - calibration module is between VCC / 16 ≤ Regout < VCC / 8, the fifth control switch and the eighth control switch are closed; when the output of the self - calibration module is between VCC / 8 ≤ Regout < VCC / 4, the fifth control switch and the seventh control switch are closed; when the output of the self - calibration module is between VCC / 4 ≤ Regout < VCC / 2, the sixth control switch and the eighth control switch are closed; when the output of the self - calibration module is between VCC / 2 ≤ Regout ≤ VCC, the sixth control switch and the seventh control switch are closed, where Regout is the output of the self - calibration module and VCC is the voltage value of the voltage source.

4. The temperature detection circuit according to claim 1, wherein: The self - calibration module includes the first to fourth registers. The first register is connected to the analog - to - digital conversion unit through the eleventh control switch and connected to the temperature inverse calculation unit through the twelfth control switch. The second register is connected to the analog - to - digital conversion unit through the thirteenth control switch and connected to the temperature inverse calculation unit through the fourteenth control switch. The third register is connected to the analog - to - digital conversion unit through the fifteenth control switch and connected to the temperature inverse calculation unit through the sixteenth control switch. The fourth register is connected to the analog - to - digital conversion unit through the seventeenth control switch and connected to the temperature inverse calculation unit through the eighteenth control switch.

5. The temperature detection circuit according to claim 4, characterized in that: When the eleventh control switch is closed, the voltage source is sampled and the voltage value of the voltage source is saved in the first register; when the thirteenth control switch is closed, the voltage divider resistor is sampled and the value of the voltage divider resistor is saved in the second register, wherein the voltage divider resistor is Wherein, Rtemp0 is the resistance value of the temperature-sensitive resistor found at temperature T0, Vout is the output of the analog-to-digital conversion unit, PGA is the amplification factor of the signal amplification circuit, and VCC is the voltage value of the voltage source stored in the first register; when the fourth control switch and the seventeenth control switch are closed, the signal input node is set to 0 and the output of the analog-to-digital conversion unit is stored as the offset voltage in the fourth register.

6. The temperature detection circuit according to claim 5, characterized in that: The temperature inverse calculation unit includes: a voltage-resistance conversion module and a resistance-temperature lookup index; when the fifteenth control switch is closed, the voltage-resistance conversion module calculates the resistance value of the temperature sensitive resistor Wherein, Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification factor of the signal amplification circuit, VCC is the voltage value of the voltage source stored in the first register, Rv is the resistance value of the voltage divider resistor stored in the second register, and Voso is the offset voltage stored in the fourth register; the resistance-temperature lookup index searches for the corresponding temperature value based on Rtemp.

7. The temperature detection circuit according to claim 5, characterized in that: The temperature-sensitive resistor aging monitoring module is connected to the self-calibration module through a nineteenth control switch. The temperature-sensitive resistor aging monitoring module includes a resistance inverse calculation module, a fifth register, and a logic control module. The fifth register stores the resistance value Rtempn found at temperature Tn. When the nineteenth control switch is closed at temperature Tn, the resistance inverse calculation module calculates the resistance value of the temperature-sensitive resistor. Wherein, Regout is the output of the self-calibration module when the fifteenth control switch is closed, PGA is the amplification factor of the signal amplification circuit, VCC is the voltage value of the voltage source stored in the first register, Rv is the resistance value of the voltage divider resistor stored in the second register, and Voso is the offset voltage stored in the fourth register; the logic control module determines whether Rtemp is in the range of [(1-a)*Rtempn, (1+a)*Rtempn]. If not, the logic control module alarms, wherein 0 <a<1。

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