A temperature sensing element and thermostat
By configuring positive and negative offsets in the bandgap reference circuit and using an analog-to-digital converter module to perform two quantization summations and averaging, the problems of high layout area and power consumption in traditional technologies are solved, achieving high efficiency and accuracy in temperature measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANJING VPS SEMICONDUCTOR TECHNOLOGY CO LTD
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional chopper technology has high layout area cost and power consumption when eliminating the low offset voltage output of bandgap reference circuits.
By configuring positive and negative offsets in the bandgap reference circuit and performing two quantizations using an analog-to-digital converter module and then summing and averaging, the influence of offset voltage on temperature measurement is eliminated. Temperature sensing elements are fabricated using integrated circuit technology or discrete components.
This effectively reduces chip area and power consumption while improving the accuracy and efficiency of temperature measurement.
Smart Images
Figure CN224536396U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of temperature detection, and in particular to a temperature sensing element and a thermostat. Background Technology
[0002] Temperature sensing elements play a crucial role in temperature detection and control, digitally measuring temperatures by converting non-electrical signals from nature into electrical voltage values. With the increasing scale of chips today, integrated temperature sensors, by integrating circuit components onto silicon semiconductors, offer a range of advantages including high accuracy, high reliability, low power consumption, and customizability.
[0003] Integrated temperature sensors mainly consist of a temperature sensing circuit and an analog-to-digital conversion circuit. The temperature sensing element is mainly based on three types: BJT transistor, MOSFET, and resistor.
[0004] Even when using a bandgap reference circuit constructed with BJTs (Browser-Jet Transistors) that offers the best accuracy, performance, and a more mature structure, offset voltage still exists in the circuit and can severely affect the accuracy of temperature measurements. To eliminate the offset voltage output from the bandgap, traditional chopping techniques require a high-frequency clock to mix the offset to a higher frequency band, followed by filtering it out with a low-pass filter. High-frequency clocks and low-pass filters have relatively large layout area costs and high power consumption. Utility Model Content
[0005] Therefore, the technical problem to be solved by this utility model is: in order to eliminate the low offset voltage output of the bandgap, the layout area cost of traditional chopper technology is relatively large and the power consumption is also relatively high.
[0006] The above-mentioned technical problems are solved by the following technical solution: This utility model proposes a temperature sensing element, comprising,
[0007] The bandgap reference circuit includes a first input terminal connected to a first control source, and a VPTAT output port and a VBG output port for outputting VPTAT and VBG respectively. The VPTAT output port and the VBG output port are connected to an analog-to-digital converter module, and the VPTAT and VBT values obtained by the second measurement are output to the analog-to-digital converter module.
[0008] The analog-to-digital converter module includes a sample-and-hold circuit electrically connected to the VPTAT output port, a quantization unit electrically connected between the VBG output port and the sample-and-hold circuit, and a storage and processing circuit electrically connected between the quantization unit and the decoder.
[0009] The quantization unit is configured to quantize the VPTAT and VBG signals and transmit the quantized result to the storage and processing circuit. The storage and processing circuit is configured to sum and average the quantized values and transmit the result to the decoder.
[0010] In a preferred embodiment of the temperature sensing element of this utility model: the bandgap reference circuit includes a load transistor, an output transistor, and a switching transistor, each of which is provided in pairs; the source of the switching transistor is connected to the source of the output transistor, and the drain of the switching transistor is connected to the drain of the output transistor.
[0011] In this configuration, the source and drain of each switching transistor are respectively connected to different output transistors.
[0012] In a preferred embodiment of the temperature sensing element of this utility model: the load transistor includes a first MOS transistor and a second MOS transistor, and the output transistor includes a third MOS transistor and a fourth MOS transistor;
[0013] The sources of the first and second MOSFETs are both connected to the input power supply, the source of the third MOSFET is connected to the drain of the first MOSFET, and the source of the fourth MOSFET is connected to the drain of the second MOSFET.
[0014] In a preferred embodiment of the temperature sensing element of this utility model: the drain of the fourth MOS transistor is connected to a resistor, and the first output terminal is disposed between the fourth MOS transistor and the resistor.
[0015] In a preferred embodiment of the temperature sensing element of this utility model: the drain of the third MOS transistor is connected to a reference resistor, and the second output terminal is disposed between the third MOS transistor and the reference resistor.
[0016] In a preferred embodiment of the temperature sensing element of this utility model: the switching transistor includes a fifth MOS transistor and a sixth MOS transistor, the source of the fifth MOS transistor is connected to the drain of the first MOS transistor, and the drain of the fifth MOS transistor is connected between the fourth MOS transistor and the first output terminal;
[0017] The source of the sixth MOS transistor is connected to the drain of the second MOS transistor, and the drain of the sixth MOS transistor is connected between the third MOS transistor and the second output terminal.
[0018] In a preferred embodiment of the temperature sensing element of this utility model: the bandgap reference circuit further includes an operational amplifier and a second control source.
[0019] The gates of both the first and second MOS transistors are connected to the output of the operational amplifier.
[0020] The gates of the third MOS transistor and the fourth MOS transistor are both connected to the first control source;
[0021] The gates of the fifth and sixth MOS transistors are interconnected and both are connected to the second control source.
[0022] In a preferred embodiment of the temperature sensing element of this utility model: the bandgap reference circuit, the analog-to-digital converter module, and the decoder are manufactured using integrated circuit technology.
[0023] In a preferred embodiment of the temperature sensing element of this utility model: the bandgap reference circuit, the analog-to-digital conversion module, and the decoder are made of corresponding discrete components.
[0024] This utility model proposes a thermostat, which also includes,
[0025] A temperature control element, wherein the temperature control element receives the temperature value output by the temperature sensing element and compares it with a standard temperature value;
[0026] A temperature-changing element is used to receive signals from a temperature-controlling element and change its own temperature value.
[0027] The beneficial effects of this invention are as follows: This invention configures the low offset voltage in the bandgap reference to be divided into positive offset and negative offset. Then, the two quantization results are added together and averaged by the subsequent analog-to-digital conversion module to eliminate the influence of offset voltage on temperature measurement. This invention has a simple structure and saves chip area and power consumption. Attached Figure Description
[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments of this utility model will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this utility model and are not intended to limit the scope of this utility model. Wherein:
[0029] Figure 1 A connection diagram of the temperature sensing element is shown;
[0030] Figure 2 A schematic diagram of the circuit connection of the bandgap reference circuit is shown;
[0031] Figure 3 A connection diagram of the thermostat is shown. Detailed Implementation
[0032] To enable those skilled in the art to better understand this utility model, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0033] The terminology used in this invention refers to those general terms currently widely used in the art in consideration of the functionality of this invention; however, these terms may vary according to the intent, precedent, or new technology of those skilled in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of this invention. Therefore, the terminology used in this specification should not be construed as simple names, but rather based on the meaning of the terms and the overall description of this invention.
[0034] Reference Figure 1 This embodiment provides a temperature sensing element, including a bandgap reference circuit 100, a decoder 200, and an analog-to-digital converter module 300.
[0035] The bandgap reference circuit 100 includes a first input terminal connected to the first control source SEL, and a VPTAT output port and a VBG output port for outputting VPTAT and VBG respectively. The VPTAT and VBG output ports are connected to an analog-to-digital converter (ADC) module 300, and output the remeasured VPTAT and VBT values to the ADC module 300. The ADC module 300 includes a sample-and-hold circuit 301 electrically connected to the VPTAT output port, a quantization unit 302 electrically connected between the VBG output port and the sample-and-hold circuit 301, and a storage and processing circuit 303 electrically connected between the quantization unit 302 and the decoder 200. The quantization unit 302 is configured to quantize the VPTAT and VBG signals and transmit the quantized result to the storage and processing circuit 303. The storage and processing circuit 303 is configured to sum and average the quantized values and transmit the result to the decoder 200.
[0036] Where VPTAT is the positive temperature coefficient voltage and VBG is the reference voltage.
[0037] The bandgap reference circuit 100 is used to generate the reference voltage VBG and the positive temperature coefficient voltage VPTAT.
[0038] The decoder 200 outputs a TEMP signal.
[0039] The analog-to-digital converter module 300 samples and holds the temperature coefficient voltage VPTAT output by the bandgap reference circuit 100 and quantizes it using the reference voltage VBG as the reference voltage. After two quantizations, the summation and averaging are performed to output the signal D<9:0>.
[0040] Decoder 200 converts D<9:0> into a temperature TEMP output.
[0041] Wherein, TEMP = K*D<9:0> + B, where K is the slope and B is the initial value, which can be obtained through simulation or testing.
[0042] The sample-and-hold circuit 301 is used to receive the positive temperature coefficient voltage VPTAT, the quantization unit 302 is used to quantize the reference voltage VBG signal and the positive temperature coefficient voltage VPTAT, and the storage and processing circuit 303 is used to sum and average the quantized values.
[0043] The sample-and-hold circuit 301 is the front-end part of the analog-to-digital converter module 300. Its main function is to receive the positive temperature coefficient voltage VPTAT output by the bandgap reference circuit 100 and stably capture and hold this voltage value during the analog-to-digital conversion process. The input terminal of the sample-and-hold circuit 301 is directly connected to the first output terminal of the bandgap reference circuit 100. The positive temperature coefficient voltage VPTAT it receives is an analog voltage signal that is positively correlated with temperature, and its value changes with temperature. The function of the sample-and-hold circuit 301 is to "freeze" the input analog signal at a stable voltage value at the moment of analog-to-digital conversion, thereby ensuring the accuracy of the analog-to-digital conversion.
[0044] The quantization unit 302 is the core component of the analog-to-digital conversion module 300. Its main function is to convert the analog voltage signal output by the sample-and-hold circuit 301 into a digital signal. The quantization unit 302 uses the reference voltage VBG as the quantization reference to convert the voltage value of the positive temperature coefficient voltage VPTAT into the corresponding digital code value.
[0045] The storage and processing circuit 303 is the back-end part of the analog-to-digital converter module 300. Its main function is to store the digital code value output by the quantization unit 302 and sum and average the results of two quantizations to eliminate the influence of offset voltage on temperature measurement. The storage and processing circuit 303 receives the digital code value output by the quantization unit 302 and stores it in an internal register or memory. These stored digital code values can be used for subsequent digital processing. To eliminate the influence of offset voltage in the bandgap reference circuit 100 on temperature measurement, the storage and processing circuit 303 sums and averages the results of two quantizations. Specifically, it adds the quantization results under two different configurations and then takes the average value to eliminate the influence of offset voltage. The summed and averaged digital code value is finally output to the decoder 200 for further temperature calculation and data processing.
[0046] The second output terminal is connected to the input terminal of the quantization unit 302, the first output terminal is connected to the input terminal of the sample-and-hold circuit 301, the output terminal of the sample-and-hold circuit 301 is connected to the input terminal of the quantization unit 302, the output terminal of the quantization unit 302 is connected to the input terminal of the storage and processing circuit 303, and the output terminal of the storage and processing circuit 303 is connected to the input terminal of the decoder 200.
[0047] The sample-and-hold circuit 301 is used to stably capture the positive temperature coefficient voltage VPTAT from the bandgap reference circuit 100 during the analog-to-digital conversion (ADC) module 300 conversion process, and hold this voltage value until the ADC module 300 completes the conversion. This ensures the accuracy of the conversion result, unaffected by input signal fluctuations or other interference during the conversion process.
[0048] The quantization unit 302 is used to convert the temperature-related analog voltage signal generated by the bandgap reference circuit 100 into a digital signal for further processing and temperature calculation.
[0049] The storage and processing circuit 303 is used to store the results of the two quantizations, then sum the two results and take the average value, and finally output the average value to the decoder 200.
[0050] The bandgap reference circuit 100, the analog-to-digital converter module 300, and the decoder 200 are fabricated using integrated circuit technology.
[0051] Among them, by using integrated circuit technology, the bandgap reference circuit 100, the analog-to-digital converter module 300 and the decoder 200 can be integrated on the same chip, which greatly reduces the chip area and volume.
[0052] Integrated circuit manufacturing processes, through meticulous manufacturing techniques and rigorous quality control, ensure consistent circuit performance. In mass production, integrated circuits exhibit relatively high yield rates and stable performance.
[0053] The bandgap reference circuit 100, the analog-to-digital converter module 300, and the decoder 200 are made of corresponding discrete components.
[0054] In this discrete component circuit, each part is independent, which makes debugging and maintenance more convenient. If a component fails, that component can be replaced directly without replacing the entire chip.
[0055] How to use temperature sensing elements.
[0056] The first step is to enable temperature detection.
[0057] The second step is to configure the SEL signal to be 0 through the first input terminal.
[0058] The third step is to sample and hold the positive temperature coefficient voltage VPTAT by the analog-to-digital converter module 300, and quantize it using the reference voltage VBG as the reference voltage, and save the quantized code value as D0<9:0>.
[0059] The fourth step is to configure the SEL signal to be 1 through the first input terminal.
[0060] The fifth step is that the analog-to-digital converter module 300 samples and holds the temperature coefficient voltage VPTAT, and quantizes it with the reference voltage VBG as the reference voltage, and saves the quantized code value, which is denoted as D1<9:0>.
[0061] Step 6: Summate D0 and D1 and take the average to obtain:
[0062] D<9:0>=(D0<9:0>+D1<9:0>) / 2.
[0063] Step 7: Translate D<9:0> into temperature TEMP and output it. TEMP = K*D<9:0> + B, where K is the slope and B is the initial value, which can be obtained through simulation or testing.
[0064] In the third step, due to the offset voltages ΔVPTAT and ΔVBG of the positive temperature coefficient voltage VPTAT and reference voltage VBG output by the bandgap reference circuit 100, the quantization formula for D0 is:
[0065]
[0066] In step five, due to the offset voltages ΔVPTAT and ΔVBG of the temperature coefficient voltage VPTAT and reference voltage VBG output by the bandgap reference circuit 100, the quantization formula for D1 is:
[0067]
[0068] Fourier expansion of the quantization formulas for D0 and D1 yields ΔVBG, which is very small relative to VBG. Ignoring the multiplicity terms in formulas one and two of the Fourier expansion:
[0069] Formula 1:
[0070]
[0071] Formula 2:
[0072]
[0073] In the fourth term of Formula 1 and Formula 2, the fourth term is the product of ΔVPTAT and ΔVBG, which is usually very small and can be ignored.
[0074] Therefore, summing and averaging D0 and D1 yields Formula 3:
[0075]
[0076] As can be seen from Formula 3, averaging the two quantization results can eliminate the influence of offset voltage on temperature measurement.
[0077] Reference Figure 2 This embodiment provides a bandgap reference circuit 100, including a load transistor, an output transistor, and a switching transistor, each of which is provided in pairs. The source of the switching transistor is connected to the source of the output transistor, and the drain of the switching transistor is connected to the drain of the output transistor.
[0078] In this configuration, the source and drain of each switching transistor are connected to different output transistors respectively.
[0079] The load transistors include a first MOSFET M1 and a second MOSFET M2, and the output transistors include a third MOSFET M3 and a fourth MOSFET M4.
[0080] The sources of the first MOSFET M1 and the second MOSFET M2 are both connected to the input power supply. The source of the third MOSFET M3 is connected to the drain of the first MOSFET M1. The source of the fourth MOSFET M4 is connected to the drain of the second MOSFET M2.
[0081] The drain of the fourth MOSFET M4 is connected to resistor R4, and the first output terminal is located between the fourth MOSFET M4 and resistor R4.
[0082] The drain of the third MOSFET M3 is connected to a reference resistor R3, and the second output terminal is located between the third MOSFET M3 and the reference resistor R3.
[0083] The switching transistors include a fifth MOSFET M5 and a sixth MOSFET M6. The source of the fifth MOSFET M5 is connected to the drain of the first MOSFET M1, and the drain of the fifth MOSFET M5 is connected between the fourth MOSFET M4 and the first output terminal.
[0084] The source of the sixth MOSFET M6 is connected to the drain of the second MOSFET M2, and the drain of the sixth MOSFET M6 is connected between the third MOSFET M3 and the second output terminal.
[0085] Among them, the drain of the fifth MOSFET M5 is connected between the fourth MOSFET M4 and the first output terminal, and the drain connection point of the fifth MOSFET M5 is the first node NR. The drain of the sixth MOSFET M6 is connected between the third MOSFET M3 and the second output terminal, and the drain connection point of the sixth MOSFET M6 is the second node PR.
[0086] The bandgap reference circuit 100 also includes an operational amplifier OTA0 and a second control source SELB.
[0087] The gates of the first MOSFET M1 and the second MOSFET M2 are both connected to the output terminal of the operational amplifier OTA0.
[0088] The gates of the third MOSFET M3 and the fourth MOSFET M4 are both connected to the first control source SEL;
[0089] The gates of the fifth MOSFET M5 and the sixth MOSFET M6 are interconnected and both are connected to the second control source SELB.
[0090] The first control source SEL can output the SEL signal, and the second control source SELB can output the SELB signal, where SELB is the inverted signal of SEL.
[0091] The positive temperature coefficient voltage VPTAT output in the bandgap reference circuit 100 is denoted as VPTAT. 输出 When there is no offset voltage in the bandgap reference circuit 100, the positive temperature coefficient voltage VPTAT output by the bandgap reference circuit 100 is expressed as VPTAT. 标准 In the bandgap reference circuit 100, the offset positive temperature coefficient voltage VPTAT is represented as ΔVPTAT. Similarly, VBG is represented... 输出 VBG 标准 And ΔVBG.
[0092] The majority of offsets in the circuit are caused by the input pair and the tail current transistor. This could be due to a discrepancy in the gate voltages of the first MOSFET M1 and the second MOSFET M2. It could also be caused by the input pair and the tail current transistor within the OTA0 circuit itself.
[0093] If there is an offset voltage between the gate voltages of the first MOSFET M1 and the second MOSFET M2, assuming that a low offset voltage causes the gate voltage of the first MOSFET M1 to increase and the gate voltage of the second MOSFET M2 to decrease, then when the SEL signal is low and the SELB signal is high, VPTAT 输出 =VPTAT 标准 +ΔVPTAT; When SEL is high and SELB is low, VPTAT 输出 =VPTAT 标准 -ΔVPTAT.
[0094] When the input transistors and tail current transistor of OTA0 generate offset voltages, there will be an equivalent voltage offset at the input of OTA0, i.e., VIP ≠ VIN. Assuming that when the SEL signal is low and the SELB signal is high, VIP is less than VIN, then VBG... 输出 =VBG 标准 +ΔVBG; When the SEL signal is high and the SELB signal is low, VIP is greater than VIN, then VBG输出 =VBG 标准 -ΔVBG. Next, we will explain how to eliminate ΔVPTAT and ΔVBG. From the above analysis, we can conclude that when the SEL signal is low and the SELB signal is high, VPTAT... 输出 =VPTAT 标准 +ΔVPTAT,VBG 输出 =VBG 标准 +ΔVBG; When the SEL signal is high and the SELB signal is low, VPTAT 输出 =VPTAT 标准 -ΔVPTAT,VBG 输出 =VBG 标准 -ΔVBG. In chip manufacturing, misalignment is random. Misalignment between VPTAT and VBG does not necessarily mean they are in phase. This article only analyzes the case where they are in phase, and the results are applicable to all situations.
[0095] When the SEL signal is low and the SELB signal is high, the analog-to-digital converter module 300 outputs VPTAT signals. 标准 +ΔVPTAT sampling is maintained and used with VBG 标准 +ΔVBG is used as the reference voltage for quantization, and then stored in the storage and processing circuit 303; similarly, when the SEL signal is high and the SELB signal is low, the analog-to-digital converter module 300 converts VPTAT... 标准 -ΔVPTAT sampling is maintained and used with VBG 标准 -ΔVBG is used as the reference voltage for quantization, and the result is also stored in the storage and processing circuit 303. The two results are summed and averaged in the storage and processing circuit 303. This eliminates the influence of offset voltage on temperature measurement.
[0096] Reference Figure 3 This embodiment provides a thermostat, including a temperature sensing element, a temperature control element, and a temperature variable element.
[0097] The temperature sensing element detects and outputs a temperature value. The temperature control element receives the temperature value output by the temperature sensing element and compares it with a standard temperature value. The temperature variable element receives the signal from the temperature control element and adjusts its own temperature value accordingly.
[0098] The temperature sensing element generates a temperature-related voltage signal, such as a positive temperature coefficient voltage (VPTAT) signal, through the bandgap reference circuit 100. The analog-to-digital converter 300 quantizes the analog voltage signal output by the bandgap reference circuit 100 into a digital signal, and the decoder 200 converts the quantized digital signal into a temperature value TEMP. The temperature control element receives the temperature value TEMP output by the temperature sensing element and compares it with a preset standard temperature value. Based on the comparison result, it calculates the temperature deviation and generates a control signal, such as a heating or cooling signal, to adjust the operating state of the variable temperature element. The variable temperature element changes its own temperature value according to the control signal from the temperature control element to achieve constant temperature. The variable temperature element can be a heater or a cooler, and the temperature is increased or decreased by adjusting the power or flow rate. If it is a heating signal, the heating power is increased or the heater is started; if it is a cooling signal, the cooling power is increased or the cooler is started.
[0099] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of this utility model.
Claims
1. A temperature sensing element, characterized in that: include, The bandgap reference circuit (100) includes a first input terminal connected to a first control source (SEL), and a VPTAT output port and a VBG output port for outputting VPTAT and VBG respectively. The VPTAT output port and the VBG output port are connected to an analog-to-digital converter module (300) and output the VPTAT and VBT values obtained by the second measurement to the analog-to-digital converter module (300). The analog-to-digital converter module (300) includes a sample-and-hold circuit (301) electrically connected to the VPTAT output port, a quantization unit (302) electrically connected between the VBG output port and the sample-and-hold circuit (301), and a storage and processing circuit (303) electrically connected between the quantization unit (302) and the decoder (200). The quantization unit (302) is configured to quantize the VPTAT and VBG signals and transmit the quantized result to the storage and processing circuit (303). The storage and processing circuit (303) is configured to sum and average the quantized result and transmit the result to the decoder (200).
2. The temperature sensing element according to claim 1, characterized in that: The bandgap reference circuit (100) includes a load transistor, an output transistor, and a switching transistor, each of which has two load transistors. The source of the switching transistor is connected to the source of the output transistor, and the drain of the switching transistor is connected to the drain of the output transistor. In this configuration, the source and drain of each switching transistor are respectively connected to different output transistors.
3. The temperature sensing element according to claim 2, characterized in that: The load transistor includes a first MOSFET (M1) and a second MOSFET (M2), and the output transistor includes a third MOSFET (M3) and a fourth MOSFET (M4). The sources of the first MOS transistor (M1) and the second MOS transistor (M2) are both connected to the input power supply. The source of the third MOS transistor (M3) is connected to the drain of the first MOS transistor (M1). The source of the fourth MOS transistor (M4) is connected to the drain of the second MOS transistor (M2).
4. The temperature sensing element according to claim 3, characterized in that: The drain of the fourth MOS transistor (M4) is connected to a resistor (R4), and a first output terminal is provided between the fourth MOS transistor (M4) and the resistor (R4).
5. The temperature sensing element according to claim 4, characterized in that: The drain of the third MOS transistor (M3) is connected to a reference resistor (R3), and a second output terminal is provided between the third MOS transistor (M3) and the reference resistor (R3).
6. The temperature sensing element according to claim 5, characterized in that: The switching transistor includes a fifth MOS transistor (M5) and a sixth MOS transistor (M6). The source of the fifth MOS transistor (M5) is connected to the drain of the first MOS transistor (M1), and the drain of the fifth MOS transistor (M5) is connected between the fourth MOS transistor (M4) and the first output terminal. The source of the sixth MOS transistor (M6) is connected to the drain of the second MOS transistor (M2), and the drain of the sixth MOS transistor (M6) is connected between the third MOS transistor (M3) and the second output terminal.
7. The temperature sensing element according to claim 6, characterized in that: The bandgap reference circuit (100) also includes an operational amplifier (OTA0) and a second control source (SELB). The gates of both the first MOS transistor (M1) and the second MOS transistor (M2) are connected to the output terminal of the operational amplifier (OTA0); The gates of the third MOS transistor (M3) and the fourth MOS transistor (M4) are both connected to the first control source (SEL); The gates of the fifth MOS transistor (M5) and the sixth MOS transistor (M6) are interconnected and both are connected to the second control source (SELB).
8. The temperature sensing element according to claim 4, characterized in that: The bandgap reference circuit (100), analog-to-digital converter (300), and decoder (200) are fabricated using integrated circuit technology.
9. The temperature sensing element according to claim 4, characterized in that: The bandgap reference circuit (100), analog-to-digital converter (300), and decoder (200) are made of corresponding discrete components.
10. A thermostat, comprising the temperature sensing element as described in claim 9, characterized in that: It also includes, A temperature control element, wherein the temperature control element receives the temperature value output by the temperature sensing element and compares it with a standard temperature value; A temperature-changing element is used to receive signals from a temperature-controlling element and change its own temperature value.