CN211527660U - Accurate temperature measurement circuit - Google Patents
Accurate temperature measurement circuit Download PDFInfo
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- CN211527660U CN211527660U CN201922421153.4U CN201922421153U CN211527660U CN 211527660 U CN211527660 U CN 211527660U CN 201922421153 U CN201922421153 U CN 201922421153U CN 211527660 U CN211527660 U CN 211527660U
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Abstract
The utility model discloses an accurate temperature measurement circuit, including temperature measurement resistance, initial circuit, low temperature circuit, medium temperature circuit, high temperature circuit, low temperature compensating circuit, medium temperature compensating circuit, high temperature compensating circuit, MCU and power. Adopt the utility model discloses, record approximate temperature section through initial circuit, MCU selects the circuit of corresponding temperature section to carry out accurate temperature measurement according to the temperature section, and rethread compensating circuit further compensates, finally can make the total resistance of temperature measurement circuit approach temperature measurement resistance, avoids appearing the condition that several AD values correspond a temperature point to improve the precision of temperature measurement, improve the temperature measurement width.
Description
Technical Field
The utility model relates to a temperature measurement field especially relates to an accurate temperature measurement circuit.
Background
The common temperature sensors for household appliances include NTC, PTC and thermocouple. The NTC is a temperature sensor with resistance value decreasing along with temperature rising and has negative temperature coefficient; the PTC is a temperature sensor with resistance value increasing along with temperature rising and has positive temperature coefficient, which is opposite to the NTC; the detection mode of the thermocouple is different from that of NTC and PTC, and the thermocouple converts a temperature signal into an electromotive force signal.
The temperature is detected by a traditional temperature measuring instrument singlechip according to the following principle: the singlechip detects the voltage value of the IO port, and the voltage value (electromotive force signal) is converted into an 8-bit AD value which can be read by the singlechip through AD conversion of the IO port, the AD value of the singlechip rises along with the rise of the voltage value (electromotive force signal), the resistance value of the temperature sensor is obtained through circuit analysis, and then the temperature value is converted through a resistance stability table of the temperature sensor to achieve the purpose of temperature measurement.
However, the existing temperature measuring circuit has inaccurate temperature measurement, or only one temperature section is accurate, so that the high temperature section is accurate and the low temperature section is inaccurate; or the low temperature section is accurate, the high temperature section is inaccurate, and in the inaccurate temperature section, the condition that a plurality of AD values correspond to one temperature point can occur, so that the temperature measurement is not accurate enough.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that a difficult problem that the accurate temperature measurement circuit can't be at the accurate temperature measurement of full temperature section can be solved to the current temperature measurement circuit is provided.
In order to solve the technical problem, the utility model provides an accurate temperature measurement circuit, which comprises a temperature measurement resistor, an initial circuit, a low temperature circuit, a medium temperature circuit, a high temperature circuit, a low temperature compensation circuit, a medium temperature compensation circuit, a high temperature compensation circuit, a MCU and a power supply; the initial circuit comprises an initial resistor and an initial switch, one end of the initial resistor is connected with the power supply, the other end of the initial resistor is connected with the temperature measuring resistor through the initial switch, and the initial switch is also connected with the MCU; the low-temperature circuit comprises a low-temperature resistor and a low-temperature switch, one end of the low-temperature resistor is connected with the power supply, the other end of the low-temperature resistor is connected with the temperature measuring resistor through the low-temperature switch, and the low-temperature switch is also connected with the MCU; the medium-temperature circuit comprises a medium-temperature resistor and a medium-temperature switch, one end of the medium-temperature resistor is connected with the power supply, the other end of the medium-temperature resistor is connected with the temperature measuring resistor through the medium-temperature switch, and the medium-temperature switch is also connected with the MCU; the high-temperature circuit comprises a high-temperature resistor and a high-temperature switch, one end of the high-temperature resistor is connected with the power supply, the other end of the high-temperature resistor is connected with the temperature measuring resistor through the high-temperature switch, and the high-temperature switch is also connected with the MCU; the low-temperature compensation circuit comprises at least one low-temperature compensation resistor, one end of the low-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the low-temperature compensation resistor is connected with the MCU; the medium-temperature compensation circuit comprises at least one medium-temperature compensation resistor, one end of the medium-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the medium-temperature compensation resistor is connected with the MCU; the high-temperature compensation circuit comprises at least one high-temperature compensation resistor, one end of the high-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the high-temperature compensation resistor is connected with the MCU; one end of the temperature measuring resistor is grounded, and the other end of the temperature measuring resistor is connected with the MCU.
Preferably, the accurate temperature measuring circuit further comprises a voltage follower, and the temperature measuring resistor is connected with the MCU through the voltage follower.
Preferably, the accurate temperature measurement circuit further comprises a filter capacitor, one end of the filter capacitor is grounded, and the other end of the filter capacitor is connected to a node between the voltage follower and the MCU.
Preferably, the filter capacitor is a patch capacitor.
Preferably, the accurate temperature measurement circuit further comprises a voltage stabilization module, wherein one end of the voltage stabilization module is connected with the power supply, and the other end of the voltage stabilization module is connected with the initial resistor, the low-temperature resistor, the medium-temperature resistor and the high-temperature resistor respectively.
Preferably, the temperature measuring resistor is an NTC thermistor.
Preferably, the NTC thermistor is connected to the accurate temperature measuring circuit through a socket, the socket includes a first pin and a second pin, the first pin is connected to a power supply through a pull-up resistor, and the second pin is grounded.
Preferably, the socket is XH-2.54-2P.
Preferably, the MCU is BS86C 08C.
Preferably, the initial switch, the low-temperature switch, the medium-temperature switch and the high-temperature switch are all triodes.
Implement the utility model has the advantages that:
the utility model provides an accurate temperature measurement circuit records approximate temperature section through initial circuit, and MCU selects the circuit of corresponding temperature section to carry out accurate temperature measurement according to the temperature section, and rethread compensating circuit further compensates, finally can make the total resistance of temperature measurement circuit approach temperature measurement resistance, avoids appearing the condition that several AD values correspond a temperature point to improve the precision of temperature measurement, improve the temperature measurement width.
Drawings
Fig. 1 is a first circuit block diagram of the accurate temperature measurement circuit provided by the present invention;
fig. 2 is a second circuit block diagram of the accurate temperature measuring circuit provided by the utility model.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings. It is only noted that the invention is intended to be limited to the specific forms set forth herein, including any reference to the drawings, as well as any other specific forms of embodiments of the invention.
As shown in fig. 1, the utility model provides a first circuit block diagram of accurate temperature measurement circuit, including temperature measurement resistance 1, initial circuit, low temperature circuit, medium temperature circuit, high temperature circuit, low temperature compensating circuit, medium temperature compensating circuit, high temperature compensating circuit, MCU2 and power 3.
The initial circuit comprises an initial resistor 4 and an initial switch 5, one end of the initial resistor 4 is connected with the power supply 3, the other end of the initial resistor 4 is connected with the temperature measuring resistor 1 through the initial switch 5, and the initial switch 5 is further connected with the MCU2(d port).
The low-temperature circuit comprises a low-temperature resistor 6 and a low-temperature switch 7, one end of the low-temperature resistor 6 is connected with the power supply 3, the other end of the low-temperature resistor is connected with the temperature measuring resistor 1 through the low-temperature switch 7, and the low-temperature switch 7 is further connected with the MCU2(a port).
The medium-temperature circuit comprises a medium-temperature resistor 8 and a medium-temperature switch 9, one end of the medium-temperature resistor 8 is connected with the power supply 3, the other end of the medium-temperature resistor is connected with the temperature measuring resistor 1 through the medium-temperature switch 9, and the medium-temperature switch 9 is further connected with the MCU2(b port).
The high-temperature circuit comprises a high-temperature resistor 10 and a high-temperature switch 11, one end of the high-temperature resistor 10 is connected with the power supply 3, the other end of the high-temperature resistor is connected with the temperature measuring resistor 1 through the high-temperature switch 11, and the high-temperature switch 11 is further connected with the MCU2(c port).
The low-temperature compensation circuit comprises at least one low-temperature compensation resistor 12, one end of the low-temperature compensation resistor 12 is connected with the temperature measuring resistor, and the other end of the low-temperature compensation resistor 12 is connected with the MCU.
The medium temperature compensation circuit comprises at least one medium temperature compensation resistor 13, one end of the medium temperature compensation resistor 13 is connected with the temperature measuring resistor, and the other end of the medium temperature compensation resistor 13 is connected with the MCU.
The high-temperature compensation circuit comprises at least one high-temperature compensation resistor 14, one end of the high-temperature compensation resistor 14 is connected with the temperature measuring resistor, and the other end of the high-temperature compensation resistor is connected with the MCU.
One end of the temperature measuring resistor 1 is grounded, and the other end of the temperature measuring resistor is connected with the MCU.
The utility model discloses, earlier record approximate temperature section through initial circuit, MCU selects the circuit of corresponding temperature section to carry out accurate temperature measurement according to the temperature section, and rethread compensating circuit further compensates, finally can make the total resistance of temperature measurement circuit approach temperature measurement resistance, avoids appearing the condition that several AD values correspond a temperature point to improve the precision of temperature measurement, improve the temperature measurement width.
It should be noted that, the MCU changes the connection mode of the circuit by changing the state of the MCU port, for example, when RTC thermistor is used for temperature measurement, the low temperature section is 0-100 ℃, the medium temperature section is 101-200 ℃, the high temperature section is 201-300 ℃, the resistance at 50 ℃ of the temperature measurement resistor is selected as the low temperature resistance by looking up the table, the resistance at 150 ℃ of the temperature measurement resistor is selected as the medium temperature resistance, the resistance at 250 ℃ of the temperature measurement resistor is selected as the high temperature resistance, in the temperature measurement stage, the MCU sets the high level at the initial switch port, the initial switch is turned on, the temperature measurement enters the initial circuit to measure the temperature, the measured temperature is 100 ℃, therefore, the MCU sets the high level at the low temperature switch port, the low temperature switch is turned on, the temperature measurement stage enters the low temperature circuit, because the resistance at 100 ℃ of the temperature measurement resistor has a large difference with the resistances at 50 ℃ and 150 ℃, the temperature measurement accuracy does not meet, the low-temperature compensation resistor and the low-temperature resistor are connected in parallel, so that the resistance of the parallel total resistor is close to the resistance of the temperature measuring resistor at 100 ℃, and the temperature measuring precision is improved. The mode is also adopted in other temperature sections to carry out circuit compensation, and in the high temperature section, the high temperature compensation resistance can be continuously increased to improve the high temperature section measuring range of the temperature measuring circuit, so that the temperature measuring circuit has higher temperature measurement. Additionally, the utility model discloses a low temperature compensation resistance generally equals with low temperature resistance, and medium temperature compensation resistance generally equals with medium temperature resistance, and high temperature compensation resistance generally equals with high temperature resistance, therefore only need according to particular case, the quantity N that increases and decreases compensation resistance through the state that MCU changed the compensation resistance port, parallelly connected total resistance just equals dividing (N +1) of corresponding temperature measurement circuit resistance for parallelly connected total resistance can with temperature measurement resistance's resistance is equivalent, but not limited to this.
As shown in FIG. 2, the utility model provides an accurate temperature measurement circuit second circuit block diagram, accurate temperature measurement circuit still includes voltage follower 17, temperature measuring resistor passes through voltage follower 17 with MCU connects. By introducing the voltage follower 17, the current limiting effect is achieved, the normal work of the MCU is protected, the influence of other resistors in the MCU circuit on the temperature measuring circuit is avoided, and the temperature measuring precision is improved.
Preferably, the accurate temperature measuring circuit further comprises a filter capacitor 16, one end of the filter capacitor 16 is grounded, and the other end of the filter capacitor 16 is connected to a node between the voltage follower 17 and the MCU. The filter capacitor can filter out circuit clutter signals and reduce the error influence on the temperature measurement of the MCU. Further, the filter capacitor is a patch capacitor, but is not limited thereto.
Preferably, the accurate temperature measurement circuit further comprises a voltage stabilization module 15, wherein one end of the voltage stabilization module 15 is connected with the power supply 2, and the other end of the voltage stabilization module 15 is connected with the initial resistor 4, the low-temperature resistor 6, the medium-temperature resistor 8 and the high-temperature resistor 10 respectively. The voltage stabilizing module is used for stabilizing the working voltage of the temperature measuring circuit and avoiding errors caused by fluctuation of the power supply voltage.
Preferably, the temperature measuring resistor is an NTC thermistor. Furthermore, the NTC thermistor is connected to the accurate temperature measuring circuit through a socket, the socket comprises a first pin and a second pin, the first pin is connected with a power supply through a pull-up resistor, and the second pin is grounded. More preferably, the socket is XH-2.54-2P, but is not limited thereto.
Preferably, the initial switch, the low-temperature switch, the medium-temperature switch and the high-temperature switch are all triodes.
Preferably, the MCU is BS86C08C, but is not limited thereto, and the present invention is applicable to any control chip capable of implementing the above functions.
To sum up, this practicality measures roughly the temperature section through initial circuit, and MCU selects the circuit of corresponding temperature section to carry out accurate temperature measurement according to the temperature section, and rethread compensating circuit further compensates, finally can make temperature measurement circuit's total resistance be close to temperature measurement resistance, avoids appearing the condition that several AD values correspond a temperature point to improve the precision of temperature measurement, improve the temperature measurement width. Meanwhile, the measuring range of temperature measurement can be improved, and a higher temperature measuring range is achieved. In addition, the temperature measurement precision can be further improved through the voltage follower, the filter capacitor and the voltage stabilizing module.
The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many modifications and decorations can be made without departing from the principle of the invention, and these modifications and decorations are also regarded as the protection scope of the present invention.
Claims (10)
1. An accurate temperature measurement circuit is characterized by comprising a temperature measurement resistor, an initial circuit, a low-temperature circuit, a medium-temperature circuit, a high-temperature circuit, a low-temperature compensation circuit, a medium-temperature compensation circuit, a high-temperature compensation circuit, an MCU and a power supply;
the initial circuit comprises an initial resistor and an initial switch, one end of the initial resistor is connected with the power supply, the other end of the initial resistor is connected with the temperature measuring resistor through the initial switch, and the initial switch is also connected with the MCU;
the low-temperature circuit comprises a low-temperature resistor and a low-temperature switch, one end of the low-temperature resistor is connected with the power supply, the other end of the low-temperature resistor is connected with the temperature measuring resistor through the low-temperature switch, and the low-temperature switch is also connected with the MCU;
the medium-temperature circuit comprises a medium-temperature resistor and a medium-temperature switch, one end of the medium-temperature resistor is connected with the power supply, the other end of the medium-temperature resistor is connected with the temperature measuring resistor through the medium-temperature switch, and the medium-temperature switch is also connected with the MCU;
the high-temperature circuit comprises a high-temperature resistor and a high-temperature switch, one end of the high-temperature resistor is connected with the power supply, the other end of the high-temperature resistor is connected with the temperature measuring resistor through the high-temperature switch, and the high-temperature switch is also connected with the MCU;
the low-temperature compensation circuit comprises at least one low-temperature compensation resistor, one end of the low-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the low-temperature compensation resistor is connected with the MCU;
the medium-temperature compensation circuit comprises at least one medium-temperature compensation resistor, one end of the medium-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the medium-temperature compensation resistor is connected with the MCU;
the high-temperature compensation circuit comprises at least one high-temperature compensation resistor, one end of the high-temperature compensation resistor is connected with the temperature measuring resistor, and the other end of the high-temperature compensation resistor is connected with the MCU;
one end of the temperature measuring resistor is grounded, and the other end of the temperature measuring resistor is connected with the MCU.
2. The accurate temperature measurement circuit according to claim 1, further comprising a voltage follower, wherein the temperature measurement resistor is connected to the MCU through the voltage follower.
3. The accurate temperature measurement circuit of claim 2, further comprising a filter capacitor, wherein one end of the filter capacitor is grounded, and the other end of the filter capacitor is connected to a node between the voltage follower and the MCU.
4. The accurate temperature measurement circuit of claim 3, wherein the filter capacitor is a patch capacitor.
5. The accurate temperature measuring circuit according to claim 1, further comprising a voltage stabilizing module, wherein one end of the voltage stabilizing module is connected to the power supply, and the other end of the voltage stabilizing module is connected to the initial resistor, the low temperature resistor, the medium temperature resistor and the high temperature resistor.
6. The accurate temperature measuring circuit according to any one of claims 1 to 5, wherein the temperature measuring resistor is an NTC thermistor.
7. The accurate temperature measurement circuit of claim 6, wherein the NTC thermistor is connected to the accurate temperature measurement circuit through a socket, the socket comprises a first pin and a second pin, the first pin is connected to a power supply through a pull-up resistor, and the second pin is connected to ground.
8. The accurate temperature measurement circuit of claim 7, wherein the socket is XH-2.54-2P.
9. The accurate temperature measurement circuit of claim 8, wherein the MCU is BS86C 08C.
10. The accurate temperature measurement circuit of claim 9, wherein the initial switch, the low temperature switch, the medium temperature switch, and the high temperature switch are all transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922421153.4U CN211527660U (en) | 2019-12-27 | 2019-12-27 | Accurate temperature measurement circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922421153.4U CN211527660U (en) | 2019-12-27 | 2019-12-27 | Accurate temperature measurement circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211527660U true CN211527660U (en) | 2020-09-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922421153.4U Active CN211527660U (en) | 2019-12-27 | 2019-12-27 | Accurate temperature measurement circuit |
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| Country | Link |
|---|---|
| CN (1) | CN211527660U (en) |
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2019
- 2019-12-27 CN CN201922421153.4U patent/CN211527660U/en active Active
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