CN211178773U - Temperature detection circuit and electronic device - Google Patents
Temperature detection circuit and electronic device Download PDFInfo
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- CN211178773U CN211178773U CN201922247022.9U CN201922247022U CN211178773U CN 211178773 U CN211178773 U CN 211178773U CN 201922247022 U CN201922247022 U CN 201922247022U CN 211178773 U CN211178773 U CN 211178773U
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Abstract
The utility model discloses a temperature detection circuit, which relates to the technical field of temperature detection and comprises a differential circuit, a temperature sensor, a wiring impedance compensation circuit and an amplifying circuit; the differential circuit provides an adjustable constant current source for the temperature sensor, the temperature sensor outputs a temperature detection signal through the wiring impedance compensation circuit and the amplifying circuit, and the wiring impedance compensation circuit is used for compensating voltage errors measured at two ends of the temperature sensor caused by wiring impedance. The embodiment of the utility model provides an electronic equipment including above-mentioned temperature detection circuit is still disclosed. The embodiment of the utility model provides a sampling temperature sensor voltage signal can be through a line impedance compensation circuit (the electric current of line impedance is walked in the compensation) of walking before giving the ADC sampling, and this circuit can compensate and fall the line impedance of walking for it is more accurate to measure.
Description
Technical Field
The embodiment of the utility model provides a temperature detection technical field, concretely relates to temperature detection circuit and electronic equipment are related to.
Background
With the continuous development of integrated circuits, smart devices become thinner and thinner, and have more and more functions, so that the heat dissipation problem gradually becomes a factor affecting the performance of the smart devices. Taking a smart phone as an example, the smart phone has become the most unavailable consumer product for people at present, and with the development of science and technology and the arrival of 5G, the functions of the smart phone are increasingly enhanced, such as photographing, gaming, charging, mobile payment and the like, with the increasing functions of the smart phone, the importance of thermal design of the smart phone is more prominent, and the temperature inevitably becomes a key factor of the thermal design, and particularly in game, video and charging scenes, the smart phone has clear requirements for the temperature of these scenes. The thermal design of the mobile phone needs to be well done, firstly, the temperature of the mobile phone needs to be accurately measured, and the measurement control of the temperature of the smart phone also plays a great role in reducing the power consumption of the mobile phone, protecting the mobile phone and prolonging the service life of the mobile phone. The current temperature detection circuit of the smart phone is a voltage division circuit formed by a fixed resistor R and an NTC resistor, the resistance of the NTC resistor is exponentially reduced along with the temperature rise, a control chip of the smart phone reads the voltage at two ends of the NTC resistor, and the current temperature is reversely deduced through the NTC resistor temperature and a resistance formula, so that the temperature is detected.
This circuit has the following disadvantages:
1. the layout often results in a long trace, and the trace impedance causes a voltage error to be measured across the NTC resistor.
2. The signal sent to the ADC simply passes through a 0.1uf filter capacitor, which can cause inaccuracy in the ADC sampling signal.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model aims to provide a temperature detection circuit and an electronic device, which provide a more accurate temperature measurement scheme.
In a first aspect, an embodiment of the present invention provides a temperature detection circuit, which includes a differential circuit, a temperature sensor, a trace impedance compensation circuit, and an amplification circuit; the differential circuit provides an adjustable constant current source for the temperature sensor, the temperature sensor outputs a temperature detection signal through the wiring impedance compensation circuit and the amplifying circuit, and the wiring impedance compensation circuit is used for compensating voltage errors measured at two ends of the temperature sensor caused by wiring impedance.
In a preferred embodiment, the differential circuit comprises an operational amplifier U1, an operational amplifier U2, a reference voltage source, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5, wherein an inverting input terminal of the operational amplifier U1 is grounded through the resistor R1, and an inverting input terminal of the operational amplifier U1 is further connected to an output terminal of the operational amplifier U1 through the resistor R2; the output end of the operational amplifier U1 is also connected to the first end of the temperature sensor through a resistor R3; the reference voltage source is connected to the output end of an operational amplifier U2 through a resistor R5 and a resistor R4 in sequence, and the non-inverting input end of the operational amplifier U1 is connected between a resistor R5 and a resistor R4; the inverting input end of the operational amplifier U2 is connected to the output end of the operational amplifier U2, the non-inverting input end of the operational amplifier U2 is connected between the resistor R3 and the first end of the temperature sensor, and the second end of the temperature sensor is grounded.
In a preferred embodiment, the resistances of the resistor R1, the resistor R2, the resistor R4 and the resistor R5 are equal.
In a preferred embodiment, the trace impedance compensation circuit includes an operational amplifier U3, a resistor R6, a resistor R7, and a resistor R8, a non-inverting input terminal of the operational amplifier U3 is connected to the first terminal of the temperature sensor through a resistor R8, an inverting input terminal of the operational amplifier U3 is connected to the first terminal of the temperature sensor through a resistor R6, an inverting input terminal of the operational amplifier U3 is further connected to an output terminal of the operational amplifier U3 through a resistor R7, and an output terminal of the operational amplifier U3 is connected to an input terminal of the amplifying circuit;
the wiring between the first end of the temperature sensor and the resistor R6 is equivalent to a first impedance; the wiring between the first end of the temperature sensor and the resistor R8 is equivalent to a second impedance; the wiring between the second end of the temperature sensor and the ground is equivalent to a third impedance, and the wiring impedance compensation circuit forms a compensation circuit for compensating the first impedance, the second impedance and the third impedance.
In a preferred embodiment, the amplification circuit is a first order low pass and gain amplification circuit.
In a preferred embodiment, the amplifying circuit includes a resistor R9, a resistor R10, a resistor R11, a capacitor C1, and an operational amplifier U4, a non-inverting input terminal of the operational amplifier U4 is connected to an output terminal of the trace impedance compensation circuit through a resistor R9, an inverting input terminal of the operational amplifier U4 is grounded through a resistor R10, an inverting input terminal of the operational amplifier U4 is further connected to an output terminal of the operational amplifier U4 through a resistor R11, and an output terminal of the operational amplifier U4 outputs a temperature detection signal; one end of the capacitor C1 is connected between the resistor R9 and the non-inverting input terminal of the operational amplifier U4, and the other end of the capacitor C1 is grounded.
In a preferred embodiment, the temperature sensor is an NTC resistor.
In a second aspect, an embodiment of the present invention discloses an electronic device, which includes the utility model discloses the temperature detection circuit of the first aspect, temperature sensor installs on electronic device's mainboard.
In a preferred embodiment, the electronic device further comprises a CPU, a power management unit and an L ED display function module, wherein a temperature detection signal acquired by the temperature detection circuit is sent to an ADC acquisition IO port of the CPU, the CPU compares the temperature detection signal with a preset temperature threshold, the temperature threshold comprises an upper limit and a lower limit, if the temperature detection signal is greater than the upper limit or less than the lower limit, the CPU controls the electronic device to shut down through the power management unit, and the L ED display function module is connected to the CPU and configured to display the temperature detection signal.
In a preferred embodiment, the electronic device is any one of a mobile phone, a desktop computer, a notebook computer and a tablet computer.
Compared with the prior art, the embodiment of the utility model provides a measure the temperature through the method that provides constant current for temperature sensor, the current value can be adjusted, and is very little, and the consumption of temperature sensor like this also can be very little; before the voltage signal of the sampling temperature sensor is sent to the ADC for sampling, the voltage signal passes through a wiring impedance compensation circuit (current for compensating wiring impedance), and the circuit can compensate the wiring impedance, so that the measurement is more accurate.
Drawings
Fig. 1 is a schematic circuit diagram of a temperature detection circuit of embodiment 1;
fig. 2 is a functional block diagram of an electronic device of embodiment 2.
Detailed Description
Embodiments of the present invention will be further described with reference to the accompanying drawings and specific embodiments, and it should be noted that, in the premise of no conflict, any combination between the embodiments or technical features described below may form a new embodiment. Except as specifically noted, the materials and equipment used in this example are commercially available.
Example 1:
referring to fig. 1, an embodiment of the present invention provides a temperature detection circuit, which includes a differential circuit, a temperature sensor, a trace impedance compensation circuit, and an amplification circuit; the differential circuit provides an adjustable constant current source for the temperature sensor, the temperature sensor outputs a temperature detection signal through the wiring impedance compensation circuit and the amplifying circuit, and the wiring impedance compensation circuit is used for compensating voltage errors measured at two ends of the temperature sensor caused by wiring impedance.
The differential circuit measures the temperature through the method that provides constant current for temperature sensor, and the current value can be adjusted, and the current value can be very little, and like this, temperature sensor's consumption also will be very little the utility model discloses in the embodiment of preferred, temperature sensor adopts NTC resistance Rntc.
Specifically, the differential circuit comprises an operational amplifier U1, an operational amplifier U2, a reference voltage source, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5, wherein the inverting input end of the operational amplifier U1 is grounded through the resistor R1, and the inverting input end of the operational amplifier U1 is also connected to the output end of the operational amplifier U1 through the resistor R2; the output end of the operational amplifier U1 is also connected to the first end of the temperature sensor through a resistor R3; a reference voltage source is connected to the output end of the operational amplifier U2 through a resistor R5 and a resistor R4 in sequence, and the non-inverting input end of the operational amplifier U1 is connected between a resistor R5 and a resistor R4; the inverting input end of the operational amplifier U2 is connected to the output end of the operational amplifier U2, the non-inverting input end of the operational amplifier U2 is connected between the resistor R3 and the first end of the temperature sensor, and the second end of the temperature sensor is grounded.
The value of the current flowing on the temperature sensor is adjusted by adjusting the voltage value of the reference voltage source, and the value of the current is small. Setting the resistances of the resistor R1, the resistor R2, the resistor R4 and the resistor R5 to be equal (here, the amplification factor of the differential amplifier circuit is set to 1, which is convenient for calculation, and the four resistors have different amplification factors, which is not described herein), taking R1R 2R 4R 5R k Ω, R3R 2 k Ω, and the reference voltage is 2.5V as an example, the operational amplifier U1, the resistor R1, the resistor R2, the resistor R4 and the resistor R5 form the differential amplifier circuit, and since the resistances of the resistor R1, the resistor R2, the resistor R4 and the resistor R5 are equal, the amplification factor G of the differential amplifier circuit is 1, which can be obtained by referring to the principles of virtual short and virtual break:
VU1＝G×2.5V+VU2(1)
in equation (1): vU1For the output voltage, V, of U1U2And a voltage output for the operational amplifier U2.
The inverting input terminal and the output terminal of the operational amplifier U2 are connected to form a voltage follower, so that:
VU2＝VU2+＝VU2-(2)
in equation (2): vU2+For the operation amplifier U2 with the same-phase input voltage, VU2-Is the inverting input voltage of the operational amplifier U2.
Voltage across resistor R3:
VR3＝VU1-VU2+(3)
the current flowing through the resistor R3 can be calculated from equations (1), (2), and (3):
I＝VR3/R3＝2.5V/2.5KΩ＝1mA (4)
therefore, the circuit can provide 1mA current for the NTC resistor.
Since the layout often results in a long trace, the trace impedance may cause a voltage error to be measured across the NTC resistor. Therefore, in the preferred embodiment of the present invention, a trace impedance compensation circuit is provided, the trace impedance compensation circuit includes an operational amplifier U3, a resistor R6, a resistor R7 and a resistor R8, a positive phase input terminal of the operational amplifier U3 is connected to the first end of the temperature sensor through a resistor R8, a negative phase input terminal of the operational amplifier U3 is connected to the first end of the temperature sensor through a resistor R6, a negative phase input terminal of the operational amplifier U3 is further connected to an output terminal of the operational amplifier U3 through a resistor R7, and an output terminal of the operational amplifier U3 is connected to an input terminal of the amplifying circuit;
the wiring between the first end of the temperature sensor and the resistor R6 is equivalent to a first impedance; the wiring between the first end of the temperature sensor and the resistor R8 is equivalent to a second impedance; the wiring between the second end of the temperature sensor and the ground is equivalent to a third impedance, and the wiring impedance compensation circuit forms a compensation circuit for compensating the first impedance, the second impedance and the third impedance, so that the measurement is more accurate.
The amplifying circuit adopts a first-order low-pass amplifying circuit with gain, and can well send a sampling signal to an ADC in the CPU for sampling without attenuation. Specifically, the amplifying circuit comprises a resistor R9, a resistor R10, a resistor R11, a capacitor C1 and an operational amplifier U4, a positive phase input end of the operational amplifier U4 is connected to an output end of the trace impedance compensation circuit through a resistor R9, an inverting input end of the operational amplifier U4 is grounded through the resistor R10, an inverting input end of the operational amplifier U4 is further connected to an output end of the operational amplifier U4 through the resistor R11, and an output end of the operational amplifier U4 outputs a temperature detection signal; one end of the capacitor C1 is connected between the resistor R9 and the non-inverting input terminal of the operational amplifier U4, and the other end of the capacitor C1 is grounded. The resistor R9 and the capacitor C1 form a first-order filter circuit. The resistor R10, the resistor R11 and the operational amplifier U4 form an amplifying circuit with gain.
Example 2:
please refer to fig. 2, the electronic device includes necessary components such as a main board, a CPU, a power management unit, a game function module, an L CD display function module, a PCB board on which components of the temperature detection circuit are mounted, and a housing on which the PCB board, an output interface, an indicator light, etc. are mounted, in addition to the temperature detection circuit in the above embodiment, the electronic device may further include other components such as a heat sink, etc. as needed.
If the temperature of the electronic equipment is analyzed to be lower than a preset lower limit or higher than an upper limit value, the CPU can control a power management unit (specifically a power management chip) to close the electronic equipment, or the charging function is controlled through the power management unit, so that the function of protecting the electronic equipment is realized, and the L CD display function module can display the read value of the converted temperature detection signal in real time.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the embodiments of the present invention cannot be limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the embodiments of the present invention are all within the protection scope of the embodiments of the present invention.
Claims (10)
1. A temperature detection circuit is characterized by comprising a differential circuit, a temperature sensor, a wiring impedance compensation circuit and an amplifying circuit; the differential circuit provides an adjustable constant current source for the temperature sensor, the temperature sensor outputs a temperature detection signal through the wiring impedance compensation circuit and the amplifying circuit, and the wiring impedance compensation circuit is used for compensating voltage errors measured at two ends of the temperature sensor caused by wiring impedance.
2. The temperature detection circuit of claim 1, wherein the differential circuit comprises an operational amplifier U1, an operational amplifier U2, a reference voltage source, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R5, wherein an inverting input terminal of the operational amplifier U1 is grounded through a resistor R1, and an inverting input terminal of the operational amplifier U1 is further connected to an output terminal of the operational amplifier U1 through a resistor R2; the output end of the operational amplifier U1 is also connected to the first end of the temperature sensor through a resistor R3; the reference voltage source is connected to the output end of an operational amplifier U2 through a resistor R5 and a resistor R4 in sequence, and the non-inverting input end of the operational amplifier U1 is connected between a resistor R5 and a resistor R4; the inverting input end of the operational amplifier U2 is connected to the output end of the operational amplifier U2, the non-inverting input end of the operational amplifier U2 is connected between the resistor R3 and the first end of the temperature sensor, and the second end of the temperature sensor is grounded.
3. The temperature sensing circuit of claim 2, wherein the resistors R1, R2, R4 and R5 are of equal resistance.
4. The temperature detection circuit according to claim 2, wherein the trace impedance compensation circuit comprises an operational amplifier U3, a resistor R6, a resistor R7 and a resistor R8, a positive phase input terminal of the operational amplifier U3 is connected to the first end of the temperature sensor through a resistor R8, a negative phase input terminal of the operational amplifier U3 is connected to the first end of the temperature sensor through a resistor R6, a negative phase input terminal of the operational amplifier U3 is further connected to an output terminal of the operational amplifier U3 through a resistor R7, and an output terminal of the operational amplifier U3 is connected to an input terminal of the amplification circuit;
the wiring between the first end of the temperature sensor and the resistor R6 is equivalent to a first impedance; the wiring between the first end of the temperature sensor and the resistor R8 is equivalent to a second impedance; the wiring between the second end of the temperature sensor and the ground is equivalent to a third impedance, and the wiring impedance compensation circuit forms a compensation circuit for compensating the first impedance, the second impedance and the third impedance.
5. The temperature sensing circuit of claim 1, wherein the amplification circuit is a first-order low-pass and gain-with amplification circuit.
6. The temperature detection circuit of claim 5, wherein the amplifying circuit comprises a resistor R9, a resistor R10, a resistor R11, a capacitor C1 and an operational amplifier U4, a non-inverting input terminal of the operational amplifier U4 is connected to an output terminal of the trace impedance compensation circuit through a resistor R9, an inverting input terminal of the operational amplifier U4 is grounded after passing through the resistor R10, an inverting input terminal of the operational amplifier U4 is further connected to an output terminal of the operational amplifier U4 through a resistor R11, and an output terminal of the operational amplifier U4 outputs the temperature detection signal; one end of the capacitor C1 is connected between the resistor R9 and the non-inverting input terminal of the operational amplifier U4, and the other end of the capacitor C1 is grounded.
7. The temperature sensing circuit of any of claims 1-6, wherein the temperature sensor is an NTC resistor.
8. An electronic device, comprising the temperature detection circuit according to any one of claims 1 to 7, wherein the temperature sensor is mounted on a main board of the electronic device.
9. The electronic device of claim 8, further comprising a CPU, a power management unit, and an L ED display function module, wherein the temperature detection signal obtained by the temperature detection circuit is sent to an ADC acquisition IO port of the CPU, the CPU compares the temperature detection signal with a preset temperature threshold, the temperature threshold comprises an upper limit and a lower limit, if the temperature detection signal is greater than the upper limit or less than the lower limit, the CPU controls the electronic device to shut down through the power management unit, and the L ED display function module is connected with the CPU and is used for displaying the temperature detection signal.
10. The electronic device of claim 8, wherein the electronic device is any one of a mobile phone, a desktop computer, a notebook computer, and a tablet computer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922247022.9U CN211178773U (en) | 2019-12-16 | 2019-12-16 | Temperature detection circuit and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922247022.9U CN211178773U (en) | 2019-12-16 | 2019-12-16 | Temperature detection circuit and electronic device |
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| Publication Number | Publication Date |
|---|---|
| CN211178773U true CN211178773U (en) | 2020-08-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201922247022.9U Active CN211178773U (en) | 2019-12-16 | 2019-12-16 | Temperature detection circuit and electronic device |
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| CN (1) | CN211178773U (en) |
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