CN206670819U - High-precision charging gun temperature sensing circuit - Google Patents
High-precision charging gun temperature sensing circuit Download PDFInfo
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- CN206670819U CN206670819U CN201621439195.0U CN201621439195U CN206670819U CN 206670819 U CN206670819 U CN 206670819U CN 201621439195 U CN201621439195 U CN 201621439195U CN 206670819 U CN206670819 U CN 206670819U
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Abstract
The utility model discloses a kind of high-precision charging gun temperature sensing circuit, and it includes reference circuit, Wheatstone bridge, high impedance input instrument amplifier and signal isolation circuit；The reference circuit is connected to Wheatstone bridge by reference voltage；Wheatstone bridge connects charging gun and high impedance input instrument amplifier；High impedance input instrument amplifier connection signal isolation circuit, the output end output temperature signal of signal isolation circuit.Reference circuit provides reference voltage for Wheatstone bridge.Thermistor change in resistance in charging gun is converted into the change of voltage by Wheatstone bridge, and then inputting instrument amplifier by high impedance amplifies voltage signal, and MCU is input to finally by signal isolation circuit.This programme is applied to all charging electric vehicle rifles.
Description
Technical field
Charging equipment of electric automobile field is the utility model is related to, more particularly, to a kind of high-precision charging gun temperature detection
Circuit.
Background technology
With becoming increasingly popular for electric automobile, the application of charging system for electric automobile is more and more.In order to meet quickly to fill
The demand of electricity, New-energy electric vehicle is using high voltage, high current mode to charging electric vehicle, the security of its charging process
Most important with reliability, it is a very serious safety problem that wherein charging gun charging process medium temperature, which spends height, GB/T for this
20234-2015《Electric car conduction chargeable connection device》Add charging inlet temp monitoring function.
Pt1000 platinum sensors are the temperature sensors that a kind of resistance value is varied with temperature and changed, because its temperature is steady
The advantages that qualitative good, precision is high and by most of charging gun enterprises use.MCU can only sample to voltage signal, therefore will
The variable quantity that the variable quantity of Pt1000 resistance is accurately converted into voltage is the key of charging gun temperature detection success or not.
There is the scheme that a kind of Wheatstone bridge adds single amplifier in the market, can be to favour because single amplifier input impedance is low
Stone electric bridge impacts, and causes sampling error larger, and sample temperature is inaccurate.
The content of the invention
The utility model is mainly to solve the technology that sampling error present in prior art is big, sample temperature is inaccurate etc.
A kind of problem, there is provided the high-precision charging gun temperature sensing circuit that error is small, reliability is high.
The utility model is mainly what is be addressed by following technical proposals for above-mentioned technical problem：A kind of high accuracy
Charging gun temperature sensing circuit, including reference circuit, Wheatstone bridge, high impedance input instrument amplifier and signal isolation circuit；
The reference circuit is connected to Wheatstone bridge by reference voltage；Wheatstone bridge connects charging gun and high impedance input instrument
Amplifier；High impedance input instrument amplifier connection signal isolation circuit, the output end output temperature signal of signal isolation circuit.
Reference circuit provides reference voltage for Wheatstone bridge.Wheatstone bridge becomes the thermistor resistance in charging gun
Change the change for being converted into voltage, then inputting instrument amplifier by high impedance amplifies voltage signal, finally by signal isolation electricity
Road is input to MCU.
Preferably, the reference circuit includes the 13rd resistance, the 3rd electric capacity and the 5th reference voltage chip；13rd
One end of resistance is connected with system power supply VCC, and the other end of the 13rd resistance is connected with the negative electrode of the 5th reference voltage chip, the
The REF pin of five reference voltage chips are connected with the negative electrode of the 5th reference voltage chip, and the anode of the 5th reference voltage chip is with being
System ground GND_H is connected, and one end of the 3rd electric capacity is connected with the negative electrode of the 5th reference voltage chip, and the other end of the 3rd electric capacity is with being
System ground GND_H is connected, the REF pin connection Wheatstone bridge of the 5th reference voltage chip.
System power supply becomes the reference power supply that precision is high, temperature drift is small all the way that swaps out after resistance and reference voltage chip, should
Reference power supply provides reference voltage for Wheatstone bridge.
Preferably, the Wheatstone bridge, which includes first resistor, second resistance, 3rd resistor, the first transient state, suppresses two
RTD Pt1000 in pole pipe and charging gun；One end of first resistor is connected with reference voltage V REF, and first resistor is in addition
One end is connected with the negative pole of the first Transient Suppression Diode, and the positive pole of the first Transient Suppression Diode is connected with systematically GND_H,
RTD Pt1000 and the first transient voltage suppressor paralleling；One end of second resistance is connected with reference voltage V REF, the second electricity
The other end of resistance is connected with the first end of 3rd resistor, and the second end of 3rd resistor is connected with systematically GND_H；First transient state
Suppress the negative pole of diode and the first end of 3rd resistor is all connected to high impedance input instrument amplifier.
A RTD Pt1000 in three resistance and charging gun forms Wheatstone bridge, will by Wheatstone bridge
The change of Pt1000 resistances is converted into the change of voltage.
Preferably, the high impedance input instrument amplifier includes the 5th resistance, the 6th resistance, the 7th resistance, the 8th electricity
Resistance, the first operational amplifier and the second operational amplifier A unit；5 pin of the first operational amplifier and the first transient state suppress two poles
The negative pole of pipe is connected, and 6 pin of the first operational amplifier are connected with 7 pin of the first operational amplifier, 4 pin of the first operational amplifier
It is connected with systematically GND_H, 8 pin of the first operational amplifier are connected with system power supply VCC, one end of the 6th resistance and the first fortune
7 pin for calculating amplifier are connected, and the other end of the 6th resistance is connected with 3 pin of the second operational amplifier A unit, the 7th resistance
One end is connected with 3 pin of the second operational amplifier A unit, and the other end of the 7th resistance is connected with systematically GND_H；First fortune
3 pin for calculating amplifier are connected with the first end of 3rd resistor, 2 pin of the first operational amplifier and 1 pin of the first operational amplifier
It is connected, one end of the 5th resistance is connected with 1 pin of the first operational amplifier, other end and the second operation amplifier of the 5th resistance
2 pin of device A units are connected, and one end of the 8th resistance is connected with 2 pin of the second operational amplifier A unit, and the 8th resistance is in addition
One end is connected with 1 pin of the second operational amplifier A unit, and 4 pin of the second operational amplifier A unit are connected with systematically GND_H,
8 pin of the second operational amplifier A unit are connected with system power supply VCC, and 1 pin of the second operational amplifier A unit is connected to signal
Isolation circuit.
High impedance input instrument amplifier follows circuit and a differential amplifier circuit including two, and two follow circuit to form
High impedance inputs, and avoids influence of the signal conditioning circuit to Wheatstone bridge, improves sampling precision, then pass through differential amplifier circuit
Signal is amplified.
Preferably, the signal isolation circuit include the 9th resistance, the tenth resistance, the 11st resistance, the 12nd resistance,
First electric capacity, the second electric capacity, the second operational amplifier unit B, the 3rd operational amplifier and the 4th linear optical coupling；9th resistance
One end is connected with high impedance input instrument amplifier, 6 pin phases of the other end of the 9th resistance and the second operational amplifier unit B
Even, 5 pin of the second operational amplifier unit B are connected with systematically GND_H, 7 pin of the second operational amplifier unit B and the tenth electricity
One end of resistance is connected, and the other end of the tenth resistance is connected with 1 pin of the 4th linear optical coupling, and 2 pin of the 4th linear optical coupling are with being
System power supply VCC is connected, and 3 pin of the 4th linear optical coupling are connected with 6 pin of the second operational amplifier unit B, and the 4 of the 4th linear optical coupling
Pin is connected with systematically GND_H；5 pin of the 4th linear optical coupling are connected with systematically GND, 6 pin and the 3rd of the 4th linear optical coupling
2 pin of operational amplifier are connected, and one end of the first electric capacity is connected with 2 pin of the 3rd operational amplifier, the other end of the first electric capacity
It is connected with 1 pin of the 3rd operational amplifier, the 11st resistance is in parallel with the first electric capacity, 3 pin and system of the 3rd operational amplifier
Ground GND is connected, and 8 pin of the 3rd operational amplifier are connected with system power supply VDD, one end and the 3rd operation amplifier of the 12nd resistance
1 pin of device is connected, and the other end of the 12nd resistance is connected with the first end of the second electric capacity, the second end of the second electric capacity and system
Ground GND is connected；The first end of second electric capacity is the output end of signal isolation circuit.
Signal isolation circuit is isolated sampled signal by linear optical coupling, can effectively improve the anti-interference of system
Property.
The beneficial effect that the utility model is brought is, it is proposed that a kind of precision is high, the charging gun temperature of strong interference immunity
(Pt1000) circuit is detected, the device of use is cheap, saves cost, the MCU sample temperature degree of accuracy is got a promotion.
Brief description of the drawings
Fig. 1 is a kind of circuit diagram of the present utility model.
Embodiment
Below by embodiment, and with reference to accompanying drawing, the technical solution of the utility model is described in further detail.
Embodiment：A kind of high-precision charging gun temperature sensing circuit of the present embodiment, as shown in figure 1, including reference circuit,
Wheatstone bridge, high impedance input instrument amplifier and signal isolation circuit.
Described reference circuit includes the 13rd resistance R13, the 3rd electric capacity C3 and the 5th reference voltage chip U5.13rd
Resistance R13 one end is connected with system power supply VCC, the 13rd resistance R13 other end and the 5th reference voltage chip U5 the moon
Extremely it is connected, the 5th reference voltage chip U5 REF pin are connected with the 5th reference voltage chip U5 negative electrode, the 5th reference voltage core
Piece U5 anode is connected with systematically GND_H, and the 3rd electric capacity C3 one end is connected with the 5th reference voltage chip U5 negative electrode, the
The three electric capacity C3 other end is connected with systematically GND_H.
The Wheatstone bridge includes first resistor R1, second resistance R2,3rd resistor R3, RTD Rpt and the first wink
State suppresses diode D1.First resistor R1 one end is connected with reference voltage V REF, first resistor R1 other end and first
Transient Suppression Diode D1 negative pole is connected, and the first Transient Suppression Diode D1 positive pole is connected with systematically GND_H, RTD
Rpt is in parallel with the first Transient Suppression Diode D1.Second resistance R2 one end is connected with reference voltage V REF, second resistance R2's
Other end is connected with 3rd resistor R3 one end, and 3rd resistor R3 other end is connected with systematically GND_H.
The high impedance input instrument amplifier includes the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance
R8, the first operational amplifier U1 and the second operational amplifier U2.First operational amplifier U1 five pin (INB+) and the first transient state
The negative electrode for suppressing diode D1 is connected, seven pin of the pin of the first operational amplifier U1 six (INB-) and the first operational amplifier U1
(OUTB) it is connected, the first operational amplifier U1 four pin (VSS) are connected with systematically GND_H, and the eight of the first operational amplifier U1
Pin (VDD) is connected with system power supply VCC, and the 6th resistance R6 one end is connected with the first operational amplifier U1 seven pin (OUTB),
6th resistance R6 other end is connected with the second operational amplifier U2 three pin (INA+), the 7th resistance R7 one end and second
Operational amplifier U2 three pin (INA+) are connected, and the 7th resistance R7 other end is connected with systematically GND_H.First computing is put
Big device U1 three pin (INA+) are connected with second resistance R2,3rd resistor R3 tie point, the first operational amplifier U1 two pin
(INA-) it is connected with a first operational amplifier U1 pin (OUTA), the 5th resistance R5 one end is with the first operational amplifier U1's
One pin (OUTA) is connected, and the 5th resistance R5 other end is connected with the second operational amplifier U2 two pin (INA-), the 8th electricity
Resistance R8 one end is connected with the second operational amplifier U2 two pin (INA-), and the 8th resistance R8 other end and the second computing are put
The big pin (OUTA) of device U2 mono- are connected, and the second operational amplifier U2 four pin (VSS) are connected with systematically GND_H, and the second computing is put
Big device U2 octal (VDD) is connected with system power supply VCC.
The signal isolation circuit includes the 9th resistance R9, the tenth resistance R10, the 11st resistance R11, the 12nd resistance
R12, the first electric capacity C1, the second electric capacity C2, the second operational amplifier U2, the 3rd amplifier amplifier U3 and the 4th linear optical coupling U4.
9th resistance R9 one end is connected with a second operational amplifier U2 pin (OUTA), the 9th resistance R9 other end and second
The pin of operational amplifier U2 six (INB-) are connected, and the second operational amplifier U2 five pin (INB+) are connected with systematically GND_H, and second
Operational amplifier U2 seven pin (OUTB) are connected with the tenth resistance R10 one end, the tenth resistance R10 other end and the 4th line
Property optocoupler U4 a pin (LED-) be connected, the 4th linear optical coupling U4 two pin (LED+) are connected with system power supply VCC, and the 4th is linear
Optocoupler U4 three pin (PD1-) are connected with the second operational amplifier U2 six pin (INB-), the 4th linear optical coupling U4 four pin (PD1
+) be connected with systematically GND_H.4th linear optical coupling U4 five pin (PD2+) are connected with systematically GND, the 4th linear optical coupling U4
Six pin be connected with the 3rd operational amplifier U3 two pin (INA-), the first electric capacity C1 one end is with the 3rd operational amplifier U3's
Two pin (INA-) are connected, and the first electric capacity C1 other end is connected with a 3rd operational amplifier U3 pin (OUTA), the 11st electricity
Resistance R11 is in parallel with the first electric capacity C1, and the 3rd operational amplifier U3 three pin (INA+) are connected with systematically GND, and the 3rd computing is put
Big device U3 octal (VDD) is connected with system power supply VDD, the 12nd resistance R12 one end and the one of the 3rd operational amplifier U3
Pin (OUTA) is connected, and the 12nd resistance R12 other end is connected with the second electric capacity C2 one end, and other the one of the second electric capacity C2
End is connected with systematically GND.
The computational methods of the high-precision charging gun temperature sensing circuit of the present embodiment are as follows：
1. 2 voltages of Ua, Ub are calculated by Wheatstone bridge：
2. voltage Ua, Ub amplify to obtain voltage Uc by instrument discharge circuit：
3.Uc converts to obtain voltage Ud by linear optical coupling：
Four formula synthesis can obtain Ud final expression formula by more than：
Preferably, R5=R6, R7=R8, R9=R11 are taken, above formula is reduced to：
From above formula, by the size for changing R1, R2, R3, thus it is possible to vary signal magnitude, by the ratio for changing R8, R5
Example can change the multiplication factor of signal.
The utility model proposes the charging gun temperature (Pt1000) of a kind of precision height, strong interference immunity to detect circuit, adopts
Device is cheap, saves cost, has good promotional value.
Specific embodiment described herein is only to the invention spirit explanation for example.The utility model institute
Category those skilled in the art can make various modifications or supplement to described specific embodiment or using similar
Mode substitute, but without departing from principle of the present utility model or surmount scope defined in appended claims.
Although more having used the terms such as reference circuit, high impedance, signal isolation herein, it is not precluded from using other
The possibility of term.It is used for the purpose of more easily describing and explaining essence of the present utility model using these terms；Them
Any additional limitation is construed to all to disagree with the invention spirit.
Claims (3)
1. a kind of high-precision charging gun temperature sensing circuit, it is characterised in that including reference circuit, Wheatstone bridge, high impedance
Input instrument amplifier and signal isolation circuit；The reference circuit is connected to Wheatstone bridge by reference voltage；Favour stone electricity
Bridging connects charging gun and high impedance input instrument amplifier；High impedance input instrument amplifier connection signal isolation circuit, signal isolation
The output end output temperature signal of circuit.
2. high-precision charging gun temperature sensing circuit according to claim 1, it is characterised in that the reference circuit includes
13rd resistance, the 3rd electric capacity and the 5th reference voltage chip；One end of 13rd resistance is connected with system power supply VCC, and the tenth
The other end of three resistance is connected with the negative electrode of the 5th reference voltage chip, the REF pin and the 5th benchmark of the 5th reference voltage chip
The negative electrode of voltage chips is connected, and the anode of the 5th reference voltage chip is connected with systematically GND_H, one end of the 3rd electric capacity and the
The negative electrode of five reference voltage chips is connected, and the other end of the 3rd electric capacity is connected with systematically GND_H, the 5th reference voltage chip
REF pin connect Wheatstone bridge.
3. high-precision charging gun temperature sensing circuit according to claim 2, it is characterised in that the Wheatstone bridge bag
Include the RTD Pt1000 in first resistor, second resistance, 3rd resistor, the first Transient Suppression Diode and charging gun；First
One end of resistance is connected with reference voltage V REF, the other end of first resistor and the negative pole phase of the first Transient Suppression Diode
Even, the positive pole of the first Transient Suppression Diode is connected with systematically GND_H, RTD Pt1000 and the first Transient Suppression Diode
It is in parallel；One end of second resistance is connected with reference voltage V REF, the other end of second resistance and the first end phase of 3rd resistor
Even, the second end of 3rd resistor is connected with systematically GND_H；The negative pole of first Transient Suppression Diode and the first of 3rd resistor
End is all connected to high impedance input instrument amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621439195.0U CN206670819U (en) | 2016-12-26 | 2016-12-26 | High-precision charging gun temperature sensing circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621439195.0U CN206670819U (en) | 2016-12-26 | 2016-12-26 | High-precision charging gun temperature sensing circuit |
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| Publication Number | Publication Date |
|---|---|
| CN206670819U true CN206670819U (en) | 2017-11-24 |
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ID=60357319
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621439195.0U Active CN206670819U (en) | 2016-12-26 | 2016-12-26 | High-precision charging gun temperature sensing circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111765985A (en) * | 2020-06-18 | 2020-10-13 | 杭州棒糖网络科技有限公司 | Circuit and method for realizing high-precision temperature measurement based on 12-bit ADC (analog to digital converter) |
| CN112729641A (en) * | 2020-12-01 | 2021-04-30 | 上海空间推进研究所 | System and method for measuring response time of cold air thruster based on variable dielectric capacitance bridge |
| CN113091773A (en) * | 2021-03-09 | 2021-07-09 | 北京大学 | Zero temperature drift estimation method of Wheatstone bridge type sensor |
-
2016
- 2016-12-26 CN CN201621439195.0U patent/CN206670819U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111765985A (en) * | 2020-06-18 | 2020-10-13 | 杭州棒糖网络科技有限公司 | Circuit and method for realizing high-precision temperature measurement based on 12-bit ADC (analog to digital converter) |
| CN112729641A (en) * | 2020-12-01 | 2021-04-30 | 上海空间推进研究所 | System and method for measuring response time of cold air thruster based on variable dielectric capacitance bridge |
| CN113091773A (en) * | 2021-03-09 | 2021-07-09 | 北京大学 | Zero temperature drift estimation method of Wheatstone bridge type sensor |
| CN113091773B (en) * | 2021-03-09 | 2022-02-01 | 北京大学 | Zero temperature drift estimation method of Wheatstone bridge type sensor |
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