CN208704911U - A kind of three-wire system temperature sensing circuit - Google Patents
A kind of three-wire system temperature sensing circuit Download PDFInfo
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- CN208704911U CN208704911U CN201821203009.2U CN201821203009U CN208704911U CN 208704911 U CN208704911 U CN 208704911U CN 201821203009 U CN201821203009 U CN 201821203009U CN 208704911 U CN208704911 U CN 208704911U
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Abstract
The utility model relates to temperature detection technical fields, more particularly to a kind of three-wire system temperature sensing circuit, it includes constant-current source circuit, sample circuit and differential amplifier circuit, the differential amplifier circuit includes six resistance and amplifier, the connection of one sampled voltage of described first resistor one end and sample circuit, the connection of the in-phase end of the first resistor other end and amplifier, the connection of another sampled voltage of described second resistance one end and sample circuit, the other end of the second resistance and the reverse side of amplifier connect, the connection of the in-phase end of described 3rd resistor one end and amplifier, the other end of 3rd resistor and the ground terminal of amplifier connect, the connection of the reverse side of described 4th resistance one end and amplifier, and the first resistor is identical as the 4th resistance, the second resistance is identical as the resistance value of 3rd resistor, and described first The ratio between resistance and second resistance are 2.This detection circuit detection accuracy is higher.
Description
Technical field
The utility model relates to temperature detection technical field more particularly to a kind of three-wire system temperature sensing circuits.
Background technique
With the development of domestic new-energy automobile, the efficient performance of electric drive system and stability requirement are increasingly stringenter；
And important component one of of the motor as electric drive system, the accurate measurement to its internal stator temperature is judge motor performance one
Item important indicator.The prior art is all to be embedded in a warming resistance in motor stator position to hinder by specific processing circuit
The variation of value is converted into corresponding voltage value, finally, reading this voltage value and calculating to obtain motor particular position inside
Temperature value.
But because prior art motor and electric machine controller installation site are distant, cause line group between the two compared with
Greatly, so that detection accuracy is lower.
Summary of the invention
The technical problem to be solved by the utility model is to provide a kind of higher three-wire system temperature detections of detection accuracy
Circuit.
The technical scheme adopted by the utility model is a kind of three-wire system temperature sensing circuit, it include constant-current source circuit,
Sample circuit and differential amplifier circuit, differential amplifier circuit include first resistor, second resistance, 3rd resistor, the 4th resistance,
One sampled voltage of the 5th resistance, the 6th resistance and amplifier, first resistor one end and sample circuit connects, first resistor
Another sampled voltage of the connection of the in-phase end of the other end and amplifier, second resistance one end and sample circuit connects, the second electricity
The reverse side of the other end of resistance and amplifier connects, and the in-phase end of 3rd resistor one end and amplifier connects, 3rd resistor it is another
The reverse side of the connection of the ground terminal of one end and amplifier, the 4th resistance one end and amplifier connects, the output end of amplifier, the 5th
Resistance, the 6th resistance and ground are sequentially connected, and the other end of the 4th resistance is connected between the 5th resistance and the 6th resistance, amplification
The power supply termination power of device, the ground terminal ground connection of amplifier, and first resistor is identical with the 4th resistance, second resistance and the
The resistance value of three resistance is identical, and the ratio between first resistor and second resistance are 2.
Sample circuit includes PT100 temperature sensor, and first resistor one end is connect with the negative terminal of PT100 temperature sensor,
Second resistance one end is connect with the anode of PT100 temperature sensor, and PT100 temperature sensor ground terminal is grounded.
Constant-current source circuit includes the 7th resistance, the 8th resistance, source of stable pressure and triode, and the 7th resistance one end and power supply connect
It connects, the 7th resistance other end is connect with source of stable pressure input terminal, and source of stable pressure ground terminal ground connection, the collector and power supply of triode connects
It connecing, the base stage of triode is connected between the 7th resistance and source of stable pressure, and the emitter of triode and the output end of source of stable pressure connect,
The connection of the emitter of 8th resistance one end and triode, the 8th resistance other end are connect with the cathode of PT100 temperature sensor.
Second resistance is more than or equal to 100K ohm.
Using the above structure compared with prior art, the utility model has the advantage that using this difference of the application
Amplifying circuit can preferably eliminate line group, so that the accuracy of detection is higher；And constant-current source circuit provides stable electricity
Stream source has completely cut off the influence of power-supply fluctuation and noise to testing result；And it is realized by less component low in high precision
The temperature sensing circuit of error, has saved cost, and sexual valence is relatively high.
Detailed description of the invention
Fig. 1 is the circuit diagram of the utility model three-wire system temperature sensing circuit.
It is as shown in the figure: R1, first resistor；R2, second resistance；R3,3rd resistor；R4, the 4th resistance；R5, the 5th resistance；
R6, the 6th resistance；R7, the 7th resistance；R8, the 8th resistance；R9, the 9th resistance；U1, source of stable pressure；U2, amplifier；Q1, three poles
Pipe；J1, electric wire connecting junction；I0, constant-current source；U1, the first sampled voltage；U2, the second sampled voltage；U0, amplifier output voltage；VCC,
Power supply；C1, first capacitor；C2, the second capacitor.
Specific embodiment
The utility model is described further below in conjunction with attached drawing and specific embodiment, but the utility model is not only
It is limited to following specific embodiments.
As shown, a kind of three-wire system temperature sensing circuit of the application mainly includes three parts, be respectively constant-current source circuit,
Sample circuit and differential amplifier circuit.
Wherein constant-current source circuit includes the 7th resistance R7, the 8th resistance R8, source of stable pressure U1 and triode Q1, the 7th resistance
The one end R7 is connect with power supply VCC, and the 7th resistance R7 other end is connect with source of stable pressure U1 input terminal, source of stable pressure U1 ground terminal ground connection,
The collector of triode Q1 is connect with power supply VCC, and the base stage of triode Q1 is connected to the input of the 7th resistance R7 and source of stable pressure U1
Between end, the emitter of triode Q1 is connect with the output end of source of stable pressure U1, the transmitting of the 8th one end resistance R8 and triode Q1
Pole connection, the 8th resistance R8 other end are connect with the cathode of PT100 temperature sensor.Its working principle is that: pass through source of stable pressure U1
A stable voltage VREF can be exported with triode Q1, VREF is 2.5V in the application, pass through the 8th resistance R8 again later,
A constant-current source is can produce, wherein R8=2.49K, constant-current source IO=VREF/R8=1mA available in this way, then by this
Constant-current source is linked into sample circuit.
Sample circuit, including PT100 temperature sensor and electric wire connecting junction J1, the one end first resistor R1 by electric wire connecting junction J1 with
The negative terminal of PT100 temperature sensor connects, and the one end second resistance R2 is connected by the anode of electric wire connecting junction J1 and PT100 temperature sensor
It connects, and PT100 temperature sensor ground terminal is grounded by electric wire connecting junction J1, and the anode and electric wire connecting junction of PT100 temperature sensor
There are there are line group Rl, PT100 temperature sensing between the negative terminal and electric wire connecting junction J1 of line group Rl, PT100 temperature sensor between J1
There are line group Rl between the ground terminal and electric wire connecting junction J1 of device, line group Rl is bigger with the longer resistance value of line, and PT100 temperature sensor is certainly
Body resistance be Rt, variation with temperature and change.The two sampled voltage U1 obtained by sample circuit available in this way with
U2, coming out from PT100 temperature sensor anode is U1, and coming out from PT100 temperature sensor negative terminal is U2, wherein U1=IO*
(Rt+2Rl), U2=IO*Rl.
Differential amplifier circuit, including first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance
One sampled voltage U1 connection of R5, the 6th resistance R6 and amplifier U2, the one end first resistor R1 and sample circuit, the first electricity
The resistance R1 other end is connect with the in-phase end of amplifier U2, another sampled voltage U2 of the one end second resistance R2 and sample circuit connects
It connects, the other end of second resistance R2 is connect with the reverse side of amplifier U2, the in-phase end of the one end 3rd resistor R3 and amplifier U2
Connection, the other end of 3rd resistor R3 are connect with the ground terminal of amplifier U2, the reverse phase of the 4th one end resistance R4 and amplifier U2
End connection, the output end of amplifier U2, the 5th resistance R5, the 6th resistance R6 and ground are sequentially connected, and the 4th resistance R4's is another
End is connected between the 5th resistance R5 and the 6th resistance R6, the power supply termination power VCC of amplifier U2, the ground terminal of amplifier U2
Ground connection, and first resistor R1 is identical as the 4th resistance R4 resistance value, second resistance R2 is identical as the resistance value of 3rd resistor R3, and first
The ratio between resistance R1 and second resistance R2 are 2.And differential amplifier circuit further includes first capacitor C1, and power supply VCC also passes through first
Capacitor C1 ground connection.In this way through the output voltage for calculating available amplifier be U0=[(R5+R6)/R6] * [(R2+R4)/
(R3+R1)] * (R3/R2) * U1- (R4/R2) * U2 } because the application is by R1=R4=2R2=2R3, it is possible to obtain U0=[(R5
+R6)/R6]*(U1-2*U2)；Then U1=IO* (Rt+2Rl), U2=IO*Rl are brought into above-mentioned equation, available U0=[(R5+
R6)/R6] * Rt*IO, it can thus eliminate influence of the line group Rl to testing result.
The application three-wire system temperature sensing circuit further includes a low-pass filter circuit, it includes the 9th resistance R9 and the
Two capacitor C2, the 9th one end resistance R9 are connect with the output end of amplifier U2, the 9th resistance R9 other end and the second capacitor C2's
One end connection, the other end ground connection of the second capacitor C2.
The total working principle of the application is: when the resistance Rt of PT100 tissue variation with temperature and generate one it is small
When variation, differential amplifier circuit is according to the input of sampled voltage U1 and U2, by amplification factor G=(R5+R6)/R6, obtain UO=
G*Rt*IO because IO is constant-current source, therefore can organize to find out corresponding temperature value with the linear relationship of temperature according to PT100.
Finally, it should be noted that above embodiments are only to illustrate the technical solution of the utility model, rather than its limitations；
Although the utility model is described in detail with reference to the foregoing embodiments, it will be understood by those of skill in the art that its according to
It can so modify to technical solution documented by previous embodiment, or part of technical characteristic is replaced on an equal basis
It changes；And these are modified or replaceed, and the essence of corresponding technical solution is not made to be detached from various embodiments of the utility model technical side
The spirit and scope of case.
Claims (4)
1. a kind of three-wire system temperature sensing circuit, it is characterised in that: it includes constant-current source circuit, sample circuit and differential amplification
Circuit, the differential amplifier circuit include first resistor, second resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th electricity
One sampled voltage of resistance and amplifier, described first resistor one end and sample circuit connects, the first resistor other end with put
Another sampled voltage of the in-phase end connection of big device, described second resistance one end and sample circuit connects, the second resistance
The other end and the reverse side of amplifier connect, the in-phase end of described 3rd resistor one end and amplifier connects, 3rd resistor
The reverse side of the connection of the ground terminal of the other end and amplifier, described 4th resistance one end and amplifier connects, the amplifier
Output end, the 5th resistance, the 6th resistance and ground are sequentially connected, and the other end of the 4th resistance is connected to the 5th resistance and
Between six resistance, the power supply termination power of the amplifier, the ground terminal ground connection of the amplifier, and the first resistor and the
Four resistances are identical, and the second resistance is identical as the resistance value of 3rd resistor, and the ratio between the first resistor and second resistance
It is 2.
2. a kind of three-wire system temperature sensing circuit according to claim 1, it is characterised in that: the sample circuit includes
PT100 temperature sensor, described first resistor one end are connect with the negative terminal of PT100 temperature sensor, described second resistance one end
It is connect with the anode of PT100 temperature sensor, and the PT100 temperature sensor ground terminal is grounded.
3. a kind of three-wire system temperature sensing circuit according to claim 2, it is characterised in that: the constant-current source circuit includes
7th resistance, the 8th resistance, source of stable pressure and triode, described 7th resistance one end connect to power supply, the 7th resistance other end
It is connect with source of stable pressure input terminal, the source of stable pressure ground terminal ground connection, the collector of the triode connects to power supply, triode
Base stage is connected between the 7th resistance and source of stable pressure, and the emitter of triode and the output end of source of stable pressure connect, the 8th electricity
The emitter for hindering one end and triode connects, and the 8th resistance other end is connect with the cathode of PT100 temperature sensor.
4. a kind of three-wire system temperature sensing circuit according to claim 1, it is characterised in that: the second resistance be greater than etc.
In 100K ohm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821203009.2U CN208704911U (en) | 2018-07-27 | 2018-07-27 | A kind of three-wire system temperature sensing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821203009.2U CN208704911U (en) | 2018-07-27 | 2018-07-27 | A kind of three-wire system temperature sensing circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208704911U true CN208704911U (en) | 2019-04-05 |
Family
ID=65940033
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821203009.2U Active CN208704911U (en) | 2018-07-27 | 2018-07-27 | A kind of three-wire system temperature sensing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208704911U (en) |
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2018
- 2018-07-27 CN CN201821203009.2U patent/CN208704911U/en active Active
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