CN106370319A - Temperature detection circuit - Google Patents
Temperature detection circuit Download PDFInfo
- Publication number
- CN106370319A CN106370319A CN201610806097.4A CN201610806097A CN106370319A CN 106370319 A CN106370319 A CN 106370319A CN 201610806097 A CN201610806097 A CN 201610806097A CN 106370319 A CN106370319 A CN 106370319A
- Authority
- CN
- China
- Prior art keywords
- controlled switch
- resistance
- sensing circuit
- temperature sensing
- critesistor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
- G01K7/24—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor in a specially-adapted circuit, e.g. bridge circuit
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- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
The invention discloses a temperature detection circuit. The temperature detection circuit comprises a temperature detection unit comprising a thermistor and a fixed resistor which are in series connection, a first controlled switch, a second controlled switch, an amplification switch and a voltage detection unit, wherein one end of the first controlled switch is connected between the thermistor and the fixed resistor, the other end of the first controlled switch is connected with the voltage detection unit, one end of the second controlled switch is connected between the thermistor and the fixed resistor, one end of the amplification unit is connected with the other end of the second controlled switch, the other end of the amplification unit is connected with the voltage detection unit, the first controlled switch is made to realize closing when the voltage detection unit starts detection, when voltage variation amplitude is detected to be lower than a preset threshold, the first controlled switch is made to realize disconnection, and the second controlled switch is made to to realize closing. Through the temperature detection circuit, detection precision is improved when resistance change of the thermistor is not obvious, and detection precision is more uniform.
Description
Technical field
The present invention relates to temperature detection technical field is and in particular to a kind of temperature sensing circuit.
Background technology
Critesistor is the resistance that its resistance a kind of can change with temperature, is frequently used for temperature detection.A kind of existing
Temperature sensing circuit, as shown in figure 1, including critesistor 11 and the fixed resistance 12 of series connection, be connected on power supply vcc and ground
Between, take the voltage on fixed resistance to obtain ad value by analog digital conversion, Current Temperatures can be calculated by ad value.Due to temperature-sensitive
Resistance variation with temperature is not linear, so resistance in a certain section of temperature range for the temperature sensing circuit of this type
Value changes can clearly, but change just not in other temperature ranges (especially away from the obvious temperature range of temperature change)
Substantially, thus leading to the uneven of accuracy of detection.
Content of the invention
Therefore, the technical problem to be solved in the present invention is, the accuracy of detection of the temperature sensing circuit based on critesistor
Uneven.
For this reason, embodiments providing a kind of temperature sensing circuit, comprising: temperature measuring unit, including be connected in series
Critesistor and fixed resistance；First controlled switch, its one end is connected between described critesistor and described fixed resistance, separately
One end is connected with voltage detection unit；Second controlled switch, its one end be connected to described critesistor and described fixed resistance it
Between；Amplifying unit, its one end is connected with the other end of described second controlled switch, and the other end is connected with voltage detection unit；Electricity
Pressure detector unit, makes described first controlled switch closure, is less than predetermined threshold when variation in voltage amplitude is detected when starting detection
During value, so that described first controlled switch is disconnected and make described second controlled switch closure.
Preferably, described voltage detection unit, when variation in voltage amplitude is detected more than or equal to described predetermined threshold,
So that described first controlled switch is closed and so that described second controlled switch is disconnected.
Preferably, described first controlled switch is audion；And/or second controlled switch be audion.
Preferably, described first controlled switch and described second controlled switch are the audions of different conduction voltage drops.
Preferably, described amplifying unit includes operational amplifier, the resistance value resistance for r3 and resistance value is the resistance of r4,
The in-phase input end of described operational amplifier is connected with the described other end of described second controlled switch, described operational amplifier
Outfan is connected with described voltage detection unit, described resistance value be r4 resistance two ends respectively with described operational amplifier
Inverting input and described voltage detection unit connect, described resistance value be the resistance of r3 two ends respectively with described operation amplifier
The inverting input of device and earth terminal connect.
Preferably, described critesistor is ntc critesistor.
Preferably, described temperature sensing circuit includes current-limiting resistance, and it is solid with described that its one end is connected to described critesistor
Determine between resistance, the other end is connected with described first controlled switch and described second controlled switch.
Preferably, described temperature sensing circuit includes the first diode, its positive terminal and described first controlled switch and institute
State amplifying unit to connect, its negative pole end is connected with power supply.
Preferably, described temperature sensing circuit includes the second diode, its positive terminal with and described amplifying unit be connected, its
Negative pole end is connected with the positive terminal of described first diode.
Preferably, described first diode and the second diode are the diodes of different pressure drops.
The temperature sensing circuit of the embodiment of the present invention, when the change in resistance of critesistor is inconspicuous, that is, works as voltage detecting
When unit detects variation in voltage amplitude less than predetermined threshold, amplifying unit is made to turn on, thus improve the resistance in critesistor
Accuracy of detection when value changes are inconspicuous so that accuracy of detection evenly.
Brief description
In order to be illustrated more clearly that the specific embodiment of the invention or technical scheme of the prior art, below will be to concrete
In embodiment or description of the prior art the accompanying drawing of required use be briefly described it should be apparent that, below describe in
Accompanying drawing is some embodiments of the present invention, for those of ordinary skill in the art, before not paying creative work
Put, other accompanying drawings can also be obtained according to these accompanying drawings.
Fig. 1 is a kind of theory diagram of existing temperature sensing circuit；
Fig. 2 is a kind of theory diagram of temperature sensing circuit of the embodiment of the present invention；
Fig. 3 is a kind of circuit diagram of temperature sensing circuit of the embodiment of the present invention.
Specific embodiment
Below in conjunction with accompanying drawing, technical scheme is clearly and completely described with the enforcement it is clear that described
Example is a part of embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, ordinary skill
The every other embodiment that personnel are obtained under the premise of not making creative work, broadly falls into the scope of protection of the invention.
In describing the invention, it should be noted that term " " center ", " on ", D score, "left", "right", " vertical ",
The orientation of instruction such as " level ", " interior ", " outward " or position relationship are based on orientation shown in the drawings or position relationship, merely to
Be easy to describe the present invention and simplify description, rather than instruction or the hint device of indication or element must have specific orientation,
With specific azimuth configuration and operation, therefore it is not considered as limiting the invention.Additionally, term " first ", " second ",
" the 3rd " is only used for describing purpose, and it is not intended that indicating or hint relative importance.
In describing the invention, it should be noted that unless otherwise clearly defined and limited, term " installation ", " phase
Even ", " connection " should be interpreted broadly, for example, it may be being fixedly connected or being detachably connected, or is integrally connected；Can
To be to be mechanically connected or electrical connection；Can be to be joined directly together it is also possible to be indirectly connected to by intermediary, acceptable
It is the connection of two element internals, can be wireless connection or wired connection.For those of ordinary skill in the art
For, above-mentioned term concrete meaning in the present invention can be understood with concrete condition.
As long as additionally, the non-structure each other of involved technical characteristic in invention described below different embodiments
Become conflict just can be combined with each other.
Embodiment 1
As shown in Fig. 2 a kind of temperature sensing circuit of the embodiment of the present invention, comprising:
Temperature measuring unit 1, including the critesistor 11 being connected in series and fixed resistance 12, this critesistor is preferably ntc heat
Quick resistance, the uniformity of its resistance and temperature characterisitic is good, and temperature change can be responded rapidly to, and can carry out high sensitivity, high-precision
The detection of degree；The effect of this fixed resistance is partial pressure, and the voltage got is: vcc*r12/(r12+r11), wherein vcc is and temperature-sensitive
The voltage of the power supply that resistance 11 connects, r11And r12It is critesistor 11 and the resistance of fixed resistance 12 respectively；
First controlled switch 2, its one end is connected between this critesistor 11 and this fixed resistance 12, the other end and voltage
Detector unit 5 connects；
Second controlled switch 3, its one end is connected between this critesistor 11 and this fixed resistance 12；
Amplifying unit 4, its one end is connected with the other end of this second controlled switch 3, and the other end is with voltage detection unit 5 even
Connect；
Voltage detection unit 5, start detection when make this first controlled switch close, the voltage now detecting be without
The primary voltage amplifying, when variation in voltage amplitude is detected less than predetermined threshold, the change in resistance being considered as critesistor is failed to understand
Aobvious, so that this first controlled switch is disconnected and so that this second controlled switch is closed, the voltage now detecting is that amplified unit is put
Serious offense.
Specifically, the change in resistance of critesistor is inconspicuous, refers to often rise 1 degree when temperature, and its change in resistance is less than 1k,
And when change in resistance is more than or equal to 1k then it is assumed that the change in resistance of critesistor is obvious.Thus, it is possible to obtain corresponding voltage
The predetermined threshold of change, this predetermined threshold is, for example, the ad value that voltage is obtained by analog digital conversion.
The temperature sensing circuit of the embodiment of the present invention, by when the change in resistance of critesistor is inconspicuous, that is, working as voltage
When detector unit detects variation in voltage amplitude less than predetermined threshold, amplifying unit is made to turn on, thus improve in critesistor
Change in resistance inconspicuous when accuracy of detection so that accuracy of detection evenly.
Preferably, this voltage detection unit when detect variation in voltage amplitude be more than or equal to this predetermined threshold when, that is, when
When the change in resistance of critesistor is considered to change obvious, so that this first controlled switch is closed and so that this second controlled switch is broken
Open, voltage is not amplified.
Preferably, the first controlled switch and/or the second controlled switch are audions.For example, this first controlled switch is permissible
It is that high level is open-minded, low level is closed；This second controlled switch can be that low level is open-minded, and high level is closed.
Preferably, this first controlled switch and this second controlled switch are the audions of different conduction voltage drops, can save
Cost.
Preferably, this amplifying unit includes operational amplifier, the resistance value resistance for r3 and resistance value is the resistance of r4, should
The in-phase input end of operational amplifier is connected with this other end of this second controlled switch, the outfan of this operational amplifier with should
Voltage detection unit connects, and this resistance value is two ends inverting input and this electricity with this operational amplifier respectively of the resistance of r4
Pressure detector unit connects, and this resistance value is two ends inverting input and the earth terminal with this operational amplifier respectively of the resistance of r3
Connect.
Preferably, also include current-limiting resistance r2, its one end is connected between this critesistor and this fixed resistance, the other end
It is connected with this first controlled switch and this second controlled switch, for limiting the size of electric current, in case excessive the burning out of electric current is gone here and there
The components and parts of connection.
Preferably, also include the first diode, its positive terminal is connected with this first controlled switch and this amplifying unit, it is born
Extremely it is connected with power supply.This first diode does not typically turn on, only when abnormal conditions occur, the resistance of such as critesistor
Value changes are very big, or when the output voltage of this first controlled switch and/or this amplifying unit exceedes supply voltage, this first
Diode just can turn on it is ensured that the voltage that receives of voltage detection unit is not over supply voltage, and chip port will not damage.
Preferably, also include the second diode, its positive terminal with and this amplifying unit be connected, its negative pole end and the one or two
The positive terminal of pole pipe connects.
Preferably, this first diode and the second diode are the diodes of different pressure drops, with cost-effective.
Embodiment 2
With a specific embodiment continuation, the present invention will be described below.
In the present embodiment as shown in Figure 3, critesistor ntc1 mono- termination power vcc, one end is gone here and there with fixed resistance r1
Connection, the other end ground connection of fixed resistance r1.One end of current-limiting resistance r2 is connected between critesistor ntc1 and fixed resistance r1,
The other end is connected with audion q1 (e.g. 8050) and q2 (e.g. 8550), and the voltage of the other end of this current-limiting resistance r2 is
Ua, ua are also the input voltage of q1 and q2.The i/o all with main ic (being equivalent to voltage detection unit) for the base stage of audion q1 and q2
Mouth is selected to connect, when " i/o selects mouth " is output as 1 (high level), q1 turns on, and q2 closes, when " i/o selects mouth " is (low for 0
Level) when, q2 turns on, and q1 closes.The outfan of audion q2 is directly connected to the i/o ad mouth of main ic, and output voltage is un.
The outfan output voltage of audion q1 is ui, is connected with amplifying unit, amplifying unit includes operational amplifier lm358a, resistance
R4 and r3, the amplification of this discharge cell is (1+r4/r3).This amplifying unit passes through the i/o ad mouth of diode d2 and main ic
Connect, its output voltage is uf.Diode d1 is arranged between i/o ad mouth and power supply vcc.
During work, after complete machine powering, i/o first selects mouth to export 0 (low level), and q2 turns on, and q1 closes, now uad=
un, and un=ua–vq2ce, wherein, vq2ceBe triode q2 conducting after tube voltage drop.
Main ic is by the u detectingadBe converted to ad value, as the foundation judging critesistor resistance variations amplitude.Work as detection
It is less than during predetermined threshold value it is believed that critesistor resistance variations are inconspicuous to ad value, needs to be amplified, then i/o selects mouth output 1
(high level), q1 turns on, and q2 closes, now uad=uf=ui*(1+r4/r3)-vd2, wherein, vd2It is the tube voltage drop of diode d2.
And when ad value is detected and being more than or equal to predetermined threshold value it is believed that critesistor resistance variations are substantially it is not necessary to be amplified, i/o
Mouth is selected to export 0 (low level), q2 turns on, q1 closes, now uad=un.
Obviously, above-described embodiment is only intended to clearly illustrate example, and the not restriction to embodiment.Right
For those of ordinary skill in the art, can also make on the basis of the above description other multi-forms change or
Change.There is no need to be exhaustive to all of embodiment.And the obvious change thus extended out or
Change among still in the protection domain of the invention.
Claims (10)
1. a kind of temperature sensing circuit is it is characterised in that include:
Temperature measuring unit, including the critesistor being connected in series and fixed resistance；
First controlled switch, its one end is connected between described critesistor and described fixed resistance, the other end and voltage detecting
Unit connects；
Second controlled switch, its one end is connected between described critesistor and described fixed resistance；
Amplifying unit, its one end is connected with the other end of described second controlled switch, and the other end is connected with voltage detection unit；
Voltage detection unit, makes described first controlled switch closure, is less than when variation in voltage amplitude is detected when starting detection
During predetermined threshold, so that described first controlled switch is disconnected and make described second controlled switch closure.
2. temperature sensing circuit according to claim 1 is it is characterised in that described voltage detection unit, when electricity is detected
When pressure amplitude of fluctuation is more than or equal to described predetermined threshold, so that described first controlled switch is closed and make described second controlled switch
Disconnect.
3. temperature sensing circuit according to claim 1 is it is characterised in that described first controlled switch is audion；With/
Or second controlled switch be audion.
4. temperature sensing circuit according to claim 3 is it is characterised in that described first controlled switch and described second is subject to
Control switch is the audion of different conduction voltage drops.
5. temperature sensing circuit according to claim 1 it is characterised in that described amplifying unit include operational amplifier,
The resistance for r4 for the resistance and resistance value for r3 for the resistance value, the in-phase input end of described operational amplifier is controlled with described second to be opened
The described other end closing connects, and the outfan of described operational amplifier is connected with described voltage detection unit, and described resistance value is
The two ends of the resistance of r4 are connected with the inverting input of described operational amplifier and described voltage detection unit respectively, described resistance
The two ends being worth the resistance for r3 are connected with the inverting input of described operational amplifier and earth terminal respectively.
6. temperature sensing circuit according to claim 1 is it is characterised in that described critesistor is ntc critesistor.
7. it is characterised in that including current-limiting resistance, its one end is connected to institute to temperature sensing circuit according to claim 1
State between critesistor and described fixed resistance, the other end is connected with described first controlled switch and described second controlled switch.
8. temperature sensing circuit according to claim 1 is it is characterised in that include the first diode, its positive terminal and institute
State the first controlled switch and described amplifying unit connects, its negative pole end is connected with power supply.
9. temperature sensing circuit according to claim 8 it is characterised in that include the second diode, its positive terminal with and
Described amplifying unit connects, and its negative pole end is connected with the positive terminal of described first diode.
10. temperature sensing circuit according to claim 9 is it is characterised in that described first diode and the second diode
It is the diode of different pressure drops.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610806097.4A CN106370319B (en) | 2016-09-05 | 2016-09-05 | A kind of temperature sensing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610806097.4A CN106370319B (en) | 2016-09-05 | 2016-09-05 | A kind of temperature sensing circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106370319A true CN106370319A (en) | 2017-02-01 |
| CN106370319B CN106370319B (en) | 2018-12-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201610806097.4A Active CN106370319B (en) | 2016-09-05 | 2016-09-05 | A kind of temperature sensing circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108132108A (en) * | 2016-12-01 | 2018-06-08 | 新唐科技股份有限公司 | Temperature detection device and temperature detection method thereof |
| CN110132444A (en) * | 2018-02-08 | 2019-08-16 | 展讯通信（上海）有限公司 | Temperature sensing circuit |
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| JPH0548153A (en) * | 1991-08-09 | 1993-02-26 | Hioki Ee Corp | Burnout detector circuit for thermocouple thermometer |
| JP2009068895A (en) * | 2007-09-11 | 2009-04-02 | Ricoh Co Ltd | Temperature detection device |
| CN104422542A (en) * | 2013-08-28 | 2015-03-18 | 东莞赛微微电子有限公司 | Temperature detection circuit and electronic equipment |
| CN104501986A (en) * | 2014-12-16 | 2015-04-08 | 北京航天时代光电科技有限公司 | High-precision wide-range temperature measurement system |
| CN104833439A (en) * | 2015-04-07 | 2015-08-12 | 青岛歌尔声学科技有限公司 | Temperature detection circuit and electronic device with same |
| CN206114140U (en) * | 2016-09-05 | 2017-04-19 | 珠海格力电器股份有限公司 | Temperature detection circuit |
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2016
- 2016-09-05 CN CN201610806097.4A patent/CN106370319B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0548153A (en) * | 1991-08-09 | 1993-02-26 | Hioki Ee Corp | Burnout detector circuit for thermocouple thermometer |
| JP2009068895A (en) * | 2007-09-11 | 2009-04-02 | Ricoh Co Ltd | Temperature detection device |
| CN104422542A (en) * | 2013-08-28 | 2015-03-18 | 东莞赛微微电子有限公司 | Temperature detection circuit and electronic equipment |
| CN104501986A (en) * | 2014-12-16 | 2015-04-08 | 北京航天时代光电科技有限公司 | High-precision wide-range temperature measurement system |
| CN104833439A (en) * | 2015-04-07 | 2015-08-12 | 青岛歌尔声学科技有限公司 | Temperature detection circuit and electronic device with same |
| CN206114140U (en) * | 2016-09-05 | 2017-04-19 | 珠海格力电器股份有限公司 | Temperature detection circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108132108A (en) * | 2016-12-01 | 2018-06-08 | 新唐科技股份有限公司 | Temperature detection device and temperature detection method thereof |
| CN108132108B (en) * | 2016-12-01 | 2020-10-30 | 新唐科技股份有限公司 | Temperature detection device and temperature detection method thereof |
| CN110132444A (en) * | 2018-02-08 | 2019-08-16 | 展讯通信（上海）有限公司 | Temperature sensing circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106370319B (en) | 2018-12-28 |
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