CN205920425U - Temperature compensation circuit and biological identification device who has temperature compensation circuit - Google Patents
Temperature compensation circuit and biological identification device who has temperature compensation circuit Download PDFInfo
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- CN205920425U CN205920425U CN201620589848.7U CN201620589848U CN205920425U CN 205920425 U CN205920425 U CN 205920425U CN 201620589848 U CN201620589848 U CN 201620589848U CN 205920425 U CN205920425 U CN 205920425U
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Abstract
The utility model provides a temperature compensation circuit and biological identification device who has temperature compensation circuit, this circuit includes: comparator, reference voltage output circuit, at the thermistor that connects between first voltage source and the earthing terminal and the 8th resistance, at the second switch connected between second voltage source and the earthing terminal, connect first switch and heating unit between second voltage source and earthing terminal, connected node between reference voltage output circuit's output, thermistor and the 8th resistance is connected to two inputs of comparator respectively, and the control end of second switch is connected to the output of comparator, and the control end of first switch is connected to the drive end of second switch, during the output output high level of comparator, first, second switch switches on, during the output output low level of comparator, first, second switch turn -offs. The circuit can carry out temperature compensating being less than under operating temperature's the condition, make the electronic equipment can normal operating in low temperature environment, and realizes with low costsly.
Description
Technical field
This utility model is related to electronic circuit technology field, and more particularly to a kind of temperature-compensation circuit is mended with having temperature
Repay the biological identification device of circuit.
Background technology
Electronic equipment, such as some devices of the biological identification device such as iris identification instrument, face identification device are to temperature strip
Part has certain requirement, within the temperature range of needing to be operated in regulation.For example, the normal working temperature scope of LCDs
Generally -20～40 degree, LCDs are less than normal working temperature scope in temperature, display interface meeting when spending as -20
Blooming occurs, response time also can decline, the temperature low rupture that may cause LCDs again.But, part electronics
The use environment temperature of equipment may be less than the normal working temperature scope of LCDs, so, in the relatively low ring of temperature
Under border, need to carry out temperature-compensating to some devices of biological identification device, so that this device is operated within the scope of normal temperature,
Ensure these devices can normal work, also ensure not damaged by low temperature.
The Chinese patent of Application No. 20091031244.8 discloses a kind of temperature-control circuit, it include microprocessor,
The critesistor of negative temperature coefficient, the first electrical switch, the second electrical switch and heater, the first end of the first electrical switch is led to
Cross first resistance and be connected to power supply, after critesistor is in parallel with second resistor, be serially connected in first end and the ground of the first electrical switch
Between, the second end ground connection of the first electrical switch, the 3rd end of the first electrical switch is connected to the signal input pin of microprocessor
Power supply is connected to by the 3rd resistance, the signal output pin of microprocessor is connected to the first end of the second electrical switch simultaneously simultaneously
Power supply, the second end ground connection of the second electrical switch are connected to by the 4th resistance, described heater is connected to described power supply and institute
State between the 3rd end of the second electrical switch.Described temperature-control circuit, the change according to critesistor resistance adjusts the first electricity
The turn-on and turn-off of son switch, so that the level of processor output pin realizes height conversion, control leading of the second electrical switch
Lead to and turn off, and then control heater heating or stop heating.
Temperature-control circuit disclosed in prior art can make electronic equipment in the environment of low temperature can normal boot-strap, and
Keep normal work after start, but realized by processor, relatively costly.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of temperature-compensation circuit, can be less than operating temperature
In the case of carry out temperature-compensating, so that electronic equipment can be normally run in low temperature environment, and cost of implementation be low.
In order to solve the above problems, this utility model provides a kind of temperature-compensation circuit, comprising: comparator, reference electricity
Voltage follower circuit, the critesistor being sequentially connected in series between first voltage source and earth terminal and the 8th resistance, in comparator
Outfan and first voltage source between the 3rd resistor connecting, second opening of connecting between the second voltage source and earth terminal
Close, be sequentially connected in series first switch and heating unit between the second voltage source and earth terminal；Reference voltage output circuit
Connecting node between outfan, critesistor and the 8th resistance is respectively connecting to two inputs of comparator, comparator defeated
Go out the control end that end connects second switch, the drive end of second switch connects the control end of first switch；The outfan of comparator
During output high level, first switch and second switch turn on；During the outfan output low level of comparator, first switch and second
Switch OFF.
Illustrate as one, described critesistor is the critesistor of negative temperature coefficient, described reference voltage output
The outfan of circuit connects to the positive input terminal of comparator, the connecting node between described critesistor and the 8th resistance connect to than
Negative input end compared with device.
Illustrate as one, described temperature-compensation circuit also includes: the tenth resistance and the 3rd switch；Described tenth electricity
Resistance is connected in series between the 8th resistance and earth terminal, and the control end of described 3rd switch connects the outfan of comparator, described
The input of the 3rd switch connects the ungrounded end of the tenth resistance, the output head grounding of described 3rd switch；The output of comparator
During the output high level of end, the 3rd switch conduction；During the outfan output low level of comparator, the 3rd switch OFF.
Illustrate as one, the described 3rd switchs as nmos pipe, and the grid of described nmos pipe is described 3rd switch
Control end, the drain electrode of described nmos pipe is the input of described 3rd switch, and the source electrode of described nmos pipe is opened for the described 3rd
The outfan closing.
Illustrate as one, described second switch includes: npn audion, the 6th resistance and the 4th resistance；Described
The base stage of npn audion connects one end of described 6th resistance, and the other end of described 6th resistance is described second switch
Control end, the drive end of the extremely described second switch of current collection of described npn audion, the colelctor electrode of described npn audion
The second voltage source, the grounded emitter of described npn audion are connected by described 4th resistance.
Illustrate as one, described first switch is managed for pmos, the grid of described pmos pipe is described first switch
Control end, the source electrode of described pmos pipe connects described the second voltage source, and described heating unit is passed through in the drain electrode of described pmos pipe
Ground connection.
Illustrate as one, described temperature-compensation circuit also includes: be connected in series in described first voltage source and connect
Electric capacity between ground terminal.
Accordingly, this utility model additionally provides a kind of biological identification device with temperature-compensation circuit, described biology
Identifying device includes: liquid crystal display screen, metal shielding and pcb plate；Described pcb plate has temperature-compensation circuit, described temperature-compensating
Circuit is foregoing temperature-compensation circuit, and described metal shielding is located at the back side of liquid crystal display screen, described temperature-compensation circuit
Heating unit be attached on metal shielding.
Illustrate as one, described heating unit is polyimides Electric radiant Heating Film.
Compared with prior art, this utility model has the advantage that
Temperature-compensation circuit described in the utility model, the resistance causing critesistor in variation of ambient temperature changes
When so that the difference in voltage of two inputs of comparator changes, when ambient temperature be less than operating temperature when, comparator
During outfan output high level, first switch and second switch conducting, heating unit begins to warm up, carry out temperature-compensating so that
The controlled temperature device of electronic equipment starts to warm up；When ambient temperature is less than operating temperature, the outfan output of comparator is low
During level, first switch and second switch turn off, and heating unit stops heating, stop carrying out temperature-compensating.The program can be
Automatically carry out temperature-compensating less than in the case of operating temperature it is ensured that electronic equipment normally can run in low temperature environment,
And realized using the device such as comparator and switch, cost is relatively low.
In addition, this utility model can also realize the temperature with hysteresis area by increasing the tenth resistance and the 3rd switch
Compensation circuit, then, in a certain temperature range, have heating and non-heated two states, in temperature elevation process, this temperature range
Correspond to heated condition, during temperature reduces, this temperature range corresponds to stop heated condition, is prevented from ambient temperature and exists
When fluctuating around one temperature spot, temperature-compensation circuit in heated condition and stops frequently switching between heated condition.
Brief description
Fig. 1 is a kind of structural representation of this utility model temperature-compensation circuit embodiment one；
Fig. 2 is a kind of structural representation of this utility model temperature-compensation circuit embodiment two；
Fig. 3 is a kind of heated condition principle schematic of the illustration of temperature-compensation circuit of this utility model；
Fig. 4 is a kind of structural representation of the biological identification device embodiment with temperature-compensation circuit of this utility model.
Specific embodiment
Understandable for enabling above-mentioned purpose of the present utility model, feature and advantage to become apparent from, below in conjunction with the accompanying drawings and tool
Body embodiment is described in further detail to this utility model.
With reference to Fig. 1, show a kind of structural representation of the embodiment one of temperature-compensation circuit of this utility model, described temperature
Degree compensation circuit 10 include: comparator u1a, reference voltage output circuit u2, between first voltage source v1 and earth terminal successively
Between the critesistor r1 being connected in series and the 8th resistance r8, the outfan in comparator u1a and first voltage source v1, series connection connects
3rd resistor r3 connecing, the second switch q2 being connected in series between the second voltage source v2 and earth terminal, in the second voltage source and
It is sequentially connected in series first switch q1 and heating unit r5 between earth terminal；The outfan of reference voltage output circuit, temperature-sensitive electricity
Connecting node between resistance r1 and the 8th resistance r8 is respectively connecting to two inputs of comparator u1a, the outfan of comparator u1a
Connect the control end of second switch q2, the drive end of second switch q2 connects the control end of first switch q1；Comparator u1a's is defeated
When going out end output high level, first switch q1 and second switch q2 turn on；During the outfan output low level of comparator u1a, the
One switch q1 and second switch q2 turns off.
Input connection the second voltage source v2 of second switch q2, the outfan connection earth terminal of second switch q2, first
The input of switch q1 connects the second voltage source v2, and the outfan of first switch q1 connects the ungrounded end of heating unit r5.The
During one switch q1 conducting, the input of first switch q1 is connected with the outfan of first switch q1；During second switch q2 conducting, the
The input of two switch q2 is connected with the outfan of second switch q2.
In the present embodiment one, the outfan of reference voltage output circuit exports changeless reference voltage, environment temperature
Degree change causes the resistance of critesistor to change so that the difference in voltage of two inputs of comparator changes, when
When ambient temperature is less than operating temperature, during the outfan output high level of comparator, first switch and second switch turn on, heating
Unit begins to warm up, and carries out temperature-compensating so that the controlled temperature device of electronic equipment starts to warm up；When ambient temperature is less than work
When making temperature, during the outfan output low level of comparator, first switch and second switch turn off, and heating unit stops heating,
Stop carrying out temperature-compensating.The program automatically can carry out temperature-compensating in the case of less than operating temperature it is ensured that electronics
Equipment normally can run in low temperature environment, and is realized using the device such as comparator and switch, and cost is relatively low.
Illustrate as one, in the present embodiment one, described critesistor is the critesistor of negative temperature coefficient
(ntc, negative temperature coefficient), temperature raises, and the resistance of ntc critesistor reduces.Described ginseng
The outfan examining voltage follower circuit connects to the positive input terminal of comparator u1a, between described critesistor and the 8th resistance r8
Connecting node connects to the negative input end of comparator u1a.
As another illustration, in the present embodiment one, described critesistor is the critesistor of positive temperature coefficient
(ptc, positive temperature coefficient), temperature raises, and the resistance of ptc critesistor also raises.Described
The outfan of reference voltage output circuit connects to the negative input end of comparator u1a, between described critesistor and the 8th resistance r8
Connecting node connect to the positive input terminal of comparator u1a.
Illustrate as one, described heating unit is polyimides (pi, polyimide) Electric radiant Heating Film.Polyimides
Electric radiant Heating Film is with Kapton as outer insulator, with metal forming, tinsel for interior conductive heating unit, through High Temperature High Pressure heat seal
Form.Polyimides Electric radiant Heating Film has an excellent dielectric strength, excellent dielectric strength, excellent heat conduction efficiency, excellent
Resistance stability, can be widely applicable for heating art and be obtained in that at a relatively high temperature control precision.As another
Illustrate, described heating unit can also be other Electric radiant Heating Film such as pet Electric radiant Heating Film.
As one illustrate, in the present embodiment one, described temperature-compensation circuit also includes: the tenth resistance r10 and
3rd switch q3；Described tenth resistance r10 is connected in series between the 8th resistance r8 and earth terminal, the control of described 3rd switch q3
End processed connects the outfan of comparator u1a, and the input of described 3rd switch q3 connects the ungrounded end of the tenth resistance r10, institute
State the output head grounding of the 3rd switch q3.During the outfan output high level of comparator u1a, the 3rd switch q3 conducting；Comparator
During the outfan output low level of u1a, the 3rd switch q3 turns off.
In this illustration, temperature-compensation circuit has three states, if the ambient temperature of critesistor perception is t, t
< during t1, it is heated condition；T1 < t < during t2, it is heated condition or non-heated state, referred to as two condition；During t > t2, for stopping heating
State.Wherein, t1 is the minima of normal working temperature scope, is then heated less than t1；T2 is heating stop temperature, is more than
T2 then stops heating.Under original state, the control end of the 3rd switch q3 is high level, and the 3rd switch q3 is in the conduction state, electricity
Resistance r10 is shorted.If the magnitude of voltage of comparator u1a negative input end is u2, the magnitude of voltage of comparator u1a positive input terminal is u3.
The operation principle of 1 and 3 pair of compensation circuit 10 is specifically described below in conjunction with the accompanying drawings.
State 1, when t<during t1, the resistance of critesistor r1 larger so that u3=r7/ (r7+r2)>u2=r8/ (r8+
R1), the outfan output high level of comparator u1a, first switch q1, second switch q2, the 3rd switch q3 are both turned on, the second electricity
Potential source v2 is powered to heating unit r5, and heating unit r5 begins to warm up, and the tenth resistance r10 is shorted.
State 2, heating unit r5 gradually heat, when t1 < t < during t2, the resistance of critesistor r1 gradually reduces, but
Still keep u3=r7/ (r7+r2) > u2=r8/ (r8+r1), the outfan output high level of comparator u1a, first switch q1, the
Two switch q2, the 3rd switch q3 are both turned on, and heating unit r5 is still in heated condition.
State 3, temperature are gradually increasing, as t>t2 when, the resistance very little of critesistor r1, meet u3=r7/ (r7+r2)<
The outfan output low level of u2=r8/ (r8+r1), comparator u1a, first switch q1, second switch q2, the 3rd switch q3 are equal
Turn off, heating unit r5 stops heating, the tenth resistance r10 accesses circuit so that the voltage of u2 increases further.
So that temperature is gradually lowered after state 4, heating unit stopping heating, the resistance of critesistor r1 is gradually increased, when
T1 < t < during t2, meets u3=r7/ (r7+r2) <u2=(r8+r10)/(r8+r10+r1), the outfan output of comparator u1a is low
Level, first switch q1, second switch q2, the 3rd switch q3 are turned off, and heating unit r5 is still in stopping heated condition.
State 5, temperature are gradually lowered, when t<during t1, the resistance of critesistor r1 is larger, meets u3=r7/ (r7+r2)>
The outfan output high level of u2=(r8+r10)/(r8+r10+r1), comparator u1a, first switch q1, second switch q2, the
Three switch q3 are both turned on, and the tenth resistance r10 is shorted, and heating unit r5 begins to warm up state again, returns to state 1.
So far, it is capable of stopping the Automatic Cycle temperature compensation procedure of heating as t<beginning to warm up during t1, as t>t2,
< during t2, there are heating and non-heated two states, also referred to as hysteresis area in t1 < t.Without hysteresis area, then a little higher than temperature
Control point, will stop heating, temperature drop can begin to warm up when being less than temperature control point again, and temperature-compensation circuit constantly exists
Switching between being heated near temperature control point and stopped to heat.And there is the temperature-control circuit in hysteresis area, temperature liter
During, < during t2, correspond to heated condition in t1 < t；During temperature reduces, < correspond to during t2 stop heating shape in t1 < t
State, when being prevented from ambient temperature and fluctuating around a temperature spot, temperature-compensation circuit in heated condition and stops heating shape
Frequently switch between state.If it should be noted that temperature meets t1 < t < t2 when initial, due to the 3rd switch q3 conducting,
Then temperature-compensation circuit is in state 2.
It should be noted that this carries out principle as a example sentencing the temperature-compensation circuit with negative tempperature coefficient thermistor saying
Bright, the principle with the temperature-compensation circuit of semistor is similar, can cross-reference, no longer superfluous herein
State.
Illustrate as one, first switch q1 is managed for pmos, second switch q2 is ntn type audion, the 3rd switch
Q3 manages for nmos.As another illustration, first switch q1, second switch q2, the 3rd switch q3 can also be by relay
Realize.
With reference to Fig. 2, show a kind of structural representation of the embodiment two of temperature-compensation circuit of this utility model, described temperature
Degree compensation circuit 20 includes: comparator u1a, by the second resistance being sequentially connected in series between first voltage source v1 and earth terminal
Reference voltage output circuit that r2 and the 7th resistance r7 are constituted, it is sequentially connected in series between first voltage source v1 and earth terminal
The 3rd electricity being connected in series between critesistor r1 and the 8th resistance r8, the outfan in comparator u1a and first voltage source v1
Resistance r3, be connected in series between the second voltage source v2 and earth terminal second switch q2, between the second voltage source and earth terminal
It is sequentially connected in series first switch q1 and heating unit r5；Critesistor r1 is the critesistor of negative temperature coefficient, second resistance
The first connecting node between r2 and the 7th resistance r7 connects to the positive input terminal of comparator u1a, described critesistor r1 and the 8th
The second connecting node between resistance r8 connects to the negative input end of comparator u1a, and the outfan of comparator u1a connects second switch
The control end of q2, the drive end of second switch q2 connects the control end of first switch q1.Described heating unit is polyimides pi
Electric radiant Heating Film.
Described 3rd switch q3 manages for nmos, and the grid of described nmos pipe is the control end of described 3rd switch q3, described
The drain electrode of nmos pipe is the input of described 3rd switch q3, and the source electrode of described nmos pipe is the output of described 3rd switch q3
End.
Described second switch includes: npn audion, the 6th resistance r6 and the 4th resistance r4；Described npn audion
Base stage connects one end of described 6th resistance r6, and the other end of described 6th resistance r6 is the control end of described second switch q2,
The drive end of the extremely described second switch q2 of the current collection of described npn audion, the colelctor electrode of described npn audion passes through institute
State the 4th resistance r4 and connect the second voltage source v2, the grounded emitter of described npn audion.
Described first switch is managed for pmos, and the grid of described pmos pipe is the control end of described first switch q1, described
The source electrode of pmos pipe connects described the second voltage source v2, and described heating unit r5 ground connection is passed through in the drain electrode of described pmos pipe.
Under normal circumstances, first voltage source v1 is less than the second voltage source v2.Adopt as a example lm139 by comparator u1a, this device
It is+36v that part highest bears voltage, and Kapton pi Electric radiant Heating Film, according to different power, can have 12v, 36v, 48v etc.
Multiple, under identical power, voltage is higher, and electric current is less, and the electromagnetic radiation that Kapton pi Electric radiant Heating Film produces is got over
Little, to equipment cable to bear current requirements also less.So using the design of two kinds of voltage sources, comparator u1a adopt 3.3v or
Person's 5v voltage is it is ensured that relatively low power consumption works, and Kapton pi Electric radiant Heating Film adopts the model of high voltage, is protecting
In the case of card power, reduce the purpose of electric current.
Above-mentioned employ the design of two kinds of voltage sources, the ceiling voltage that the outfan of comparator u1a exports high level is that it is defeated
Enter voltage.For ensure pmos pipe q1 can reliable turn-off, need connect npn audion q2, when comparator u1a output 3.3 or
When 5v level, npn audion q2 can saturation conduction, now pmos pipe q1 grid be pulled low as reliable conducting, when comparing
When the outfan output of device u1a is low level, npn audion q2 ends, and pmos pipe q1 grid is pulled to the second voltage source
High level and reliable turn-off.
In the present embodiment two, it is assumed that the temperature of electronic equipment is heated, device is LCDs, its minimum operating temperature
It is -20 degree, when -20 spend, resistance is 20k ω to the critesistor r1 of ntc type；Under conditions of 0 degree, resistance is 10k ω.r2
=r3=r4=r6=r7=r8=r10=10k ω.
Below, the operation principle of compensation circuit 20 is illustrated.
First, by the process of low temperature to high temperature:
State 1, t<-20 degree, r1>20k ω
Nmos pipe q3 is initially in conducting state, and resistance r10 is shorted, voltage comparator u1a negative input end (the 2nd foot)
Voltage is less than 1/3rd v1, and the voltage of voltage comparator u1a positive input terminal (the 3rd foot) is equal to 1/2nd v1, thus electric
The voltage of pressure comparator u1a negative input end (the 2nd foot) is less than the voltage of positive input terminal (the 3rd foot), the output of voltage comparator u1a
End (the 1st foot) output high level, now npn audion q2 conducting, the 1st foot of pmos pipe q1 is pulled low, and pmos pipe q1 turns on,
Heating unit r5 turn-on current begins to warm up.Outfan (the 1st foot) due to voltage comparator u1a exports high level, so
Nmos pipe q3 is still in conducting state.
State 2, -20 degree < t < 0 degree, 10k ω < r1 < 20k ω
The voltage of voltage comparator u1a negative input end (the 2nd foot) is more than 1/3rd v1 and is less than 1/2nd v1, and electric
The voltage of pressure comparator u1a positive input terminal (the 3rd foot) is equal to 1/2nd v1, so voltage comparator u1a negative input end the (the 2nd
Foot) voltage be less than positive input terminal (the 3rd foot) voltage, voltage comparator u1a outfan (the 1st foot) output high level, this
When npn audion q2, pmos pipe q1 and nmos pipe q3 be in conducting state, heating unit r5 is still in heated condition.
State 3, t>0 degree, r1<10k ω
The voltage of voltage comparator u1a negative input end (the 2nd foot) is more than 1/2nd v1, voltage comparator u1a positive input
The voltage at end (the 3rd foot) is equal to 1/2nd v1, so the voltage of voltage comparator u1a negative input end (the 2nd foot) is more than just defeated
Enter the voltage at end (the 3rd foot), outfan (the 1st foot) the output low level of voltage comparator u1a, now Npn triode q2 cut-off
Turn off, the 1st foot of pmos pipe q1 is driven high, pmos pipe q1 turns off, heating unit r5 stops heating.Due to voltage comparator u1a
Outfan (the 1st foot) output low level, so nmos pipe q3 cut-off, because the tenth resistance r10 effect is so that comparator u1a
The voltage of negative input end (the 2nd foot) increases further.
2nd, by the process of high temperature to low temperature:
State 4, -20 degree < t < 0 degree, 10k ω < r1 < 20k ω
Heating unit r5 stops heating, and ambient temperature is gradually lowered, and the resistance of critesistor r1 starts to increase, due to nmos
Pipe q3 cut-off turns off, and the voltage of voltage comparator u1a negative input end (the 2nd foot) is more than 1/2nd v1 and is less than 2/3rds
V1, the voltage of voltage comparator u1a positive input terminal (the 3rd foot) is equal to 1/2nd v1, so voltage comparator u1a negative input end
The voltage of (the 2nd foot) is more than the voltage of positive input terminal (the 3rd foot), and the outfan (the 1st foot) of voltage comparator u1a exports low electricity
Flat, now Npn triode q2 cut-off turns off, and the 1st foot of pmos pipe q1 is driven high, and pmos pipe q1 turns off, and heating unit r5 stops
Heating.Outfan (the 1st foot) due to voltage comparator u1a exports low level, so nmos pipe q3 is still in cut-off state.
State 5, t<-20 degree, r1>20k ω
Nmos pipe q3 is initially located in cut-off off state, and the voltage of voltage comparator u1a negative input end (the 2nd foot) is less than two
/ mono- v1, the voltage of voltage comparator u1a positive input terminal (the 3rd foot) is equal to 1/2nd v1, so voltage comparator u1a bears
The voltage of input (the 2nd foot) is less than the voltage of positive input terminal (the 3rd foot), outfan (the 1st foot) output of voltage comparator u1a
High level, now npn audion q2 conducting, the 1st foot of pmos pipe q1 is pulled low, and pmos pipe q1 turns on, and heating unit r5 connects
Galvanization begins to warm up, and nmos pipe q3 is in the conduction state, returns to state 1 again.
The present embodiment two is capable of when t<-20 spends, and heating unit begins to warm up, as t>0 degree when stop heating from
Dynamic circulating temperature compensation process, < when t < 0 degree, has the hysteresis area of heating and non-heated two states, is prevented from -20 degree
When ambient temperature fluctuates around a temperature spot, frequently switch between heated condition and stopping heated condition.
Illustrate as one, described temperature-compensation circuit 20 also includes: is connected in series in described first voltage source v1
Electric capacity c1 and earth terminal between.Electric capacity c1, as decoupling capacitor, prevents the interference that power supply noise produces.
As another illustration, also it is parallel with light emitting diode d1 and the 9th resistance r9 at the two ends of heating unit r5
Series circuit.Described light emitting diode d1 is used as heating instruction, when it lights, represents that heating unit r5 begins to warm up,
Extinguish and represent that heating unit r5 stops heating.
The parameters such as each resistance described in the present embodiment two only illustrate, when practical application, can be according to temperature-sensitive
The specific parameter of resistance, adjusts the parameter of other resistance, thus realizing the temperature range wanted, and temperature according to used for circuit
The conditions such as the structure of device, size and radiating that degree compensates, the power of adjustment heating unit r5, second switch q2 current/voltage
Ability to bear etc..
Temperature-compensation circuit described in embodiment one and embodiment two can be used on electronic equipment, temperature being there are certain requirements
Some devices, such as LCDs etc., described electronic equipment can be biological identification device, such as iris identification instrument, face
Identifying device etc..
With reference to Fig. 4, show a kind of knot of the biological identification device embodiment with temperature-compensation circuit of this utility model
Structure schematic diagram, described biological identification device 40 includes: liquid crystal display screen 41, metal shielding 42 and pcb plate 43, and described pcb plate 43 has
There is temperature-compensation circuit 431, described temperature-compensation circuit is the temperature-compensating electricity as described in previous embodiment one, embodiment two
Road, described metal shielding 42 is attached to metal shielding located at the back side of liquid crystal display screen 41, the heating unit of temperature-compensation circuit 431
On 42.Critesistor can be arranged on outside pcb plate 43, and the ambient temperature of its perception is approximately equal to the temperature of liquid crystal display screen 41.For
Increase the heat-conducting effect of heating unit, heat-conducting silicone grease can be increased between heating unit and metal shielding 42.
Illustrate as one, described heating unit is polyimides (pi, polyimide) Electric radiant Heating Film.Polyimides
Electric radiant Heating Film is with Kapton as outer insulator, with metal forming, tinsel for interior conductive heating unit, through High Temperature High Pressure heat seal
Form.Polyimides Electric radiant Heating Film has an excellent dielectric strength, excellent dielectric strength；Excellent heat conduction efficiency is excellent
Resistance stability, can be widely applicable for heating art and be obtained in that at a relatively high temperature control precision.As another
Illustrate, described heating unit can also be other Electric radiant Heating Film such as pet Electric radiant Heating Film.
Each embodiment in this specification is all described by the way of going forward one by one, what each embodiment stressed be with
The difference of other embodiment, between each embodiment identical similar partly mutually referring to.For device embodiment
For, so description is fairly simple, in place of correlation, the part referring to temperature-compensation circuit embodiment illustrates.
Above to a kind of temperature-compensation circuit provided by the utility model and the bio-identification with temperature-compensation circuit
Device, is described in detail, and specific case used herein is explained to principle of the present utility model and embodiment
State, the explanation of above example is only intended to help understand method of the present utility model and its core concept；Simultaneously for ability
The those skilled in the art in domain, according to thought of the present utility model, all have change in specific embodiments and applications
Place, in sum, this specification content should not be construed as to restriction of the present utility model.
Claims (10)
1. a kind of temperature-compensation circuit is it is characterised in that include: comparator, reference voltage output circuit, in first voltage source and
Connect between the critesistor being sequentially connected in series between earth terminal and the 8th resistance, the outfan in comparator and first voltage source
The 3rd resistor that connects, the second switch connecting between the second voltage source and earth terminal, between the second voltage source and earth terminal
It is sequentially connected in series first switch and heating unit；Between the outfan of reference voltage output circuit, critesistor and the 8th resistance
Connecting node be respectively connecting to two inputs of comparator, the outfan of comparator connects the control end of second switch, the
The drive end of two switches connects the control end of first switch；
During the outfan output high level of comparator, first switch and second switch turn on；The outfan of comparator exports low electricity
At ordinary times, first switch and second switch turn off.
2. temperature-compensation circuit as claimed in claim 1 it is characterised in that
Described critesistor is the critesistor of negative temperature coefficient,
The outfan of described reference voltage output circuit connects to the positive input terminal of comparator, described critesistor and the 8th resistance
Between connecting node connect to the negative input end of comparator.
3. temperature-compensation circuit as claimed in claim 2 it is characterised in that
Described temperature-compensation circuit also includes: the tenth resistance and the 3rd switch；
Described tenth resistant series are connected between the 8th resistance and earth terminal, and the control end of described 3rd switch connects comparator
Outfan, described 3rd switch input connect the tenth resistance ungrounded end, described 3rd switch output head grounding；
During the outfan output high level of comparator, the 3rd switch conduction；During the outfan output low level of comparator, the 3rd switch closes
Disconnected.
4. temperature-compensation circuit as claimed in claim 3 it is characterised in that
Described 3rd switchs as nmos pipe, and the grid of described nmos pipe is the control end of described 3rd switch, described nmos pipe
The input draining as the described 3rd switch, the source electrode of described nmos pipe is the outfan of described 3rd switch.
5. the temperature-compensation circuit as described in any one of Claims 1-4 it is characterised in that
Described second switch includes: npn audion, the 6th resistance and the 4th resistance；
The base stage of described npn audion connects one end of described 6th resistance, and the other end of described 6th resistance is described the
The control end of two switches, the drive end of the extremely described second switch of current collection of described npn audion, described npn audion
Colelctor electrode by described 4th resistance connect the second voltage source, the grounded emitter of described npn audion.
6. the temperature-compensation circuit as described in any one of Claims 1-4 it is characterised in that
Described first switch is managed for pmos, and the grid of described pmos pipe is the control end of described first switch, described pmos pipe
Source electrode connects described the second voltage source, and the drain electrode of described pmos pipe is grounded by described heating unit.
7. the temperature-compensation circuit as described in any one of Claims 1-4 it is characterised in that
Described temperature-compensation circuit also includes: is connected in series in the electric capacity between described first voltage source and earth terminal.
8. a kind of biological identification device with temperature-compensation circuit is it is characterised in that described biological identification device includes: liquid crystal
Screen, metal shielding and pcb plate；
Described pcb plate has temperature-compensation circuit, and described temperature-compensation circuit is temperature-compensating electricity as claimed in claim 1
Road, described metal shielding is attached on metal shielding located at the back side of liquid crystal display screen, the heating unit of described temperature-compensation circuit.
9. biological identification device as claimed in claim 8 it is characterised in that
Described temperature-compensation circuit is the temperature-compensation circuit as described in any one of claim 2 to 7.
10. biological identification device as claimed in claim 9 it is characterised in that
Described heating unit is polyimides Electric radiant Heating Film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620589848.7U CN205920425U (en) | 2016-06-16 | 2016-06-16 | Temperature compensation circuit and biological identification device who has temperature compensation circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620589848.7U CN205920425U (en) | 2016-06-16 | 2016-06-16 | Temperature compensation circuit and biological identification device who has temperature compensation circuit |
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| Publication Number | Publication Date |
|---|---|
| CN205920425U true CN205920425U (en) | 2017-02-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201620589848.7U Active CN205920425U (en) | 2016-06-16 | 2016-06-16 | Temperature compensation circuit and biological identification device who has temperature compensation circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107450627A (en) * | 2017-09-15 | 2017-12-08 | 京信通信系统（中国）有限公司 | Temperature-control circuit |
| CN108445928A (en) * | 2018-04-23 | 2018-08-24 | 海信（山东）空调有限公司 | A kind of temperature-control circuit and frequency-variable controller of IPM |
| WO2020232831A1 (en) * | 2019-05-22 | 2020-11-26 | 苏州浪潮智能科技有限公司 | Voltage compensation method and apparatus for step-down circuit |
-
2016
- 2016-06-16 CN CN201620589848.7U patent/CN205920425U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107450627A (en) * | 2017-09-15 | 2017-12-08 | 京信通信系统（中国）有限公司 | Temperature-control circuit |
| CN107450627B (en) * | 2017-09-15 | 2022-09-16 | 京信网络系统股份有限公司 | Temperature control circuit |
| CN108445928A (en) * | 2018-04-23 | 2018-08-24 | 海信（山东）空调有限公司 | A kind of temperature-control circuit and frequency-variable controller of IPM |
| WO2020232831A1 (en) * | 2019-05-22 | 2020-11-26 | 苏州浪潮智能科技有限公司 | Voltage compensation method and apparatus for step-down circuit |
| US11901815B2 (en) | 2019-05-22 | 2024-02-13 | Inspur Su Zhou Intelligent Technology Co., Ltd. | Voltage compensation method and device of voltage reducing circuit |
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