CN105973509B - A kind of pressure sensor circuit and its adjustment method - Google Patents
A kind of pressure sensor circuit and its adjustment method Download PDFInfo
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- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
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- G01L1/2262—Measuring circuits therefor involving simple electrical bridges
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Abstract
The invention belongs to pressure sensing technology, a kind of pressure sensor circuit and its adjustment method are provided.The pressure sensor includes circuit voltage reference circuit (1), sensitive electric bridge (2), voltage amplifier circuit (3), (4) four part of current converter circuit.The pressure sensor circuit is by reasonably selecting the main devices such as voltage reference, operational amplifier, the resistance value for reducing the supply voltage of wheatstone presser sensor electric bridge, increasing total null voltage partial pressure adjustment resistor, make the static consumption electric current of sensor signal conditioning circuit no more than 3.8mA, to meet the commissioning requirements of pressure sensor；By in the reasonable amplification factor for determining three amplifier magnifiers, determine the capacity of ceramic capacitor in parallel in voltage amplifier circuit in degeneration resistors, it realizes and the high magnification numbe of presser sensor electric bridge small-signal is amplified, while making circuit that there is stability well.
Description
Technical field
The invention belongs to pressure sensing technology, it is related to a kind of pressure sensor circuit and its adjustment method.
Background technique
Pressure sensor uses two-wire system 4mA~20mA normalized current ring design, and the remote biography of electric signal may be implemented
It is defeated, have the advantages that accurate signal transmission, strong antijamming capability, static consumption electric current are low；Two-wire system design simultaneously can effectively subtract
The quantity of cable is electrically connected between few pressure sensor and system.The pressure sensor of two-wire system 4mA~20mA output is necessary
It is required that the circuit static consumption electric current of pressure sensor should be less than 3.8mA, otherwise can not debug.
Pressure sensor is frequently with sputtered film presser sensor principle or titanium/silicon-on-sapphire presser sensor principle pressure
Power sensitive core body, above-mentioned sensitivity principle be caused by the deformation of flexible sheet presser sensor electric bridge arm resistance change, thus
Realize the purpose that pressure signal is converted to resistance signal.The distinguishing feature of the pressure sensitive core sensitivity electric bridge of these principles
Have: 1) sensitivity is low, and usual Full-span output is only 1mV/V~3mV/V；2) the arm resistance value of sensitive electric bridge is usually 2.5k
Ω to 5k Ω.Pressure sensor based on sputtered film presser sensor principle or sapphire pressure sensitivity principle will realize two lines
The design requirement of 4mA~20mA output processed, there are following contradictions: the static consumption electric current in order to reduce pressure sensor circuit,
The device using low consumption electric current is needed in circuit, while reducing the supply voltage of sensitive electric bridge as far as possible；But it is quick when reducing
When the supply voltage of inductance bridge, output signal reduces therewith, in order to realize that 4mA~20mA current signal exports, needs to improve
The amplification factor of circuit, amplification factor usually require to reach 1000 times of even higher multiples.After amplification factor improves,
Bridge output signal becomes more sensitive to faint circuit noise, leads to output jump and unstable phenomenon, is not able to satisfy
The design requirement of pressure sensor.
Summary of the invention
The good pressure sensing of low, strong antijamming capability that the object of the present invention is to provide a kind of static consumption electric currents, stability
Device circuit and its adjustment method.
The technical scheme adopted by the invention is as follows: a kind of pressure sensor circuit, including voltage reference circuit 1, sensitive electric bridge
2, voltage amplifier circuit 3,4 four part of current converter circuit, wherein pressure sensor includes electrical node VCC, IOUT、SGND、V
+, Vref, Earth ,+Vin ,-Vin and Vout；Voltage reference circuit 1 and node VCC, IOUT, SGND, V+, Vref and Earth phase
Connection, sensitive electric bridge 2 are connected by node SGND, V+ and voltage reference circuit 1, sensitive electric bridge 2 by node+Vin ,-Vin with
Voltage amplifier circuit 3 connects, and voltage amplifier circuit 3 is connected by node V+, SGND, Vref and voltage reference circuit 1, and voltage is put
Big circuit 3 is connect by node Vout with current converter circuit 4, and current converter circuit 4 passes through node V+, SGND and voltage reference
Circuit 1 connects, wherein described electrical node VCC, IOUT, SGND, V+, Vref, Earth ,+Vin ,-Vin, Vout it is electrical fixed
Position be respectively the power input of pressure sensor, the current output terminal of pressure sensor, signal ground, voltage reference circuit it is defeated
The negative input of outlet, zero-bit debugging voltage output end, shielding ground, the positive input terminal of voltage amplifier circuit 3, voltage amplifier circuit 3
It holds, the output end of voltage amplifier circuit 3.
Described operational amplifier N2A, N2B, N2C and N2D select low-power consumption four-way operational amplifier.Voltage reference circuit
1 should select the voltage reference device of low-power consumption.
The output voltage amplitude of voltage reference circuit 1 determines by the following method: Uo < ﹙ 3.8-I1-I2﹚ × RB.Wherein Uo
For the output voltage of voltage reference, RBThe minimum internal resistance value of sensitive electric bridge 2, I1Disappear for the maximum static state of four-way operational amplifier
Power consumption stream, I2The static consumption electric current of maximum to set voltage reference.
Described fixed resister R2, R3, R4 ... R13, R14 select the resistance device of low inductance, wherein resistance value R3
=R4≤50k Ω, R5=R6=R7=R8 >=10k Ω, R9=R10, R11=R12, should meet R13≤0.1% × R11, and
R13≥100Ω。
Determine the calculation method of zero-bit adjustment benchmark fixed resister R2 resistance value value range are as follows: R2 ≥ ﹙ 3.8-I1-I2-
Uo/RB﹚.
According to the resistance value of each fixed resister preset in current converter circuit 4,3 output end of voltage amplifier circuit is calculated
The voltage value Uout of Vout, calculation method are as follows: Uout=(IOMAX×R13)×R9/R12.Wherein IOMAXMost for pressure sensor
Big output current amplitude.
The amplification factor A=Uout/ (Vs × Uo) of voltage amplifier circuit 3, wherein the output voltage spirit of presser sensor electric bridge
Sensitivity is Vs, and the amplification factor A of voltage amplifier circuit 3 should be not more than 150；If the amplification factor A of voltage amplifier circuit 3 is discontented
Foot requires, then should change the resistance value that fixed resister is preset in current converter circuit 4 again, method particularly includes: holding R11,
The resistance value of R12, R13 are constant, the synchronous resistance value for reducing R9, R10, until make the amplification factor A of voltage amplifier circuit 3≤
150。
According to the maximum input offset current I of operational amplifierBWith maximum input bias current IOS, and sensitive electric bridge
Minimum zero-bit output voltage UBMIN, determine the maximum value range of amplification factor adjustment resistor R100.Calculation method is as follows:
R100≤UBMIN/(IB+IOS)。
In debugging, the output of presser sensor electric bridge is maintained at zero-bit output, keeping R100 is that maximum value is constant, adjustment
The resistance value of R200 makes the output current value 4mA of pressure sensor circuit, observes the jump situation of current value.In above-mentioned condition
Under, gradually from 0.01uF by the capacitance of ceramic capacitor C3, C4, until being further continued for after output is stablized by the capacitance of C3, C4
Increase 50%, the final value as C3, C4 capacitance.
The adjustment method of pressure sensor circuit, detailed process is as follows: low-power consumption in step 1, selection voltage reference circuit 1
Accurate device operational amplifier and voltage reference, step 2 measure the minimum internal resistance value of sensitive electric bridge 2, and step 3 determines voltage reference
The output voltage amplitude of voltage reference in circuit 1, step 4 determine that zero-bit adjusts benchmark fixed resister in voltage reference circuit 1
Resistance value, the main devices determined respectively by steps 1 and 2,3,4, the output voltage amplitude value range of voltage reference, zero
The value range of position adjustment benchmark fixed resister R2 resistance value guarantees that the static consumption electric current of pressure sensor circuit is less than
3.8mA meets the commissioning requirements of pressure sensor；The resistance value of fixed resister, makes in step 5, preset current conversion circuit 4
Voltage signal amplification is more accurate, improves the output impedance of current converter circuit 4；Step 6 calculates the output of voltage amplifier circuit 3
The voltage value of Vout, step 7, the amplification factor for determining voltage amplifier circuit 3 are held, step 8 is determined and put in voltage amplifier circuit 3
The maximum value of big multiple adjustment resistor, step 9, two operations selected in voltage amplifier circuit 3 for differential amplification are put
The resistance value value range of the negative-feedback fixed resister of big device, by amplifying in step 6,7,8,9 realization voltage amplifier circuits 3
Multiple adjusts the maximum value of resistor, the negative-feedback in voltage amplifier circuit 3 for two operational amplifiers of differential amplification
The resistance value value range of fixed resister, makes operational amplifier work in optimum state, and reduction is defeated due to operational amplifier
Enter the influence that offset current and bias current amplify small-signal, improves the stability of amplification voltage；Step 10, selected voltage
The resistance value of remaining fixed resister in amplifying circuit 3；Step 11, determine in voltage amplifier circuit 3 be used for differential amplification two
The capacitance of the negative feedback capacitor of a operational amplifier, to guarantee that the work of voltage amplifier circuit 3 in stable state, avoids exporting
The fluctuation of voltage and the output for influencing pressure sensor；Step 12, the parameter for determining other components in circuit；Step 13 is adjusted
Zero-bit adjusts the resistance of amplification factor adjustment resistor in variable resistance and voltage amplifier circuit 3 in whole voltage reference circuit 1
Value exports the zero-bit of pressure sensor and meets the requirements with output valve when maximum pressure.
The present invention is with beneficial effect: pressure sensor of the present invention include circuit voltage reference circuit 1, sensitive electric bridge 2,
Voltage amplifier circuit 3,4 four part of current converter circuit.The pressure sensor circuit is put by reasonable selection voltage reference, operation
The main devices such as big device reduce the supply voltage of wheatstone presser sensor electric bridge, increase total null voltage partial pressure adjustment resistor
Resistance value makes the static consumption electric current of sensor signal conditioning circuit no more than 3.8mA, so that the debugging for meeting pressure sensor is wanted
It asks；By it is reasonable determine three amplifier magnifiers amplification factor, determine degeneration resistors in voltage amplifier circuit
On ceramic capacitor in parallel capacity, realize and the high magnification numbe of presser sensor electric bridge small-signal amplified, while have circuit
There is stability well.Pressure sensor circuit provided by the invention and its adjustment method may be implemented to sputtered film pressure
The output of 4mA~20mA two-wire system standard current signal is realized in the amplification of the muting sensitivities sensitivity bridge output signal such as sensitive electric bridge,
Small, the operation is stable, feature with high accuracy with static state consumption electric current.
Detailed description of the invention
Fig. 1 is pressure sensor circuit structural schematic diagram of the present invention；
Fig. 2 is pressure sensor adjustment method flow chart of the present invention；
Wherein: 1-voltage reference circuit, 2-sensitive electric bridges, 3-voltage amplifier circuits, 4-current converter circuits.
Specific embodiment
1 invention is further described in detail with reference to the accompanying drawings of the specification.
As shown in Figure 1, pressure sensor circuit includes voltage reference circuit 1, sensitive electric bridge 2, voltage amplifier circuit 3, electricity
Flow 4 four part of conversion circuit；Pressure sensor circuit includes electrical node VCC, IOUT、SGND、V+、Vref、Earth、+Vin、-
Vin and Vout；Voltage reference circuit 1 and node VCC, IOUT, SGND, V+, Vref be connected with Earth, sensitive electric bridge 2 passes through
Node SGND, V+ and voltage reference circuit 1 connect, and sensitive electric bridge 2 is connect by node+Vin ,-Vin with voltage amplifier circuit 3,
Voltage amplifier circuit 3 is connected by node V+, SGND, Vref and voltage reference circuit 1, and voltage amplifier circuit 3 passes through node
Vout is connect with current converter circuit 4, and current converter circuit 4 is connected by node V+, SGND and voltage reference circuit 1.
Voltage reference circuit 1 is power-switching circuit, including three end filter Z1 and Z2, switching diode D1, fixed electricity
Hinder device R1 and R2, transient voltage suppressor D2, capacitor C1, C2 and C3, voltage reference N1, adjustable resistor R200.Electricity
Pressing reference circuit 1 includes six electrical node power positive end VCC, current output terminal IOUT, signal ground SGND, voltage reference output
Hold V+, zero-bit adjustable voltage Vref and shielding ground Earth.The input terminal connecting node VCC of three end filter Z1, three end filters
The positive terminal of the output end connection switch diode D1 of Z1；The output end of three end filter Z2 connects IOUT；Three end filter Z1,
The ground terminal of Z2 is connect with node Earth；The negative pole end of one end connection switch diode D1 of fixed resister R1, the other end
The power input of the negative pole end of transient voltage suppressor D2, one end of capacitor C1 and C2, voltage reference N1 are connected simultaneously；
Output end, the connection positive terminal of transient voltage diode D2, the other end of capacitor C1 and C2, voltage base of three end filter Z2
The power supply negative terminal connection of quasi- N1 is connect with node SGND.One end of fixed resister R2 is connect with node V+, the other end and section
Point Vref connection；One end of variable resistance R200 is connect with node Vref, and the other end is connect with node SGND.Voltage reference electricity
The function on road 1 is by supply voltage through power input VCC and current output terminal IOUTPass through three end filter Z1 and Z2, switch
Diode D1, fixed resister R1, transient voltage suppressor D2 are inputed to after the processing of the devices such as capacitor C1, C2 and C3
Voltage reference device, voltage reference device export high-precision reference voltage by node V+, to sensitive electric bridge 2, power supply amplification
Circuit 3 and current converter circuit 4 provide operating voltage, meanwhile, the precision voltage reference exported using voltage reference circuit 1 is logical
It crosses fixed resister R2 and adjustable resistor R200 is divided, to provide adjustable high-accuracy voltage, pass through node Vref
Voltage amplifier circuit 3 is inputed to, for adjusting the zero-bit output voltage of voltage amplifier circuit 3.
Wheatstone presser sensor electric bridge 2 is the quick electric bridge of four arm strengths, has tetra- nodes of a, b, c, d, and node a is the defeated of electric bridge
Anode out, node b are the power positive end of electric bridge, and node c is the output negative terminal of electric bridge, and node d is the power supply negative terminal of electric bridge.Node
B is connect with the node V+ of voltage reference circuit 1, and node d is connect with 2 node SGND of voltage reference circuit.Wheatstone presser sensor
Electric bridge 2 is used to the pressure signal that pressure sensor inputs being converted into electric signal, exports differential electricity by node a and node c
Press signal.
Voltage amplifier circuit 3 is improved three amplifiers magnifier, and voltage amplifier circuit 3 includes operational amplifier
N2A, N2B and N2C, fixed resister R3, R4, R5, R6, R7 and R8, capacitor C4, C5 and C6, variable resistance R100.Node
+ Vin is connect with the node a of wheatstone presser sensor electric bridge 2, and the node c of node-Vin and wheatstone presser sensor electric bridge 2 connects
It connects；The positive input terminal of operational amplifier N2A is connect with node+Vin, the input terminal and fixed resister R4 of operational amplifier N2A
It is connected with one end of capacitor C4, the output end of operational amplifier N2A and the other end of fixed resister R4 and capacitor C4 connect
It connects.The positive input terminal of operational amplifier N2B is connect with node-Vin, the input terminal of operational amplifier N2B while and fixed resistance
Device R3 is connected with one end of capacitor C5, and the output end of operational amplifier N2B is simultaneously with fixed resister R3's and capacitor C5
Other end connection.One end of variable resistance R100 is connect with the negative input end of operational amplifier N2A, variable resistance R100's
The other end is connect with the negative input end of operational amplifier N2B.One end of resistor R5 and the output end of operational amplifier N2A connect
It connects, the other end of resistor R5 is connect with the negative input end of operational amplifier N2C.One end of resistor R6 and voltage reference circuit
1 node Vref connection, the other end of resistor R6 are connect with the positive input terminal of operational amplifier N2C.One end of resistor R7
It is connect with the output end of operational amplifier N2B, the other end of resistor R7 is connect with the positive input terminal of operational amplifier N2C.Fortune
The negative input end for calculating amplifier N2C is connect with one end of resistor R8 and capacitor C6 respectively, the output end of operational amplifier N2C
It is connect respectively with the other end of resistor R8 and capacitor C6.Node Vout is connect with the output end of operational amplifier N2C.Operation
The power positive end of amplifier N2A, N2B, N2C are connect with node V+, the power supply negative terminal and node of operational amplifier N2A, N2B, N2C
SGND connection.Voltage amplifier circuit 3 is to realize to amplify the difference voltage signal that sensitive electric bridge 2 exports by above-mentioned device
Afterwards, electric current conversion 4 is inputed to by node Vout, the adjustment to amplification factor is realized by R200.In voltage amplifier circuit 3
C4, C5 are connected in parallel on respectively in operational amplifier N2A, N2B degeneration resistors R3, R4, and main function is when presser sensor electric bridge 2
Noise and interference signal when the difference voltage signal of output is smaller, during elimination voltage amplification.
Current converter circuit 4 is improved Howland current pump circuit, including operational amplifier N2D, fixed resister
R9, R10, R11, R12, R13 and R14, capacitor C7 and C8, triode D3.One end of fixed resister R9 and voltage amplification electricity
The node Vout connection on road 3, the other end of fixed resister R9 are connect with the positive input terminal of operational amplifier N2D, and with fixation
One end of resistance R12 connects.One end of fixed resister R10 is connect with node SGND；The other end and fortune of fixed resister R10
Calculate the negative input end connection of amplifier N2D.One end of fixed resister R11 is connect with one end of capacitor C11, and is put with operation
The negative input end of big device N2D links together；The other end of fixed resister R11 is connect with the other end of capacitor C11, and with
One end of fixed resister R13, one end of capacitor C8, triode D3 emitter link together.Fixed resister R13's
The other end and node SGND, and connect with the other end of fixed resistance R12；The other end of capacitor C8 and the base stage of triode D3
Connection, and link together with the output end of operational amplifier N2D；One end of fixed resister R14 and the current collection of triode D3
Pole connection, the other end of fixed resister R14 are connect with node V+.The power positive end of operational amplifier N2D is connect with node V+,
The power supply negative terminal of operational amplifier N2D is connect with node SGND；Current converter circuit 4 is realized 3 output voltage of amplifying circuit
It is further amplified, and converts proportional current signal output.
The adjustment method of pressure sensor circuit of the present invention, in conjunction with Fig. 2 pressure sensor adjustment method flow chart, to specific
Implementation process is described in detail as follows:
Step 1:
Low-power consumption accurate device operational amplifier and voltage reference are selected according to Fig. 1 circuit, to guarantee pressure sensor electricity
The static consumption electric current on road is less than 3.8mA, meets the condition of two-wire system 4mA~20mA electric current output；
The alternative condition of operational amplifier are as follows: low static consumption electric current: described operational amplifier N2A, N2B, N2C and N2D
The static consumption electric current summation of the maximum of four-operational amplifier is I1；Permission works normally under single supply, low-voltage input condition；
For output voltage amplitude as close possible to working power voltage, track to track operational amplifier is especially suitable；
The alternative condition of voltage reference are as follows: low static consumption electric current, if the static consumption electric current of the maximum of voltage reference is I2；
Output voltage amplitude can be programmed or be can adjust by output pin；Output voltage has the characteristics that high-precision；
Step 2:
In the case where sensitive electric bridge difference is powered, in maximum operating range, the minimum internal resistance value of sensitive electric bridge is measured
RB, as the foundation for determining that voltage reference output voltage amplitude calculates；
Step 3:
The calculation method of the output voltage amplitude value range of voltage reference are as follows: Uo < ﹙ 3.8-I1-I2﹚ × RB；
Step 4:
Static consumption electric current in order to guarantee pressure sensor circuit is electric to meet the pressure sensor no more than 3.8mA
Road has the condition of adjustable.Then there is the value range of determining zero-bit adjustment benchmark fixed resister R2 resistance value are as follows: R2 ≥ ﹙
3.8-I1-I2-Uo/RB﹚.
Output voltage amplitude value range, the zero-bit of the main devices, voltage reference that are determined respectively by steps 1 and 2,3,4
The value range for adjusting benchmark fixed resister R2 resistance value ensure that the static consumption electric current of pressure sensor circuit is less than
3.8mA meets the commissioning requirements of pressure sensor.
Step 5:
The resistance value of main fixed resister, should meet the following conditions: R9=R10, R11 in preset current conversion circuit 4
The resistance value of=R12, R11, R12 are much larger than R13, should meet R13≤0.1% × R11, and the Ω of R13 >=100.
The matching of R9 and R10, R11 and R12 make voltage signal amplify more accurate, R13≤0.1% × R11, it is therefore an objective to mention
The output impedance of high current conversion circuit 4.
Step 6:
According to the resistance value of above-mentioned preset each fixed resister of current converter circuit 4, calculation pressure sensor is completely measured
When journey exports, the voltage value calculating formula of 3 output end vo ut of voltage amplifier circuit are as follows: Uout=(IOMAX×R13)×R9/R12.Its
Middle IOMAXFor the maximum output current amplitude of pressure sensor.
Step 7:
According to the output sensitivity of presser sensor electric bridge, the amplification factor of voltage amplifier circuit 3 is determined.If presser sensor is electric
The output voltage sensitivity of bridge is Vs, then the amplification factor A=Uout/ (Vs × Uo) of voltage amplifier circuit 3.Voltage amplifier circuit
3 amplification factor A should be not more than 150.
It, should be again preset according to fixed resister in step 5 change current converter circuit 4 if being unsatisfactory for above-mentioned requirements
Resistance value, when specific amplification suitably reduces the resistance value of R9.
Step 8:
According to the maximum input offset current I of operational amplifierBWith maximum input bias current IOS, and sensitive electric bridge
Minimum zero-bit output voltage UBMIN, determine the maximum value of amplification factor adjustment resistance R100.Calculation method is as follows: R100≤
UBMIN/(IB+IOS)。
Step 9:
According to the amplification factor A and amplification factor of voltage amplifier circuit 3 adjust resistance R100, calculate fixed resister R3,
The resistance value value range of R4, calculation method are as follows: R3=R4≤R100 × (A-1)/2.
The Standard resistance range of R100, the value range of step 9 control R3 and R4 are controlled by step 8, makes operational amplifier work
Make to reduce the influence for amplifying small-signal due to the input offset current and bias current of operational amplifier in optimum state,
Improve the stability of amplification voltage.
Step 10:
The resistance value of remaining fixed resister in selected voltage amplifier circuit 3.The following conditions should be met: R5=R6=R7=
R8≥10kΩ。
Step 11:
In debugging, the output of presser sensor electric bridge is maintained at zero-bit output, keeping R100 is that maximum value is constant, adjustment
The resistance value of R200 makes the output current value 4mA of pressure sensor circuit, observes the jump situation of current value.In above-mentioned condition,
The capacitance of C3, C4 are gradually increased from ceramic capacitor C3=C4=0.01uF, until after output is stablized, then by the electricity of C3, C4
Capacity increases 50%, as the final value of C3, C4 capacitance, to guarantee that the work of voltage amplifier circuit 3 in stable state, avoids
The fluctuation of output voltage and the output for influencing pressure sensor.
Step 12:
The requirements such as the Electro Magnetic Compatibility according to pressure sensor determine the parameter of other components in circuit, as Z1, Z2,
The specification and parameter of the devices such as D1, D2, C1, C2, R1, R14.
Step 13:
By adjusting variable resistance R100 and R200, exporting the zero-bit of pressure sensor is 4mA, and when maximum pressure is defeated
It is out 20mA.
Embodiment
As shown in Fig. 2, sensitive electric bridge 2 selects sputtered film presser sensor electric bridge, output sensitivity 1.5mV is sensitive
The bridge resistance minimum value of electric bridge is 3.2k Ω, and minimum zero-bit output voltage is 0.1mV, and implementation steps are as follows:
Step 1, selection low-power consumption accurate device operational amplifier and voltage reference:
Main low-power consumption accurate device operational amplifier and voltage reference are selected according to Fig. 1 circuit.
The alternative condition of operational amplifier are as follows: low static consumption electric current: described operational amplifier N2A, N2B, N2C and N2D
The static consumption electric current summation of the maximum of four-operational amplifier is I1, then should have I1≤1.5mA；Allow in single supply, low-voltage input
Under the conditions of work normally；For output voltage amplitude as close possible to working power voltage, track to track operational amplifier is especially suitable.Such as
The low-power consumption four-way operational amplifiers such as track to track four-way operational amplifier OP491 or ADA4091-4 are selected, tune can be met
Examination requires.
The alternative condition of voltage reference are as follows: low static consumption electric current, if the static consumption electric current of the maximum of voltage reference is I2,
Should then there be I2≤1.2mA；Output voltage amplitude can be programmed or be can adjust by output pin；Output voltage has high-precision
Feature.Such as programmable high-precision voltage reference AD584.
Step 2, the minimum internal resistance value for measuring sensitive electric bridge:
In the case where sensitive electric bridge difference is powered, in maximum operating range, the minimum internal resistance value of sensitive electric bridge is measured
RB。
The sputtered film presser sensor electric bridge of selection, the minimum internal resistance value R in operating temperature rangeB=3.2k Ω.
Step 3, the output voltage amplitude for determining voltage reference:
The output voltage amplitude of voltage reference: Uo < ﹙ 3.8-I is determined by calculating formula1-I2﹚ × RB。
The track to track four-way operational amplifier OP491 that step 1 selects, maximum static consumption electric current I1≤1.2mA；It can
Program high-precision voltage reference AD584, maximum static consumption electric current I2≤1.0mA.And the minimum internal resistance value R of sensitive electric bridgeB=
3.2k Ω then has Uo < ﹙ 3.8-I1-I2﹚ × RB=5.12V.
The output voltage of programmable high-precision voltage reference AD584 is selected as Uo=5V.
Step 4, the resistance value for determining zero-bit adjustment benchmark fixed resister R2:
Determine the resistance value of zero-bit adjustment benchmark fixed resister R2.In order to guarantee the static consumption of pressure sensor circuit
Electric current meets the condition that the pressure sensor circuit has adjustable no more than 3.8mA.Then have: R2 ≥ ﹙ 3.8-I1-I2-
Uo/RB﹚.
According to above-mentioned confirmable parameter, it may be determined that R2 >=133k Ω can use R2=200k Ω.
The resistance value of main fixed resister in step 5, preset current conversion circuit 4；
The resistance value of main fixed resister, should meet the following conditions: R9=R10, R11 in preset current conversion circuit 4
The resistance value of=R12, R11, R12 are much larger than R13, should generally meet R13≤0.1% × R11, and the Ω of R13 >=100.
According to the resistance value of fixed resister main in above-mentioned condition preset current conversion circuit 4, R9=R10=is such as taken
47k Ω, R11=R12=200k Ω, R13=150 Ω.
Step 6, the voltage value for calculating 3 output end vo ut of voltage amplifier circuit:
According to the resistance value of above-mentioned preset each fixed resister of current converter circuit 4, calculation pressure sensor is completely measured
When journey exports, the voltage value calculating formula of 3 output end vo ut of voltage amplifier circuit are as follows: Uout=(IOMAX×R13)×R9/R12.Its
Middle IOMAXFor the maximum output current amplitude of pressure sensor, IOMAX=(20-4) mA=16mA.
Then Uout=(I(OMAX)× R13) × R9/R12=564mV.
Step 7, the amplification factor for determining voltage amplifier circuit 3:
According to the output sensitivity of presser sensor electric bridge, the amplification factor of voltage amplifier circuit 3 is determined.If presser sensor is electric
The output voltage sensitivity of bridge is Vs, then the amplification factor A=Uout/ (Vs × Uo) of voltage amplifier circuit 3.Voltage amplifier circuit
3 amplification factor A should be not more than 150.
It, should be again preset according to fixed resister in step 5 change current converter circuit 4 if being unsatisfactory for above-mentioned requirements
Resistance value, when specific amplification suitably reduces the resistance value of R9.
The sputtered film presser sensor electric bridge of above-mentioned use, the sensitivity of output voltage are 1.5mV/V, then can according to above formula
Amplification factor A=Uout/ (Vs × Uo)=75.2 < 150 for calculating voltage amplifier circuit 3, meets design requirement.
Step 8, the maximum value for determining amplification factor adjustment resistance R100:
According to the maximum input offset current I of operational amplifierBWith maximum input bias current IOS, and sensitive electric bridge
Minimum zero-bit output voltage UBMIN, determine the maximum value range of amplification factor adjustment resistance R100.Calculation method is as follows: R100
≤UBMIN/(IB+IOS)。
It inquires known to OP491 tables of data: the maximum input offset current I of operational amplifierB=95nA, maximum input biasing
Electric current IOS=22nA.The sputtered film presser sensor electric bridge of above-mentioned use is measured under the conditions of operating voltage Uo, minimum output electricity
Press UBMIN=0.1mV.
Amplification factor adjusts resistance R100≤UBMIN/(IB+IOSThe Ω of)=854.7.
Step 9, the value range for determining fixed resister R3, R4:
According to the amplification factor A and amplification factor of voltage amplifier circuit 3 adjust resistance R100, calculate fixed resister R3,
The resistance value of R4, calculation method are as follows: R3=R4≤R100 × (A-1)/2.
The parameter determined according to abovementioned steps: the Ω of A=75.2, R100≤854.7 is calculated: R3=R4=≤R100 ×
(A-1)/2=31.709k Ω.
Based on the above calculated values, the stability margin for considering holding circuit takes R3=R4=15k Ω.
The resistance value of remaining fixed resister in step 10, selected voltage amplifier circuit 3:
The resistance value of remaining fixed resister, should meet the following conditions: R5=R6=R7=in selected voltage amplifier circuit 3
R8≥10kΩ。
Select R5=R6=R7=R8=200k Ω.
Step 11, the capacitance for determining capacitor C3, C4:
In debugging, the output of presser sensor electric bridge is maintained at zero-bit output, keeping R100 is that maximum value is constant, adjustment
The resistance value of R200 makes the output current value 4mA of pressure sensor circuit, observes the jump situation of current value.In above-mentioned condition,
The capacitance of C3, C4 are gradually increased from ceramic capacitor C3=C4=0.01uF, until after output is stablized, then by the electricity of C3, C4
Capacity increases 50%.
According to the above method, as C3=C4=0.47uF, zero current output is stablized；Therefore final to choose C3=C4=
1uF。
Step 12, the parameter of other components in circuit is determined:
Electro Magnetic Compatibility according to pressure sensor etc. itself it is determined that in circuit other components parameter, as Z1, Z2,
The specification and parameter of the devices such as D1, D2, C1, C2, R1, R14.
Step 13, adjustment variable resistance R100 and R200:
By adjusting variable resistance R100 and R200, exporting the zero-bit of pressure sensor is 4mA, and when maximum pressure is defeated
It is out 20mA.
It is with good stability according to the pressure sensor that foregoing circuit structure and adjustment method design by verifying,
Composition error is respectively less than ± 1% in (- 40~70) DEG C temperature range.
Claims (8)
1. a kind of pressure sensor circuit, it is characterised in that: including voltage reference circuit (1), sensitive electric bridge (2), voltage amplification
Circuit (3), (4) four part of current converter circuit, wherein pressure sensor includes electrical node VCC, IOUT、SGND、V+、
Vref, Earth ,+Vin ,-Vin and Vout；Voltage reference circuit (1) and node VCC, IOUT, SGND, V+, Vref and Earth phase
Connection, sensitive electric bridge (2) are connected by node SGND, V+ and voltage reference circuit (1), sensitive electric bridge (2) by node+
Vin ,-Vin are connect with voltage amplifier circuit (3), and voltage amplifier circuit (3) passes through node V+, SGND, Vref and voltage reference electricity
Road (1) connection, voltage amplifier circuit (3) are connect by node Vout with current converter circuit (4), and current converter circuit (4) is logical
It crosses node V+, SGND and voltage reference circuit (1) connects, wherein described electrical node VCC, IOUT、SGND、V+、Vref、
The electrical Location of Earth ,+Vin ,-Vin, Vout are respectively that the power input of pressure sensor, the electric current of pressure sensor are defeated
Outlet, signal ground, the output end of voltage reference circuit, zero-bit debugging voltage output end, shielding ground, voltage amplifier circuit (3)
Positive input terminal, the negative input end of voltage amplifier circuit (3), voltage amplifier circuit (3) output end；Voltage reference circuit (1)
Output voltage amplitude determines by the following method: Uo < ﹙ 3.8-I1-I2﹚ × RB, wherein Uo is the output voltage of voltage reference, RB
For the minimum internal resistance value of sensitive electric bridge (2), I1For the static consumption electric current of maximum of four-way operational amplifier, I2To set voltage base
The static consumption electric current of quasi- maximum determines the calculation method of the fixed resister R2 resistance value range of zero-bit adjustment benchmark are as follows: R2
≥ ﹙ 3.8-I1-I2-Uo/RB﹚, the one end the fixed resister R2 are connect with node V+, and the other end is connect with node Vref.
2. pressure sensor circuit according to claim 1, which is characterized in that voltage reference circuit (1) is filtered including three ends
Wave device Z1 and Z2, switching diode D1, fixed resister R1, transient voltage suppressor D2, capacitor C1, C2 and C3 are electric
Press benchmark N1, adjustable resistor R200；Voltage amplifier circuit (3) includes operational amplifier N2A, N2B and N2C, fixed resister
R3, R4, R5, R6, R7 and R8, capacitor C4, C5 and C6, variable resistance R100；Current converter circuit (4) includes operation amplifier
Device N2D, fixed resister R9, R10, R11, R12, R13 and R14, capacitor C7 and C8, triode D3；The operational amplifier
N2A, N2B, N2C and N2D are low consumed power operational amplifier, and voltage reference circuit (1) selects the voltage reference device of low-power consumption.
3. pressure sensor circuit according to claim 2, which is characterized in that described fixed resister R2, R3, R4 ...
R13, R14 select the resistance device of low inductance, wherein resistance value R3=R4≤50k Ω, R5=R6=R7=R8 >=10k Ω,
R9=R10, R11=R12 meet R13≤0.1% × R11, and the Ω of R13 >=100.
4. pressure sensor circuit according to claim 3, which is characterized in that according to preset in current converter circuit (4)
Each fixed resister resistance value, calculate voltage amplifier circuit (3) output end vo ut voltage value Uout, calculation method are as follows:
Uout=(IOMAX× R13) × R9/R12, wherein IOMAXFor the maximum output current amplitude of pressure sensor.
5. pressure sensor circuit according to claim 4, which is characterized in that the amplification factor A of voltage amplifier circuit (3)
=Uout/ (Vs × Uo), wherein the output voltage sensitivity of presser sensor electric bridge is Vs, the times magnification of voltage amplifier circuit (3)
Number A should be not more than 150；If the amplification factor A of voltage amplifier circuit (3) is unsatisfactory for requiring, electric current conversion should be changed again
The preset resistance value of fixed resister in circuit (4), method particularly includes: it keeps the resistance value of R11, R12, R13 constant, synchronizes and subtract
The resistance value of small R9, R10, until making amplification factor A≤150 of voltage amplifier circuit (3).
6. pressure sensor circuit according to claim 5, which is characterized in that lost according to the maximum input of operational amplifier
Adjust electric current IBWith maximum input bias current IOS, and the minimum zero-bit output voltage U of sensitive electric bridgeBMIN, determine amplification factor
The maximum value range of resistance R100 is adjusted, calculation method is as follows: R100≤UBMIN/(IB+IOS)。
7. pressure sensor circuit according to claim 6, it is characterised in that: in debugging, by presser sensor electric bridge
Output is maintained at zero-bit output, and keeping R100 is that maximum value is constant, adjusts the resistance value of R200, makes the output of pressure sensor circuit
Current value is 4mA, observes the jump situation of current value, under the above conditions, gradually from ceramic capacitor C3=C4=0.01uF
Increase the capacitance of C3, C4, until after output is stablized, then by the capacitance increase 50% of C3, C4, as C3, C4 capacitance
Final value.
8. a kind of adjustment method based on pressure sensor circuit described in claim 1, which is characterized in that detailed process is such as
Under: low-power consumption accurate device operational amplifier and voltage reference in step 1, selection voltage reference circuit (1), step 2, measurement are quick
Inductance bridge (2) minimum internal resistance value, step 3, the output voltage amplitude for determining voltage reference in voltage reference circuit (1), step 4,
The resistance value for determining zero-bit adjustment benchmark fixed resister in voltage reference circuit (1), passes through step 1, step 2, step 3, step
Minimum internal resistance value, the voltage reference of the rapid 4 low-power consumption accurate device operational amplifiers determined respectively and voltage reference, sensitive electric bridge
Output voltage amplitude value range, zero-bit adjustment benchmark fixed resister R2 resistance value value range, guarantee pressure sensing
The static consumption electric current of device circuit is less than 3.8mA, meets the commissioning requirements of pressure sensor；Step 5, preset current conversion circuit
(4) resistance value of fixed resister in keeps voltage signal amplification more accurate, improves the output impedance of current converter circuit (4)；
Step 6, the voltage value for calculating voltage amplifier circuit (3) output end vo ut, step 7, the times magnification for determining voltage amplifier circuit (3)
Number, step 8, the maximum value for determining amplification factor adjustment resistor in voltage amplifier circuit (3), step 9, selected voltage amplification
Resistance value value range in circuit (3) for the negative-feedback fixed resister of two operational amplifiers of differential amplification, passes through
The maximum value of amplification factor adjustment resistor in voltage amplifier circuit (3) is realized, for the two of differential amplification in step 6,7,8,9
The resistance value value range of the negative-feedback fixed resister of a operational amplifier makes operational amplifier work in optimum state, subtracts
The influence that small input offset current and bias current due to operational amplifier amplifies small-signal improves the steady of amplification voltage
It is qualitative；The resistance value of fixed resister R5, R6, R7, R8 in step 10, selected voltage amplifier circuit (3)；Step 11 determines electricity
The capacitance in amplifying circuit (3) for the negative feedback capacitor of two operational amplifiers of differential amplification is pressed, to guarantee voltage
Amplifying circuit (3) works in stable state, avoids the fluctuation of output voltage and influences the output of pressure sensor；Step 12, really
Determine the parameter of other components in circuit, other components include Z1, Z2, D1, D2, C1, C2, R1, R14；Step 13, adjustment electricity
Zero-bit in reference circuit (1) is pressed to adjust the resistance that amplification factor in variable resistance and voltage amplifier circuit (3) adjusts resistor
Value exports the zero-bit of pressure sensor and meets the requirements with output valve when maximum pressure.
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| US10215653B2 (en) * | 2017-04-06 | 2019-02-26 | Nxp Usa, Inc. | Signal interface circuit and pressure sensor system including same |
| CN108871633B (en) * | 2017-05-10 | 2021-11-30 | 盾安传感科技有限公司 | Signal conditioning circuit of pressure sensor |
| CN108151771A (en) * | 2017-12-20 | 2018-06-12 | 哈尔滨广瀚燃气轮机有限公司 | A kind of gas turbine throttle position transmitter |
| US11877864B2 (en) * | 2019-05-29 | 2024-01-23 | Measurement Specialties, Inc. | Voltage nulling pressure sensor preamp |
| CN112179528A (en) * | 2020-08-21 | 2021-01-05 | 武汉中航传感技术有限责任公司 | CMOS integrated circuit and pressure sensor |
| CN112379246B (en) * | 2020-11-17 | 2024-05-17 | 西北机电工程研究所 | Method for debugging interface circuit of thin film type pressure sensor based on wearable equipment |
| CN113984251B (en) * | 2021-10-26 | 2023-09-22 | 西安微电子技术研究所 | Debugging method of silicon piezoresistive pressure sensor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201293698Y (en) * | 2008-12-02 | 2009-08-19 | 西安中星测控有限公司 | Pressure transmitter with temperature compensation circuit |
| CN201331406Y (en) * | 2008-12-02 | 2009-10-21 | 西安中星测控有限公司 | Intelligent pressure transmitter |
| CN103905027A (en) * | 2012-12-28 | 2014-07-02 | 北京谊安医疗***股份有限公司 | Circuit for converting voltage signals into 4-20mA current signals |
| CN203719620U (en) * | 2014-03-03 | 2014-07-16 | 陈维林 | Portable low-power static state resistance strain gauge |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5950327A (en) * | 1982-09-16 | 1984-03-23 | Yamatake Honeywell Co Ltd | Current-pressure transducer |
| JPH11337430A (en) * | 1998-05-26 | 1999-12-10 | Yokogawa Electric Corp | Bridge-type sensor |
-
2016
- 2016-05-06 CN CN201610296426.5A patent/CN105973509B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201293698Y (en) * | 2008-12-02 | 2009-08-19 | 西安中星测控有限公司 | Pressure transmitter with temperature compensation circuit |
| CN201331406Y (en) * | 2008-12-02 | 2009-10-21 | 西安中星测控有限公司 | Intelligent pressure transmitter |
| CN103905027A (en) * | 2012-12-28 | 2014-07-02 | 北京谊安医疗***股份有限公司 | Circuit for converting voltage signals into 4-20mA current signals |
| CN203719620U (en) * | 2014-03-03 | 2014-07-16 | 陈维林 | Portable low-power static state resistance strain gauge |
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