CN110631610A - Resistive sensor array test circuit based on two-wire system equipotential method - Google Patents
Resistive sensor array test circuit based on two-wire system equipotential method Download PDFInfo
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- CN110631610A CN110631610A CN201810640921.2A CN201810640921A CN110631610A CN 110631610 A CN110631610 A CN 110631610A CN 201810640921 A CN201810640921 A CN 201810640921A CN 110631610 A CN110631610 A CN 110631610A
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/16—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance
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Abstract
The invention discloses a resistive sensor array test circuit based on a two-wire system equipotential method, and belongs to the technical field of sensors. The test circuit being directed to common row and column linesMA x N two-dimensional resistive sensor array; the test circuit includes: a current feedback operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NThe device comprises a multi-way switch for selecting one from the row lines, a test current setting resistor, a reference voltage source and two connecting wires which are respectively arranged for each row line and each column line of the resistive sensor array. The invention also discloses a test method of the test circuit and a sensing system. Compared with the prior art, the method takes a two-wire system equipotential method as a key technology, can effectively eliminate the measurement errors generated by the lead resistance of the connecting cable, the contact resistance of the cable joint and the conduction resistance of the multi-way switch channel, and greatly improves the measurement precision of the resistive sensor array.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a resistive sensor array test circuit.
Background
The array type sensing device is a device which combines a plurality of sensing elements with the same performance according to the structure of a two-dimensional array, and can change or generate corresponding forms and characteristics by detecting the change of parameters focused on the array. This feature is widely used in biosensing, temperature sensing, and thermal imaging based on infrared sensors, among others.
The resistive sensor array is widely applied to an infrared imaging simulation system, force touch sensing and temperature touch sensing. Taking the temperature sense of touch as an example, because the temperature sense sensing device involves heat transfer and temperature sensing, the device puts high requirements on temperature measurement accuracy and resolution for obtaining the thermal properties of the object, and puts high requirements on spatial resolution capability for further obtaining the thermal properties represented by different position materials of the object.
The quality or resolution of a resistive sensor array needs to be increased by increasing the number of sensors in the array. However, as the size of the sensor array increases, information acquisition and signal processing for all components becomes difficult. Typically, all of the resistive sensors of an M x N array are accessed individually, each resistive sensor having two ports, requiring 2 x M x N connecting wires. The connection mode not only has complex connection, but also can only select a single resistor to be tested each time, and has slow scanning speed, long period and low efficiency. To reduce the complexity of device interconnections, researchers have proposed two-dimensional array structures that share row and column lines. FIG. 1 shows the structure of a two-dimensional resistive sensor array sharing row and column lines. As shown in FIG. 1, the sensor array includes two sets of orthogonal lines as common row lines and common column lines, respectivelyM×NThe two-dimensional structure of the physical quantity sensitive resistor (i.e. resistive sensor) array is distributed, one end of each physical quantity sensitive resistor in the array is connected with a corresponding row line, the other end is connected with a corresponding column line, each resistor in the array has a unique combination of the row line and the column line and is positioned at the second positioniGo to the firstjFor resistance of the columnR ij It is shown that, among others,Min the case of the number of rows,Nis the number of columns. With such a structure, can be made as followsM×NOf the two-dimensional structure of (2) only requiresM+NThe number of wires ensures that any one particular resistive element can be accessed by controlling the corresponding combination of row and column lines, and therefore the number of wires required is greatly reduced.
The method comprises the steps of connecting a test circuit through a long cable, connecting a plurality of leads of the long cable with lead resistors, wherein the resistance values of the lead resistors are basically the same among the leads made of materials with equal length and the like and are increased along with the increase of the length of the cable, connecting contacts between a plug and a socket of the cable with contact resistors, and changing the resistance values of the contact resistors within a certain range (about 0 ~ 3 omega) according to different contact states (the contact states of the contacts change along with time, mechanical vibration and the like) of each pair of contacts.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a resistive sensor array test circuit based on a two-wire system equipotential method and a test method thereof, which can effectively eliminate measurement errors generated by connecting cable lead resistance, cable joint contact resistance and multi-channel switch channel on-resistance and greatly improve the measurement accuracy of a resistive sensor array.
The invention specifically adopts the following technical scheme to solve the technical problems:
resistive sensor array test circuit based on two-wire system equipotential method, wherein the resistive sensor array shares row wires and column wiresMA x N two-dimensional resistive sensor array; the test circuit includes: a current feedback operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NA multi-way switch for selecting one from multiple column lines, a test current setting resistor, a reference voltage source, and a resistor for each column line and row line of the resistive sensor arrayTwo connecting wires are arranged;Na plurality of row line driving operational amplifiers,NMultiple switches for selecting one from two column lines and resistive sensor arrayNThe row lines are in one-to-one correspondence, each row line is connected with the output end of the corresponding row line driving operational amplifier through a connecting line, the row line is connected with the inverting input end of the corresponding row line driving operational amplifier through another connecting line, and the non-inverting input end of each row line driving operational amplifier is connected with a zero potential or the output end of the current feedback operational amplifier through the common end of the alternative multi-way switch of the row line corresponding to the non-inverting input end of the row line driving operational amplifier; equipotential potentialMSelecting a multiple-way switchMIndependent end, equal currentMSelecting a multiple-way switchMA separate terminal andMthe row lines are in one-to-one correspondence, and each row line is in equipotential with the corresponding row line through a connecting lineMThe corresponding independent ends of one multi-way switch are connected and connected with equal current through another connecting wireMSelecting corresponding independent ends of a multi-way switch to be connected; equipotential potentialMThe common end of a selected multi-way switch is connected with the inverting input end of the current feedback operational amplifier, and the non-inverting input end of the current feedback operational amplifier is connected with a zero potential; constant currentMAnd the common end of one of the multi-way switches is connected with one end of a test current setting resistor, and the other end of the test current setting resistor is connected with a reference voltage source.
As for any resistive sensor to be tested in the resistive sensor array, the method for testing the test circuit first gates the resistive sensor to be tested, which specifically includes the following steps: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential, and the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential through equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula
：
Wherein the content of the first and second substances,
the potential at the output terminal of the operational amplifier is fed back for current,
setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,
a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
The following technical scheme can be obtained according to the same invention concept:
resistive sensor array test circuit based on two-wire system equipotential method, wherein the resistive sensor array shares row wires and column wiresMA x N two-dimensional resistive sensor array; wherein the test circuit comprises: a current feedback operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NThe circuit comprises a multi-way switch for selecting one from multiple column lines, a test current setting resistor, a reference voltage source and two connecting wires which are respectively arranged for each row line and column line of the resistive sensor array;Na plurality of row line driving operational amplifiers,NMultiple switches for selecting one from two column lines and resistive sensor arrayNThe row lines are in one-to-one correspondence, each row line is connected with the output end of the corresponding row line driving operational amplifier through a connecting line, the row line is connected with the reverse phase input end of the corresponding row line driving operational amplifier through another connecting line, and the non-phase input end of each row line driving operational amplifier is more than one selected from the row lines corresponding to the row line driving operational amplifierThe common end of the circuit switch is connected with a reference voltage source or the output end of the current feedback operational amplifier; equipotential potentialMSelecting a multiple-way switchMIndependent end, equal currentMSelecting a multiple-way switchMA separate terminal andMthe row lines are in one-to-one correspondence, and each row line is in equipotential with the corresponding row line through a connecting lineMThe corresponding independent ends of one multi-way switch are connected and connected with equal current through another connecting wireMSelecting corresponding independent ends of a multi-way switch to be connected; equipotential potentialMThe common end of one of the multi-way switches is connected with the inverting input end of the current feedback operational amplifier, and the non-inverting input end of the current feedback operational amplifier is connected with a reference voltage source; constant currentMThe common end of one of the multi-way switches is connected with one end of a test current setting resistor, and the other end of the test current setting resistor is connected with zero potential.
As for any resistive sensor to be tested in the resistive sensor array, the method for testing the test circuit first gates the resistive sensor to be tested, which specifically includes the following steps: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with the reference voltage source, and the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with the reference voltage source through equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula
：
Wherein the content of the first and second substances,the potential at the output terminal of the operational amplifier is fed back for current,
setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
A sensing system comprising an array of resistive sensors sharing row and column lines and a corresponding test circuitMThe resistance sensor array testing circuit is a resistance sensor array testing circuit based on the two-wire system equipotential method.
Compared with the prior art, the invention has the following beneficial effects:
1. aiming at the detection requirement of the resistive sensor array, on the basis of not improving the interconnection complexity of the array, a two-wire system voltage feedback method is taken as a key technology, so that the crosstalk error caused by the channel conduction resistance of a multi-channel selector, the contact resistance of a test cable joint and a long test cable is effectively eliminated, the measurement precision is improved, and meanwhile, the resistance range of a physical quantity sensitive resistor in the resistive sensor array is expanded; the invention can also effectively eliminate the interference of space electromagnetic noise;
2. the low-cost multiplexer with large channel on-resistance can be applied to the resistive sensor array, so that the cost of the test circuit is reduced;
3. the influence of the cable joint contact with the resistance value changing along with time and the contact state on the measurement precision of the resistive sensor array is eliminated, so that the resistive sensor array or a test circuit thereof can be replaced by the application system through a plug and a socket which are convenient to insert and pull, and the measurement precision of the application system can be ensured.
4. The crosstalk error caused by the long test cable is eliminated, so that the long test cable can be applied to a resistive sensor array, and the flexible resistive sensor array is particularly suitable for the measurement of the flexible resistive sensor array with the requirement on the space size of a test circuit.
Drawings
FIG. 1 is a schematic view of a common row and column lineMThe structure schematic diagram of the x N two-dimensional resistive sensor array;
FIG. 2 is a schematic diagram of an equipotential testing circuit of a conventional shared row-column resistive sensor array;
FIG. 3 is a test principle equivalent diagram of the test circuit of FIG. 2;
FIG. 4 is a schematic diagram of one embodiment of a test circuit of the present invention;
FIG. 5 is a test principle equivalent diagram of the test circuit of FIG. 4;
FIG. 6 is a schematic diagram of another embodiment of a test circuit of the present invention;
fig. 7 is a test principle equivalent diagram of the test circuit of fig. 6.
Detailed Description
The technical scheme of the invention is explained in detail in the following with the accompanying drawings:
the principle of an equipotential test circuit sharing a row-column resistive sensor array is shown in fig. 2, fig. 3 is an equivalent diagram of the test principle, and the current unit under test in the diagramR xy Is composed ofM×NIn arrays of shared row-column line resistive sensorsR 11 . In this circuit there is only one connection line between each row or column line of the array and the test circuit. In ideal working state, the circuit has channel on-resistance of one-out-of-two multi-way switch for all column linesR sc Cumulative resistance of lead resistance and joint contact resistance of drive connecting wireR Lc Is ignored, thusR xy Voltage of column lineV cy =V xy The voltage of the other column line is 0; simultaneous equal currentMChannel on-resistance of one-by-one multi-way switchR sr Cumulative resistance of lead resistance and joint contact resistance of equal current connecting wireR Lr Neglected, due to the action of ideal current feedback operational amplifier, the unit under testVoltage of column lineV rx =0. Due to voltages of other column lines andV rx equal, so that of the unit under test: (N-1) the current on the row adjacent cell is 0; meanwhile, the reverse input end of the current feedback operational amplifier has large impedance, and the leakage current is ignored, so thatR xy Current ofI xy And testing the current setting resistanceR set Current ofI set Is equal toI set =-V I /R set =V xy /R xy . Due to the fact thatV I AndR set in the known manner, it is known that,R xy voltage ofV xy Can be measured and then calculatedR xy 。
Under the actual working condition of the test circuit, the channel on-resistance of the two-way switch of the column line of the tested unitR sc Cumulative resistance of lead resistance and joint contact resistance of drive connecting wireR Lc Is present, resulting inV cy AndV xy not equal; at the same time, the current is equal in the row line direction of the tested unitMChannel on-resistance of one-by-one multi-way switchR sr Cumulative resistance of lead resistance and joint contact resistance of equal current connecting wireR Lr Is present, resulting inV rx Not equal to 0. The ideal isolation working condition of the circuit tested by the equal potential method is destroyed by the two main factors caused by the channel on-resistance of the row connecting cable, the column connecting cable and the multi-way switch, so that the ideal isolation working condition is ensuredR xy The measurement error becomes large.
In order to overcome the defects of the test circuit shown in FIG. 2 and eliminate the influence of the lead resistance of the connecting cable, the contact resistance of the cable joint, the channel conduction resistance of the multi-way switch and the like, the invention provides a resistive sensor array test circuit based on a two-wire system equipotential method, and the equipotential method of a double-connecting wire is utilized to measure the common potentialA row and column line resistive sensor array is used. FIG. 4 shows the basic principle of an embodiment of the test circuit of the present invention, in which the current unit under test is shownR xy Is composed ofM×NIn arrays of shared row-column line resistive sensorsR 11 (ii) a Fig. 5 is a test principle equivalent diagram of the test circuit shown in fig. 4. Compared with the prior art test circuit of FIG. 2, as shown in FIG. 4, the present invention isM×NEach row line and column line of the shared row-column line resistive sensor array are additionally provided with a connecting line, namely each column line and each column line correspond to two connecting lines (for convenience of distinction, from the functional point of view, the two connecting lines of the same row line are respectively called a driving connecting line and a driving sampling following connecting line, and the two connecting lines of the same column line are respectively called an equal current connecting line and an equal potential connecting line); meanwhile, an operational amplifier is added to each column driving end of the test circuit, and the operational amplifier is used as a column line driving operational amplifier. Thus, in the equipotential method test circuit of the double-connection line, a current feedback operational amplifier is arrangedNThe same-phase input end of each column line driving operational amplifier is correspondingly connected with a column line alternative multi-way switch, and an equipotential is indirectly arranged between the reverse-phase input end and the row line of the current feedback operational amplifierMSelecting a multi-way switch to set the resistance at the test currentR set The column line is also connected with an equal currentMSelecting a multi-way switch; that is, each row line is connected to the equipotential line through an equipotential connecting lineMCorresponding independent ends of a multi-way switch are selected to be connected and connected with equal current through another equal current connecting wireMSelecting corresponding independent ends of a multi-way switch to be connected; equipotential potentialMThe common end of a selected multi-way switch is connected with the inverting input end of the current feedback operational amplifier, and the non-inverting input end of the current feedback operational amplifier is connected with a zero potential; constant currentMAnd the common end of one of the multi-way switches is connected with one end of a test current setting resistor, and the other end of the test current setting resistor is connected with a reference voltage source.
As shown in fig. 4, each column line of the common row line resistive sensor array module is connected to the output end of its corresponding column line driving op-amp via a driving connection line, and the column lines are connected to the output end of the corresponding column line driving op-ampThe other driving sampling following connecting wire is connected with the reverse phase input end of the corresponding column line driving operational amplifier; the non-inverting input end of each column line driving operational amplifier is connected with zero potential or feedback voltage through the common end of a corresponding column line two-way or one-way switchV xy Connecting; gating feedback voltage of non-inverting input end of column line driving operational amplifier where tested unit is locatedV xy And the non-inverting input end of the other column line driving operational amplifier gates zero potential. On the premise that the driving capability of the row line driving operational amplifier is enough, due to the virtual short action of the row line driving operational amplifier, the voltage of the row line at the position of the row line driving operational amplifier changes along with the voltage of the same-phase input end of the row line, and therefore the voltage of the row line at the position of the tested unitV cy Is equal toV xy And the other column line voltage is 0. Thus, the cumulative resistance of the lead resistance of the driving connecting wire and the joint contact resistance thereof is realizedR Lc Thereby eliminatingR Lc Impact on test results. Simultaneously, the input impedance of the column line driving operational amplifier and the resistance value of the on-resistance of the channel of the two-way or one-out-of-column line multi-way switchR sc Compared with the prior art, the circuit has the advantages that due to the virtual breaking effect of the column line driving operational amplifier, the voltage of the same-phase input end of the column line driving operational amplifier is equal to the input voltage (zero potential or feedback voltage) of the column line two-way or one-way switchV xy ) Equal potential method test circuit capable of eliminating double connection linesR sc To pairR xy The effect of the measurement results.
As shown in fig. 4, each row line of the shared row-line resistive sensor array is connected to an equal current through an equal current connection lineMSelecting one of the independent terminals of a multi-way switch to connect with the corresponding independent terminal, and keeping the current equalMThe common terminal of one of the multi-way switches is connected with a test current setting resistorR set (ii) a During testing, only the row line of the tested unit is equal to the currentMOne of the multi-way switches is selected to be turned on, and other row lines are suspended, so that only the row line connection of the tested unit is connectedR set (ii) a Each row line is also connected with the equal potential through another equal potential connecting lineMSelecting a corresponding independent terminal of a multi-way switchAre connected while being at the same timeMThe common end of one of the multi-way switches is connected with the inverting input end of the current feedback operational amplifier; during testing, only the row line where the tested unit is located is equipotentialMAnd selecting a multi-way switch for gating, and suspending other row lines, so that only the row line where the tested unit is located is connected with the inverted input end of the current feedback operational amplifier. FromV I First, a test current is passedR set Then passing through equal currentsMAnd selecting a multi-way switch, and connecting the multi-way switch to the row line of the tested unit through the equal current connecting line again, and then connecting the multi-way switch to the column line of the tested unit through the tested unit. The input impedance of the inverting input end of the current feedback operational amplifier is very large and is far greater than the equipotentialMSelect a multiple switch channel on resistanceR sr Lead resistor and joint contact resistor of equipotential connecting lineR Lr The sum of the two-phase current feedback operational amplifier can be considered as that the voltage of the inverting input end of the current feedback operational amplifier is equal to the voltage of the line voltage of the tested unit, and the value of the sum is 0; the input impedance of the inverting input end of the current feedback operational amplifier is large and far greater than that of the inverting input end of the current feedback operational amplifierR set Equal current ofMSelect a multiple switch channel on resistanceR sr Lead resistor of constant current connecting wire and joint contact resistor thereofR Lr Cumulative resistance ofR er Therefore, the leakage current of the inverting input end of the current feedback operational amplifier can be ignored; while the other column lines and the tested row line keep equal zero potential, the leakage current on the adjacent unit of the tested unit row is zero. Thus, it is possible to provideR set AndR xy the passing currents are equal, and the current also passes the equal current at the same timeMSelecting an accumulated resistance caused by the combination of the conduction resistance of a multi-way switch channel, the lead resistance of an equal current connecting line, the contact resistance of an equal current connecting line joint and the likeR er While the current value is unchanged. Due to the fact thatR set AndR xy the currents on are equal becauseR set Is known, then if it is knownR set The precise voltage across can be determinedI xy . WhileV xy It can be measured to obtain the result,so that it can be calculated accuratelyR xy 。
But due to accumulated resistanceR er Is caused to pass throughR set Current ofI real =-V I /(R set +R er )=V xy /R xy And the ideal set currentI set =-V I /R set Difference, so if neglectedR er Will cause additional errors in the test results of the unit under test. Due to the fact thatR xy 、R set AndR er the currents flowing in are equal, so the invention adoptsR xy =V xy ×R set /(V e -V I ) To obtainR xy The resistance value of (c). It can be found that this formula does notR er The presence of the one or more of,R er the effect of (c) is completely eliminated. Due to the fact thatR set AndV I is known, andV e andV xy we can measure and get, finally realizeR xy And (4) measuring a true value. Specifically, any one resistive sensor to be tested is firstly gated, specifically as follows: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential, and the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential through equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula
：
Wherein the content of the first and second substances,
for current feedback the potential at the output of the op-amp (i.e. the feedback voltage),setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,
a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
FIG. 6 shows another embodiment of the test circuit of the present invention, showing a current cell under testR xy Is composed ofM×NIn arrays of shared row-column line resistive sensorsR 11 (ii) a Fig. 7 is a test principle equivalent diagram of the test circuit. As shown in fig. 6, the test circuit of the present embodiment is equivalent to exchange the reference voltage source and the zero potential access position in the test circuit of fig. 4, that is, the original zero potential position in the test circuit of fig. 4 is changed to the reference voltage source, and the original reference voltage source position is changed to the zero potential. The test method of the test circuit comprises the following specific steps:
for any resistive sensor to be tested in the resistive sensor array, the resistive sensor to be tested is gated first, specifically as follows: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, and the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with the reference electric circuitSource of voltage and pass equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula：
Wherein the content of the first and second substances,
the potential at the output terminal of the operational amplifier is fed back for current,
setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,
a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
The basic principle of the test circuit to eliminate the channel on-resistance of the multiplexer, the contact resistance of the test cable connector, and the crosstalk error caused by the long test cable is the same as that of fig. 4, and can be clearly understood by those skilled in the art from the above description and fig. 6 and 7; for the sake of brevity, no further description is provided herein. Compared with the test circuit in fig. 4, by adopting the test circuit in fig. 6, all operational amplifiers can adopt rail-to-rail unipolar operational amplifiers, and only unipolar reference voltage sources need to be provided at the moment, so that the power supply cost is reduced.
In summary, with the test circuit of the present invention, the real resistance of any unit to be tested in the resistive sensor array sharing the row line can be accurately measured, and the influence caused by the lead resistances of the row line and the row line of the resistive sensor array, the contact resistances of the joints thereof, and the on-resistance of the multi-way switch channel is completely eliminated.
In contrast to the traditional single connection line equipotential method, one test terminal connecting each row column line in a common row-column line resistive sensor array becomes two test terminals (ii) ((iii))N×MThe number of array test terminals is given byN+M) Become 2: (N+M) One); the number of connecting cable leads is also doubled correspondingly (N×MThe number of connection cable leads required for the array is: (N+M) Root change to 2: (N+M) Root); one more test circuit is also neededMSelect a multiple switch andNan operational amplifier.
Furthermore, it is to be emphasized that: the above-mentioned rows and columns are relative concepts, which can be fully interchanged by those skilled in the art, and therefore, such simple variations based on the idea of the present invention are still covered by the technical solution of the present invention.
Claims (5)
1. Resistive sensor array test circuit based on two-wire system equipotential method, wherein the resistive sensor array shares row wires and column wiresMA x N two-dimensional resistive sensor array; wherein the test circuit comprises: a current feedback operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NThe circuit comprises a multi-way switch for selecting one from multiple column lines, a test current setting resistor, a reference voltage source and two connecting wires which are respectively arranged for each row line and column line of the resistive sensor array;Na plurality of row line driving operational amplifiers,NMultiple switches for selecting one from two column lines and resistive sensor arrayNThe row lines are in one-to-one correspondence, each row line is connected with the output end of the corresponding row line driving operational amplifier through a connecting line, the row line is connected with the reverse phase input end of the corresponding row line driving operational amplifier through another connecting line, and the non-phase input end of each row line driving operational amplifier is alternatively multiplexed with the corresponding row lineThe common end of the switch is connected with the zero potential or the output end of the current feedback operational amplifier; equipotential potentialMSelecting a multiple-way switchMIndependent end, equal currentMSelecting a multiple-way switchMA separate terminal andMthe row lines are in one-to-one correspondence, and each row line is in equipotential with the corresponding row line through a connecting lineMThe corresponding independent ends of one multi-way switch are connected and connected with equal current through another connecting wireMSelecting corresponding independent ends of a multi-way switch to be connected; equipotential potentialMThe common end of a selected multi-way switch is connected with the inverting input end of the current feedback operational amplifier, and the non-inverting input end of the current feedback operational amplifier is connected with a zero potential; constant currentMAnd the common end of one of the multi-way switches is connected with one end of a test current setting resistor, and the other end of the test current setting resistor is connected with a reference voltage source.
2. The method for testing a test circuit according to claim 1, wherein for any one resistive sensor to be tested in the resistive sensor array, the resistive sensor to be tested is first gated as follows: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential, and the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with zero potential through equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula
：
Wherein the content of the first and second substances,
the potential at the output terminal of the operational amplifier is fed back for current,
setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
3. Resistive sensor array test circuit based on two-wire system equipotential method, wherein the resistive sensor array shares row wires and column wiresMA x N two-dimensional resistive sensor array; wherein the test circuit comprises: a current feedback operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NThe circuit comprises a multi-way switch for selecting one from multiple column lines, a test current setting resistor, a reference voltage source and two connecting wires which are respectively arranged for each row line and column line of the resistive sensor array;Na plurality of row line driving operational amplifiers,NMultiple switches for selecting one from two column lines and resistive sensor arrayNThe row lines are in one-to-one correspondence, each row line is connected with the output end of the corresponding row line driving operational amplifier through a connecting line, the row line is connected with the inverting input end of the corresponding row line driving operational amplifier through another connecting line, and the non-inverting input end of each row line driving operational amplifier is connected with a reference voltage source or the output end of the current feedback operational amplifier through the common end of the alternative multi-way switch of the row line corresponding to the non-inverting input end of the row line driving operational amplifier; equipotential potentialMSelecting a multiple-way switchMIndependent end, equal currentMSelecting a multiple-way switchMA separate terminal andMthe row lines are in one-to-one correspondence, and each row line is in equipotential with the corresponding row line through a connecting lineMOne of the multiple switches is connected with the corresponding independent end and connected with the other switch through the other connecting wireElectric currentMSelecting corresponding independent ends of a multi-way switch to be connected; equipotential potentialMThe common end of one of the multi-way switches is connected with the inverting input end of the current feedback operational amplifier, and the non-inverting input end of the current feedback operational amplifier is connected with a reference voltage source; constant currentMThe common end of one of the multi-way switches is connected with one end of a test current setting resistor, and the other end of the test current setting resistor is connected with zero potential.
4. The method for testing a test circuit according to claim 3, wherein for any one resistive sensor to be tested in the resistive sensor array, the resistive sensor to be tested is first gated as follows: by the saidNThe non-inverting input end of the column line driving operational amplifier corresponding to the column line of the resistive sensor to be tested is connected with the output end of the current feedback operational amplifier, the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with the reference voltage source, and the non-inverting input ends of the other column lines corresponding to the column line driving operational amplifiers are connected with the reference voltage source through equal currentsMSelecting one multi-way switch and equal potentialMSelecting a multi-way switch to enable the row line where the resistive sensor to be tested is located to be simultaneously communicated with the inverted input end of the current feedback operational amplifier and the test current setting resistor, and other row lines to be suspended; then, the resistance of the resistive sensor to be measured is calculated by using the following formula：
Wherein the content of the first and second substances,the potential at the output terminal of the operational amplifier is fed back for current,setting resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,
a reference voltage provided for a reference voltage source,
the resistance value of the resistor is set for the test current.
5. A sensing system comprising an array of resistive sensors and corresponding test circuitry, wherein the array of resistive sensors is common to both row and column linesMA x N two-dimensional resistive sensor array, wherein the test circuit is the resistive sensor array test circuit based on the two-wire system equipotential method of claim 1 or 3.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115628761A (en) * | 2022-09-30 | 2023-01-20 | 华南理工大学 | Low-power-consumption anti-disturbance resistance type sensor and wearable equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115628761A (en) * | 2022-09-30 | 2023-01-20 | 华南理工大学 | Low-power-consumption anti-disturbance resistance type sensor and wearable equipment |
| CN115628761B (en) * | 2022-09-30 | 2023-10-13 | 华南理工大学 | Low-power-consumption anti-disturbance resistance type sensor and wearable equipment |
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