阅读说明：本技术 一种基于二线制等电势法的阻性传感器阵列测试电路 (Resistive sensor array test circuit based on two-wire system equipotential method ) 是由 赵莉民 于 2018-06-20 设计创作，主要内容包括：本发明公开了一种基于二线制等电势法的阻性传感器阵列测试电路,属于传感器技术领域。所述测试电路针对共用行线和列线的<I>M</I>×N二维阻性传感器阵列,包括：一个等电流驱动运放、<I>N</I>个列线驱动运放、一个等电流<I>M</I>选一多路开关、一个等电势<I>M</I>选一多路开关、<I>N</I>个列线二选一多路开关、测试电流采样电阻、基准电压源,以及为所述阻性传感器阵列的每一条行线和列线分别设置的两根连接线。本发明还公开了上述测试电路的测试方法及一种传感系统。相比现有技术,本发明以二线制等电势法为关键技术,可有效消除连接电缆引线电阻、线缆接头触点电阻以及多路开关通道导通电阻所产生的测量误差,大幅提高阻性传感器阵列的测量精度。(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 for common row and column lines M A xn two-dimensional resistive sensor array, comprising: an equal current drive operational amplifier, N A row line driving operational amplifier, an equal current M Selecting one multi-way switch and one equal potential M A multi-way switch is selected, N The device comprises a multi-way switch for selecting one from the row lines, a test current sampling 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 invention takes the two-wire system equipotential method as the 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 resistanceMeasurement accuracy of the linear sensor array.)

1. A resistive sensor array test circuit based on a two-wire system equipotential method is disclosed, wherein the resistive sensor array shares row lines and column linesMA x N two-dimensional resistive sensor array; wherein the test circuit comprises: an equal current drive 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 sampling 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 inverted input end of the corresponding row line driving operational amplifier through another connecting line, and each row line is connected with the inverted input end of the corresponding row line driving operational amplifier through another connecting lineThe non-inverting input end of the driving operational amplifier is connected with a zero potential or a reference voltage source through the common end of the two-way switch of the corresponding column line; 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 reverse-phase input end of the equal current drive operational amplifier, and the non-phase input end of the equal current drive operational amplifier is connected with zero potential; constant currentMThe common end of a selected multi-way switch is connected with one end of a test current sampling resistor, and the other end of the test current sampling resistor is connected with the output end of the equal current drive operational amplifier.

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 a reference voltage source by the multi-way switch, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with zero potential, and the non-inverting input ends of the column line driving operational amplifiers corresponding to the other column lines are connected with zero potential by equal currentMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

3. A resistive sensor array test circuit based on a two-wire system equipotential method is disclosed, wherein the resistive sensor array shares row lines and column linesMA x N two-dimensional resistive sensor array; wherein the test circuit comprises: an equal current drive 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 sampling 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 zero potential or a reference voltage source 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 lineMSelect oneThe corresponding independent ends of the multi-way switches 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 equal current drive operational amplifier, and the non-inverting input end of the equal current drive operational amplifier is connected with a reference voltage source; constant currentMThe common end of a selected multi-way switch is connected with one end of a test current sampling resistor, and the other end of the test current sampling resistor is connected with the output end of the equal current drive operational amplifier.

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 zero potential, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with a reference voltage source, and equal currents are passed throughMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMSelecting a multiple-way switchThe common terminal is connected to the potential of one terminal,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

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.

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:

a resistive sensor array test circuit based on a two-wire system equipotential method is disclosed, wherein the resistive sensor array shares row lines and column linesMA x N two-dimensional resistive sensor array; the test circuit includes: an equal current drive operational amplifier,NA row line driving operational amplifier, an equal currentMSelecting one multi-way switch and one equal potentialMA multi-way switch is selected,NOne-column line two-selection multi-way switch and test currentThe resistance sensor comprises a sampling 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 zero potential or a reference voltage source 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 reverse-phase input end of the equal current drive operational amplifier, and the non-phase input end of the equal current drive operational amplifier is connected with zero potential; constant currentMThe common end of a selected multi-way switch is connected with one end of a test current sampling resistor, and the other end of the test current sampling resistor is connected with the output end of the equal current drive operational amplifier.

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 a reference voltage source by the multi-way switch, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with zero potential, and the non-inverting input ends of the column line driving operational amplifiers corresponding to the other column lines are connected with zero potential by equal currentMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

The following technical scheme can be obtained according to the same invention concept:

a resistive sensor array test circuit based on a two-wire system equipotential method is disclosed, wherein the resistive sensor array shares row lines and column linesMA x N two-dimensional resistive sensor array; the test circuit includes: an equal current drive 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 sampling 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, and the row line is simultaneously connected with the reverse phase output of the corresponding row line driving operational amplifier through another connecting lineThe input end is connected, the non-inverting input end of each column line driving operational amplifier is connected with a zero potential or a reference voltage source through the common end of the two-way switch of the corresponding column line; 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 equal current drive operational amplifier, and the non-inverting input end of the equal current drive operational amplifier is connected with a reference voltage source; constant currentMThe common end of a selected multi-way switch is connected with one end of a test current sampling resistor, and the other end of the test current sampling resistor is connected with the output end of the equal current drive operational amplifier.

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 zero potential, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with a reference voltage source, and equal currents are passed throughMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

A sensing system comprising an array of resistive sensors sharing row and column lines and a corresponding test circuitMThe testing circuit is a resistive sensor array testing circuit based on a two-wire system equipotential method according to any one of the above technical schemes.

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 this test circuit there is only one connection line between each row or column line of the array and the test circuit. The testing circuit has the channel on-resistance of the alternative multi-way switch of all the column lines under the ideal working stateR _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 _I The voltage of the other column line is 0; simultaneous equal currentMSelect one to open moreOff channel on-resistanceR _sr Cumulative resistance of lead resistance and joint contact resistance of equal current connecting wireR _Lr Neglected, the voltage of the column line where the tested unit is located due to the action of the ideal equal current drive operational amplifierV _rx =0. At the same time, since the voltages of other column lines are 0, (< i > C </i >) of the cell under testN-1) the current on the row adjacent cell is 0; meanwhile, the impedance of the inverting input end of the equal current drive operational amplifier is large, and the leakage current is ignored, so thatR _xy Current ofI _xy And testing the current sampling resistorR _test Current ofI _test Is equal toI _test =-V _I /R _xy =V _test /R _test . Due to the fact thatV _I AndR _test in the known manner, it is known that,R _test voltage ofV _test Can be measured and then calculatedR _xy =-R _test ×V _I /V _test 。

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 _I not equal; at the same time, the channel on-resistance of the two-way switch for the row line in the row line direction of the tested unitR _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.

To overcome this problemThe test circuit shown in fig. 2 has the defects that the influence of the lead resistance of a connecting cable, the contact resistance of a cable joint, the channel conduction resistance of a multi-way switch and the like is eliminated, the invention provides a resistive sensor array test circuit based on a two-wire system equipotential method, and a shared row and column line resistive sensor array is measured by using the equipotential method of a double-connecting wire. 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 an equivalent diagram of the testing principle of the testing circuit of 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. Therefore, in the equipotential method test circuit of the double-connection line, an equal current drives an operational amplifierNThe same phase input end of each row line driving operational amplifier is correspondingly connected with a row line alternative multi-way switch, and an equal potential is arranged between the opposite phase input end and the row line of the equal current driving operational amplifierMSelecting a multi-way switch to test the current sampling resistorR _test 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 reverse-phase input end of the equal current drive operational amplifier, and the non-phase input end of the equal current drive operational amplifier is connected with zero potential; constant currentMSelecting a common terminal and testing power of a multi-way switchOne end of the current sampling resistor is connected, and the other end of the test current sampling resistor is connected with the output end of the equal current drive operational amplifier.

As shown in fig. 4, each column line of the common row line resistive sensor array is connected to the output end of its corresponding column line driving op-amp through one driving connection line, and at the same time, the column line is connected to the inverting input end of its corresponding column line driving op-amp through another driving sampling following connection line; the non-inverting input end of each column line driving operational amplifier is connected with zero potential or reference voltage through the common end of a corresponding column line two-way or one-way switchV _I Connecting; during testing, the non-inverting input end of the row line driving operational amplifier where the tested unit is located is connected with the reference voltage through the row line two-way or one-way switchV _I And the non-inverting input end of the operational amplifier driven by the other column lines is connected with 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 _I 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 reference voltage) of the column line two-way or one-way switchV _I ) Equal, equal potential method circuit capable of eliminating double connection wireR _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 end of a multi-way switch is connected with a test current sampling circuitResistance deviceR _test When testing, only the row line where the tested unit is located is equalized by 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 _test (ii) a Each row line is also connected with the equal potential through another equal potential connecting lineMOne corresponding independent end of a multi-way switch is selected to be connected, and the equal potentials are simultaneouslyMThe common end of a multi-way switch is connected with the reverse phase input end of the equal current drive operational amplifier, and only the row line where the tested unit is located is equal in potential during testingMAnd 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 inverting input end of the equal current drive operational amplifier. Voltage following of column line of resistive sensor to be testedV _I Change of (2), test currentI _xy Firstly through the resistive unit to be tested to the row line thereof, and secondly through equal currentsMOne-by-one multi-way switch connectionR _test And then the voltage of the row line of the resistive unit to be detected is also connected to the inverting end of the equal current drive operational amplifier. The input impedance of the equal current drive operational amplifier inverting input end is very large and far greater than the equal potentialMSwitch channel on-resistance of one-selection multi-way switchR _sr Lead resistor and joint contact resistor of equipotential connecting lineR _Lr The sum of the two-phase current is considered to be 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 equal current drive operational amplifier inverting input end is very large and far greater than that of the equal current drive operational amplifier inverting input endR _test Equal current ofMSwitch channel on-resistance of one-selection multi-way switchR _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 equal current drive 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 _test AndR _xy the passing currents are equal, and the currents are also simultaneously passedOver-equal currentMSelecting an accumulated resistance caused by the on-resistance of a switch channel of a multi-way switch, 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 _test AndR _xy the currents on are equal becauseR _test Is known, then if it is knownR _test The precise voltage across can be determinedI _xy . WhileV _test Can be measured and thus calculated accuratelyR _xy 。

But due to accumulated resistanceR _er Is caused to pass throughR _test Current ofI _xy =V _test /(R _test +R _er )=-V _I /R _xy And the ideal currentI _ideal = V _test /R _test Difference, cumulative resistanceR _er Resulting in an error voltage ofV _e Therefore if neglectedR _er Will cause additional errors in the test results of the unit under test. Due to the fact thatR _xy 、R _test AndR _er the currents flowing in the upper part are equal, so that the current can be adoptedR _xy = R _test ×V _I /(V _e -V _test ) 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 _test AndV _I is known, andV _e andV _test we can measure and get, finally realizeR _xy And (4) measuring a true value. Specifically, for any resistive sensor to be tested in the resistive sensor array, the resistive sensor to be tested is first gatedThe sex sensor comprises the following specific components: 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 a reference voltage source by the multi-way switch, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with zero potential, and the non-inverting input ends of the column line driving operational amplifiers corresponding to the other column lines are connected with zero potential by equal currentMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

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 of fig. 6. As shown in FIG. 6, the test circuit of the present embodiment corresponds to the base in the test circuit of FIG. 4The switch-in position of the quasi-voltage source and the zero potential is exchanged, namely, the original zero potential position in the test circuit shown in fig. 4 is changed into a reference voltage source, and the original reference voltage source position is changed into 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 zero potential, the non-inverting input ends of the column line driving operational amplifiers corresponding to other column lines are connected with a reference voltage source, and equal currents are passed throughMSelecting 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 equal current drive operational amplifier and the test current sampling 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,a reference voltage provided for a reference voltage source,sampling resistance and constant current for testing currentMThe common end of one of the multi-way switches is connected with the potential of one end,for driving the potential of the output end of the operational amplifier by equal current,the resistance value of the current sampling resistor is tested.

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.

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.