CN118169472A - Detection circuit with variable resistor array, method for obtaining variable resistor value and film type pressure sensor - Google Patents
Detection circuit with variable resistor array, method for obtaining variable resistor value and film type pressure sensor Download PDFInfo
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- CN118169472A CN118169472A CN202211570265.6A CN202211570265A CN118169472A CN 118169472 A CN118169472 A CN 118169472A CN 202211570265 A CN202211570265 A CN 202211570265A CN 118169472 A CN118169472 A CN 118169472A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/14—Measuring resistance by measuring current or voltage obtained from a reference source
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- G—PHYSICS
- 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
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Abstract
The invention discloses a detection circuit with a variable resistor array, which eliminates crosstalk among detection units in the detection circuit through a circuit structure with innovative design and greatly improves detection accuracy. Further, the invention also discloses a method for obtaining the resistance value of the variable resistor in the detection circuit with the variable resistor array and a film type pressure sensor adopting the structure of the detection circuit with the variable resistor array.
Description
Technical Field
The invention belongs to the technical field of detection, and particularly relates to a detection circuit with a variable resistor array, a method for obtaining a variable resistance value and a film type pressure sensor.
Background
The array piezoresistor sensor is a piezoresistor sensor, and is provided with a plurality of load sensor elements which are arranged in an array and serve as detection units, and the load sensor elements are equivalent to a detection circuit with a variable resistor array. Because isolation is not arranged among all the detection units, the traditional detection circuit can cause crosstalk between the gated detection units and the ungated detection units when pressure detection is carried out, and the crosstalk can be increased along with the increase of the array number, so that the accuracy of a detection result can be greatly influenced.
Disclosure of Invention
In order to solve the problems, the invention provides a detection circuit with a variable resistor array, which eliminates crosstalk among detection units in the detection circuit through a circuit structure with innovative design, and greatly improves the detection accuracy. Further, the invention also discloses a method for obtaining the resistance value of the variable resistor in the detection circuit with the variable resistor array and a film type pressure sensor adopting the structure of the detection circuit with the variable resistor array.
The specific technical scheme of the invention comprises the following steps:
a first aspect of the present invention provides a detection circuit with a variable resistance array, which mainly includes an excitation input module, a sensing array module, and a signal output module; the sensing array module comprises a variable resistor array formed by a plurality of variable resistors, wherein the variable resistor array comprises row branches and column branches, in the variable resistor array, the X ends of the variable resistors in the same row are connected in parallel with the same row branch, and the Y ends of the variable resistors in the same column are connected in parallel with the same column branch; the excitation input module comprises a row grounding end, an excitation butt joint end and an input selection switch, wherein the row grounding end is grounded, the excitation butt joint end is used for being connected with external excitation equipment, and the row branch is connected with the row grounding end or the excitation butt joint end through the input selection switch corresponding to the row branch; the signal output module comprises a column grounding end, a signal output end and an output selection switch, wherein the column grounding end is grounded, the signal output end is used for obtaining an output signal of the detection circuit, and the column branch is connected with the column grounding end or the signal output end through the corresponding output selection switch.
Optionally, the row ground terminal is directly grounded, and the column ground terminal is directly grounded; or the row grounding end is directly grounded, the column grounding end is grounded through an operational amplifier circuit, and when the column branch is communicated with the column grounding end, the operational amplifier circuit is used for controlling the current of the column branch.
Optionally, the operational amplifier is provided with an operational amplifier and a feedback resistor, the inverting input end of the operational amplifier is connected with the output selection switch, the non-inverting input end is grounded, and the feedback resistor is arranged between the inverting input end and the output end of the operational amplifier.
Optionally, the excitation input module comprises an excitation module which is arranged in one-to-one correspondence with each row of branches, and the excitation module is configured with a row of grounding terminals, an excitation butt-joint terminal and an input selection switch; the row branch is connected with a row grounding end or an excitation butt end through an input selection switch in the corresponding excitation module.
Optionally, the excitation input module includes a row of ground terminals, an excitation docking terminal, and input selection switches corresponding to the row branches; the row branch is connected with a row grounding end or an excitation butt joint end through an input selection switch corresponding to the row branch.
Optionally, the signal output module includes a row of ground terminals, a signal output terminal, and an output selection switch corresponding to the row of branches; the column branch is connected with the signal output end or the column grounding end through the corresponding output selection switch.
Optionally, the signal output module includes a signal output end, and an output selection switch and a column grounding end which are arranged corresponding to the column branch; the row branch is connected with the signal output end or the row grounding end corresponding to the signal output end through the output selection switch corresponding to the row branch.
Optionally, the variable resistor is any one of a piezoresistor, a temperature sensitive resistor, a photoresistor and a gas sensitive resistor.
Optionally, the variable resistor is a resistor formed by the cooperation of the sensing material and the sensing electrode.
Optionally, the signal output module further comprises a voltage division module, wherein the voltage division module comprises a voltage division resistor and a voltage division switch, and the voltage division resistor is connected to the signal output end in parallel through the voltage division switch.
Optionally, the voltage dividing resistor comprises at least two fixed value resistors with different resistance values, one end of the fixed value resistor is connected to the signal output end in parallel through the voltage dividing switch, and the other end of the fixed value resistor is grounded.
A second aspect of the present invention provides a method for obtaining a variable resistance value in the detection circuit with a variable resistance array disclosed in the first aspect of the present invention, which mainly includes:
Controlling input selection switches corresponding to the row branches to enable the row branch of the variable resistor to be detected to be communicated with an excitation butt joint end, and the other row branches to be connected with a row grounding end, wherein excitation signals input by the excitation butt joint end are voltage signals;
controlling the output selection switch corresponding to the column branch circuit to enable the column branch circuit where the variable resistor to be detected is positioned to be communicated with the signal output end, and the other column branch circuits are communicated with the column grounding end;
Acquiring an input voltage signal of a line branch of a variable resistor to be detected;
controlling the state of the voltage dividing switch to respectively obtain a first voltage signal output by the signal output end in the state that no voltage dividing resistor is connected in parallel to the signal output end and a second voltage signal output by the signal output end in the state that the voltage dividing resistor is connected in parallel to the signal output end;
And solving the resistance value of the variable resistor to be measured based on the input voltage signal, the first voltage signal, the second voltage signal and the voltage dividing resistor.
Optionally, the method further comprises: when the voltage dividing resistor has more than two resistance values, the voltage dividing resistor connected in parallel to the signal output end is selected according to the first voltage signal.
Optionally, solving the resistance value of the variable resistor to be measured based on the input voltage signal, the first voltage signal, the second voltage signal and the voltage dividing resistor specifically includes:
wherein Rsi is a variable resistor to be detected, rt is a voltage dividing resistor connected in parallel to a signal output end, and V0 is an input voltage signal; v1 is a first voltage signal and V2 is a second voltage signal.
Optionally, the input voltage signal is a voltage signal input by the excitation docking terminal; or the input voltage signal is a voltage signal at the connection part of the row branch of the variable resistor to be detected and the corresponding input selection switch.
A third aspect of the present invention provides a method for obtaining a variable resistance value in the detection circuit with a variable resistance array disclosed in the first aspect of the present invention, which mainly includes:
Controlling input selection switches corresponding to the row branches to enable the row branch of the variable resistor to be detected to be communicated with an excitation butt joint end, and the other row branches to be connected with a row grounding end, wherein excitation signals input by the excitation butt joint end are current signals;
controlling the output selection switch corresponding to the column branch circuit to enable the column branch circuit where the variable resistor to be detected is positioned to be communicated with the signal output end, and the other column branch circuits are communicated with the column grounding end;
acquiring a current signal input by the excitation butt joint end, an input voltage signal of a row branch circuit of the variable resistor to be detected and a third voltage signal output by the signal output end;
and solving the resistance value of the variable resistor to be measured based on the input voltage signal and the third voltage signal and the current signal.
The fourth aspect of the present invention is to disclose a film type pressure sensor, which mainly includes a pressure sensing part and a signal transmission part; the pressure sensing part comprises a sensing material layer and an array electrode layer, wherein an array electrode is arranged on the array electrode layer, and the array electrode and the sensing material layer are oppositely arranged to form a variable resistor array in the detection circuit with the variable resistor array disclosed in the first aspect of the invention; the signal transmission part comprises an excitation input module and a signal output module in the detection circuit with the variable resistor array disclosed in the first aspect of the invention.
The invention has at least the following beneficial effects:
(1) The detection circuit with the variable resistor array disclosed by the invention eliminates the crosstalk influence of other variable resistors on the detection of the variable resistor to be detected by arranging the grounding end of the row-column branch, and greatly improves the detection accuracy.
(2) The invention does not need to arrange an output end in each row and each column like the traditional detection circuit, and a plurality of sensing units arranged in an array in the sensing array share one output line, namely the whole circuit only needs to arrange one signal output end, thereby greatly simplifying the circuit arrangement.
(3) According to the variable resistor voltage divider, the signal output end is connected with the voltage dividing module in parallel, when the input excitation signal is a voltage signal, the voltage dividing module can be controlled to be on-off to respectively obtain two output voltage signals, and then the resistance value of the variable resistor to be measured is solved.
(4) According to the invention, the voltage dividing resistor with various resistance values can be configured in the voltage dividing module, and an accurate detection result can be obtained under the condition of low detection precision by selecting the adaptive voltage dividing resistor.
(5) According to the invention, the operational amplifier circuit is arranged at the grounding end of the column branch circuit, and the operational amplifier circuit is used for controlling the current flowing through the variable resistor, so that the phenomenon of inaccurate detection result caused by resistance heating due to the fact that a large current flows through the variable resistor is avoided.
(6) The thin film pressure sensor with the variable resistor array can avoid the influence of parasitic capacitance through the arrangement of the row grounding end, and further provides the accuracy of a detection result.
Drawings
Fig. 1 is a block diagram of a circuit connection with a variable resistor array disclosed in embodiment 1.
Fig. 2 is a schematic diagram of a 2 row by 2 column variable resistor array.
Figure 3 is a schematic diagram of one embodiment of a stimulus input module in a circuit with a2 row by 2 column variable resistor array.
FIG. 4 is a schematic diagram of one embodiment of a signal output module in a circuit having a2 row by 2 column variable resistor array.
Fig. 5 is a schematic diagram of another embodiment of a stimulus input module in a circuit with a2 row by 2 column variable resistor array.
Fig. 6 is a schematic diagram of a circuit with 2 row by 2 column variable resistor arrays with a row ground and a column ground directly grounded.
Fig. 7 is a schematic diagram of an operational amplifier circuit with a row ground connection in a circuit having a2 row by 2 column variable resistor array.
Fig. 8 is a schematic diagram of another embodiment of a signal output module in a circuit having a2 row by 2 column variable resistor array.
Fig. 9 is a schematic diagram of yet another embodiment of a signal output module in a circuit having a2 row by 2 column variable resistor array.
Fig. 10 is a circuit schematic with a 4 row by 4 column variable resistor array.
Fig. 11 is a schematic diagram of a thin film pressure sensor disclosed in example 2.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
Referring to fig. 1, embodiment 1 discloses a circuit with a variable resistor array, which mainly includes an excitation input module, a sensing array module and a signal output module, wherein the sensing array module is electrically connected with the excitation input module and the signal output module. The excitation input module is used for inputting excitation signals to the sensing array module, the signal output module is used for obtaining output excitation signals after the variable resistors are arranged, and resistance information of the corresponding variable resistors in the sensing array module can be obtained through analysis of the output excitation signals.
Specifically, the sensing array module includes a variable resistor array formed by a plurality of variable resistors, and the variable resistor array includes different row branches and different column branches. In the variable resistor array, the X ends of the variable resistors in the same row are connected in parallel with the branches in the same row, and the Y ends of the variable resistors in the same column are connected in parallel with the branches in the same column. For example, if the sensing array module includes m×n variable resistors, the m×n variable resistors may form a variable resistor array of M rows×n columns, the variable resistors of the same row are connected in parallel to the same row branch, and the variable resistors of the same column are connected in parallel to the same column branch, so the sensing array module includes M row branches and N column branches. Wherein M and N are positive integers greater than 1, and M and N may be equal or unequal. For example, the sensing array module may be a variable resistor array of 2 rows by 2 columns, or a variable resistor array of 4 rows by 4 columns, or a variable resistor array of 16 rows by 32 columns, or a variable resistor array of 32 rows by 16 columns, or a variable resistor array of 64 rows by 64 columns, or the like. In the present invention, the variable resistors of the same row refer to the variable resistors connected in parallel to the same row branch without other variable resistors, and the variable resistors of the same column refer to the variable resistors connected in parallel to the same column branch without other variable resistors.
As an explanation, referring to fig. 2, the sensing array module in fig. 2 includes a2 row×2 column variable resistor array, where two ends of each variable resistor are defined as an X end and a Y end, the variable resistors in the same row refer to the variable resistors in the same row and the variable resistors in the same column refer to the variable resistors in the same column and the Y end is connected to the variable resistors in the same column. For example, the X terminal of the variable resistor Rs1 and the X terminal of the variable resistor Rs2 are both connected to the row branch 1, so that the variable resistor Rs1 and the variable resistor Rs2 are in the same row branch; the Y terminal of the variable resistor Rs1 and the Y terminal of the variable resistor Rs3 are both connected to the column branch 1, so that the variable resistor Rs1 and the variable resistor Rs3 are in the same column branch. That is, the arrangement mode of the variable resistor array mainly depends on the arrangement logic on the circuit, and the specific position of each variable resistor can be adjusted according to the actual requirement.
In the present invention, the variable resistor is set to a resistor whose resistance value changes with a change in a specific variable, and for example, the variable resistor may be a varistor whose resistance value changes with the magnitude of pressure applied to the resistor; the variable resistor can also be a temperature sensitive resistor, the resistance value of which changes along with the environmental temperature of the resistor, and can also be a photoresistor, a gas sensitive resistor and the like. It should be appreciated that the variable resistance may be not only a separate resistance, but also a resistance formed by the sensing material and the sensing electrode in cooperation.
It is understood that since the variable resistor is set to a resistance whose resistance value changes with a change of a certain specific variable, the change of the corresponding specific variable can be obtained by obtaining the resistance change or resistance value of the corresponding variable resistor. For example, when the variable resistor is a varistor (i.e., a piezoresistive resistor), the pressure change condition can be obtained by the resistance value change of the variable resistor; when the variable resistor is a temperature-sensitive resistor, the temperature change can be obtained by the change of the resistance value of the variable resistor.
Referring to fig. 3, the excitation input module includes an excitation module, which includes an input selection switch (single pole double throw switch, as shown by Ds1 and Ds2 in fig. 3), a row ground terminal, and an excitation docking terminal, where the row ground terminal is grounded, and the excitation docking terminal is used to connect to an external excitation device. As one implementation mode, the excitation input module comprises excitation modules which are arranged in one-to-one correspondence with each row of branches, and the input selection switch is butted with the corresponding row of branches to control one of the row grounding end or the excitation butt joint end to be communicated with the corresponding row of branches. When the input selection switch is communicated with the excitation butt joint end, the external excitation equipment transmits an excitation signal to a corresponding row branch in the sensing array module through the excitation butt joint end; when the input selection switch is communicated with the row grounding end, the corresponding row branch circuit is grounded.
The number of the excitation butt ends is not particularly limited, and as an implementation manner, as shown in fig. 5 below, the excitation input module is provided with only one excitation butt end, that is, each excitation module shares one excitation butt end, and at this time, the excitation butt end is provided with butt ports equal to the number of the row branches, and each butt port is correspondingly provided with each row branch. Meanwhile, the excitation module is provided with input selection switches and row grounding ends, wherein the number of the input selection switches is equal to that of the row branches, and each input selection switch is used for controlling one of the corresponding row grounding ends or excitation butt joint ends to be communicated with the row branches. Similarly, the number of the row grounding ends is not particularly limited, and as another implementation mode, the excitation input module is only provided with one row grounding end, and each excitation module shares one row grounding end.
Referring to fig. 4, the signal output module at least includes a column ground, a signal output and an output selection switch, wherein the output selection switch is used for controlling one of the column ground and the signal output to be communicated with a corresponding column branch. When the output selection switch is communicated with the signal output end, if the excitation signal passes through the corresponding column branch, the output excitation signal can be obtained from the signal output end; when the output selection switch is communicated with the column grounding end, the corresponding column branch is grounded.
The invention does not limit the number of the column grounding terminals, as an implementation mode, the signal output module can be provided with only one column grounding terminal, the column grounding terminal is provided with butt joint ports with the same number as the column branches, each butt joint port is correspondingly arranged with each column branch, and the connection or disconnection of each column branch and the column grounding terminal is respectively controlled by controlling the output selection switch corresponding to each column branch. As another embodiment, the signal output module may be provided with column grounding terminals equal in number to the column branches, each column grounding terminal being provided corresponding to each column branch, and the connection or disconnection between each column branch and the column grounding terminal being controlled by controlling the output selection switch corresponding to each column branch.
In the present invention, the row and column branches in the sense array module are for illustration only and are not limiting in structure. That is, the stimulation input modules may interface with the row branches of the sense array modules, and the stimulation input modules may interface with the column branches of the sense array modules. When the excitation input module is in butt joint with a row branch in the sensing array module, the signal output module is in butt joint with a column branch in the sensing array module; when the excitation input module is butted with the column branch in the sensing array module, the signal output module is butted with the row branch in the sensing array module. The invention is illustrated, but not limited to, with the excitation input module interfacing with a row leg in the sense array module, and the signal output module interfacing with a column leg in the sense array module.
In the invention, the excitation signal input through the excitation input module can be a voltage signal or a current signal, and the signal output through the signal output end is a voltage signal. When the resistance information of a certain variable resistor to be detected is required to be obtained, an input selection switch in an excitation input module is required to be controlled to be communicated with an excitation butt joint end of a row branch where the variable resistor to be detected is located, other ungrounded row branches are communicated with corresponding row grounding ends through corresponding input selection switches, and then external excitation equipment transmits excitation signals to the row branch where the variable resistor to be detected is located through the excitation butt joint end; in the sensing array module, the output selection switch corresponding to the column branch of the variable resistor to be detected is communicated with the column branch and the signal output end, and the output selection switches of other column branches are communicated with the corresponding column grounding end. When an excitation signal is transmitted to the variable resistor to be detected through the row branch, the variable resistor to be detected and other variable resistors in the same row of the branch are in parallel connection, so that the other variable resistors in the same row with the variable resistor to be detected cannot cause crosstalk influence on the variable resistor to be detected; because other ungated row branches are directly grounded through the row grounding end and other ungated column branches are directly grounded through the column grounding end, both ends of the variable resistors on the branches which are ungated in the row branches and the column branches are grounded, the two ends of the variable resistors are equipotential, and thus no current flows through the variable resistors, and the problem of signal crosstalk generated by the variable resistors to be tested due to the serial-parallel connection of the variable resistors of other columns is eliminated.
Referring to fig. 6, as an embodiment, the row ground may be a directly grounded ground port, and the column ground may be a directly grounded ground port. The arrangement mode is simple and convenient in structure, reduces the introduction of components and parts, and is more convenient to process and manufacture.
Referring to fig. 7, as another embodiment, the row ground may be a directly grounded ground port, and the column ground may be a grounded op-amp circuit, where the op-amp circuit controls the magnitude of the current in the column branch when the column branch is connected to the column ground. It will be appreciated that since the other resistors in the same column of branches as the variable resistor to be tested are in series voltage division relationship with the variable resistor to be tested, current will still flow through these series connected variable resistors. Since the resistance of the variable resistors is changed by the influence of external specific variables in the invention, if the variable resistors to be measured are directly grounded, the current passing through the variable resistors will become larger when the resistance of the variable resistors is smaller. It can be appreciated that when a larger current passes through the resistor, the heat generated by the resistor is increased, and the continuous heat generation affects the resistance value of the resistor. The invention obtains the corresponding specific variable by obtaining the resistance information of the variable resistor, and the resistance value of the variable resistor is influenced by the specific variable and the self-heating, so the adverse effect of the heating of the variable resistor on the detection result of the specific variable can be reduced by controlling the current flowing through the variable resistor. It can be understood that in this embodiment, the column grounding terminal is configured with an operational amplifier circuit, and the operational amplifier circuit can control the current flowing through the variable resistor, so that the condition that a large current accelerates the heating of the variable resistor through the variable resistor is avoided, and more accurate specific variable information can be obtained when the variable resistor is detected.
As an embodiment, the operational amplifier circuit may specifically include an operational amplifier U1 and a feedback resistor RF, where an inverting input terminal of the operational amplifier U1 is connected to the output selection switch, a non-inverting input terminal is grounded, and the feedback resistor RF is disposed between the inverting input terminal and the output terminal of the operational amplifier U1.
When the excitation signal input by the excitation input module is a current signal, the voltage signal at the joint of the excitation butt joint end and the row branch and the voltage signal at the signal output end can be obtained, and the resistance information of the variable resistor to be detected can be calculated through the two voltage signals and the input current signal, namely, the difference value of the two voltage signals is divided by the input current signal to obtain the resistance value of the variable resistor to be detected.
Referring to fig. 8, as another embodiment, when the excitation signal input by the excitation input module is a voltage signal, the signal output module further includes a voltage division module, the voltage division module includes at least one grounded fixed resistor R1 and a voltage division switch Dsx, one end of the fixed resistor R1 is grounded, and the other end is connected to the voltage division switch Dsx; the other end of the voltage dividing switch Dsx is connected in parallel to the signal output end, that is, the fixed value resistor R1 is connected with or disconnected from the column branch (or the signal output end) through the voltage dividing switch Dsx. The constant value resistor is connected to the circuit to perform voltage division, so the constant value resistor R1 is a voltage division resistor.
It can be understood that when the excitation signal is a voltage signal, since the other variable resistors in the same row of branches as the variable resistor to be measured are in parallel connection with the variable resistor to be measured, the other variable resistors in the same row of branches do not divide the voltage signal input into the column branch of the variable resistor to be measured; and the other variable resistors in the same column branch with the variable resistor to be tested are in series connection with the variable resistor to be tested, so that the voltage signals input into the column branch are distributed. In the invention, the resistance value of the variable resistor is unknown, so that the factor influencing the output voltage signal has two parts, one part is the resistance value of the variable resistor to be tested, and the other part is the resistance value of other variable resistors of the same column branch. In order to obtain the resistance of the resistor to be measured, the voltage dividing module is controlled to be connected and disconnected to obtain two output voltage signals respectively, and the resistance of the variable resistor to be measured is solved through the two output voltage signals.
Specifically, when the resistance information of a certain variable resistor needs to be acquired, an input selection switch is controlled to be communicated with the row branch and an excitation butt joint end, other ungated row branches are connected with a grounding end through corresponding input selection switches, and then external excitation equipment transmits a voltage signal to the row branch of the variable resistor to be detected through the excitation butt joint end; the output selection switches of the column branches corresponding to the variable resistor to be detected in the sensing array module are communicated with the column branches and the signal output end, and the output selection switches of other column branches are communicated with the column grounding end. In one state, a voltage dividing switch in the voltage dividing module is disconnected, namely a fixed value resistor is disconnected from a column branch, at the moment, other variable resistors on the column branch where the variable resistor to be detected is positioned can be simplified into parallel connection and then connected with the variable resistor to be detected in series, and an output voltage signal can be obtained through a signal output end; in another state, a switch in the voltage dividing module is closed, the fixed value resistor is communicated with a column branch circuit where the variable resistor to be detected is located, at the moment, other variable resistors and the fixed value resistor on the column branch circuit where the variable resistor to be detected is located can be simplified into parallel connection and then connected with the variable resistor to be detected in series, and an output voltage signal can be obtained through an output end. It can be understood that the factors influencing the output voltage signal have two parts, one part is the resistance value of the variable resistor to be measured, and the other part is the resistance value of other variable resistors in the same column of branches, but the embodiment respectively obtains the voltage signals output twice by controlling the connection and disconnection of the voltage dividing module, and the resistance value of the variable resistor to be measured can be solved by the voltage signals output twice.
It is to be understood that the connection and disconnection sequence of the voltage dividing module is not particularly limited in the present invention. As an implementation manner, the voltage dividing switch in the voltage dividing module can be firstly opened, the voltage signal output by the signal output end is obtained for the first time, then the voltage dividing switch in the voltage dividing module is closed, and the voltage signal output by the signal output end is obtained for the second time; as another embodiment, the voltage dividing switch in the voltage dividing module may be turned on first, the voltage signal outputted for the first time is obtained through the signal output terminal, and then the voltage dividing switch in the voltage dividing module is turned off, and the voltage signal outputted for the second time is obtained through the signal output terminal.
It can be understood that when the voltage dividing switch in the voltage dividing module is turned off, other variable resistors on the column branch where the variable resistor to be measured is located can be compared with the parallel variable resistor to be measured and then are connected in series, and the resistor after the parallel connection of the other variable resistors on the column branch is defined as Rss; when a switch in the voltage division module is closed, other variable resistors and fixed-value resistors on a column branch where the variable resistor to be detected is located can be compared with the parallel variable resistor to be detected and then are connected in series, the fixed-value resistor on the column branch is defined as R1, the resistor after the parallel variable resistor and the fixed-value resistor are Rsa, and the following formula (1) can be obtained:
It will be appreciated that the primary factor affecting the two output voltage signal magnitude changes is the magnitude of Rss and Rsa. If the resistance values of Rss and Rsa are relatively close, the voltage signals output twice are relatively close; if the difference between the resistance values of Rss and Rsa is larger, the difference between the voltage signals output by two times is larger. When the voltage signals output by the two times are relatively close in size, the output voltage signals with higher precision are required to be obtained, and then an accurate detection result can be obtained. That is, if the detection accuracy of the output voltage signal is low, and the resistance values of Rss and Rsa are relatively close, it is difficult to determine whether the obtained detection result is accurate. In the invention, in order to further improve the accuracy of the detection result, the Rsa is controlled to make the difference between the resistance values of Rss and Rsa larger, so that the obtained detection result can be judged whether to be accurate or not by enlarging the difference between the magnitudes of the voltage signals output twice even under the condition of lower detection precision.
It will be appreciated that the main factor affecting the size of Rsa is the relative size of R1 and Rss, and that when R1 is much smaller than Rss, rsa is much smaller than Rss as can be seen from equation (1). However, the size of the Rsa is changed by an external influence factor, so in this embodiment, in order to further avoid the influence of the change of the size of the Rsa, the voltage division module includes a plurality of fixed resistors with different resistance values, and the gating or the switching-off of the different fixed resistors is implemented through a plurality of switches or a single-pole multi-throw switch. That is, the fixed-value resistors with different resistance values can be selected to be suitable for different Rss, and the judgment of the Rss size can be performed by the voltage signal obtained when the voltage dividing switch is turned off.
For example, as shown in fig. 9, the voltage dividing module includes three fixed-value resistors with different resistance values, namely, R1, R2, R3, and the gating or the disconnection of the different fixed-value resistors is realized by a single-pole three-throw switch, namely, the fixed-value resistors R1, R2, R3 can be all connected into the circuit as voltage dividing resistors.
Referring to fig. 10, for better understanding, the present invention is illustrated by the following circuit: the input excitation signal is a voltage signal, the sensing array module comprises 4 rows and 4 columns, namely 16 variable resistors, the row grounding end is directly grounded, the column grounding end is provided with an operational amplifier circuit, and the voltage dividing module is provided with a voltage dividing switch and two selectable fixed-value resistors.
When the resistance value information of Rs1 needs to be acquired, controlling an input selection switch Ds10 of a branch circuit 1 which is in the same row with the Rs1 so as to enable the row branch circuit 1 to be communicated with an excitation butt joint end Vext 1; the input selection switches Ds20, ds30, and Ds40 corresponding to the column branches 2, 3, and 4 are controlled so that the column branches 2, 3, and 4 are respectively connected to the corresponding column ground. In the sensing array module, an output selection switch Ds01 of the same column branch 1 as Rs1 is communicated with a signal output end Vout, and output selection switches Ds02, ds03 and Ds04 of column branches 2, 3 and 4 are respectively communicated with corresponding column grounding ends.
It will be appreciated that when the voltage signal is transmitted to the row branch 1, since Rs1, rs2, rs3 and Rs4 on the row branch 1 are in parallel relationship, rs2, rs3 and Rs4 will not have a crosstalk effect on Rs 1; and because other ungated row branches are grounded through row grounding and other ungated column branches are grounded through column grounding, both ends of the variable resistor on the ungated row branches and the ungated column branches are grounded. Namely, both ends of Rs6, rs7, rs8, rs10, rs11, rs12, rs14, rs15 and Rs16 are grounded, and it is understood that the two ends of the resistor are grounded so that the voltages at both ends of the resistor are the same, and thus no current flows through them, thereby eliminating the problem of signal crosstalk caused by the series-parallel connection of the resistors to Rs 1.
The external excitation device is controlled to transmit a voltage signal to the row branch 1 through the excitation butt joint end Vext1, at the moment, the input voltage signal of the row branch 1 is V0, a voltage dividing switch in the voltage dividing module is disconnected, and the output voltage signal V1 is obtained through the signal output end Vout. In the column branch 1, rs5, rs9, and Rs13 in the same column as Rs1 are equivalent to being connected in parallel and then connected in series with Rs1, and the resistance obtained by connecting Rs5, rs9, and Rs13 in parallel is defined as Rss, so that the following formulas (2) and (3) can be obtained:
Further, the constant value resistor to be connected in the voltage dividing module is pre-judged through the obtained voltage signal V1, namely, the scheme of the voltage dividing resistor to be connected in parallel is determined; then the resistor is connected with the column branch 1, and the rest state is kept unchanged. The invention uses the connected fixed value resistor R1 as the voltage dividing resistor Rt for illustration, the fixed value resistor R1 is connected with the column branch 1, R1, rs5, rs9 and Rs13 which are in the same column with Rs1 are equivalent to being connected in parallel and then connected in series with Rs1, and the output voltage signal V2 is obtained through the signal output end Vout, so that the following formula (4) can be obtained:
the following equation (5) can be obtained by combining equation (3) with equation (4):
It can be understood that, since R1 is a fixed resistor with a known resistance value, V0 is an input voltage signal of the line branch 1 with a known magnitude, and V1 and V2 can be obtained by the above two detections, respectively, so that the magnitude of Rs1 can be obtained by the formula (5). Similarly, the resistance of other variable resistors can be obtained by the above embodiment, and only the gating of the corresponding row branches and column branches is controlled according to the corresponding control logic relationship, which is not repeated one by one.
It can be understood that when the external excitation device transmits the voltage signal to the row branch through the excitation butt joint end, certain loss (such as voltage loss caused by the line resistance) may occur in the transmission process of the voltage signal, so that the voltage signal provided by the external excitation device is directly used as the input voltage signal of the row branch where the variable resistor to be detected is located to calculate the resistance value of the variable resistor to be detected, which may affect the accuracy of the detection result. In order to further improve the accuracy of the detection result, the embodiment can avoid the influence caused by voltage loss by acquiring the voltage signal at the connection position of the row branch of the variable resistor to be detected and the corresponding input selection switch and using the voltage signal as the input voltage signal of the row branch of the variable resistor to be detected.
Embodiment 2 of the present invention discloses a thin film pressure sensor, which includes a pressure sensing portion and a signal transmission portion, wherein the pressure sensing portion is provided with a sensing array module as described in embodiment 1, and the corresponding variable resistor is a piezoresistive resistor, i.e. the resistance value of the variable resistor changes with the applied pressure. The pressure sensing part comprises a sensing material layer and an array electrode layer, wherein an array electrode is arranged on the array electrode layer, and the array electrode and the sensing material layer are oppositely arranged to form a variable resistor array in the sensing array module. The signal transmission part comprises an excitation input module and a signal and output module as described in embodiment 1, and the connection mode of the pressure sensing part and the signal output part can be the same as that described in embodiment 1.
Referring to fig. 11, it can be understood that the sensing material layer and the array electrode layer disposed opposite to each other form parasitic capacitance, and when an excitation signal is input through the signal transmission portion, the parasitic capacitance formed between the sensing material layer and the array electrode layer stores charges, and when the stored charges are released, the stored charges will affect the output voltage obtained by the signal output terminal if passing through the column branch where the variable resistor to be tested is located. The invention is connected with the row grounding end through the row branch, and the charges can be released through the row grounding end, so that the influence of the charges stored in the parasitic capacitance on the output voltage signal is avoided, and the accuracy of the detection result is further improved. That is, in the embodiment of the present invention, the row grounding terminal is not only used to cooperate with the column grounding terminal to avoid the influence caused by crosstalk, but also can release the charges stored in the parasitic capacitor through the row grounding terminal, so that the influence of the stored charges on the output voltage signal is further avoided, and the present invention has high practicality and popularization value.
Finally, it should be noted that while the above describes embodiments of the invention in terms of drawings, the present invention is not limited to the above-described embodiments and fields of application, which are illustrative, instructive, and not limiting. Those skilled in the art, having the benefit of this disclosure, may effect numerous forms of the invention without departing from the scope of the invention as claimed.
Claims (17)
1. A detection circuit with a variable resistance array, which is characterized by comprising an excitation input module, a sensing array module and a signal output module; the sensing array module comprises a variable resistor array formed by a plurality of variable resistors, and the variable resistor array comprises a row branch and a column branch; in the variable resistor array, the X ends of the variable resistors in the same row are connected in parallel with the branches in the same row, and the Y ends of the variable resistors in the same column are connected in parallel with the branches in the same column; the excitation input module comprises a row grounding end, an excitation butt joint end and an input selection switch, wherein the row grounding end is grounded, the excitation butt joint end is used for being connected with external excitation equipment, and the row branch is connected with the row grounding end or the excitation butt joint end through the input selection switch corresponding to the row branch; the signal output module comprises a column grounding end, a signal output end and an output selection switch, wherein the column grounding end is grounded, the signal output end is used for obtaining an output signal of the detection circuit, and the column branch is connected with the column grounding end or the signal output end through the corresponding output selection switch.
2. The detection circuit of claim 1, wherein the row ground is directly grounded and the column ground is directly grounded; or the row grounding end is directly grounded, the column grounding end is grounded through an operational amplifier circuit, and when the column branch is communicated with the column grounding end, the operational amplifier circuit is used for controlling the current of the column branch.
3. The detecting circuit according to claim 2, wherein the operational amplifier has an inverting input terminal connected to the output selection switch and a feedback resistor provided between the inverting input terminal and the output terminal of the operational amplifier.
4. The detection circuit of claim 1, wherein the excitation input module comprises excitation modules arranged in one-to-one correspondence with each row of branches; the excitation module is provided with a row of grounding terminals, an excitation butt-joint terminal and an input selection switch; the row branch is connected with a row grounding end or an excitation butt end through an input selection switch in the corresponding excitation module.
5. The detection circuit of claim 1, wherein the excitation input module comprises a row of ground terminals, an excitation docking terminal, and input selection switches disposed corresponding to the row branches; the row branch is connected with a row grounding end or an excitation butt joint end through an input selection switch corresponding to the row branch.
6. The detecting circuit according to claim 1, wherein the signal output module includes a column ground, a signal output, and an output selection switch provided corresponding to the column branch; the column branch is connected with the signal output end or the column grounding end through the corresponding output selection switch.
7. The detecting circuit according to claim 1, wherein the signal output module includes a signal output terminal, and an output selection switch and a column ground terminal provided corresponding to the column branch; the row branch is connected with the signal output end or the row grounding end corresponding to the signal output end through the output selection switch corresponding to the row branch.
8. The detection circuit of claim 1, wherein the variable resistor is any one of a varistor, a temperature sensitive resistor, a photoresistor, and a gas sensitive resistor.
9. The detection circuit of claim 1, wherein the variable resistance is a resistance formed by the sensing material and the sensing electrode in cooperation.
10. The detection circuit according to any one of claims 1 to 9, wherein the signal output module further comprises a voltage dividing module; the voltage dividing module comprises a voltage dividing resistor and a voltage dividing switch, and the voltage dividing resistor is connected to the signal output end in parallel through the voltage dividing switch.
11. The detecting circuit according to claim 10, wherein the voltage dividing resistor comprises at least two fixed value resistors with different resistance values, one end of the fixed value resistor is connected to the signal output end in parallel through the voltage dividing switch, and the other end is grounded.
12. A method for obtaining the resistance value of the variable resistor in the detection circuit with the variable resistor array according to claim 10 or 11, comprising:
Controlling input selection switches corresponding to the row branches to enable the row branch of the variable resistor to be detected to be communicated with an excitation butt joint end, and the other row branches to be connected with a row grounding end, wherein excitation signals input by the excitation butt joint end are voltage signals;
controlling the output selection switch corresponding to the column branch circuit to enable the column branch circuit where the variable resistor to be detected is positioned to be communicated with the signal output end, and the other column branch circuits are communicated with the column grounding end;
Acquiring an input voltage signal of a line branch of a variable resistor to be detected;
controlling the state of the voltage dividing switch to respectively obtain a first voltage signal output by the signal output end in the state that no voltage dividing resistor is connected in parallel to the signal output end and a second voltage signal output by the signal output end in the state that the voltage dividing resistor is connected in parallel to the signal output end;
And solving the resistance value of the variable resistor to be measured based on the input voltage signal, the first voltage signal, the second voltage signal and the voltage dividing resistor.
13. The method as recited in claim 12, further comprising: when the voltage dividing resistor has more than two resistance values, the voltage dividing resistor connected in parallel to the signal output end is selected according to the first voltage signal.
14. The method according to claim 12 or 13, wherein solving the resistance value of the variable resistor to be measured based on the input voltage signal, the first voltage signal, the second voltage signal and the voltage dividing resistor, specifically comprises:
wherein Rsi is a variable resistor to be detected, rt is a voltage dividing resistor connected in parallel to a signal output end, and V0 is an input voltage signal; v1 is a first voltage signal and V2 is a second voltage signal.
15. A method as claimed in claim 12 or 13, wherein the input voltage signal is a voltage signal input at the excitation docking terminal; or the input voltage signal is a voltage signal at the connection part of the row branch of the variable resistor to be detected and the corresponding input selection switch.
16. A method for obtaining the resistance value of the variable resistor in the detection circuit with the variable resistor array according to any one of claims 1 to 11, comprising:
Controlling input selection switches corresponding to the row branches to enable the row branch of the variable resistor to be detected to be communicated with an excitation butt joint end, and the other row branches to be connected with a row grounding end, wherein excitation signals input by the excitation butt joint end are current signals;
controlling the output selection switch corresponding to the column branch circuit to enable the column branch circuit where the variable resistor to be detected is positioned to be communicated with the signal output end, and the other column branch circuits are communicated with the column grounding end;
acquiring a current signal input by the excitation butt joint end, an input voltage signal of a row branch circuit of the variable resistor to be detected and a third voltage signal output by the signal output end;
and solving the resistance value of the variable resistor to be measured based on the input voltage signal and the third voltage signal and the current signal.
17. The film type pressure sensor is characterized by comprising a pressure sensing part and a signal transmission part; the pressure sensing part comprises a sensing material layer and an array electrode layer, wherein an array electrode is arranged on the array electrode layer, and the array electrode and the sensing material layer are oppositely arranged to form a variable resistance array in the detection circuit with the variable resistance array according to any one of claims 1 to 11; the signal transmission section includes the excitation input module and the signal output module in the detection circuit with the variable resistor array as claimed in any one of claims 1 to 11.
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