HK1243160A1 - An apparatus and method for sensing - Google Patents

Description

Apparatus and method for sensing

Technical Field

Examples of the present disclosure relate to an apparatus and method for sensing. Certain non-limiting examples relate to sensor circuits for use in sensor arrays.

Background

Conventional sensor systems for reading or measuring output signals from sensors are not always optimal. For example, some conventional systems for sensing a particular property (e.g., temperature, humidity, pressure, stress, strain, and light) may involve reading out and measuring an output signal, such as a voltage, from a sensor, which may be used to determine the property to which the sensor responds. Some conventional sensor systems may have limited ability to detect small changes in sensor voltage output.

The listing or discussion of any previously published document or any background in this specification should not be taken as an admission that the document or background is part of the state of the art or is common general knowledge. One or more aspects/examples of the present disclosure may or may not address one or more of the background issues.

Disclosure of Invention

In accordance with at least some, but not necessarily all, examples of the disclosure there is provided an apparatus comprising a sensor circuit comprising a first output, a second output, and a sensor arranged in a bridge circuit arrangement;

wherein the sensor circuit is configured such that the sensor measurement can be determined based on a voltage difference between the first and second output terminals; and wherein the apparatus is configured to prevent current from being able to flow from the first output to the second output through the sensor circuit.

The bridge circuit arrangement is a wheatstone bridge arrangement.

One or more of the devices may be provided as part of a module, apparatus, or arranged in an array.

According to at least some, but not necessarily all, examples of the disclosure there is provided a method comprising preventing current from flowing through a sensor circuit from an output of the sensor circuit to another output of the sensor circuit, wherein the sensor circuit comprises: a sensor disposed in a bridge circuit arrangement; wherein the sensor circuit is configured such that the sensor measurement can be determined based on a voltage difference between outputs of the sensor circuit.

In accordance with at least some, but not necessarily all, examples of the disclosure there is provided an apparatus comprising components configured to enable the apparatus to at least perform the above-described method.

Drawings

For a better understanding of the detailed description of the invention and the various examples of the disclosure that may be used for certain embodiments, reference will now be made, by way of example only, to the accompanying drawings in which:

fig. 1 schematically illustrates an example apparatus according to the present disclosure;

fig. 2 schematically illustrates another example apparatus of the present disclosure;

fig. 3A and 3B illustrate circuit diagrams of sensor circuits of example apparatus of the present disclosure;

FIGS. 4A and 4B show circuit diagrams of arrays of the sensor circuits of FIGS. 3A and 3B, respectively, of an example of an apparatus according to the present disclosure;

fig. 5 shows an arrangement of a sensor circuit of an example of an apparatus according to the present disclosure;

FIG. 6 illustrates a selector circuit for use in selecting individual ones of the sensor circuits of FIG. 5; and

fig. 7 shows a flow chart of an example method of the present disclosure.

Detailed Description

The figures schematically show an apparatus 100, the apparatus 100 comprising:

a sensor circuit 101 comprising a first output 104, a second output 105 and a sensor 102 arranged in a bridge circuit arrangement 103;

wherein the sensor circuit 101 is configured such that the sensor measurement value can be determined based on a voltage difference between the first output 104 and the second output 105 of the sensor circuit 101;

and wherein the apparatus 100 is configured to prevent current from being able to flow from the first output 104 through the sensor circuit 101 to the second output 105.

Examples of the present disclosure will now be described with reference to the accompanying drawings. Like reference numerals are used to denote like features in the drawings. For purposes of clarity, not all reference numbers will necessarily be displayed in all figures.

Fig. 1 schematically illustrates an apparatus 100 according to an example of the present disclosure. The apparatus 100 includes a sensor circuit 101. The sensor circuit is configured in a bridge circuit arrangement 103 and comprises a sensor 102 within the bridge circuit arrangement 103.

The bridge circuit arrangement 103 comprises two branches ABC and AB' C. Each branch comprises at least two arms, i.e. the first branch ABC comprises arms AB and BC and the second branch AB ' C comprises arms AB ' and B ' C. Each circuit branch of the sensor circuit includes an output located at an intermediate point along the respective branch. The first output 104 is located at an intermediate point B between the arms AB and BC of the first branch ABC. Similarly, the second output terminal 105 is located at an intermediate point B 'in the second branch AB' C between the arms AB 'and B' C.

The sensor circuit has input terminals 106 and 107, whereby an input voltage can be supplied to the sensor circuit. The first input 106 is located at a node a common to both the first and the second branch, i.e. where the two branches ABC and AB' C start branching off from each other. The second end 107 is located at a node C common to both the first and second branches, i.e. where the two branches ABC and AB' C come together. Voltage V_DMay be provided to input 106 and terminal 107 may be connected to a lower potential, such as ground.

The sensor 102 is located in one of the arms AB 'of one of the branches AB' C of the sensor circuit 101. The sensor measurement may be determined based on a voltage difference between the output terminals 104 and 105 of the sensor circuit.

The sensor 102 may be a resistive type sensor whose resistance value varies according to the property that the sensor is configured to measure. The sensor may have a nominal impedance value (which may have both resistive and reactive components), where both the real and imaginary parts may change, or only one component may change for detection/measurement. Each of the other arms AB, BC and B' C of the sensor circuit 101 may be provided with one or more electrical components 108, 109 and 110.

The bridge arrangement of the sensor circuit arrangement may comprise, inter alia, a wheatstone bridge arrangement, for example. In case the bridge circuit arrangement comprises a wheatstone bridge arrangement, the electrical components 108, 109 and 110 of each arm each have their own impedance value (which may have both resistive and reactive components). The electrical component may be used as a reference component for known impedance values. In some examples, the electrical component may correspond to a resistor. In one particular example, the values of resistors 108 and 109 may be the same (R)₀) And the value of resistor 110 is related to the nominal resistance (R) of sensor 102_G) The same is true. Electric powerVariation of resistance (Δ R)_G) A voltage difference may be caused to be provided between the output terminals 104 and 105. The measurement of the parameter of the sensor may be determined based on the measurement of the voltage difference between the output terminals 104 and 105. The use of an electrical bridge arrangement, such as a wheatstone bridge arrangement, enables high accuracy resistance measurements of the sensor and thus high accuracy sensor measurements.

The apparatus 100 is configured to prevent current from being able to flow from one output to the other through the sensor circuit. For example, the arrangement may be configured such that when a voltage is to be applied to the outputs 104 and 105, current will not flow from the output 105 to the output 104 through the arms B 'a and AB, and likewise current will not flow from the output 105 to the output 104 through the arms B' C and CB. Similarly, the arrangement may be configured to prevent current from flowing from output 104 to output 105 through arms BA and AB ', and likewise to prevent current from flowing from output 104 to output 105 through arms BC and CB'. The prevention of current flow from one output to the other is illustratively shown with a deleted arrow.

The component blocks 102, 108, 109, 110 of each arm of fig. 1 are functional, and the functions described may or may not be performed by a single physical entity (e.g., the combined resistor and diode arm described with reference to fig. 3A, 3B, 4A, 4B, and 5).

The device may be provided with one or more electrical components and/or components for preventing current from being able to flow from one output to another via the arms of the sensor circuit. In some examples, such a component may be one or more of any device, mechanism, or circuit configured to prevent current from being able to flow from one output to another via an arm of the sensor circuit. In some examples, such an assembly may be an arrangement of electrical components arranged to prevent current from being able to flow from one output to another via an arm of the sensor circuit, in particular for example by means of suitably provided diodes, transistors and/or switches.

Preventing current (i.e. the direction of current) from flowing from one of the output terminals to the other output terminal via the arms of the sensor circuit prevents a voltage difference applied to the output terminals from causing current to flow through the sensor circuit. This allows the output of the first sensor circuit to be coupled in parallel with the other outputs of the other sensor circuits without adversely affecting the overall output. In fact, any additional sensor circuit connected in parallel will be "open" or actually "electrically isolated" from the output voltage of the first sensor circuit. The impedance of any such additional sensor circuits connected in parallel does not affect the output of the first sensor circuit. This may avoid a "voltage drop" of the output voltage of the first sensor circuit, which may otherwise have occurred if the output voltage was allowed to cause current to flow through each of the other sensor circuits, i.e. due to wiring (routing) resistance and transistor channel resistance. The output of the device may also be more resilient to changes in the impedance of the various sensing circuits that may occur under changing environmental conditions (e.g., temperature or humidity). It is also possible to provide a single output common to all parallel connected sensor circuits so that only a single output is required to read out the entire array even though each sensor of the array may have very different impedance values. This can reduce the number of pinouts if each sensor circuit has its own separate pinout. This may provide a simplified overall architecture that may enable the apparatus of the present disclosure to be combined and scaled to any size sensor array of sensor circuits with minimal loss in sensor readout accuracy. Examples of the present disclosure enable providing an array of sensor circuits, wherein each sensor circuit may have a different impedance value, and the sensors of each sensor circuit may be configured to sense different properties/parameters, such as, inter alia, one or more of: temperature, humidity, pressure, stress, strain, and light.

In some examples, the sensor may include a graphene-based sensor. The graphene-based sensor may be configured as, for example, a photodetector and/or a biosensor, among others.

Graphene-based sensors may be implemented as Graphene Field Effect Transistor (GFET) structures, where the sensing layer is used directly over the graphene layer. The charge generated in the sense layer gates the GFET device and changes the current flowing through the device. In this manner, the GFET may be considered to be virtually equivalent to a variable resistor that can be read using the sensor circuit described above. Examples of the present disclosure may enable coupling outputs of multiple graphene-based sensor circuits in parallel. This may allow measurements from multiple graphene-based sensors to be read out from a single common output pair, and thus only a pair of pinouts is required (i.e., a pair of pinouts is required for each individual sensor circuit of the multiple sensor circuits). Thus, a simpler/reduced complexity arrangement for reading out/measuring a plurality of sensor circuits may be provided.

Fig. 2 schematically shows a further apparatus 200 comprising a combination of the sensor circuit 101 of fig. 1 and a second sensor circuit 201. The output of the first sensor circuit 101 is connected in parallel with the output of the second sensor circuit 201.

The input terminals 106 and 107 of the first sensor circuit 101 are selectively coupled to the input voltage V via switches 205 and 205', respectively_DAnd a lower potential, e.g., ground. Similarly, the second sensor circuit 201 is selectively coupled to the input voltage V via respective switches 206 and 206_DAnd to ground.

The parallel coupling of all outputs of the sensor circuits is such that only a single overall output 208, 209 is provided for all sensor circuits, thereby facilitating readout of the outputs from the individual sensor circuits. It will be appreciated that additional circuitry may be provided, the outputs of which may be connected in parallel to form a sensor array.

The ability to selectively couple each sensor circuit to an input voltage may enable individual selection/addressing of an individual sensor circuit from among multiple sensor circuits of the array, such that the measured array output at terminals 208 and 209 corresponds to the output of the individually selected/addressed sensor circuit.

Decoupling of the unselected sensor circuits from the input voltage means that the unselected sensor circuits do not produce a voltage difference on their outputs. Thus, the unselected sensor circuits do not contribute any voltage to the entire array voltage output. Decoupling the unselected sensor circuits from ground eliminates the possibility of a wiring path for current to flow from the output of the unselected sensor circuits to ground (e.g., from B' to C or from B to C).

Thus, examples of the present disclosure may provide an addressing scheme for reading out measurements from each sensor circuit in the array without cross-talk with other sensor circuits in the array, and avoid any contamination of the signals output from selected sensor circuits due to other (non-selected) sensor circuits in the array.

Fig. 3A shows an example of an apparatus 300 of the present disclosure, in particular a circuit diagram showing the arrangement of the electrical components of the sensor circuit 301, and a circuit diagram of the components 205, 205' for selectively coupling the sensor circuit to an input voltage. In the example of fig. 3A, such components for selecting/addressing the sensor circuit correspond to components for selectively coupling/decoupling the sensor circuit 301 to the input voltage V_DAnd switches 205 and 205' to ground.

The sensor circuit 301 is arranged in a wheatstone bridge configuration. When the switches 205 and 205' are closed and the voltage V is applied_DCoupled to ground through the sensor circuit, the sensor circuit 301 functions similar to a conventional voltage divider wheatstone bridge in that all diodes are forward biased under this condition. Based on the voltage difference between the outputs 304 and 305, a measurement from the sensor can be determined. The use of a wheatstone bridge configuration may allow for very small changes in the impedance or resistance of the sensor to be detected, so that very high accuracy measurements may be measured. For example, where impedance components are used and impedance values (rather than pure resistance values) are measured, a DC voltage may be used to select a particular sensor circuit and bias the diodes, while then a small AC signal may be applied through the circuit andand the resulting AC signal can be measured at the output (both its magnitude and phase).

In the first arm AB of the first branch ABC, has a standard resistance value R₀Is arranged in series with a diode that is forward biased with respect to the input voltage (i.e., such that current can flow from node a to B but not from node B to a). Similarly, in the second arm BC of the first branch ABC, there is a standard resistance value R₀Is arranged in series with the diode, which is again forward biased. In each of the arms AB ' and B ' C of the second branch AB ' C, a diode is provided, which is arranged to be forward biased. Furthermore, in the first arm AB' of the second branch, a sensor is arranged in series with the diode. Nominal value of the sensor is R_GHowever, the resistance of the sensor is configured to change Δ R_GWherein the change in resistance is dependent on the parameter sensed by the sensor. In the second arm B' C of the second branch, a reference value R is arranged in series with the diode_GOf the other resistor.

Thus, each arm comprises a diode configured to be forward biased to enable current to flow through each branch in only one aspect, i.e. from a to B to C via the first branch and from a to B' to C via the second branch. While the diodes are also configured to prevent current from flowing from one output 304 to the other output 305 through the arms of the sensor circuit, i.e. to prevent any current from flowing from output 304 to output 305 through arms BA and AB '(or arms BC and CB'), and likewise to prevent any current from flowing from output 305 to output 304 through arms B 'a and AB (or arms B' C and CB).

Fig. 3B shows an apparatus 300 'having a sensor circuit 301 and alternative components 305, 305' for selectively coupling the sensor circuit to an input voltage. In the example of fig. 3B, such components for selecting/addressing the sensor circuit include an arrangement of transistors 306, 307, and 308 for selectively coupling/decoupling the sensor circuit 301 to the input voltage V_DAnd to ground.

In some examples, the components for selecting/addressing the sensor circuit and the components configured to couple/decouple the sensor circuit to the input voltage and/or ground may be an arrangement of electrical components that are suitably configured circuitry in this regard or suitably arranged in this regard.

The transistor 306 is provided with: is connected to V_DIs connected to V_GAnd a source connected to an input of the sensor circuit 301 at node a. The transistor 307 is provided with: drain of sensor circuit 301 at node C, to V_GAnd a source connected to the drain of transistor 308. The gate of transistor 308 is connected to V_DAnd its source connected to ground. With such a structure, the source terminal is connected to a lower potential (e.g., ground) and the drain terminal is connected to a higher potential (e.g., V)_D)。

The devices 300 and 300' each provide an architecture of sensor circuit 301 that allows the outputs of multiple sensor circuits to be coupled together in parallel to form an array such that only one output is required to read out a measurement from the sensor array. This is achieved by the sensor circuits being arranged in a wheatstone bridge configuration with a diode in each branch and the components being configured to selectively couple/decouple each sensor circuit to the input voltage.

Certain examples of the present disclosure provide an architecture for a sensor circuit and sensor array that may provide the following advantages:

a sensor readout with a high signal-to-noise ratio,

an architecture that can be scaled to any size of sensor array without loss of sensor readout accuracy, and/or

Even though each sensor circuit may have very different standard impedance values, only a single output is required to read out the entire array.

Examples of the present disclosure may be applicable to large area arrays, such as photodetectors, or equally to low cost flexible sensor array devices, e.g. multi-sensing surfaces for wearable electronics.

Fig. 4A shows a device 400 comprising an array of the devices 300 of fig. 3A. The devices 300 are arranged in rows and columns that may be selectively coupled to V by selectively coupling particular ones of the devices 300 to V_DAnd ground to selectively address and read out individually, i.e., close the switches 205 and 205 'of a particular selected device 300, while decoupling all remaining devices 300 from the input voltage and ground, i.e., open the switches 205 and 205' of the unselected apparatus 300.

In the array 400 of FIG. 4A, where the outputs of each device 300 are coupled in parallel, the entire array (exemplified in this case by the 3 × 3 array) is measured from a single output 401 corresponding to the voltage between nodes B and B' of the selected sensor circuit (the unselected sensor circuits and V)_DAnd ground decoupled and therefore does not provide/contribute any output).

An active matrix backplane may be provided to selectively couple each selected sensor circuit at a voltage V_DAnd ground, while other sensor circuits are not coupled to voltage V_DOr to ground.

Although the output voltage of a selected sensor circuit (e.g., sensor 1,1) is coupled in parallel to all other sensor circuits, there is always a reverse biased diode in each arm of each other sensor circuit, while all other sensor circuits are coupled with V_DAnd ground decoupling, which effectively means that all other sensor circuits except for all sensor circuits currently being addressed/selected and measured are "open" and effectively electrically isolated from the output voltage of the selected sensor circuit. Advantageously, the impedance of the other sensor circuits does not affect the output voltage of the selected sensor circuit measured at the array output 401.

In some examples, the component configured to selectively address one or more of the plurality of sensor circuits for reading the output therefrom may be one or more of any device, mechanism, circuit, or arrangement configured/arranged to selectively address electrical components of one or more of the plurality of sensor circuits for reading the output therefrom. In some examples, the component configured to couple the selected one or more of the plurality of sensor circuits to the input voltage and/or ground may be one or more of any device, mechanism, circuit, or arrangement of electrical components configured/arranged to couple the selected one or more of the plurality of sensor circuits to the input voltage and/or ground. In some examples, the component configured to decouple the unselected one or more of the plurality of sensor circuits to the input voltage and/or ground may be one or more of any device, mechanism, circuit, or arrangement of electrical components configured/arranged to decouple the unselected one or more of the plurality of sensor circuits to the input voltage and/or ground.

FIG. 4B shows an array 400' of the apparatus 300' of FIG. 3B arranged in a row and column matrix of 3 × 3, instead of switches 205 and 205' according to FIG. 3A, for selectively coupling and decoupling each sensor circuit 301 to an input voltage V_DAnd the components to ground are instead provided by transistors. An arrangement of transistors 306, 307 and 308 is provided for each sensor circuit. The transistors may form an active matrix backplane that drives the array of sensor circuits.

In array 400', V_DIs a column voltage (e.g. V) applied to one column at a time_D,1、V_D,2And V_D,3One of) V_GIs a row voltage (e.g., V) applied to one row at a time_G,1、V_G,2And V_G,3One of the above). With the arrangement of fig. 4B, only when all three transistors have gate voltages applied, i.e. only when V_DAnd V_GAre non-zero and are large enough to switch the transistor to a conductive "ON" state, a sensor circuit 300' of the plurality of sensor circuits may be coupled to V_DAnd ground.

When the rows and columns thereof are respectively provided withV_GAnd V_DWhile a single sensor circuit may be selected/addressed (excluding all others), the remaining sensor circuits will remain unselected/unaddressed. Row and column voltages V_GAnd V_DMay be addressed sequentially one at a time via a multiplexing circuit (not shown).

In the array 400' (and in the transistor architecture 600 of fig. 6), in each "cell" of the array, two transistors (306 and 307 with respect to fig. 3B) pass the row voltage V_GNTo gate, but only one transistor (308 with respect to fig. 3B) passes the column voltage V_DNTo gate. In other examples, the input voltage V may be at the upper node (a) and_Dwith a further transistor arranged therebetween, wherein such a transistor passes V_DTo gate. This means that V was not applied_DWill be decoupled, thereby providing an alternative component for selectively decoupling the sensor circuitry. In the arrangements of fig. 4B and 6, such additional V is not required_DGated transistor, since a diode is provided in the branch of the sensor circuit. Thus, for example, in FIG. 4B, if one wants to pass through row V_G1Applying a voltage and in column V_D1Applying a voltage at other V_GNRows and V_DNAddressing sensors 1,1 while having zero voltage at the column, then for example sensors 1,2 will also be addressed by V_G1The gated transistor is placed in the ON state, which means that the upper node (point a) of the sensors 1,2 is actually connected to V_D2(which is at zero potential). However, no current can flow from the output of the sensor circuit 1,2 to V due to the diode in the branch of the sensor circuit 1,2_D2. Thus, in the configuration of the example of fig. 4B and 6, no additional column voltage V as described above is required_DNThe gated transistor decouples the sensor circuit from the input voltage.

In some examples, the component for selectively addressing one or more of the plurality of sensor circuits may be one or more of any device, mechanism, circuit, or arrangement of electrical components configured/arranged to selectively address one or more of the plurality of sensor circuits. In some examples, the component for selectively coupling each of the plurality of sensor circuits to the input voltage and/or ground may be one or more of any device, mechanism, circuit, or arrangement of electrical components configured/arranged to selectively couple each of the plurality of sensor circuits to the input voltage and/or ground. In some examples, the component for selectively decoupling each of the plurality of sensor circuits to the input voltage and/or ground may be one or more of any device, mechanism, circuit, or arrangement of electrical components configured/arranged to selectively decouple each of the plurality of sensor circuits to the input voltage and/or ground.

This enables the voltage drop across the forward biased diode to be well controlled and small compared to the voltage drop across the resistor in each sensor circuit, with the incorporation of a diode in each sensor circuit to allow the outputs of all sensor circuits to be coupled in parallel as a single output. Thus, even when small relative changes in the sensor impedance are to be measured, the diode will produce minimal error in the output voltage of each sensor circuit.

The sensors and electrical impedance components/resistors in the various sensor circuits of the array may have very different nominal impedance values, but may still use the same single output for sensor readout, using one single voltage output coupled from the output of the array.

The sensor array can be arbitrarily scaled in terms of the number of sensor circuits and the physical size of the entire array on the substrate. Since the output voltage of the sensor circuit can be measured with a minimum current, the influence of the resistance of the connector wiring on the readout accuracy and the detection sensitivity is small.

The architecture of the present disclosure is particularly applicable to large area sensor arrays where the voltage drop along the conductor wiring may be significant, particularly where the wiring is printed.

In addition to large area applications, the sensor circuit and sensor array structure may also be well suited for flexible or stretchable electronic applications. Where the array is configured to be flexible or stretchable, the sensors, transistors and diodes may be discrete components and assembled on a flexible or stretchable carrier substrate. In some examples, the sensors and sensor circuitry themselves may be disposed on a layer of the substrate that is different from the layer of the substrate on which the components for each sensor are disposed (e.g., an active matrix backplane). In such an example, the two layers may be connected to each other by vias.

Fig. 5 shows an arrangement of sensor circuits 301 arranged in an array and in which the outputs of each sensor circuit are connected in parallel to provide a single output for the array. Apparatus 500 includes an array of sensor circuits 301 that does not include components for selectively coupling each sensor circuit to an input voltage and ground (rather, such selective coupling/decoupling by having disposed therein components for selectively coupling and decoupling each sensor circuit 301 to V_DAnd the grounded component, are provided separately by apparatus 600 of fig. 6). Apparatus 500 provides a wheatstone bridge sensor array and apparatus 600 provides a transistor backplane/selector circuit for selecting individual ones of the sensor circuits for reading out measurements from the selected sensor circuits at a single array output.

A plurality of sensor circuits 301 of array 500 can be disposed on a first substrate 503 (while an array of components for selectively addressing each of the various sensor circuits and selectively coupling/decoupling each sensor circuit to an input voltage and ground can be disposed on a second substrate 603, as shown in fig. 6).

The transistor architecture of fig. 6 may be provided on a substrate/layer 603 separate from the substrate/layer 503 providing the sensor circuit arrangement 500. The transistor backplane 600 may be implemented using Organic Field Effect Transistors (OFETs). The transistor backplane 600 may be suitably interconnected to the sensor circuit arrangement 500 by vias at the coupling terminals 501 and 601 and the terminals 502 and 602.

Sensor circuit and/or sensor including circuit and for selectively coupling sensor circuit to V_DAnd the entire structure of the grounded components, can be fabricated using printed electronics fabrication methods such as screen printing, ink jet, gravure, flexographic printing, or by aerosol jet deposition.

The apparatus described above may be provided as one or more of a module, a device, or a sensor array.

Fig. 7 shows a flow chart of a method 700 of the present invention.

In block 701, current is prevented from flowing out from an output of a sensor circuit to another output of the sensor circuit through the sensor circuit itself. In block 702, an output of a sensor circuit is connected in parallel with an output of at least a second sensor circuit. In block 703, one of the sensor circuit and the second sensor circuit is coupled to an input voltage and/or ground. In block 704, the other of the sensor circuit and the second sensor circuit is decoupled from the input voltage and/or ground.

It will be appreciated that multiple sensor circuits may be used in the above-described method, and that one or more sensor circuits may be selected for coupling to the input voltage/ground, and the remaining, non-selected sensor circuits are decoupled from the input voltage/ground.

The flow chart of fig. 7 represents one possible scenario. The order of the blocks shown is not absolutely required, so in principle the various blocks may be performed out of order. Not all blocks are necessary.

The illustration of a particular order to the blocks does not necessarily indicate a required or preferred order to the blocks and the order and arrangement of the blocks may be varied. Furthermore, some blocks may be omitted.

In some examples, one or more blocks may be performed in a different order, or overlapping in time, series, or parallel. One or more blocks may be omitted or added in some combination.

According to another example of the present disclosure, there is provided an apparatus comprising components configured to enable the apparatus to perform at least the above method.

Although examples of the apparatus have been described in terms of comprising various components, it will be appreciated that the components may be implemented as or controlled by respective processing elements or processors of the apparatus. In this regard, each component described below may be one or more of any device, assembly, circuit, or arrangement of electrical components configured to perform the respective functions of the respective components as described above. For example, the diodes of the sensor circuit that prevent the current of the arms of the branch from "flowing backwards" may be replaced with switches or transistors in each arm between each output and the common output line, e.g. at points B and B'. (however, the use of transistors may result in a decrease in the accuracy of the sensor measurement or detection due to the small voltage output and due to possible variations in the channel resistance of the transistors).

Features described in the above description may be used in combinations other than the combinations explicitly described. The examples of the disclosure and appended claims may be combined as appropriate in any manner apparent to one of ordinary skill in the art.

The term "comprising" is used herein in an inclusive rather than exclusive sense. Any reference to X including Y means that X may include only one Y or may include more than one Y. If the exclusive meaning of "comprising" is intended, this will be expressly made in this context by reference to "comprising only one" or by using "consisting of …".

In this specification, the meaning of "connected," "coupled," and derivatives thereof mean operatively connected/coupled. It should be understood that there may be any number or combination of intermediate members (including no intermediate members).

In this specification, reference has been made to various examples. The description of features or functions relating to the examples indicates the presence of such features or functions in the examples. The use of the terms "example" or "such as" or "may" herein means that the features or functionality are present in at least the described example, whether explicitly stated or not, and may be, but are not necessarily present in some or all of the other examples, whether described as examples or not. Thus, "an example," "e.g.," or "may" refers to a particular instance of a class of examples. The property of the instance may be only that of the instance or that of the class or a subclass of the class, the subclass including some but not all instances of the class.

In this specification, unless explicitly stated otherwise, a reference to "a (a)/an (an)/the" (feature, element, component, assembly ]) is to be interpreted as "at least one" (feature, element, component, assembly).

The foregoing description describes some examples of the present disclosure, however those of ordinary skill in the art will recognize that possible alternative structural and method features that provide equivalent functionality to the specific examples of such structures and features described above and have been omitted from the foregoing description for the sake of brevity and clarity. Nonetheless, the above description should be implicitly understood to include references to such alternative structures and method features providing equivalent functionality, unless such alternative structures or method features are explicitly excluded from the above description of embodiments of the disclosure.

Although features are described with respect to particular examples, those features may also be present in other examples, whether described or not. It should be appreciated that variations to the examples may be made without departing from the scope of the invention as set forth in the claims.

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the applicant claims protection in respect of any novel feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (18)

1. An apparatus, comprising:

a sensor circuit comprising a first output, a second output, and a sensor disposed in a bridge circuit arrangement;

wherein the sensor circuit is configured to: enabling a sensor measurement to be determined based on a voltage difference between the first output and the second output; and

wherein the apparatus is configured to: such that current is prevented from flowing from the first output to the second output through the sensor circuit.

2. The apparatus of the preceding claim 1, wherein the bridge circuit arrangement is a wheatstone bridge arrangement.

3. The apparatus of any one or more of the preceding claims, further comprising at least a second sensor circuit comprising a further first output and a further second output, and wherein the output of the sensor circuit is connected in parallel with the further output of the at least second sensor circuit.

4. The apparatus of claim 3, wherein the apparatus is configured to one or more of:

selectively coupling and decoupling one or more of the sensor circuit and the at least a second sensor circuit from an input voltage; and

selectively coupling and decoupling one or more of the sensor circuit and the at least a second sensor circuit from ground.

5. The apparatus of any one or more of the preceding claims, wherein the bridge circuit arrangement comprises a plurality of circuit branches, wherein a circuit branch of the plurality of circuit branches comprises a plurality of arms, and wherein an arm of the plurality of arms comprises at least one impedance component.

6. The apparatus of any one or more of the preceding claims, wherein the bridge circuit arrangement comprises a plurality of circuit branches, wherein a circuit branch of the plurality of circuit branches comprises a plurality of arms, and wherein an arm of the plurality of arms comprises at least one diode.

7. The apparatus of any one or more of the preceding claims, wherein the bridge circuit arrangement comprises a plurality of circuit branches, wherein a circuit branch of the plurality of circuit branches comprises a plurality of arms, and wherein an arm of the plurality of arms comprises at least one transistor.

8. The apparatus of any one or more of the preceding claims, wherein the bridge circuit arrangement comprises a plurality of circuit branches, wherein a circuit branch of the plurality of circuit branches comprises a plurality of arms, and wherein an arm of the plurality of arms comprises at least one switch.

9. The apparatus of any one or more of the preceding claims, further comprising a plurality of sensor circuits.

10. The apparatus of claim 9, further comprising a component configured to selectively address one or more of the plurality of sensor circuits to read an output therefrom.

11. The apparatus of any one or more of the preceding claims 9-10, further comprising a component configured to couple a selected one or more of the plurality of sensor circuits to an input voltage and/or ground.

12. The apparatus of any one or more of claims 9 to 11, further comprising components configured to decouple unselected sensor circuits from input voltage and/or ground.

13. The apparatus of any one or more of the preceding claims 9 to 12, wherein the plurality of sensor circuits are disposed on a first substrate, and wherein the apparatus comprises a second substrate comprising one or more of:

a component for selectively addressing one or more of the plurality of sensor circuits;

a component for selectively coupling one or more of the plurality of sensor circuits to an input voltage and/or ground; and

a component for selectively decoupling one or more of the plurality of sensor circuits from an input voltage and/or ground.

14. A module, device or array comprising one or more of the apparatuses of any one or more of the preceding claims.

15. A method comprising causing, at least in part, actions that result in:

preventing current from flowing through a sensor circuit from an output of the sensor circuit to another output of the sensor circuit, wherein the sensor circuit comprises:

a sensor disposed in the bridge circuit arrangement; wherein the sensor circuit is configured to: enabling a sensor measurement to be determined based on a voltage difference between outputs of the sensor circuit.

16. The method of claim 15, comprising causing, at least in part, actions that result in:

the output of the sensor circuit is connected in parallel with the output of at least a second sensor circuit.

17. An apparatus of any one or more of claims 15 to 16, further comprising an action that causes, at least in part, one or more of:

coupling the sensor circuit to an input voltage and/or ground; and

decoupling the second sensor terminal from an input voltage and/or ground.

18. An apparatus comprising components configured to enable the apparatus to perform at least a method according to one or more of claims 15 to 16.