Dynamic bridge diagnostic

Electronic sensors frequently use resistive transducers to form a sensing bridge circuit (hereinafter “a sensing bridge”). A sensing bridge may be coupled to an interface circuit, which receives signals generated by the sensing bridge and generates output data based on the signals. Depending on the physical parameter that is being measured with the sensing bridge, the output data may identify temperature, light intensity, color, magnetic field flux density, pressure, speed of a target, position of a target, current flow rate, and/or any other physical parameter that can be measured with resistive transducers. When any of the resistive transducers in a sensing bridge fails, or when any connection within the sensing bridge (such as a connection between the resistive transducer and the interface circuit fails), the output data that is generated by the interface circuit may become inaccurate or unavailable. The lack of accuracy or availability of the output data may cause equipment that uses the output data to fail. In safety-critical applications, such as autonomous driving, any such failure may pose danger to human life and property.

According to aspects of the disclosure, an apparatus is provided, comprising: a plurality of terminals for coupling the apparatus to a sensing bridge, a switching circuitry that is coupled to at least one of the plurality of terminals, and a processing circuitry that is configured to: cause the switching circuitry to couple the plurality of terminals to a voltage source, a ground source, and the processing circuitry in accordance with a first connection profile, detect a failure of the sensing bridge or a connection between the sensing bridge and any of the plurality of terminals, select a second connection profile based on a type of the failure, and cause the switching circuitry to couple the plurality of terminals to the voltage source, the ground source, and the processing circuitry in accordance with the second connection profile.

According to aspects of the disclosure, an apparatus is provided, comprising: a plurality of terminals for coupling the apparatus to a sensing bridge, and a processing circuitry that is configured to: generate an output signal in accordance with a first signal processing profile, detect a failure in the sensing bridge or a connection between the sensing bridge and any of the plurality of terminals, select a second signal processing profile based on the type of the failure, and generate the output signal in accordance with the second signal processing profile, wherein generating the output signal in accordance with the first signal processing profile includes generating the output signal based on both a first signal that is generated by the sensing bridge and a second signal that is generated by the sensing bridge, and wherein generating the output signal in accordance with the second signal processing profile includes generating the output signal based on only one of the first signal and the second signal.

According to aspects of the disclosure, a method is provided for operating a sensing bridge, the method comprising: causing a switching circuitry to couple a plurality of terminals to a voltage source, a ground source, and a processing circuitry in accordance with a first connection profile, detecting a failure in the sensing bridge or a connection between the sensing bridge and any of the plurality of terminals, selecting a second connection profile based on a type of the failure, and causing the switching circuitry to couple the plurality of terminals to the voltage source, the ground source, and the processing circuitry in accordance with the second connection profile.

The foregoing features may be more fully understood from the following description of the drawings in which:

FIG. 1A is a diagram of an example of a sensing bridge, according to aspects of the disclosure;

FIG. 1B is a diagram of an example of an interface circuit, according to aspects of the disclosure;

FIG. 1C is a diagram showing in further detail the interface circuit of FIG. 1B , according to aspects of the disclosure;

FIG. 1D is a diagram illustrating an example of connection profiles for an interface circuit, according to aspects of the disclosure;

FIG. 1E is a diagram illustrating an example of signal processing profiles for an interface circuit, according to aspects of the disclosure;

FIG. 1F is a table illustrating aspects of the operation of the interface circuit of FIG. 1B , according to aspects of the disclosure;

FIG. 2A is a diagram of an example of an interface circuit, according to aspects of the disclosure;

FIG. 2B is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2C is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2D is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2E is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2F is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2G is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2H is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2I is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2J is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2K is a diagram illustrating an example of a connection profile for an interface circuit, according to aspects of the disclosure;

FIG. 2L is a table illustrating aspects of the operation of the interface circuit of FIG. 1B , according to aspects of the disclosure; and

FIG. 3 is a flowchart of an example of a process, according to aspects of the disclosure.

FIG. 1A is a diagram of an example of a sensing bridge 110 , according to the aspects of the disclosure. According to the present example, the sensing bridge 110 is a Wheatstone bridge including a plurality of sensing elements R 1 -R 4 and a plurality of nodes N 1 -N 4 . According to the example of FIG. 1 , each of the sensing elements R 1 -R 4 includes a strain gauge. However, alternative implementations are possible in which any of the sensing elements R 1 -R 4 includes a different type of sensing element, such as a light-sensing element (e.g., a photodiode) or a magnetic field sensing element (e.g., a Hall plate, a Giant Magnetoresistive (GMR) element, a Tunnel Magnetoresistive (TMR) element, etc.). Although in the example of FIG. 1A , each of the blocks labeled R 1 -R 4 represents a single sensing element, it will be understood that in some implementations each of the blocks R 1 -R 4 may correspond multiple sensing elements. Although in the example of FIG. 1A , the sensing bridge 110 is a Wheatstone bridge, alternative implementations are possible in which the sensing bridge 110 is an H-bridge, and/or any other suitable type of sensing bridge. Stated succinctly, the present disclosure is not limited to any specific implementation of the sensing bridge 110 .

FIG. 1B is a diagram of an interface circuit 120 that is configured to drive the sensing bridge 110 . As illustrated, the interface circuit 120 may include a switching circuitry 130 , a voltage regulator 142 , a ground source 144 , and a control circuitry 146 .

The switching circuitry 130 may include multiplexers 132 - 138 , and it may be configured to dynamically change the pinout of the interface circuit 120 in response to a control signal 147 that is provided to the switching circuitry 130 by the control circuitry 146 . Multiplexer 132 may be configured to couple terminal T 3 to any of (i) voltage regulator 142 , (ii) ground source 144 , (iii) internal port P 1 of control circuitry 146 , and (iv) internal port P 2 of control circuitry 146 . Multiplexer 134 may be configured to couple terminal T 4 to any of (i) voltage regulator 142 , (ii) ground source 144 , (iii) internal port P 1 of control circuitry 146 , and (iv) internal port P 2 of control circuitry 146 . Multiplexer 136 may be configured to couple terminal T 1 to any of (i) voltage regulator 142 , (ii) ground source 144 , (iii) internal port P 1 of control circuitry 146 , and (iv) internal port P 2 of control circuitry 146 . And multiplexer 138 may be configured to couple terminal T 2 to any of (i) voltage regulator 142 , (ii) ground source 144 , (iii) internal port P 1 of control circuitry 146 , and (iv) internal port P 2 of control circuitry 146 .

Together, multiplexers 132 - 138 may be configured to couple any one of terminals T 1 -T 4 to the voltage regulator 142 . In other words, the multiplexers 132 - 138 may enable the interface circuit 120 to apply a voltage signal Vbrg that is provided by the voltage regulator 142 at any one of the nodes N 1 -N 4 of the sensing bridge 110 . Together, multiplexers 132 - 138 may be configured to couple any one of the terminals T 1 -T 4 to the ground source 144 . In other words, the multiplexers 132 - 138 may enable the interface circuit 120 to apply a ground signal Vgnd that is provided by the ground source 144 at any one of the nodes N 1 -N 4 of the interface circuit 120 . Together, multiplexers 132 - 138 may be configured to couple any one of the terminals T 1 -T 4 to the internal port P 1 of the control circuitry 146 . In other words, the multiplexers 132 - 138 may enable the internal port P 1 to be coupled to any one of the nodes N 1 -N 4 of the sensing bridge 110 . Together, multiplexers 132 - 138 may be configured to couple any one of the terminals T 1 -T 4 to the internal port P 2 of the control circuitry 146 . In other words, the multiplexers 132 - 138 may enable the internal port P 2 to be coupled to any one of the nodes N 1 -N 4 of the sensing bridge 110 .

The voltage regulator 142 may include any suitable type of electronic circuit or element that is configured to provide the voltage signal Vbrg to the sensing bridge 110 . The ground source 144 may include a ground terminal that is provided on the packaging of the interface circuit (e.g., see terminal 163 , which is shown in FIG. 1C ). The ground source 144 may be configured to provide a ground signal Bgnd to the sensing bridge 110 . The ground signal Bgnd may be equal to 0V, −Vbrg, and/or any other suitable type of reference voltage value. Although in the example of FIG. 1B , the ground source 144 includes a ground terminal, alternative implementations are possible in which ground source 144 includes any suitable type of circuitry that is configured to provide a reference voltage to the sensing bridge 110 .

The control circuitry 146 may include any suitable type of processing circuitry that is arranged to receive at least one of signals Vp and Vn from the sensing bridge 110 and generate output data 152 based on one or both of the received signal(s). The signals Vp and Vn may be generated by the sensing bridge 110 , and, in one particular example, they may indicate pressure that is being applied on the sensing bridge 110 . Similarly, the output data 152 may also indicate the pressure that is being applied on sensing bridge 110 . As is discussed further below, the output data may be generated by performing temperature compensation (and/or other types of compensation) on the signals Vp and Vn. The output data 152 may be provided for further processing to an Electronic Control Unit (ECU) and/or any other electronic device that is operatively coupled to the interface circuit 120 .

The control circuitry 146 may also generate a degraded-accuracy flag 154 . When the output data 152 is generated based on both the signal Vp and Vn, the degraded accuracy flag may be set by the control circuitry 146 to a first value (e.g., ‘0’). When the signal output data 152 is generated based on only one of the signals Vp and Vn, the degraded-accuracy flag 154 may be set to a second value (e.g., ‘1’). When the degraded-accuracy flag 154 is set to the second value, this may indicate that the output data 152 represents pressure (or another physical quantity that is measured by the sensing bridge 110 ) less accurately than when the degraded-accuracy flag 154 is set to the first value (e.g., ‘0’). The degraded accuracy flag 154 may be supplied to the same ECU or another device that receives the output data 152 , and it may be used by the ECU (or another device) for the purposes of processing the output data 152 .

The control circuitry 146 may be configured to provide the switching circuitry 130 with a control signal 147 . The control signal 147 may specify the state of each of the multiplexers 132 - 138 . More particularly, the value of the control signal 147 may specify the current pinout of the interface circuit 120 . In this regard, it will be understood that the control circuitry 146 may generate the control signal 147 , such that, at any given time: (i) only one of the terminals T 1 -T 4 is coupled to the voltage regulator 142 ; only one of the terminals T 1 -T 4 is coupled to the ground source 144 ; only one of the terminals T 1 -T 4 is coupled to the internal port P 1 of the control circuitry 146 ; and only one of the terminals T 1 -T 4 is coupled to the internal port P 2 of the control circuitry 146 . In other words, the control circuitry 146 may be configured to operate the switching circuitry 130 in such manner that each of the voltage regulator 142 , the ground source 144 , the internal port P 1 , and the internal port P 2 is coupled to only one of the terminals T 1 -T 4 at any given time of the operation of the interface circuit 120 .

FIG. 1C is a schematic diagram of the interface circuit 120 showing the control circuitry 146 in further detail. As illustrated, the interface circuit 120 may also include a power supply terminal 161 and a ground terminal 163 . Furthermore, the control circuitry 146 may include an analog-to-digital converter (ADC) 172 , a filter and compensation processor 174 , and a switching control block 176 .

The ADC 172 may include any suitable type of analog-to-digital converter. The ADC 172 may receive signals Vp and Vn from the sensing bridge 110 , digitize the received signals Vp and Vn, and provide the digitized signals Vp and Vn to the filter and compensation processor 174 .

The filter and compensation processor 174 may include any suitable type of processing circuitry, such as a general-purpose processor, a special-purpose processor, an application-specific integrated circuit (ASIC), a Field-Programmable Gate Array (FPGA), etc. The filter and compensation processor 174 may be configured to receive the digitized signals Vp and Vn, and apply one or more digital filters to the digitized signals Vp and/or Vn. Furthermore, the filter and compensation processor 174 may generate the output data 152 based on the signals Vp and Vn. As is discussed further below, the output data 152 may be generated based on one or both of the signals Vp and Vn.

The filter and compensation processor 174 may generate the output data 152 by performing gain and offset adjustment on the signals Vp and Vn (e.g., on one of the signals Vp and Vn or on their difference). The gain and/or offset adjustment may be performed based on a signal that is received from a temperature sensor 177 . Although in the example of FIG. 1C the compensation block performs temperature compensation, it will be understood that the present disclosure is not limited to any specific type of compensation being performed by the filter and compensation processor 174 .

The filter and compensation processor 174 may be configured to generate a signal 175 and provide the signal 175 to the switching control block 176 . The signal 175 may specify a desired connection profile. The desired connection profile may be the same or similar to any of the connection profiles that are discussed further below with respect to FIGS. 1D and 1F . The desired connection profile may be selected by the filter and compensation processor 174 in accordance with a process 300 , which is discussed further below with respect to FIG. 3 .

The switching control block 176 may include any suitable type of electronic circuitry for controlling the state of the switching circuitry 130 . In operation, the switching control block 176 may receive the signal 175 from the filter and compensation processor. Based on the signal 175 , the switching control block may set the control signal 147 to a value, which causes the switching circuitry 130 to connect the sensing bridge 110 to the interface circuit in accordance with the connection profile that is specified by the signal 175 .

The filter and compensation processor 174 and the switching control block 176 are provided as an example only. Although in the example of FIG. 1C , the filter and compensation processor 174 and the switching control block 176 are depicted as discrete components, it will be understood that, in some implementations, they may be partially or fully integrated with one another. Those of ordinary skill in the art will readily appreciate that there are various ways to generate output data based on signals that are generated by a sensing bridge. Furthermore, those of ordinary skilled in the art will readily appreciate that there are various ways to perform gain and offset adjustment on signal(s) that are generated by a sensing bridge. In this regard, it will be understood that the present disclosure is not limited to any specific implementation of the filter and compensation processor 174 and/or the control circuitry 146 .

According to the example of FIG. 1C , the processing circuitry 146 may be coupled to a voltage and current detector 178 . The voltage and current detector 178 may include any suitable type of circuitry that is configured to detect one or more of, the voltage at any of terminal T 1 , T 2 , T 3 , and T 4 (and/or nodes N 1 , N 2 , N 3 , N 4 of the sensing bridge 110 ) and provide an indication of the detected voltage to the control circuitry 146 . Additionally or alternatively, in some implementations the voltage and current detector 178 may be configured to measure the voltage at any of the internal ports P 1 and P 2 and provide an indication of the measured voltage to the control circuitry 146 . Additionally or alternatively, in some implementations, the voltage the and current detector 178 may be configured to detect the current across the sensing bridge 110 (e.g., by measuring the current between any two of the terminals T 1 , T 2 , T 3 , and T 4 ) and provide an indication of the measured current to the control circuitry 146 .

FIG. 1D illustrates a plurality of connection profiles for coupling the sensing bridge 110 to the interface circuit 120 . More particularly, shown in FIG. 1D is a regular connection profile CP_REG, a first connection profile CP_ 1 , and a second connection profile CP_ 2 .

The sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG, when no failures are present in the sensing bridge 110 and/or any connections between the sensing bridge 110 and the interface circuit 120 . Furthermore, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG when the connection between the interface circuit 120 and one of the nodes N 1 and N 2 has become open, but the sensing bridge 110 remains able to receive the voltage signal Vbrg and the ground signal Bgnd at nodes N 3 and N 4 , respectively. When the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG, the voltage signal Vbrg may be applied at node N 3 of the sensing bridge 110 and the ground signal Bgnd may be applied at node N 4 of the sensing bridge 110 . Furthermore, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG, the internal port P 1 of the control circuitry 146 may be coupled to node N 1 of the sensing bridge 110 , and/or the internal port P 2 of the control circuitry 146 may be coupled to node N 2 of the sensing bridge.

The sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the first connection profile CP_ 1 when a connection between node N 4 of the sensing bridge 110 and the interface circuit 120 is open (e.g., due to mechanical or electrical damage), and the sensing bridge 110 can no longer receive the ground signal Bgnd at node N 4 . When the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the first connection profile CP_ 1 , the voltage signal Vbrg may be applied at node N 1 of the sensing bridge 110 , the ground signal Bgnd may be applied at node N 2 of the sensing bridge 110 , and node N 3 of the sensing bridge 110 may be coupled to internal port P 1 of the control circuitry 146 . Furthermore, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the first connection profile CP_ 1 , node N 4 of the sensing bridge may be disconnected from the interface circuit 120 (and/or the control circuitry 146 ).

The sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the second connection profile CP_ 2 when a connection between node N 3 of the sensing bridge 110 and the interface circuit 120 is open (e.g., due to mechanical or electrical damage), and the sensing bridge 110 can no longer receive the voltage signal Vbrg at node N 3 . When the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the second connection profile CP_ 2 , the voltage signal Vbrg may be applied at node N 1 of the sensing bridge 110 , the ground signal Bgnd may be applied at node N 2 of the sensing bridge 110 , and node N 4 of the sensing bridge 110 may be coupled to internal port P 1 of the control circuitry 146 . Furthermore, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the second connection profile CP_ 2 , node N 3 of the sensing bridge may be disconnected from the interface circuit 120 (and/or the control circuitry 146 ).

FIG. 1E illustrates a plurality of signal processing profiles of the interface circuit 120 . More particularly, shown in FIG. 1E is a signal processing profile SIG_NP, a signal processing profile SIG_P, and a signal processing profile SIG_N.

When the interface circuit 120 operates in accordance with the signal processing profile SIG_NP, the output data 152 is generated based on signals that are received at both of internal ports P 1 and P 2 . Put differently, when the interface circuit 120 operates in accordance with the signal processing profile SIG_NP, both signals Vp and Vn, which are produced by the sensing bridge 110 , are used to generate the output data 152 . As can be readily appreciated, when the interface circuit 120 operates in accordance with the first signal processing profile SIG_NP, the sensing bridge 110 is used as a full bridge.

When the interface circuit 120 operates in accordance with the signal processing profile SIG_P, the output data 152 is generated based on a signal that is received at only one of internal ports P 1 and P 2 . More specifically, when the interface circuit 120 operates in accordance with the signal processing profile SIG_P, only signal Vp (but not signal Vn) is used to generate the output data 152 . As can be readily appreciated, when the interface circuit 120 operates in accordance with the signal processing profile SIG_P, the sensing bridge 110 is used as a half-bridge.

When the interface circuit 120 operates in accordance with the signal processing profile SIG_N, the output data 152 is generated based on a signal that is received at only one of internal ports P 1 and P 2 . More specifically, when the interface circuit 120 operates in accordance with the signal processing profile SIG_N, only signal Vn (but not signal Vp) is used to generate the output data 152 . As can be readily appreciated when the interface circuit 120 operates in accordance with the signal processing profile SIG_N, the sensing bridge 110 is used as a half-bridge.

FIG. 1F depicts an example of a truth table 180 , which describes the operation of the interface circuit 120 in further detail. More particularly, in operation, the control circuitry 146 (which is part of the interface circuit 120 ) may detect when there is a failure in the sensing bridge 110 and/or a connection between the sensing bridge 110 and the interface circuit 120 . When such failure is detected, the control circuitry 146 may cause the switching circuitry 130 to change the connection profile of the sensing bridge 110 . Furthermore, when such failure is detected, the control circuitry 146 may also change the signal processing profile that is used by the interface circuit 120 to generate the output data 152 . In other words, the control circuitry 146 may respond to certain failures in the sensing bridge 110 and/or a connection between the sensing bridge 110 and the interface circuit 120 by changing the connection profile of the sensing bridge 110 and/or by changing the signal processing profile that is used to generate the output data 152 . Doing so may allow the sensing bridge 110 and the interface circuit 120 to remain operational, despite the failures.

In some implementations, to detect whether a failure is present in the sensing bridge 110 or a connection between the sensing bridge 110 and the interface circuit, the control circuitry 146 may monitor one or more of: (1) the voltage at terminal T 1 of the sensing bridge 110 , (2) the voltage at terminal T 2 of the sensing bridge 110 , (3) the voltage at terminal T 3 of the sensing bridge 110 , (4) the voltage at terminal T 4 of the sensing bridge 110 , (4) the common-mode voltage Vcm of the sensing bridge 110 , and (5) the current across the sensing bridge 110 . The current across the sensing bridge 110 may be detected by monitoring the current between any two terminals of the interface circuit 120 that are used for suppling the voltage signal Vbrg and ground signal Bgnd to the sensing bridge 110 . In some implementations, the common-mode voltage Vcm of the sensing bridge 110 may be equal to the half-sum of the voltages at internal ports P 1 and P 2 , and it can be defined in accordance with Equation 1 below (assuming bridge resistance value very similar):

Vcm = 1 2 ⁢ ( Vp ⁢ ⁢ 1 + Vp ⁢ ⁢ 2 ) ( 1 )

where Vcm is the common-mode voltage of the sensing bridge 110 , Vp 1 is the voltage at internal port P 1 of the interface circuit 120 , and Vp 2 is the voltage at internal port P 2 . When the sensing bridge 110 and the interface circuit 120 are operating correctly, the value of Vp 1 may be equal to the level of signal Vp, which is generated by the sensing bridge 110 . When the sensing bridge 110 and the interface circuit 120 are operating correctly, the value of Vp 2 may be equal to the level of signal Vn, which is generated by the sensing bridge 110 .

Additionally or alternatively, in some implementations, the common mode voltage Vcm of the sensing bridge 110 may be calculated by determining either one of Vp 1 or Vp 2 . As can be readily appreciated, when the equivalent resistances R 1 , R 2 , R 3 , and R 4 (shown in FIG. 1A ) are the same, the common mode voltage Vcm may be equal to either one of the Vp 1 and Vp 2 . During normal operation of the bridge 110 , the values of Vp 1 and Vp 2 may be determined in accordance with equations 2 and 3 below:

Vp ⁢ ⁢ 1 = Vbrg * ( R ⁢ ⁢ 2 R ⁢ ⁢ 1 + R ⁢ ⁢ 2 ) ( 2 ) Vp ⁢ ⁢ 2 = brg * ( R ⁢ ⁢ 4 R ⁢ ⁢ 3 + R ⁢ ⁢ 4 ) ( 3 )

When the interface circuit 120 loses reception of (i.e. connection to) the voltage signal Vp (e.g., due to a failure of the sensing bridge 110 or a failure of a connection between the sensing bridge and the port P 1 ), the voltage at internal port P 1 may be pulled up by pull-up resistor PR 1 (shown in FIG. 1A ) to a value that is outside of the normal range for the signal Vp (i.e., Vbrg in the present example). As is discussed further below, deviations of the voltage at internal port P 1 from the normal range for the signal Vp may be used to detect failures in the sensing bridge 110 or a connection between the sensing bridge 110 and the interface circuit 120 . Similarly, when the interface circuit 120 loses reception of the voltage signal Vn (e.g., due to a failure of the sensing bridge 110 or a failure of a connection between the sensing bridge and the port P 2 ), the voltage at internal port P 2 may be pulled up by pull-up resistor PR 2 to a value that is outside of the normal range for the signal Vn (i.e., Vbrg in the present example). As is discussed further below, deviations of the voltage at internal port P 2 from the normal range for the signal Vn may be used to detect failures in the sensing bridge 110 or a connection between the sensing bridge 110 and the interface circuit 120 . Although in the example of FIG. 1A , resistors PR 1 and PR 2 are pull-up resistors, alternative implementations are possible in which any of resistors PR 1 and PR 2 is a pull down resistor. As illustrated, table 180 includes columns 171 A-H. Column 171 A identifies a plurality of failures that may be experienced by the sensing bridge 110 and/or interface circuit 120 . Column 171 B identifies the voltage at terminal T 3 of the sensing bridge when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 C identifies the voltage at terminal T 1 of the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 D identifies the voltage at terminal T 2 of the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 E identifies the voltage at terminal T 4 of the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 F identifies the common voltage of the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 G identifies the current across the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG and one of the failures identified in column 171 A occurs. Column 171 H identifies the connection profile, which the sensing bridge 110 is transitioned to when any of the failures identified in column 171 A is detected by the control circuitry 146 . Column 171 H further identifies the signal processing profile, which the interface circuit 120 is transitioned to when any of the failures identified in column 171 A is detected by the control circuitry 146 .

Table 180 describes the value of the voltage at any of terminals T 1 -T 4 , and the common-mode voltage Vcm in terms of a threshold value Vbrg. According to the present example, Vbrg is the level of the voltage signal Vbrg when the sensing bridge 110 and the interface circuit 120 are operating correctly. Furthermore, table 180 describes the current across the sensing bridge 110 in terms of a value NC. According to the present example, NC is the level of current across the sensing bridge 110 when the sensing bridge 110 and the interface circuit 120 are operating correctly.

Row 173 A identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 and the interface circuit 120 are operating correctly. Specifically, row 173 A indicates that when no failures are present in the sensing bridge 110 or a connection between the sensing bridge 110 and the interface circuit 120 : (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be substantially equal to Vbrg/2; (iii) the voltage at terminal T 2 would be substantially equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially equal to Vbrg/2; (vi) the current across the sensing bridge 110 would be equal to NC. Furthermore, row 173 A indicates that when the sensing bridge 110 and the interface circuit 120 are operating correctly, the sensing bridge 110 may be connected to the interface circuit 120 in accordance with the regular connection profile CP_REG, and the signal processing profile of the interface circuit 120 may be SIG_NP. According to the present example, the voltage at a terminal is substantially equal to Vbrg/2 if the voltage at the terminal is within 15% of Vbrg/2.

Row 173 B identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 loses reception of the voltage signal Vbrg from the interface circuit 120 . Specifically, row 173 B indicates that when the sensing bridge 110 no longer receives the voltage signal Vbrg from the interface circuit 120 : (i) the voltage at terminal T 3 would be floating; (ii) the voltage at terminal T 1 would be equal to 0; (iii) the voltage at terminal T 2 would be equal to 0; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be equal to 0; and (vi) the current across the sensing bridge 110 would be equal to 0. Row 173 B also indicates that when the sensing bridge 110 loses reception of the voltage signal Vbrg, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the first connection profile CP_ 1 . Row 173 B further indicates that when the sensing bridge 110 loses reception of the voltage signal Vbrg, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 C identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 loses reception of the ground signal Bgnd from the interface circuit 120 . Specifically, row 173 C indicates that when the sensing bridge 110 no longer receives the ground signal Vgnd from the interface circuit 120 : (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg; (iii) the voltage at terminal T 2 would be equal to Vbrg; (iv) the voltage at terminal T 4 would be floating; (v) the common-mode voltage Vcm of the sensing bridge 110 would be equal to Vbrg; and (vi) the current across the sensing bridge 110 would be equal to 0. Row 173 C also indicates that when the sensing bridge 110 loses reception of the ground signal Vgnd, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the second connection profile CP_ 2 . Row 173 C further indicates that when the sensing bridge 110 loses reception of the ground signal Vgnd, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 D identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 1 is open. Specifically, row 173 D indicates that when the sensing element R 1 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to 0; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 173 D also indicates that when the sensing element R 1 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 D further indicates that when the sensing element R 1 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 E identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 2 is open. Specifically, row 173 E indicates that when the sensing element R 2 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to Vbrg; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 173 E also indicates that when the sensing element R 2 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 E further indicates that when the sensing element R 2 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 F identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 3 is open. Specifically, row 173 F indicates that when the sensing element R 3 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to 0; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 173 F also indicates that when the sensing element R 3 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 F further indicates that when the sensing element R 3 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_N.

Row 173 G identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 4 is open. Specifically, row 173 G indicates that when the sensing element R 4 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 173 G also indicates that when the sensing element R 4 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 G further indicates that when the sensing element R 4 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_N.

Row 173 H identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the interface circuit 120 loses reception of the signal Vp at the internal port P 1 . Specifically, row 173 H indicates that when the connection between the internal port P 1 and the sensing bridge 110 becomes open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be floating; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially equal to NC. Row 173 H also indicates that when the connection between the internal port P 1 and the sensing bridge 110 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 H further indicates that when the connection between the internal port P 1 and the sensing bridge 110 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_N.

Row 173 I identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the interface circuit 120 loses reception of the signal Vn at the internal port P 2 . Specifically, row 173 I indicates that when the connection between the internal port P 2 and the sensing bridge 110 becomes open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be floating; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially equal to NC. Row 173 I also indicates that when the connection between the internal port P 2 and the sensing bridge 110 becomes open, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 I further indicates that when the connection between the internal port P 3 and the sensing bridge 110 becomes open, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 J identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 1 is shorted. Specifically, row 173 J indicates that when the sensing element R 1 becomes shorted: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to Vbrg; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially greater than NC. Row 173 J also indicates that when the sensing element R 1 becomes shorted, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 J further indicates that when the sensing element R 1 becomes shorted, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 K identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 2 is shorted. Specifically, row 173 K indicates that when the sensing element R 2 becomes shorted: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to 0; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially greater than NC. Row 173 K also indicates that when the sensing element R 2 becomes shorted, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 K further indicates that when the sensing element R 2 becomes shorted, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_P.

Row 173 L identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 3 is shorted. Specifically, row 173 L indicates that when the sensing element R 3 is shorted: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially greater than NC. Row 173 L also indicates that when the sensing element R 3 becomes shorted, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 L further indicates that when the sensing element R 3 becomes shorted, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_N.

Row 173 M identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 4 is shorted. Specifically, row 173 M indicates that when the sensing element R 4 is shorted: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to 0; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially greater than NC. Row 173 M also indicates that when the sensing element R 4 becomes shorted, the control circuitry 146 may leave unchanged the connection profile of the sensing bridge 110 . Row 173 M further indicates that when the sensing element R 4 becomes shorted, the control circuitry 146 may transition the interface circuit 120 from signal processing profile SIG_NP to signal processing profile SIG_N.

As used throughout the disclosure, the phrase “substantially greater” shall be interpreted as “greater than by a predetermined amount.” As used throughout the disclosure, the phrase “substantially less” shall be interpreted as “less than by a predetermined amount (e.g., less by 25% or more).” As used throughout the disclosure, the phrase “equal to” shall be interpreted as “exactly the same as” or “within a predetermined amount from.”

FIG. 2A is a schematic diagram of the interface circuit 120 in accordance with another implementation. Unlike the implementation discussed with respect to FIG. 1C , in this implementation, the interface circuit 120 may include one or more backup resistors, and the switching circuitry 130 may include additional switches for connecting any of the backup resistors 202 between any of the terminals T 1 -T 4 . In this implementation, the interface circuit 120 may also include pull-up resistors PR 1 and PR 2 , which are arranged to pull up the voltage at internal ports P 1 and P 2 , respectively.

The backup resistors 202 may be used to maintain the functionality of the sensing bridge 110 when any of the sensing elements R 1 -R 4 fails. For example, when any of the sensing elements R 1 -R 4 is open, the control circuitry 146 may cause the switching circuitry 130 to connect one of the backup resistors 202 in parallel with the shorted sensing element (e.g., see FIGS. 2E-H ). As another example, when the sensing bridge 110 loses reception of the voltage signal Vbrg, the control circuitry 146 may cause the switching circuitry 130 to connect a network of serially-coupled backup resistors between terminals T 1 and T 2 (and between nodes N 1 -N 2 ), and supply the signal Vbrg at the connection between any two of the serially-coupled resistors (e.g., see FIG. 2C ). As yet another example, when the sensing bridge 110 loses reception of the ground signal Bgnd, the control circuitry 146 may cause the switching circuitry 130 to connect a network of serially-coupled backup resistors between terminals T 1 and T 2 (and between nodes N 1 -N 2 ), and supply the ground signal Bgnd at the connection between any two of the serially-coupled resistors (e.g., see FIG. 2D ). According to the present example, the backup resistors 202 are integrated into the same packaging as the interface circuit 120 (e.g., the backup resistors 202 are internal to the interface circuit 120 ). However, it will be understood that alternative implementations are possible in which the backup resistors 202 are provided separately from the interface circuit 120 .

The pull-up resistor PR 1 may be configured to pull up the voltage at internal port P 1 to the value of Vbrg when the internal port P 1 loses connection to sensing bridge 110 (and/or when the internal port P 1 losses reception of the signal Vp). As is discussed further below, when the internal port P 1 loses connection to the sensing bridge 110 , the pull-up resistor PR 1 may enable the interface circuit 120 to detect that the port P 1 has lost connection to the sensing bridge 110 and trigger the activation of one or more of the back-up resistors 202 , causing the one or ore of the backup resistors 202 to apply voltage Vbrg/2 at the internal port P 1 . The pull-up resistor PR 2 may be configured to pull up the voltage at internal port P 2 to the value of Vbrg when the internal port P 2 loses connection to sensing bridge 110 (and/or when the internal port P 2 losses reception of the signal Vn). As is discussed further below, when the internal port P 2 loses connection to the sensing bridge 110 , the pull-up resistor PR 2 may enable the interface circuit 120 to detect that the port P 2 has lost connection to the sensing bridge 110 and trigger the activation of one or more of the back-up resistors 202 , causing the one or more of the backup resistors 202 to apply voltage Vbrg/2 at the internal port P 2 . Although in the example of FIG. 1 , the resistors PR 1 and PR 2 are pull-up resistors, alternative implementations are possible in which any of the resistors PR 1 and PR 2 is a pull-down resistor (e.g., a pull-down resistor connected to ground).

FIG. 2B is a diagram showing the state of backup resistors 202 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG. According to the example of FIG. 2B , the backup resistors 202 include a backup resistor BR 1 and a backup resistor BR 2 that is coupled in series with the backup resistor BR 1 . Furthermore, according to the example of FIG. 2B , the switching circuitry 130 includes a switch S 1 , a switch S 2 , and a switch S 3 . Switch S 1 may be configured to couple backup resistor BR 1 to terminal T 1 ; switch S 2 may be configured to couple backup resistor BR 2 to terminal T 2 , and switch S 2 may be configured to couple backup resistors BR 1 and BR 2 to one of the voltage regulator 142 and the ground source 144 .

It will be recalled that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile, the voltage signal Vbrg is applied at node N 3 of the sensing bridge, the ground signal Bgnd is applied at node N 4 of the sensing bridge 110 , the internal port P 1 of the control circuitry 146 is coupled to node N 1 of the sensing bridge 110 , and the internal port P 2 of the control circuitry 146 is coupled to node N 2 of the sensing bridge 110 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular profile, the backup resistors BR 2 and BR 1 are disconnected from the sensing bridge 110 .

FIG. 2C shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a third connection profile CP_ 3 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the third connection profile CP_ 3 , backup resistors BR 1 and BR 2 are coupled to terminals T 1 and T 2 by switches S 1 and S 2 , respectively. Furthermore, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the third connection profile CP_ 3 , backup resistors BR 1 and BR 2 may be coupled to the voltage regulator 142 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the third connection profile CP_ 3 when the connection between the voltage regulator 142 and the sensing bridge 110 has failed, and the sensing bridge 110 has stopped receiving power from the interface circuit 120 as a result. Connecting the sensing bridge 110 in accordance with the third connection profile CP_ 3 may effectively cause sensing elements R 1 and R 3 to be replaced with backup resistors BR 1 and BR 2 , respectively.

FIG. 2D shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a fourth connection profile CP_ 4 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the fourth connection profile CP_ 4 , backup resistors BR 1 and BR 2 are coupled to terminals T 1 and T 2 by switches S 1 and S 2 , respectively. Furthermore, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the fourth connection profile CP_ 4 , backup resistors BR 1 and BR 2 are coupled to the ground source 144 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the fourth connection profile CP_ 4 when the connection between the voltage regulator 142 and the sensing bridge 110 has failed, and the sensing bridge 110 has stopped receiving the ground signal Bgnd from the interface circuit 120 as a result. Connecting the sensing bridge 110 in accordance with the fourth connection profile CP_ 4 may effectively cause sensing elements R 2 and R 4 to be replaced with backup resistors BR 1 and BR 2 , respectively.

FIG. 2E is a diagram showing the state of backup resistors 202 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG. According to the example of FIG. 2E , the backup resistors 202 include a backup resistor BR 1 . Furthermore, according to the example of FIG. 2E , the switching circuitry 130 includes a switch S 1 and a switch S 2 . Switches S 1 and S 2 are configured to couple the backup resistor BR 1 between any two of the terminals T 1 -T 4 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the regular connection profile CP_REG, the backup resistor BR 1 may be disconnected from the sensing bridge 110 .

FIG. 2F shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a fifth connection profile CP_ 5 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the fifth connection profile CP_ 5 , the switches S 1 and S 2 are arranged to couple the backup resistor BR 1 between terminals T 2 and T 3 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the fifth connection profile CP_ 5 when the sensing element R 1 fails and becomes open as a result. Connecting the sensing bridge 110 in accordance with the fifth connection profile CP_ 5 may effectively cause the sensing element R 1 to be replaced with the backup resistor BR 1 .

FIG. 2G shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a sixth connection profile CP_ 6 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the sixth connection profile CP_ 6 , the switches S 1 and S 2 are arranged to couple the backup resistor BR 1 between terminals T 2 and T 4 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the sixth connection profile CP_ 6 when the sensing element R 2 fails and becomes open as a result. Connecting the sensing bridge 110 in accordance with the sixth connection profile CP_ 6 may effectively cause the sensing element R 2 to be replaced with the backup resistor BR 1 .

FIG. 2H shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a seventh connection profile CP_ 7 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the seventh connection profile CP_ 7 , the switches S 1 and S 2 are arranged to couple the backup resistor BR 1 between terminals T 1 and T 3 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the seventh connection profile CP_ 7 when the sensing element R 3 fails and becomes open as a result. Connecting the sensing bridge 110 in accordance with the seventh connection profile CP_ 7 may effectively cause the sensing element R 3 to be replaced with the backup resistor BR 1 .

FIG. 2I shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with an eighth connection profile CP_ 8 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the eighth connection profile CP_ 8 , the switches S 1 and S 2 are arranged to couple the backup resistor BR 1 between terminals T 1 and T 4 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the eighth connection profile CP_ 8 when the sensing element R 4 fails and becomes open as a result. Connecting the sensing bridge 110 in accordance with the eighth connection profile CP_ 8 may effectively cause the sensing element R 4 to be replaced with the backup resistor BR 1 .

FIG. 2J shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a ninth connection profile CP_ 9 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the ninth connection profile CP_ 9 , the internal port P 1 of the control circuitry 146 is disconnected from the sensing bridge, and the voltage at the internal port P 1 is set to Vbrg/2 by one or more the backup resistors 202 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the ninth connection profile CP_ 9 when the internal port P 1 becomes disconnected from the sensing bridge 110 as a result of the failure of the connection between the internal port P 1 and the sensing bridge 110 .

FIG. 2K shows the sensing bridge 110 when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with a tenth connection profile CP_ 10 . As illustrated, when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the tenth connection profile CP_ 10 , the internal port P 2 of the control circuitry 146 is disconnected from the sensing bridge, and the voltage at the internal port P 2 is set to Vbrg/2 by one or more the backup resistors 202 . In some respects, the sensing bridge 110 may be coupled to the interface circuit 120 in accordance with the tenth connection profile CP_ 10 when the internal port P 2 becomes disconnected from the sensing bridge 110 as a result of the failure of the connection between the internal port P 2 and the sensing bridge 110 . FIG. 2L depicts an example of a truth table 280 , which describes the operation of the interface circuit 120 in further detail. Truth table 280 has the same format as truth table 180 . Unlike truth table 180 , truth table 280 identifies alternative actions that are taken by the interface circuit 120 when any of the sensing elements R 1 -R 1 is open, and which utilize backup resistors 202 . Furthermore, unlike truth table 180 , truth table 280 identifies alternative actions that are taken by the interface circuit 120 when any of the sensing elements R 1 -R 1 is shorted, and which utilize backup resistors 202 . And still furthermore, unlike truth table 180 , truth table 280 identifies alternative actions that are taken by the interface circuit 120 when the interface circuit loses reception of any of the signals Vp or Vn, and which utilize backup resistors 202 .

In operation, the control circuitry 146 (which is part of the interface circuit 120 ) may detect when there is a failure in the sensing bridge 110 and/or a connection between the sensing bridge 110 and the interface circuit 120 . As discussed above with respect to FIG. 1F , the failure may be detected by monitoring one or more of: (1) the voltage at terminal T 1 of the sensing bridge 110 , (2) the voltage at terminal T 2 of the sensing bridge 110 , (3) the voltage at terminal T 3 of the sensing bridge 110 , (4) the voltage at terminal T 4 of the sensing bridge 110 , (4) the common-mode voltage Vcm of the sensing bridge 110 , and the current across the sensing bridge 110 . When such failure is detected, the control circuitry 146 may cause the switching circuitry 130 to change the connection profile of the sensing bridge 110 .

Row 273 A identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 and the interface circuit 120 are operating correctly. Specifically, row 273 A indicates that when no failures are present: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be equal to Vbrg/2; (vi) the current across the sensing bridge 110 would be equal to NC. Furthermore, row 273 A indicates that when the sensing bridge 110 and the interface circuit 120 are operating correctly, the sensing bridge 110 may be connected to the interface circuit 120 in accordance with the regular connection profile CP_REG, and the signal processing profile of the interface circuit 120 may be SIG_NP.

Row 273 B identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 loses reception of the voltage signal Vbrg from the interface circuit 120 (e.g., due to a failure of a connection between the sensing bridge 110 and the interface circuit 120 ). Specifically, row 273 B indicates that when the sensing bridge 110 no longer receives the voltage signal Vbrg from the interface circuit 120 : (i) the voltage at terminal T 3 would be floating; (ii) the voltage at terminal T 1 would be equal to 0; (iii) the voltage at terminal T 2 would be equal to 0; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be equal to 0; and (vi) the current across the sensing bridge 110 would be equal to 0. Row 273 B also indicates that when the sensing bridge 110 loses reception of the voltage signal Vbrg, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the third connection profile CP_ 3 . Row 273 B further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the third connection profile CP_ 3 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 C identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing bridge 110 loses reception of the ground signal Bgnd from the interface circuit 120 (e.g., due to a failure of a connection between the sensing bridge 110 and the interface circuit 120 ). Specifically, row 273 C indicates that when the sensing bridge 110 no longer receives the ground signal Bgnd from the interface circuit 120 : (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg; (iii) the voltage at terminal T 2 would be equal to Vbrg; (iv) the voltage at terminal T 4 would be floating; (v) the common-mode voltage Vcm of the sensing bridge 110 would be equal to Vbrg; and (vi) the current across the sensing bridge 110 would be equal to 0. Row 273 C also indicates that when the sensing bridge 110 loses reception of the ground signal Bgnd, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the fourth connection profile CP_ 4 . Row 273 C further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the fourth connection profile CP_ 4 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 D identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 1 is open. Specifically, row 273 D indicates that when the sensing element R 1 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to 0; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 D also indicates that when the sensing element R 1 becomes open, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the fifth connection profile CP_ 5 . Row 273 D further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the fifth connection profile CP_ 5 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 E identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 2 is open. Specifically, row 273 E indicates that when the sensing element R 2 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be equal to Vbrg; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 E also indicates that when the sensing element R 2 becomes open, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the sixth connection profile CP_ 6 . Row 273 E further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the sixth connection profile CP_ 6 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 F identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 3 is open. Specifically, row 273 F indicates that when the sensing element R 3 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to 0; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially less than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 F also indicates that when the sensing element R 3 becomes open, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the seventh connection profile CP_ 7 . Row 273 F further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the seventh connection profile CP_ 7 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 G identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the sensing element R 4 is open. Specifically, row 273 G indicates that when the sensing element R 4 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 G also indicates that when the sensing element R 4 becomes open, the control circuitry 146 may transition the sensing bridge 110 from the regular connection profile CP_REG to the eighth connection profile CP_ 8 . Row 273 G further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the eighth connection profile CP_ 8 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 H identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the interface circuit 120 loses reception of the signal Vp at the internal port P 1 . Specifically, row 273 H indicates that when the connection between the internal port P 1 and the sensing bridge 110 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be floating; (iii) the voltage at terminal T 2 would be equal to Vbrg/2; (iv) the voltage at terminal T 4 would be equal to 0; and (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 H also indicates that when the connection between the internal port P 1 and the sensing bridge 110 becomes open, the sensing bridge 110 may assume the ninth connection profile CP_ 9 (e.g., by virtue of the internal port P 1 being disconnected from the sensing bridge 110 ). Row 273 H further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the ninth connection profile CP_ 9 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

Row 273 I identifies the state of the interface circuit 120 (and/or sensing bridge 110 ) when the interface circuit 120 loses reception of the signal Vn at the internal port P 2 . Specifically, row 273 I indicates that when the connection between the internal port P 2 and the sensing bridge 110 is open: (i) the voltage at terminal T 3 would be equal to Vbrg; (ii) the voltage at terminal T 1 would be equal to Vbrg/2; (iii) the voltage at terminal T 2 would be floating; (iv) the voltage at terminal T 4 would be equal to 0; and (v) the common-mode voltage Vcm of the sensing bridge 110 would be substantially greater than Vbrg/2; and (vi) the current across the sensing bridge 110 would be substantially less than NC. Row 273 I further indicates that when the sensing bridge 110 is coupled to the interface circuit 120 in accordance with the tenth connection profile CP_ 10 , the interface circuit 120 may continue operating in accordance with signal processing profile SIG_NP. However, the interface circuit may set the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

FIG. 3 is flowchart of an example of a process 300 , according to aspects of the disclosure. According to the example of FIG. 3 , the process 300 is substantially performed by the control circuitry 146 of the interface circuit 120 . However, it will be understood that alternative implementations are possible in which the process 300 is performed by another system component. Stated succinctly, the present disclosure is not limited to any specific implementation of the process 300 .

At step 302 , the sensing bridge 110 is coupled to the interface circuit 120 . More particularly, node N 1 of the sensing bridge is coupled to terminal T 1 of the interface circuit 120 ; node N 2 of the sensing bridge is coupled to terminal T 2 of the interface circuit 120 ; node N 3 of the sensing bridge is coupled to terminal T 3 of the interface circuit 120 ; and node N 4 of the sensing bridge is coupled to terminal T 4 of the interface circuit 120 .

At step 304 , the control circuitry 146 causes the switching circuitry 130 to couple the sensing bridge 110 to the voltage regulator 142 , the ground source 144 , and the filter and compensation processor 174 in accordance with the regular connection profile CP_REG. (E.g., see FIG. 1A , FIG. 2B , or FIG. 2E .)

At step 306 , the control circuitry 146 generates the output data 152 in accordance with the signal processing profile SIG_NP.

At step 308 , the control circuitry 146 detects one or more of the current across the sensing bridge 110 , and the voltage at each (or any) of the terminals T 1 -T 4 of the interface circuit 120 .

At step 310 , the control circuitry 146 determines whether there is a failure in the sensing bridge 110 or a connection between any of the terminals T 1 -T 4 and the sensing bridge 110 . The determination may be made based on one or more of the following values: (i) the level of the current across the bridge, (ii) the voltage level at terminal T 1 , (iii) the voltage level at terminal T 2 , (iv) the voltage level at terminal T 3 , and (v) the voltage level at terminal T 4 . In some implementations, the control circuitry 146 may determine that a failure exists when the detected values match the values listed in any of rows 173 B-M of table 180 . (E.g., see FIG. 1F .) Additionally or alternatively, in some implementations, the control circuitry 146 may determine that a failure exists when the detected values match the values listed in any of rows 273 B-I of table 280 . (E.g., see FIG. 2L .) Additionally or alternatively, in some implementations, the control circuitry 146 may determine that no failures exist when the detected values match the values listed in row 173 A of table 180 . (E.g., see FIG. 1F .) Additionally or alternatively, in some implementations, the control circuitry 146 may determine that no failures exist when the detected values match the values listed in row 273 A of table 280 . (E.g., see FIG. 2L .) If a failure is detected, the process 300 proceeds to step 312 . Otherwise, step 310 is executed again.

At step 312 , the control circuitry 146 selects an alternative connection profile based on a type of the failure that is detected at step 310 . In some implementations, selecting the alternative profile may include: (i) selecting one the tables 180 and 280 ; (ii) identifying a row in the selected table that matches the values detected at step 308 ; and (iii) identifying an alternative connection profile that is identified in the row. As discussed above with respect to FIGS. 1F and 2L , the alternative connection profile may be any of the connection profiles CP 1 - 10 , which are discussed above with respect to FIGS. 1D, 2C -D, and 2 F-I.

At step 314 , the control circuitry 146 causes the switching circuitry 130 to couple the sensing bridge 110 to the voltage regulator 142 , the ground source 144 , and the filter and compensation processor 174 in accordance with the alternative connection profile.

At step 316 , the control circuitry 146 selects an alternative signal processing profile based on a type of the failure that is detected at step 310 . In some implementations, selecting the alternative profile may include: (i) selecting one the tables 180 and 280 ; (ii) identifying a row in the selected table that matches the values detected at step 308 ; and (iii) identifying an alternative signal processing profile that is identified in the row. As discussed above with respect to FIG. 1E , the alternative signal processing profile may include either the signal processing profile SIG_N or the signal processing profile SIG_P.

At step 318 , the control circuitry 146 generates the output data 152 in accordance with the alternative signal processing profile. As noted above, in some implementations, the signal processing profile may remain unchanged. When this is the case, the output data 152 may be generated in accordance with the signal processing profile SIG_NP.

At step 320 , the control circuitry 146 sets the degraded-accuracy flag 154 to the first value, which indicates that the output data 152 has a reduced accuracy.

FIG. 3 is provided as an example. At least some of the steps discussed with respect to FIG. 3 can be performed in a different order, in parallel, or altogether omitted. For example, in some implementations, step 316 may be omitted.

According to the example of FIGS. 1A-3 , the sensing bridge 110 and the interface circuit 120 are separate from one another. However, alternative implementations are possible in which the sensing bridge 110 and the interface circuit 120 are integrated with one another (e.g., integrated into the same semiconductor packaging). In implementations in which the interface circuit 120 and the sensing bridge are separate of one another, any of the terminals T 1 -T 4 may include a contact pad, a pin, and/or any other suitable type of element for establishing electric contact. In implementations, in which the interface circuit 120 and the sensing bridge 110 are integrated into the same semiconductor packaging, any of the terminals T 1 -T 4 may include an internal point of contact between the sensing bridge 110 and the interface circuit 120 . Stated succinctly, the term “terminal” shall be interpreted broadly to refer to either a node in a circuit or an element, such as a contact pad, for establishing electrical contact.

In some implementations, any of the tables 180 and 280 may be implemented as one or more searchable data structures that are stored in a memory (not shown) of the control circuitry 146 . Additionally or alternatively, in some implementations, any of the tables 180 and 280 may be implemented by using combinatorial logic. Such combinatorial logic may be configured to select a connection profile based on one or more of: (i) the voltage at any of terminals T 1 -T 4 , (ii) the current across the sensing bridge 110 , and (iii) the common-mode voltage Vcm of the sensing bridge 110 . Stated succinctly, the present disclosure is not limited to any specific method for selecting a signal processing profile or a connection profile for the sensing bridge 110 in accordance with the relationships discussed with respect to tables 180 and 280 .

The processes described herein may be implemented in hardware, software, or a combination of the two. The processes described herein may be implemented in computer programs executed on programmable computers/machines that each includes a processor, a non-transitory machine-readable medium or another article of manufacture that is readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and one or more output devices. Program code may be applied to data entered using an input device to perform any of the processes described herein and to generate output information.

The system may be implemented, at least in part, via a computer program product, (e.g., in a non-transitory machine-readable storage medium such as, for example, a non-transitory computer-readable medium), for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). Each such program may be implemented in a high-level procedural or object-oriented programming language to work with the rest of the computer-based system. However, the programs may be implemented in assembly, machine language, or Hardware Description Language. The language may be a compiled or an interpreted language, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or another unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communication network. A computer program may be stored on a non-transitory machine-readable medium that is readable by a general or special purpose programmable computer for configuring and operating the computer when the non-transitory machine-readable medium is read by the computer to perform the processes described herein. For example, the processes described herein may also be implemented as a non-transitory machine-readable storage medium, configured with a computer program, where upon execution, instructions in the computer program cause the computer to operate in accordance with the processes. A non-transitory machine-readable medium may include but is not limited to a hard drive, compact disc, flash memory, non-volatile memory, volatile memory, magnetic diskette and so forth but does not include a transitory signal per se.

Having described preferred embodiments, which serve to illustrate various concepts, structures and techniques, which are the subject of this patent, it will now become apparent that other embodiments incorporating these concepts, structures and techniques may be used. Accordingly, it is submitted that the scope of the patent should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the following claims.