A sensor circuit incorporates an analogue to digital converter for providing a digital signal derived from sensing elements connected in a bridge configuration. The sensor circuit comprises first and second paths comprising respective first and second sensing elements connected between first and second supply lines; an analogue to digital converter having a differential input connected to receive a differential voltage signal (Vinp-Vinn) between the first and second sensing elements and an output for providing a digital output signal (Dout) representing a difference between the first and second sensing elements, the analogue to digital converter comprising: current sources connected between the first and second supply lines, each current source being switchably connected to either the first or second sensing elements; and control logic configured to selectively switch current from each of the current sources to either the first path or the second path in dependence on the differential voltage signal.

Precision AC and DC voltage, current, phase, power and energy measurements and calibrations with current ranges from 1 uA to 20 kA and voltage ranges from 1V to 1000 kV are now performed with accuracies of better than one part per million. Continued demand for improved accuracy has led the inventors to address remnant magetization within the current comparators that form the basis of the measuring process within many of the measurement instruments providing the precision AC and DC measurements and calibrations. Accordingly, the inventors present current comparator and measurement system architectures together with control protocols to provide for correction of this remnant magnetization.

A system, in some embodiments, comprises: a multi-resistor Wheatstone bridge supplied by a first current source; and a second current source coupled to the bridge and configured to at least partially compensate for a voltage detected by an analog-to-digital converter (ADC), said voltage indicative of an alteration of a physical parameter affecting the bridge, wherein the ADC produces a digital code that represents said voltage.

Sensor devices disclosed herein allow multiple analytes or organisms to be individually tagged and selectively detected. When a binding event occurs one or more nanoswitches close and the corresponding array resistance value produces a voltage imbalance in the Wheatstone Bridge. The voltage detected by the voltage meter will then exhibit unique value change corresponding to the particular nanoswitche(s) in the array that are closed due to a binding event. Similarly the same functionalization chemistry can be used on all nanoswitches so that the voltage detected by the voltage meter corresponds to concentration levels of the target analyte. Multiple functionalization chemistries on each switch can also be used to improve selectivity for more complex analytes. In some disclosed embodiments, the Wheatstone bridge voltage is tied to a predetermined resistance change rather than to smaller resistance changes that would occur from functionalization of one leg of a nanowire Wheatstone bridge.

A sensor system with performance compensation testing capability includes a sensor device, a resistance bridge, a signal conditioning circuit, a first test connector, and a second test connector. The resistance bridge circuit is disposed on the sensor device and includes an excitation terminal, a circuit common terminal, and two output terminals, and is configured, upon being energized, to supply a bridge output voltage across the two output terminals. The signal conditioning circuit is electrically coupled to the excitation terminal, the circuit common terminal, and the two output terminals, and is configured to supply a sensor output signal representative of bridge output voltage. The first test connector is electrically coupled to one of the two output terminals and is configured to be coupled to an impedance test device. The second test connector is electrically coupled to the circuit common terminal and is configured to be coupled to the impedance test device.

A method for ascertaining an inner resistance of a supply network for supplying energy to an occupant protection system of a vehicle. The occupant protection system includes a charging unit connected to the supply network using a primary interface and to an energy buffer store using a secondary interface for the temporary storage of energy for activating occupant protection devices system and for supplying the system after being separated from the supply network. The method includes impressing a first charge current value at the secondary interface, and a first current/voltage at the primary interface during the impression. Further, a second, different, charge current value is impressed at the secondary interface. The method also includes determining a second current/voltage at the primary interface during the impression, and ascertaining the inner resistance of the supply network, using the detected first current and second current and/or the first voltage and the second voltage.

A sensor system with performance compensation testing capability includes a sensor device, a resistance bridge, a signal conditioning circuit, a first test connector, and a second test connector. The resistance bridge circuit is disposed on the sensor device and includes an excitation terminal, a circuit common terminal, and two output terminals, and is configured, upon being energized, to supply a bridge output voltage across the two output terminals. The signal conditioning circuit is electrically coupled to the excitation terminal, the circuit common terminal, and the two output terminals, and is configured to supply a sensor output signal representative of bridge output voltage. The first test connector is electrically coupled to one of the two output terminals and is configured to be coupled to an impedance test device. The second test connector is electrically coupled to the circuit common terminal and is configured to be coupled to the impedance test device.

A monitoring method is adapted for a circuit board. The circuit board includes a board body, a main circuit, and a standby circuit. The main circuit is located on the board body. The standby circuit is located on the board body, and is electrically connected to the main circuit. The standby circuit includes a first pressure detection circuit and a control circuit. The first pressure detection circuit is located at an area being monitored of the board body, and the control circuit outputs a first signal or a second signal according to a first detection value and a first predetermined range of the first pressure detection circuit.

Measurement circuitry comprising: a first half bridge, comprising: a first impedance coupled between an input voltage node for receiving an input voltage and a first node; and a second impedance coupled between the first node and a reference voltage node, the first impedance or the second impedance comprising a first voltage-controlled oscillator (VCO) having a first input coupled to the first node and a first output for outputting a first oscillating signal having a first frequency proportional to a current flowing in the half bridge.

Example embodiments relate to sensor readout systems and sensor readout methods. One example sensor readout system includes a signal generator configured to generate a biasing signal. The sensor readout system also includes a first chopper configured to modulate the biasing signal using a chopping signal with a chopping frequency f.sub.chop to generate a modulated biasing signal. Additionally, the sensor readout system includes a Wheatstone bridge circuit that includes resistive branches. At least one of the resistive branches includes an impedance-based sensor. The Wheatstone bridge circuit is configured to receive the modulated biasing signal and to generate a sensing signal based on the modulated biasing signal. Further, the sensor readout system includes a second chopper configured to modulate the sensing signal using the chopping signal with the chopping frequency f.sub.chop to generate a modulated sensing signal.