Abstract: An apparatus comprises an integrated circuit that includes an input to receive an electrical input signal from an electronic sensor, wherein the input signal includes a direct current (DC) offset and a varying signal component; a digital-to-analog converter (DAC) circuit configured to subtract the DC offset from the input signal; a programmable gain amplifier (PGA) operatively coupled to the DAC circuit, wherein the PGA circuit is configured to apply signal gain to the varying signal component of the input signal; and a measurement circuit configured to generate a measure of the varying signal component.

Abstract: An impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

Abstract: A sample-and-hold amplifier can include: an operational amplifier; a sampling capacitor having a first terminal coupled to an inverting input terminal of the operational amplifier, and a second terminal coupled to a reference ground; and a switching circuit configured to switch feedback paths of the sample-and-hold amplifier in a first stage and a second stage, such that an offset voltage of the operational amplifier is at least partially eliminated.

Abstract: An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Abstract: A device and method for measuring the internal impedance of an electronic sensor uses configurable gain stages to selectively apply different excitation signals to the sensor under test in order to ensure adequate signal-to-noise ratio to provide accurate measurement of the internal impedance over a broader range of internal impedances than the prior art.

Abstract: An impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: An impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: Various examples are directed to a measurement system for measuring an electrical property of skin comprising an excitation circuit, a receiver circuit, and a sequencer circuit. The excitation circuit may generate a periodic excitation signal that, when provided to the skin, generates a response signal in the skin indicative of the electrical property. The sequencer circuit may be configured to activate the excitation circuit to provide the excitation signal to the skin. While the excitation circuit is activated to provide the excitation signal to the skin, the sequencer circuit may activate the receiver circuit to execute a first sample cycle to generate a first plurality of samples of the response signal. A first value for the electrical property of the skin may be determined based at least in part on the first plurality of samples of the response signal.

Abstract: An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Abstract: An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Abstract: The sensor interface IC measures or calibrates a target resistance to be used as a gain resistor for a TIA amplifier in the sensor interface IC. One or more excitation currents are generated in response to different specified excitation voltages that are applied to an external calibration resistor having a specified calibration resistance value. Response voltages are measured across the target resistor, respectively in response to the corresponding different one or more excitation currents. The resistance value of the target resistor is determined using a difference between the measured response voltages, a difference between the specified excitation voltages, and the specified calibration resistance value.

Abstract: A electrochemical or other sensor interface circuit architecture can deliver substantial DC offset bias to an electrochemical or other sensor separately or independently from delivering a time-varying AC excitation signal, which can then be provided with higher resolution, which, in turn, can allow better resolution of the measured response signal providing the impedance characteristic of sensor condition. For example, a differential time-varying AC excitation signal for the sensor condition characteristic can be delivered separately and independently from a differential stable (e.g., DC or other) bias signal, such as by using separate digital-to-analog converters (DACs), so that providing the more stable signal does not limit the resolution and accuracy of the time-varying signal, such as by using up the dynamic range of a single DAC.

Abstract: Various examples are directed to a measurement system for measuring an electrical property of skin comprising an excitation circuit, a receiver circuit, and a sequencer circuit. The excitation circuit may generate a periodic excitation signal that, when provided to the skin, generates a response signal in the skin indicative of the electrical property. The sequencer circuit may be configured to activate the excitation circuit to provide the excitation signal to the skin. While the excitation circuit is activated to provide the excitation signal to the skin, the sequencer circuit may activate the receiver circuit to execute a first sample cycle to generate a first plurality of samples of the response signal. A first value for the electrical property of the skin may be determined based at least in part on the first plurality of samples of the response signal.

Abstract: The sensor interface IC measures or calibrates a target resistance to be used as a gain resistor for a TIA amplifier in the sensor interface IC. One or more excitation currents are generated in response to different specified excitation voltages that are applied to an external calibration resistor having a specified calibration resistance value. Response voltages are measured across the target resistor, respectively in response to the corresponding different one or more excitation currents. The resistance value of the target resistor is determined using a difference between the measured response voltages, a difference between the specified excitation voltages, and the specified calibration resistance value.

Abstract: Techniques for generating a diagnostic waveform for a sensor are provided. In an example, a control circuit for an electrochemical sensor can include power supply inputs configured to receive a supply voltage, a first signal generator configured to receive control information and to generate a first signal on a first output using the supply voltage and the control information, a second signal generator configured to receive the control information and to provide a second signal on a second output, using the supply voltage and the control information. An output voltage between the first output and the second output, in a diagnostic mode of operation of the control circuit, can include a periodic signal having a peak-to-peak voltage greater than the supply voltage.

Abstract: A electrochemical or other sensor interface circuit architecture can deliver substantial DC offset bias to an electrochemical or other sensor separately or independently from delivering a time-varying AC excitation signal, which can then be provided with higher resolution, which, in turn, can allow better resolution of the measured response signal providing the impedance characteristic of sensor condition. For example, a differential time-varying AC excitation signal for the sensor condition characteristic can be delivered separately and independently from a differential stable (e.g., DC or other) bias signal, such as by using separate digital-to-analog converters (DACs), so that providing the more stable signal does not limit the resolution and accuracy of the time-varying signal, such as by using up the dynamic range of a single DAC.