Analog Devices Global

Leicheng Chen

GuangYang Qu

Hanqing Wang

Yimiao Zhao

Tony Yincai Liu

Junbiao Ding

Shurong Gu

Michael Looney

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.

Internal integrated circuit resistance calibration

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.

Impedance characteristic circuit for electrochemical sensor

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Leicheng Chen