Internal integrated circuit resistance calibration

A sensor interface integrated circuit (IC) for measuring a resistance value of a target resistor using an excitation current that is subject to reduction by an external sensor leakage current of a sensor coupled to the IC, the sensor interface IC including:

• a current sensor circuit, including at least one target resistor for sensing the response current produced by the sensor;
• and
• a resistance value measurement circuit, coupled to the target resistor to measure a resistance value of the target resistor, the resistance value measurement circuit including:
• a voltage excitation circuit to apply one or more specified excitation voltages to a calibration resistor having a specified calibration resistance value to generate, in response, a different respective excitation current for each specified excitation voltage;
• a voltage measurement circuit to measure a different respective response voltage across the target resistor respectively in response to each corresponding different excitation current;
• and
• a computation circuit to determine the resistance value of the target resistor using a difference between the measured different respective response voltages, a difference between the one or more specified excitation voltages, and the specified calibration resistance value.

A sensor interface integrated circuit (IC) for measuring or calibrating a resistance value of a target resistor using an excitation current that is subject to reduction by an external sensor leakage current of a sensor coupled to the IC, the sensor interface IC including:

• a current sensor circuit, including at least one target resistor for sensing the response current produced by the sensor;
• and
• a resistance value measurement or calibration circuit, coupled to the target resistor to measure or calibrate a resistance value of the target resistor, the resistance value measurement or calibration circuit including:
• a current excitation circuit to apply one or more specified excitation currents through a calibration resistor having a specified calibration resistance value;
• a voltage measurement circuit to measure a different respective response voltage across the target resistor respectively in response to each corresponding different excitation current;
• and
• a computation circuit to determine the resistance value of the target resistor using a difference between the measured different respective response voltages, a difference between the one or more specified excitation currents, and the specified calibration resistance value.