Amplification interface, and corresponding measurement system and method for calibrating an amplification interface

An amplification interface, comprising:

• first and second differential input terminals, wherein the first differential input terminal is coupled to a current indicative of a quantity measured by a first sensor, and the second differential input terminal is coupled to a reference current indicative of a reference quantity measured by a second sensor;
• first and second differential output terminals;
• a first current generator configured to couple a first compensation current to the first differential input terminal;
• a second current generator configured to couple a second compensation current to the second differential input terminal;
• a first analog integrator coupled between the first differential input terminal and the first differential output terminal, the first analog integrator comprising a first operational amplifier having a non-inverting input connected to a reference voltage, an inverting input connected to the first differential input terminal, and an output coupled to the first differential output terminal;
• a second analog integrator coupled between the second differential input terminal and the second differential output terminal, the second analog integrator comprising a second operational amplifier having an inverting input connected to the reference voltage, a non-inverting input connected to the second differential input terminal, and an output coupled to the second differential output terminal;
• a sample-and-hold circuit connected between the outputs of the first and second analog integrators and the first and second differential output terminals;
• and
• a control circuit configured to control the first and second current generators, first and second analog integrators, and sample-and-hold circuit.

An amplification interface, comprising:

• a first analog integrator having an input receiving a measurement sensor current, wherein the first analog integrator is configured to be reset or activated in response to a reset signal;
• a second analog integrator having an input receiving a reference sensor current, wherein the second analog integrator is configured to be reset or activated in response to the reset signal;
• a first current generator having an output connected to the input of the first analog integrator, wherein the first current generator is configured to generate a first compensation current as a function of a drive signal;
• a second current generator having an output connected to the input of the second analog integrator, wherein the second current generator is configured to generate a second compensation current as a function of a complement of the drive signal;
• a control circuit configured to:
• generate the reset signal such that the first and second analog integrators are periodically reset during a reset interval and activated during a measurement interval;
• and
• generate the drive signal based upon an offset in the sensor current and the reference sensor current;
• wherein the current generator is further configured to generate a first current or a second current based upon a logic value of the drive signal;
• and
• wherein the control circuit is configured to:
• determine a first duration and a second duration, wherein a sum of the first duration and the second duration corresponds to a duration of the measurement interval;
• and
• during the measurement interval, set the drive signal to a first logic value for the first duration and set the drive signal to a second logic value for the second duration.