Method for compensating for an internal voltage offset between two inputs of an amplifier

An integrated circuit, comprising:

• a first operational amplifier having an internal voltage offset between a positive input and a negative input;
• and
• a circuit for calibrating the internal voltage offset between the positive input and the negative input of the first operational amplifier;
• wherein the circuit for calibrating comprises:
• a switching circuit configured to couple the negative input and the positive input of the first operational amplifier to a same voltage level, such that the first operational amplifier is configured to generate a comparison current at an output of the first operational amplifier, wherein a sign of the comparison current is representative of a sign of the internal voltage offset on the positive input and the negative input of the first operational amplifier;
• a current-to-voltage converter circuit configured to bias the output of the first operational amplifier to a threshold voltage and to generate a control voltage comprising a sum of the threshold voltage and a voltage conversion of the comparison current;
• and
• a compensation circuit configured to generate a compensation signal for compensating the internal voltage offset between the positive input and the negative input of the first operational amplifier dependent on the control voltage.

A method, comprising:

• connecting a positive input and a negative input of an operational amplifier to a same voltage level, wherein the operational amplifier has an internal voltage offset;
• generating a current at an output of the operational amplifier having a sign dependent on a sign of the internal voltage offset;
• converting the current to a control voltage;
• and
• processing the control voltage to generate a calibration current applied to the operational amplifier to compensate for the internal voltage offset between the positive input and the negative input of the operational amplifier.

An integrated circuit, comprising:

• an operational amplifier having an internal voltage offset between a positive input and a negative input;
• and
• a circuit for calibrating the internal voltage offset between the positive input and the negative input of the operational amplifier;
• wherein the circuit for calibrating comprises:
• a switching circuit configured to connect the positive input and the negative input of the operational amplifier to a same voltage level;
• a current to voltage converter configured to convert a current generated at an output of the operational amplifier to a control voltage;
• wherein the current has a sign dependent on a sign of the internal voltage offset;
• and
• a processing circuit configured to process the control voltage to generate a calibration current applied to the operational amplifier to compensate for the internal voltage offset between the positive input and the negative input of the operational amplifier.