Amplification circuit and method of compensating for voltage offset of inputs

An audio sensing circuit, comprising:

• an audio sensor electrically coupled between first and second supply voltage nodes;
• an amplifier configured to amplify first and second input electrical signals, the amplifier including:
• first and second input nodes configured to receive the first and second input electrical signals, and
• first and second output nodes configured to output first and second output electrical signals having amplified voltages relative to the first and second input electrical signals;
• a set of resistive devices electrically coupled between the second input node of the amplifier and the second supply voltage node, the audio sensor being coupled to the second input node through a first portion of the set of resistive devices and coupled to the second supply voltage node through a second portion of the set of resistive devices;
• and
• a variable resistive device electrically coupled to the second input node of the amplifier, the variable resistive device being configured to have a selected resistance value to compensate for a direct current (DC) voltage difference between the first and second input electrical signals based on a DC voltage difference between the first and second output electrical signals that are output from the first and second output nodes of the amplifier.

A method of adjusting an input direct current (DC) voltage difference between first and second input electrical signals at first and second input nodes of an amplifier of an amplification circuit, the method comprising:

• generating a detection result indicating a DC voltage difference between first and second output electrical signals that are output from first and second output nodes of the amplifier;
• determining a set of settings, for setting a resistance value of a variable resistive device, based on the detection result when the amplification circuit is in a calibration mode;
• and
• setting the variable resistive device electrically coupled to the second input node of the amplifier to have the resistance value to compensate for the DC voltage difference between the first and second input electrical signals at the first and second input nodes of the amplifier based on the DC voltage difference between the first and second output electrical signals that are output from the first and second output nodes of the amplifier.