Amplifier with sample and average common mode feedback resistor

An amplifier comprising:

• an amplifier circuit having an inverting input, a non-inverting input, and a first feedback path between an output of the amplifier circuit and one of the inverting input or the non-inverting input of the amplifier circuit;
• a feedback capacitor forms part of the first feedback path;
• a feedback resistor in parallel with the feedback capacitor forms part of the first feedback path, wherein the feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit;
• and
• a control circuit configured to supply a drive signal for controlling the switched capacitor resistor, where switching frequency of the drive signal is less than lower bound of bandwidth of an input signal to the amplifier circuit.

An amplifier circuit comprising:

• a differential amplifier circuit having an inverting input, a non-inverting input, a first output with a first feedback path between the first output of the amplifier circuit and the inverting input of the amplifier circuit, and a second output with a second feedback path between the second output of the amplifier circuit and the non-inverting input of the amplifier circuit;
• a first feedback capacitor forms part of the first feedback path;
• a first feedback resistor in parallel with the first feedback capacitor forms part of the first feedback path, wherein the first feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the first output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the inverting input of the amplifier circuit;
• a second feedback capacitor forms part of the second feedback path;
• a second feedback resistor in parallel with the second feedback capacitor forms part of the second feedback path, wherein the second feedback resistor is comprised of a low pass filter in series with a switched capacitor resistor, such that the low pass filter is electrically coupled to the second output of the amplifier circuit and the switched capacitor resistor is electrically coupled to the non-inverting input of the amplifier circuit;
• and
• a control circuit configured to supply a drive signal for controlling the switched capacitor resistors, where switching frequency of the drive signal is less than lower bound of bandwidth of an input signal to the amplifier circuit.