DC offset cancellation and crosspoint control circuit

An amplifier method, comprising:

• amplifying differential input signals into differential output signals;
• generating a programmably adjustable crosspoint offset in the differential output signals;
• generating a programmably adjustable cutoff frequency of a feedback circuit between the differential output signals and the differential input signals, including adjusting the programmably adjustable cutoff frequency of the feedback circuit as a low pass filter;
• and
• generating a filter resistance for the low pass filter based in part on a variable resistance in the feedback circuit, the variable resistance controlled by a resistance control circuit.

An amplifier method comprising:

• amplifying differential input signals into differential output signals;
• generating a programmably adjustable crosspoint offset in the differential output signals;
• generating a programmably adjustable cutoff frequency of a feedback circuit between the differential output signals and the differential input signals;
• and
• generating filter capacitance for a low pass filter using a capacitance multiplier circuit.

An amplifier circuit, comprising:

• a differential amplifier circuit including differential inputs to couple to differential input signals and differential outputs to couple to differential output signals;
• and
• a feedback circuit coupled between the differential outputs and the differential inputs, the feedback circuit including:
• a crosspoint control circuit coupled to the differential outputs and including programmably adjustable current sources to cooperatively generate a programmably adjustable crosspoint offset in the differential output signals;
• an offset frequency adjustment circuit coupled to the crosspoint control circuit;
• and
• a feedback amplifier circuit coupled to the offset frequency adjustment circuit and the differential inputs.