Patent ID: 7532427

Claim:
An amplifier system with feedback current cancellation, comprising: an amplifier that includes an input, an output, and at least one stage; a feedback network that includes a first resistance having a first end that communicates with the input of the amplifier and an opposite end that communicates with the output of the amplifier; first and second replica circuits that approximately replicate DC characteristics of the output and the input of the amplifier, respectively; a buffer that includes an input that communicates with the first replica circuit and an output; a second resistance that includes a first end that communicates with the output of the buffer and an opposite end; a third resistance that includes a first end that communicates with the opposite end of the second resistance and an opposite end that communicates with the second replica circuit; an operational amplifier (op-amp) that includes a first input that communicates with the first end of the third resistance, a second input that communicates with the opposite end of the third resistance, and an output; a transistor that includes a control terminal that communicates with the output of the op-amp and a first terminal that communicates with the opposite end of the second resistance; and a first current mirror that provides a first current at the input of the amplifier that is proportional to a second current flowing through the transistor.