Abstract: Fast settling circuits and methods designed to align input signal amplitude level and to remove DC offset voltages with minimal loss of low frequency signal in receiving analog circuits are disclosed. With the key innovative circuits and methods for signal peak alignment, the disclosed circuits and methods achieve fast settling without significant attenuation of the input signal. Peak aligning circuits and methods can be implemented along with conventional RC AC coupling circuits. In applying the aligning circuits and methods to differential signal pair, DC offsets can be easily removed.

Abstract: A fast-setting DC offset removal circuit with continuous cutoff frequency switching is disclosed. In the preferred embodiment, the circuit is implemented using a pair of RC filters for receiving a differential signal pair and a continuous, variable resistance control circuit. The control circuit can be current-controlled or voltage controlled to provide fast settling of the received signal and the removal of the DC offset components. Additionally, by using a current-controlled control circuit, the cutoff frequency of the RC filter can be ramped from high to low in a continuous manner, thereby minimizing the generation of DC offsets.