Voltage regulator based loop filter for loop circuit and loop filtering method

摘要

A filter circuit includes an amplifier circuit, a resistor-capacitor (RC) network and a first voltage follower. The amplifier circuit has a first input terminal, a second input terminal and an output terminal. The amplifier circuit is configured to output a first output signal from the output terminal according to a first voltage signal at the first input terminal and a second voltage signal at the second input terminal. The RC network, coupled to the first input terminal, is configured to produce the first voltage signal at least in response to a first current signal applied to the first input terminal. The first voltage follower, coupled to the output terminal, is configured to receive the first output signal, and generate a first filtered signal in response to the first output signal.