New notch low pass filter for use in switching audio amplification

In this paper a novel switched audio amplifier filter topology is proposed and its design criteria are presented. It permits improved attenuation of the switching frequency components and load impedance variation with very low gain variation in the audio band. The new filter configuration allows the use of simple converter topologies while obtaining the same output voltage ripple levels as in multilevel converters. The construction of a prototype is addressed and experimental results are presented, showing the feasibility of the proposed method.