Traditional class D amplifiers present significant design challenges in compact applications such as portable consumer sound systems and smart speakers. These challenges include relatively low efficiency, high heat generation even at low to medium listening levels, and a need for bulky and costly filters to reduce out of band noise.
A relatively new range of class D amplifiers address these limitations using so-called multilevel amplification. This approach improves power consumption while inherently reducing interference and out of band noise. In addition, manufacturing costs are reduced by eliminating or minimizing the use of filters, which also helps save design space. | 
