By having a one-tenth of idle power consumption and a much higher music playback efficiency, the multilevel class D amplifiers can extend the playback time of a battery power system by as much as 30% or more. The designer can also reduce the battery capacity and still get the same music playback time performance, which results in reduced system cost. In the meantime, the multi-level class D IC and its output filtering inductors also generates less heat in the system, which enables optimized system thermal design especially in the AC-powered audio applications.