2 ms·

I'm assuming that they need to have some type of power supply between the battery and the voltage rails of the amplifier to convert the 3.7V (or whatever) batte

I'm assuming that they need to have some type of power supply between the battery and the voltage rails of the amplifier to convert the 3.7V (or whatever) battery voltage to something higher. I would be surprised if this power supply worked the other way around (i.e., can sink current). I always assumed that the damping action of an amplifier would ultimately result in the extra energy being dissipated as heat.

londons_explore 4y ago
Class D amplifiers typically run direct off battery voltage in portable systems - although sometimes you go for a 2S or 3S or 4S design for more volts and more power output for a fixed impedance speaker. The controller chip compensates for any sag in the supply voltage.