The automotive industry is rapidly migrating from 12 V to 48 V electrical architectures to support growing power demands from compute and electrified subsystems. Audio amplifiers appear well positioned to benefit through reduced current, lower conductor losses, increased instantaneous power capability, and an additional 12 dB of voltage headroom for improved transient reproduction in non-boosted amplifier systems. However, directly scaling conventional Class D amplifier architectures and ICs to 48 V introduces significant and often underestimated challenges. Usage weighted analysis of real audio content shows that over 95% of playback occurs below 5 W output power, where conduction losses are minimal and voltage dependent switching losses dominate efficiency and thermal behavior. The resulting impacts on efficiency, EMI, noise floor, thermal design, and system architecture motivate a re examination of long standing assumptions for next generation 48 V automotive audio systems.
