1 Introduction

Traditional audio amplifier architectures rely on a single high-voltage supply rail (PVDD) for output stage switching and amplification, alongside a low-voltage rail for I/Os and LDOs. However, during idle periods—when no audio signal is present—amplifiers continue to switch, resulting in poor power efficiency. Because the switching occurs exclusively on the high-voltage rail, the excess voltage headroom leads to idle efficiencies falling below 20%. To overcome this limitation, Texas Instruments has introduced the Y-Bridge power architecture. This intelligent design allows the amplifier to seamlessly alternate between two supply rails based on the output power demand. By optimizing the supply voltage in real time, the Y-Bridge architecture significantly reduces idle power consumption—by up to 90%—and improves efficiency by 15% to 20% at lower output levels, all without compromising audio performance. Combined with TI’s advanced speaker protection and signal processing algorithms, this design empowers OEMs to maximize battery life and overall system performance in next-generation portable audio applications.