New audio amplifiers feature multilevel switching amplifier technology

24-11-2022 | Infineon | Semiconductors

MERUS multilevel switching technology from Infineon Technologies AG is created to provide low switching losses and highly efficient amplification at low and high output power, obtaining the desired benefits in such applications. The new ICs provide the second generation of this technology and come in a compact 40-pin QFN package. They primarily address applications including battery-powered speakers, conference speakers, Bluetooth/wireless/smart speakers and soundbars, and multi-channel/multi-room audio systems.

The new family comprises the MA2304DNS with an integrated, fully configurable DSP and the MA2304PNS with audio limiter and volume control features. These devices offer second-generation multilevel-switching class D audio amplifiers with an inductor-less operation and offer a BTL-rated output of 2 x 37W and a power supply voltage range (PVDD) of 10V to 20V for high-fidelity audio performance. The five-level voltage modulation provides an ultralow idle power of 52mW without requiring complex dynamic rail‑tracking systems. This is at least five times lower than the traditional class D audio amplifiers, making these devices excellent for battery-powered speaker applications with extended battery life and/or reduced battery cell cost.

At low output power, the efficiency can be higher than 80% providing extended battery life and simple thermal management in multi-channel products. Multilevel switching also relaxes EMC necessities and allows inductor-less applications at full power range with lower cost. Compared to conventional two- and three-level class D audio amplifiers, the reduced EMI emissions provide fast time-to-market with no compromise in audio performance or efficiency. In mains‑powered multi-channel applications, the reduced and scalable EMI allows otherwise impossible industrial designs without requiring a heatsink or a conventional LC filter.

A high-order internal feedback loop ensures low THD and low noise floor for outstanding audio performance. The inductor‑less application contributes to the smallest output filtering, bypassing bulky inductors, lowering system cost with no output power limitations. The integrated DSP in the device is highly configurable and can correct imperfections and tune real speaker applications with, e.g., equalisation, limiting, and other similar functions. It provides a simpler volume control and limiter for systems where an application/connectivity processor does the audio processing.