The LC output filters of Class-D audio amplifiers can be simplified if overall feedback is applied to the amplifier – ‘after‑filter’ feedback. Stabilising such systems is notoriously complex. Step forward NXP, which at ISSCC 2017 described a five‑channel 80W/channel audio amplifier for automotive use. To achieve stability, it has integrated low-latency ΔΣ ADCs, each consuming …
Read full article: ISSCC: Audio amp gets after-filter feedback