Integrated Pop-Click Noise Suppression, EMI Reduction, and Short-Circuit Detection for Class-D Audio Amplifiers

Circuit techniques that overcome practical noise, reliability, and EMI limitations are reported. An auxiliary loop with ramping circuits suppresses pop-and-click noise to 1 mV for an amplifier with 4 V-achievable output voltage. Switching edge rate control enables the system to meet the EN55022 Class-B standard with a 15 dB margin. An enhanced scheme detects short-circuit conditions without relying on overlimit current events.