An 8 $\Omega$ 2.5 W 1%-THD 104 dB(A)-Dynamic-Range Class-D Audio Amplifier With Ultra-Low EMI System and Current Sensing for Speaker Protection

Class-D amplifiers for portable devices are now demanding more than 2 W 1% THD output power on 8 Ω speakers in smartphone and tablet for a better multi-media user experience. However higher acoustic power brings a lot of additional constraints such as speaker damage, more EMI energy and battery reset. The presented paper demonstrates a 2.5 W 1% THD into 8 Ω Class-D amplifier with 104 dB(A) dynamic range using a new power stage architecture to reduce silicon area. The design includes a ULEMI system to reduce high frequency energy without impact on audio band noise and an embedded load current sensing for speaker protection algorithm.