A $2 \times 70$ W Monolithic Five Level Class D Audio Power Amplifier in 180 nm BCD
A 2 x 70 W from 24 V into 4 O class D audio power amplifier in 30/40 V 180 nm bipolar CMOS DMOS is presented. The device employs a flying capacitor (FC) three level half bridge topology to reduce switching frequency and filter/load power losses in near idle operation. This is combined with a fourth order analog feedback system for shaping noise introduced by the digital FC voltage control loop. A power efficient gate drive scheme suitable for power converters with multiple floating switching devices is also presented, including a compact fast low power dV/dt robust high voltage level shifter circuit. Power efficient operation from idle to full power operation is demonstrated along with a very high audio performance of 0.003% THD N at 10 W/1 kHz into 4 O.
IEEE Journal of Solid State Circuits