JSSC 2009第12期Other0.25μm BCD工艺

A 20 W/Channel Class-D Ampliﬁer With Near-Zero Common-Mode

一种新型D类放大器，采用BD调制技术实现无滤波器操作并降低辐射。

THD+N 0.19% @1kHz, 90%效率 @10W, 12V供电, 8Ω负载

D类放大器BD调制共模辐射无滤波器高效率

▸新型BD调制技术保持输出共模恒定

▸无需LC滤波器即可满足FCC B类辐射标准

▸高效率与高音频性能并存

Abstract

A class-D ampliﬁer that employs a new modulation scheme and associated output stage to achieve true ﬁlter-less oper- ation is presented. It uses a new type of BD modulation that keeps the output common-mode constant, thereby removing a major con- tributor to radiated emissions, typically an issue for class-D ampli- ﬁers. The ampliﬁer meets the FCC class B standard for radiated emissions without any LC ﬁltering. It can accomplish this without any degradation to audio performance and while retaining high efﬁciency. THD+N is 0.19% at 1 kHz while supplying 5 W to an 8 Ohm load from a 12 V supply. Efﬁciency is 90% while providing 10 W under the same supply and load conditions. The new output stage occupies 1.8 mm /50per channel using the high voltage devices of a 0.25 m BCD process.