A Novel Filterless Class-D Audio Power Amplifier

With the rapid growth of electronic technology, the portable electronic devices expand very speedily. Class-d has been used in DVD,digital TV,MP4,Mobile phone and so on widely. Its biggest advantage is high efficiency, thus requiring less power from the power supply and smaller heat sinks for the amplifier. The efficiency of translation is more than 80%, even reach 100% in theory. The market of Class-d will be larger and larger. This paper is based on the project which is"Filterless High Efficiency 2.5W Switching Audio Amplifier"in Xi'an Power-Rail Micro.Co.,Ltd.This paper introduces a Filterless High Efficiency 2.5W Switching Audio Amplifier particularly. The system and the important modules will been designed. This paper also will introduce the results of the simulation. The CMOS chip will adopt the fully differential operation amplifier as the input and the H bridge output. Thus PCB can omit the LC filter. Because the loudspeaker is also a filter. The paper will introduce the modules including input, output, PWM, OSC., dead time ,PTAT and so on. The frequency of this chip is about 300KHz,the area of this CMOS chip is about 1600*1600μm2.Finally, the simulation has completed by using the Cadence software with the CSMC 0.5μm CMOS process. Many kinds of simulations are finished based on various spice models, operating-temperature and supply-voltage, with the results of the circuit optimized. The simulation results show that the performance in application is excellent and can meet the prospective specifications.