Chip Design Of High Efficiency Class D Audio Power Amplifier

While audio power amplifier is widely used, class D audio power amplifier hasbecome the development trend of audio power amplifier. Class D has high efficiency、lowpower consumption、low degree of distortion and other advantages. It can prolong theservice life of the batteries and provide the high fidelity. Therefore, with the developmentof technology、cost reduction、energy saving and the unceasing enhancement of narrowarea demand, class D audio power amplifier has the broad prospects.The core of this paper is designing a high efficiency class D power amplifier circuit.This paper analyzes four kinds of audio power amplifiers’ principle and summarizes theiradvantages and disadvantages, and highlights the advantages of class D audio poweramplifier. The chip design includes the overall structure design、 the module circuit designand simulation、integrated circuit simulation and optimization and layout drawing andoptimization.Using CSMC0.5um Mixed Signal CMOS process,the author designs poweramplifier of each module, including the bandgap reference, pre-op amps, comparators,triangular wave generator, the dead time, the power output stage, and over-temperature,over-current protection circuit.The author use Spectre to carry out simulation analysis,adjusting circuit performance optimization. According to the basic rules of the analog ICLayout Design, the author using Virtuoso draws each module circuit’s layout, and finallydraws the overall layout.This subject reduces the total harmonic distortion (THD) and improve the outputefficiency,using PWM (pulse width modulation) technology、double input and full bridgeoutput structure. The design has good performance of all difference operational amplifierand comparator, using the feedback loop, increasing the power supply rejection ratio andlinearity. Using no filter structure,the chip reduces the area and the cost. The designrealizes the chip of the high efficiency up to97%, THD less than1%.