| Class D plays an important role in the audio-market.Being small and efficient, it wins great shares of the market. Part of electronic portable devices and home audio equipments, even more and more car audio systems have been equipped with Class D power amplifier.This paper presents a dual-channel Class D power amplifier based on CMOS process. This chip adopts a structure of differential inputs and H-bridge outputs. The amplifier adopts double-sided natural sampling pulse width modulation scheme , greatly reduces the quiescent current compared the traditional PWM scheme. There is a possibility of having all the significant distortion components to be outside the audio band thus enabling a filter free class D amplifier .The differential system adopts negative feedback technology, allowing the system to achieve a lower total harmonic distortion and a higher power supply rejection.It operates with a 12V to 15V supply voltage and it can drive stereo speaker as low as 4 ohm.The biggest output power in each channel is 12W. The amplifier gain is controlled with a dc voltage offering a range from -40dB to 36dB.It can be applied to LCD monitors, TV sets and loudspeakers and so on.The simulation results show that this chip has a good performance and meets the design requirements. |
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