A new stereo enhancement circuit for class-D amplifier

This paper presents a novel stereo enhancement structure for the surround stereo class-D audio amplifier. The principle of this stereo enhancement scheme has been analyzed. It shows that the amplifier with this proposed circuit have a better live effect than the traditional class-D audio amplifiers. In this circuit, the input audio signal from one channel can be amplified in the two channels at the same time, by a way of cross-coupling. The ratio of gains in the two channels also can be adjusted by changing the external resistance, which improves the stereo effect. A practical implementation in a CMOS 0.18-μm process has been done to validate the theoretical results. When a sine signal with 1KHz frequency and 100mV amplitude is applied in one channel, and a DC applied signal in the other, the amplifier demonstrates a gain difference of 9.4 dB.