High Dynamic Range Class D Power Amplifier Based on Matching Gain Switching

Class D power amplifiers currently have a high demand for high dynamic range. At present, the optimization of SPWM to improve the dynamic range is limited, this paper proposes a method based on matching gain switching to improve the dynamic range significantly. Firstly, the mathematical model of Class D power amplifier based on bipolar SPWM is constructed, and the dynamic range expression of Class D power amplifier and the factors affecting the dynamic range are given. Secondly, the dynamic range is improved by adding the matching gain switching circuit. The dynamic range increment expression and the inductance limit in the matching gain switching circuit are derived. The final simulation results show that the matching gain switching method can increase the dynamic range of class D power amplifier, and the error of dynamic range increment and theoretical calculation is less than 4%.