The Study Of Half Bridge Switching Power Amplifier With Double-Frequency

The power amplifier has extensive application in industry, aviation electronics, communications, home entertainment and etc. Switching power amplifier has advantage over volume, efficiency and power dissipation because of its high efficiency. At present, People pay more and more attention to switching power amplifier which becomes the hotspot in power electronics field.The advantage of the switching amplifier is the high efficiency, but the distortion is still bigger than the linear amplifier because of the switching working and it's non-linear. One of the effective methods to enhance the class D amplifier fidelity is to increase the main circuit switching frequency, but this way will add the power consumption and descend the efficiency. It will limit the development of the switching frequency's increase and the applying field of the switching amplifier. So how to keep both high efficiency and low distortion is the emphases of the study of the switching amplifier.Based on the reference [11], a new double-frequency half-bridge switching power amplifier is proposed. The basic idea is to build an accessorial circuit through adding a half-bridge switch and an output inductor on the base of the original double-frequency half-bridge switching power amplifier. One cycle control is used to obtain the high frequency main switching working, and the accessorial switch works in low frequency through the constant frequency hysteresis control. The output inductor current of the accessorial circuit can track totally the one of main circuit and have the function of distributaries. In this way, though the main switch works in high frequency, its current and the power consumption is reduced largely. The majority of the current pass the accessorial switch, but the switching frequency is low, so the switch consumption is not high. This method can reduce the switch consumption and improve the efficiency of the switching power amplifier. The contents in this paper are as follows:1. Introduce the principle and configuration of the switching power amplifier. Analysis and simulate the one-cycle half-bridge switching power amplifier. Build the small signal model.2. Analysis the double-frequency half-bridge switching power amplifier proposed by the reference [11]. Build the AC small signal model, and prove that the characteristics of the double-frequency half-bridge switching power amplifier and one-cycle half-bridge switching power amplifier are same in Time and Frequency, decouple the high and low...