Main sources of EMI of Class D power amplifier IC

Class D power amplifier IC has been plagued by EMI. The main sources of EMI are:

    1. High frequency energy released by output square wave during high low switching

     2. Due to the existence of the "dead time", after the dead time is released, the diode of the power tube body reversely recovers causing peak energy

    3. The ringing energy superimposed on the output square wave caused by stray capacitance and inductance on the PCB The traditional Class D power amplifier IC generally uses the switch tube to directly drive the output power of the power tube. It can be said that the rise and fall time and waveform of the output square wave are completely out of control. As shown in Figure 1,2, the output square wave of the traditional Class D power amplifier IC in practical applications has a large overshoot and a long ringing time, and the rise time and fall time are completely out of control. Therefore, there will be a lot of EMI interference.