Digital Audio Power Amplifier is such a amplifier that adopt PWM of the input audio signal or PCM digital information transformation into a PWM (pulse brightness Modulation) or PDM (pulse density modulation) signal pulse, Then PWM or PDM signal to the control pulse high power switching device / Off Audio Power Amplifier, also known as the switch amplifier, or class D amplifier, with the power and cooling requirements of low, and output power, high efficiency, wide frequency response, small size, high signal-to-noise ratio advantage.
This paper describes the design of the Class D power amplifier, it from the input signal processing circuit, switch signal forming circuit, High-power switching circuit and a low-pass filter in four parts.
Input signal formed by the PWM circuit, the input signal amplitude changes converted into pulse width changes.
Switching power circuit used to MOS - FET power switching devices bridge control the entire way. Bridge approach of the two diagonal tube rotation opposite condition-off.
Low-pass filter effect will be to create the entire pulse waveform simulation waveform beautiful, that is filtered PWM carrier components. Use small power loss LC-filter.
Keywords： Pulse width modulator , Full-bridge inverter circuit , Dead time
