Patent ID: 9515617
Filing Date: 2016-12-06
CPC Classification: H02M,H03F,H04R

Claim Text:
1. A class D audio amplifier comprising: a first output driver comprising an output node connectable to a loudspeaker load to supply a load signal thereto, said first output driver comprising an upper leg coupled between a first DC supply voltage and the output node and a lower leg coupled between the output node and a second DC supply voltage, the upper leg comprising a first semiconductor switch and a second semiconductor switch coupled in series and controlled by first and second switch control terminals, respectively, the lower leg comprising a third semiconductor switch and a fourth semiconductor switch coupled in series and controlled by third and fourth switch control terminals, respectively; a controller adapted to receive an audio input signal and derive first, second, third and fourth pulse width or pulse density modulated control signals therefrom, the controller being configured to apply the first, second, third and fourth pulse width or pulse density modulated control signals to the first, second, third and fourth switch control terminals, respectively, the first, second, third and fourth pulse width modulated control signals being configured to, in a first state, connect a first terminal of the DC voltage source to the output node through the first and third semiconductor switches, and in a second state, connect a second terminal of the DC voltage source to the output node through the fourth and second semiconductor switches; and a first DC voltage source configured to set a first predetermined DC voltage difference between a first node, located between the first and second semiconductor switches, and a second node, located between the third and fourth semiconductor switches.