AUDIO AMPLIFIER USING MULTI-LEVEL PULSE WIDTH MODULATION
First Claim
Patent Images
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;
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.
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Abstract
The present invention relates in one aspect to a class D audio amplifier with improved output driver topology supporting multi-level output signals such as 3-level, 4-level or 5-level pulse width or pulse density modulated output signals for application to a loudspeaker load. The present class D audio amplifiers are particularly well-suited for high-volume consumer audio applications and solutions.
68 Citations
32 Claims
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1. A class D audio amplifier comprising:
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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; 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 28, 30, 31)
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17-27. -27. (canceled)
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29. (canceled)
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32. (canceled)
Specification