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US 8,149,061 B2Granted
Class H amplifier
AssigneeNXP B.V.
InventorHan Martijn Schuurmans
Life of this patent
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Abstract
A class H amplifier circuit includes a Buck converter 20 and a charge pump 30 which are used to generate voltages which are used in turn to power an output driver 10. A feedback path 36 controls the loop. The circuit is particularly suitable as a high efficiency circuit for driving headphones or loudspeakers.
Claims13
A class H amplifier circuit, comprising:
- a voltage rail generating circuit comprising:
- a control input;
- a pulse width modulator connected to the control input;
- a Buck converter connected to an output of the pulse width modulator for generating a voltage on a positive output node;
- an inverting charge pump connected to the positive output node for generating a negative voltage on a negative output node, the negative voltage being the negative of the voltage on the positive output node;
- a feedback path feeding back the voltage on the negative output node to sum with the signal on the control input to control the pulse width modulator, to provide a feedback loop including the Buck converter, inverting charge pump and pulse width modulator;
- the class H amplifier circuit further comprising an output driver driven by a positive voltage rail connected to the positive output node and a negative voltage rail connected to the negative output node.
4 more elements
Dependencies are inferred from the claim text.