Amplifier circuit and method of amplifying a signal in an amplifier circuit
AssigneeWolfson Microelectronics plc
InventorJohn Paul Lesso
Life of this patent
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Abstract
An amplifier circuit, comprising: an input, for receiving an input signal to be amplified; a power amplifier, for amplifying the input signal; a switched power supply, having a switching frequency, for providing at least one supply voltage to the power amplifier; and a dither block, for dithering the switching frequency of the switched power supply. The dither block is controlled based on the input signal. Another aspect of the invention involves using first and second switches, each having different capacitances and resistances, and using the first or second switch depending on the input signal or volume signal. Another aspect of the invention involves controlling a bias signal provided to one or more components in the signal path based on the input signal or volume signal.
Claims30
A charge pump circuit comprising:
- a switch array for providing, in use, a plurality of switch connections;
- wherein said charge pump circuit is operable in at least first and second modes, wherein in said first and second modes different combinations of said switch connections are switched in sequence to generate different output voltages in each mode;
- and
- wherein at least a first switch connection comprises a plurality of parallel switches configured such that the energy required to operate the first switch connection can be varied in use in at least one of said first and second modes.
A charge pump circuit comprising:
- a switch array for providing, in use, a plurality of switch connections;
- wherein said charge pump circuit is operable in at least first and second modes, wherein in said first and second modes different combinations of said switch connections are switched in sequence to generate different output voltages in each mode;
- and
- wherein at least a first switch connection comprises a plurality of parallel switches configured such that the gate area the first switch connection can be varied in use in at least one of said modes.
A charge pump circuit for supplying one or more supply voltages to an audio amplifier circuit, said charge pump circuit comprising:
- a switch array for providing, in use, a plurality of switch connections;
- wherein at least a first switch connection comprises a plurality of parallel switches configured such that the energy required to operate the first switch connection can be varied in use;
- and
- wherein said charge pump circuit is configured to selectively vary the parallel switches used for said first switch connection based on a volume control signal.
A charge pump circuit for supplying one or more supply voltages to an audio amplifier circuit, said charge pump circuit comprising:
- a switch array for providing, in use, a plurality of switch connections;
- wherein at least a first switch connection comprises a plurality of parallel switches configured such that the energy required to operate the first switch connection can be varied in use;
- and
- wherein said charge pump circuit is configured to selectively vary the parallel switches used for said first switch connection based on a feedforward control signal indicative of the signal to be amplified by the audio amplifier.
A charge pump circuit for supplying one or more supply voltages to an audio amplifier circuit, said charge pump circuit comprising:
- a switch array for providing, in use, a plurality of switch connections;
- wherein at least a first switch connection comprises a plurality of parallel switches configured such that the energy required to operate the first switch connection can be varied in use;
- and
- wherein said charge pump circuit is configured to selectively vary the parallel switches used for said first switch connection based on an input signal for said audio amplifier circuit.
Dependencies are inferred from the claim text.