Multi-mode amplifier system
First Claim
1. An amplifier system comprising:
- a power amplifier operative to amplify an input signal, the power amplifier having an input terminal and a supply terminal, the power amplifier being a linear class type amplifier that operates as a constant class amplifier; and
a mode selector that controls the operation of the amplifier system between an envelope tracking mode, a polar mode and a linear mode by providing a selected amplifier input to the input terminal and a selected amplifier supply signal to the supply terminal based on a characteristic of the input signal.
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Accused Products
Abstract
An amplifier system is provided that switches between a linear mode of operation, an envelope tracking mode of operation and a polar mode of operation. The amplifier system switches between modes of operation based upon a characteristic of an input signal relative to a first threshold level and a second threshold level. A mode selector selects the operation mode by transmitting an amplitude modulated signal plus a variable headroom voltage to a supply terminal of a power amplifier during the envelope tracking mode, an amplitude modulated signal to the supply terminal and phase modulated input signal during the polar mode and a substantially constant amplitude signal to the supply terminal during the linear mode.
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Citations
28 Claims
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1. An amplifier system comprising:
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a power amplifier operative to amplify an input signal, the power amplifier having an input terminal and a supply terminal, the power amplifier being a linear class type amplifier that operates as a constant class amplifier; and a mode selector that controls the operation of the amplifier system between an envelope tracking mode, a polar mode and a linear mode by providing a selected amplifier input to the input terminal and a selected amplifier supply signal to the supply terminal based on a characteristic of the input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An amplifier system comprising:
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a power amplifier; a modulation amplifier having an output coupled to a supply terminal of the power amplifier; a first digital-to-analog converter (DAC) coupled to an input terminal of the power amplifier; a second DAC coupled to an input terminal of the modulation amplifier; and a digital system having a first output coupled to an input of the first DAC and a second output coupled to the input of the second DAC, the digital system controls the operation of the amplifier system between an envelope tracking mode, a polar mode and a linear mode based on an amplitude level of an input signal, the amplifier system operates in the linear mode for low amplitude level input signals below about a first threshold level, the polar mode for peak level input signals above about a second threshold level, and in the envelope tracking mode for signals between about the first threshold level and the second threshold level, the second threshold level having an amplitude substantially equal to a headroom voltage below a peak voltage of the input signal, the headroom voltage being associated with the envelope tracking mode. - View Dependent Claims (15, 16, 17, 18)
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19. An amplifier system comprising:
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means for amplifying a phase and/or amplitude modulated input signal; and means for switching modes of operation of the amplifier system between an envelope tracking mode, a polar mode and a linear mode based on an amplitude level of the input signal relative to a first threshold level and a second threshold level, the amplifier system operates in the linear mode for input signal amplitudes below about the first threshold level, the polar mode for input signal amplitudes above about the second threshold level, and in the envelope tracking mode for input signal amplitudes between about the first threshold level and about the second threshold level, the second threshold level having an amplitude substantially equal to a headroom voltage below a peak voltage of the input signal, the headroom voltage being associated with the envelope tracking mode. - View Dependent Claims (20, 21, 22)
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23. A method of amplifying an input signal with a power amplifier, the method comprising:
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switching modes of operation of the power amplifier between envelope tracking mode, polar mode and linear mode based on a characteristic of the input signal relative to a first threshold level and a second threshold level; transmitting a composite signal to the input terminal and a variable amplitude signal with a headroom amplitude that ensures the amplifier is not significantly in the gain compression region during envelope tracking mode operation, transmitting a phase modulated component of the input signal to an input terminal of a power amplifier and an amplitude modulated component of the input signal to a supply terminal of the power amplifier during polar mode operation, and transmitting a composite signal to the input terminal and a constant amplitude component to the supply terminal during linear mode operation, the second threshold level being substantially equal to the headroom amplitude below a peak voltage of the input signal; and amplifying the input signal via the power amplifier. - View Dependent Claims (24, 25, 26, 27)
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28. An amplifier system comprising:
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a power amplifier operative to amplify an input signal, the power amplifier having an input terminal and a supply terminal; a mode selector that controls the operation of the amplifier system between an envelope tracking mode, a polar mode and a linear mode by providing a selected amplifier input to the input terminal and a selected amplifier supply signal to the supply terminal based on a characteristic of the input signal; and a digital cross-cancellation component that generates a reference signal corresponding to a desired output signal of the amplifier system, the reference signal being combined with a portion of an output signal from the power amplifier to determine an error signal, the error signal being inverted and combined with a delayed version of the output signal of the power amplifier to generate a final output signal.
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Specification