N-way Doherty distributed power amplifier with power tracking
First Claim
1. A power tracking system for power amplifiers comprising:
- an N-way Doherty distributed amplifier comprising a power splitter with a plurality of outputs and N amplifiers, wherein N is an integer of three or more and an output of the plurality of outputs is coupled to a plurality of the N amplifiers;
an RF input;
power detection circuitry responsive to a signal representative of the RF input; and
adaptive bias supply circuitry responsive to the power detection circuitry for adjusting DC bias applied to the N-way Doherty distributed amplifier in accordance with variations in the RF input.
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Accused Products
Abstract
A power amplifier using N-way Doherty structure with adaptive bias supply power tracking for extending the efficiency region over the high peak-to-average power ratio of the multiplexing modulated signals such as wideband code division multiple access and orthogonal frequency division multiplexing is disclosed. In an embodiment, the present invention uses a dual-feed distributed structure to an N-way Doherty amplifier to improve the isolation between at least one main amplifier and at least one peaking amplifier and, and also to improve both gain and efficiency performance at high output back-off power. Hybrid couplers can be used at either or both of the input and output. In at least some implementations, circuit space is also conserved due to the integration of amplification, power splitting and combining.
230 Citations
27 Claims
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1. A power tracking system for power amplifiers comprising:
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an N-way Doherty distributed amplifier comprising a power splitter with a plurality of outputs and N amplifiers, wherein N is an integer of three or more and an output of the plurality of outputs is coupled to a plurality of the N amplifiers; an RF input; power detection circuitry responsive to a signal representative of the RF input; and adaptive bias supply circuitry responsive to the power detection circuitry for adjusting DC bias applied to the N-way Doherty distributed amplifier in accordance with variations in the RF input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for processing an RF input, the method comprising:
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dividing the RF input into a plurality of resultant signals; routing at least one of the resultant signals to a main amplifier; routing another of the resultant signals to a plurality of peaking amplifiers; detecting a power variable of a signal representative of the RF input; and adaptively controlling one or more bias voltages of at least one of the amplifiers based at least partly on the power variable, wherein the main and peaking amplifiers are amplifiers in an N-way Doherty distributed amplifier. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification