High linearity doherty communication amplifier with phase control
First Claim
1. A system for operating a power amplifier in a mobile handset, comprising:
- a carrier amplifier having a carrier input terminal and a carrier output terminal;
a peak amplifier having a peak input terminal, a peak output terminal and a control terminal for receiving a voltage control signal, the peak amplifier configured to vary at least one characteristic of the power amplifier based upon the voltage control signal;
an active phase shifter, coupled to the carrier input terminal and the peak input terminal, for generating a peak amplifier input signal delayed in phase from a carrier amplifier input signal; and
an output matching unit, coupled to the carrier output terminal and the peak output terminal, for transmitting a carrier output power signal and a peak output power signal and forming a power amplifier output power signal at a power amplifier output stage.
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Accused Products
Abstract
A high linearity Doherty power amplifier with phase delay generation and control via passive and active components. In one embodiment, phase delay generation and control is implemented by an active phase shifter comprising a lower differential unit for generating a first differential output signal, an upper differential unit for generating a second differential output signal, and a phase control unit for tuning a phase difference between the first and second differential output signals within a phase tolerance. In addition, to improve efficiency and linearity characteristics, the power amplifier receives a voltage control signal to bias a supplemental amplifier so that the power amplifier operates in a Doherty mode in a low output power range and in a non-Doherty mode in a high output power range.
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Citations
37 Claims
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1. A system for operating a power amplifier in a mobile handset, comprising:
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a carrier amplifier having a carrier input terminal and a carrier output terminal;
a peak amplifier having a peak input terminal, a peak output terminal and a control terminal for receiving a voltage control signal, the peak amplifier configured to vary at least one characteristic of the power amplifier based upon the voltage control signal;
an active phase shifter, coupled to the carrier input terminal and the peak input terminal, for generating a peak amplifier input signal delayed in phase from a carrier amplifier input signal; and
an output matching unit, coupled to the carrier output terminal and the peak output terminal, for transmitting a carrier output power signal and a peak output power signal and forming a power amplifier output power signal at a power amplifier output stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for providing phase control in a Doherty communication amplifier, the Doherty communication amplifier including a carrier amplifier and a peak amplifier, comprising:
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processing an input signal via an active phase shifter to generate a differential output, the differential output further comprising a first differential output signal and a second differential output signal, the first differential output signal and the second differential output signal having a phase difference; and
tuning the phase difference to within a phase tolerance based upon input signal characteristics. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A system for providing phase control in a Doherty communication amplifier, the Doherty communication amplifier including a carrier amplifier and a peak amplifier, comprising:
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means for processing an input signal via an active phase shifter to generate a differential output, the differential output further comprising a first differential output signal and a second differential output signal, the first differential output signal and the second differential output signal having a phase difference; and
means for tuning the phase difference to within a phase tolerance based upon input signal characteristics. - View Dependent Claims (34, 35, 36, 37)
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Specification