Constant gain nonlinear envelope tracking high efficiency linear amplifier
First Claim
1. A power amplifier system, comprising:
- an input for receiving an RF input signal including a modulated RF carrier having a dynamically varying envelope;
an RF amplifier receiving and amplifying the RF input signal including said carrier and envelope, the RF amplifier having a power supply input and the RF amplifier having a saturation region;
a DC power supply;
a variable power supply circuit coupled to the input, the DC power supply and the RF amplifier power supply input for providing a supply voltage to the RF amplifier which increases with the input signal power to maintain substantially constant RF amplifier gain up to the beginning of said amplifier saturation region; and
a phase compensation circuit coupled to the input for adjusting the phase of the input signal to compensate for phase variations due to the variable power supply.
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Accused Products
Abstract
An envelope tracking radio frequency (RF) power amplifier having an adaptive envelope signal processing circuit is disclosed. An RF input voltage is sampled by the adaptive envelope signal processing circuit which provides control signals to the power supply which supplies voltages to RF power devices in order to simultaneously satisfy two operating conditions: a) provide best possible efficiency of the power amplifier stages depending on the input signal characteristics and b) provide compensation for RF transistor AM-AM and AM-PM distortion compensation across the power range. In particular, the voltage control provides for constant power amplifier gain across the input signal dynamic range, thus minimizing power amplifier amplitude distortions and extending the useful power amplifier linear dynamic range up to saturation point. The power amplifier thus exhibits better linearity and efficiency than offered by conventional techniques and topologies.
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Citations
20 Claims
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1. A power amplifier system, comprising:
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an input for receiving an RF input signal including a modulated RF carrier having a dynamically varying envelope;
an RF amplifier receiving and amplifying the RF input signal including said carrier and envelope, the RF amplifier having a power supply input and the RF amplifier having a saturation region;
a DC power supply;
a variable power supply circuit coupled to the input, the DC power supply and the RF amplifier power supply input for providing a supply voltage to the RF amplifier which increases with the input signal power to maintain substantially constant RF amplifier gain up to the beginning of said amplifier saturation region; and
a phase compensation circuit coupled to the input for adjusting the phase of the input signal to compensate for phase variations due to the variable power supply. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for amplifying a high frequency modulated signal, comprising:
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receiving a high frequency modulated input signal having a carrier and a dynamically varying envelope providing a varying input signal power;
amplifying said high frequency modulated input signal, including said carrier and varying envelope, with a power amplifier module, said power amplifier module having a saturation region;
providing a DC supply voltage to said power amplifier module;
detecting a signal related to the power of the high frequency modulated input signal;
controlling the DC supply voltage of said power amplifier module in response to the detected signal to maintain substantially constant gain up to the beginning of said saturation region; and
adjusting the phase of the input signal to compensate for phase variations introduced by controlling the supply voltage of the power amplifier module. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for amplifying a high frequency modulated signal, comprising:
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receiving a high frequency modulated input signal having a carrier and a dynamically varying envelope providing a varying input signal power;
amplifying said high frequency modulated input signal, including said carrier and varying envelope, with a power amplifier module, said power amplifier module having a saturation region;
detecting a signal related to the power of the high frequency modulated input signal;
providing a variable DC supply voltage to said power amplifier module in response to the detected signal which continuously increases in a higher power input signal range extending up to the beginning of said saturation region; and
adjusting the phase of said input signal with a continuously increasing phase adjustment in said higher power signal range;
wherein the gain and phase are maintained substantially constant up to the beginning of said saturation region. - View Dependent Claims (17, 18, 19, 20)
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Specification