Asymmetric multilevel backoff amplifier with radio-frequency splitter
A radio frequency (RF) amplification system or transmitter includes one or more power amplifiers and a controller that is configured to adjust amplitudes and phases of RF input signals of the one or more power amplifiers and supply voltages applied to the one or more power amplifiers. The system may include a single digital-to-RF modulator and a power divider to drive multiple power amplifiers. A power combiner may also be provided to combine outputs of the power amplifiers. In at least one implementation, amplitude adjustment of the RF input signals of the one or more power amplifiers may be used to provide transmit power control and/or power backoff.
1. A radio frequency (RF) amplification system, comprising:
a digital-to-RF modulator to generate a modulated RF signal based on input information indicative of amplitude values and phase values;
a plurality of RF amplifiers;
an RF power divider to split the modulated RF signal into a plurality of RF input signals for the plurality of RF amplifiers;
at least one voltage control unit to provide variable supply voltages to the plurality of RF amplifiers in response to at least one control signal; and
a controller to receive input data and to provide input information to the digital-to-RF modulator and the at least one control signal to the at least one voltage control unit based, at least in part, upon the received input data.
2. The RF amplification system of claim 1 further comprising an RF power combiner to combine amplified RF signals received from the plurality of RF amplifiers into a combined signal.
3. The RF amplification system of claim 2 wherein the RF power divider is configured to split the modulated RF signal into a plurality of RF signals having relative phases delays and wherein the RF power combiner is configured to match the relative phase delays such that the amplified RF signals are combined in phase.
4. The RF amplification system of claim 2 wherein the RF power divider comprises a Wilkinson divider, a transmission-line splitter, a lumped-element splitting network, or a hybrid coupler.
5. The amplification system of claim 2 wherein the RF power combiner comprises a Wilkinson combiner, a hybrid combiner, a Chireix combiner, a non-isolating combiner, transmission lines, a lumped-element reactive combiner, or a Doherty combiner.
6. The amplification system of claim 2 wherein the RF power divider is configured to split the modulated RF signal into a first RF signal having a first power level and a second RF signal having a second power level.
7. The amplification system of claim 6 wherein the first and second power levels are selected based upon power ratings for a first and second one of the plurality of RF amplifiers, respectively.
8. The RF amplification system of claim 2 wherein the at least one voltage control unit is configured to provide variable supply voltages selected from a plurality of discrete voltage levels.
9. The RF amplification system of claim 8 wherein the at least one voltage control unit is configured to generate the discrete voltage levels using a single-input, multiple-output power converter.
10. The RF amplification system of claim 9 wherein the single-input, multiple-output power converter is provided as a switched-capacitor converter, a resonant switched-capacitor converter, or a single-inductor multiple-output converter.
11. The RF amplification system of claim 8 wherein the at least one voltage control unit comprises transition shaping filters.
12. The RF amplification system of claim 2 comprising a plurality of voltage control units to provide variable supply voltages to respective ones of the plurality of RF amplifiers.
13. A radio frequency (RF) amplification system, comprising:
a digital-to-RF modulator having a digital input port and an RF output port;
a plurality of RF amplifiers, each of the RF amplifiers having an RF input port and an RF output port;
an RF power divider having an RF input port coupled to the RF output port of the digital-to-RF modulator and having a like plurality of RF output ports with each of the RF output ports coupled to an RF input port of a respective one of the plurality of RF amplifiers;
at least one voltage control unit to provide variable supply voltages to selected ones of the plurality of RF amplifiers in response to at least one control signal; and
a controller to receive input data and to provide input information to the digital-to-RF modulator and the at least one control signal to the at least one voltage control unit based, at least in part, upon the received input data.
14. The RF amplification system of claim 13 further comprising an RF power combiner to combine amplified RF signals received from the plurality of RF amplifiers into a combined signal.
15. The RF amplification system of claim 14 wherein the RF power divider is configured to split the modulated RF signal into a plurality of RF signals having relative phases delays and wherein the RF power combiner is configured to match the relative phase delays such that the amplified RF signals are combined in phase.
16. The RF amplification system of claim 14 wherein the RF power divider comprises a Wilkinson divider, a transmission-line splitter, a lumped-element splitting network, or a hybrid coupler.
17. The amplification system of claim 14 wherein the RF power combiner comprises a Wilkinson combiner, a hybrid combiner, a Chireix combiner, a non-isolating combiner, transmission lines, a lumped-element reactive combiner, or a Doherty combiner.
18. The amplification system of claim 14 wherein the RF power divider is configured to split the modulated RF signal into a first RF signal having a first power level and a second RF signal having a second power level.
19. The amplification system of claim 18 wherein the first and second power levels are selected based upon power ratings for a first and second one of the plurality of RF amplifiers, respectively.
20. The RF amplification system of claim 14 wherein the at least one voltage control unit is configured to provide variable supply voltages selected from a plurality of discrete voltage levels.
21. The RF amplification system of claim 20 wherein the at least one voltage control unit is configured to generate the discrete voltage levels using a single-input, multiple-output power converter.
22. The RF amplification system of claim 21 wherein the single-input, multiple-output power converter is provided as a switched-capacitor converter, a resonant switched-capacitor converter, or a single-inductor multiple-output converter.
23. The RF amplification system of claim 20 wherein the at least one voltage control unit comprises transition shaping filters.
24. The RF amplification system of claim 14 comprising a plurality of voltage control units to provide variable supply voltages to respective ones of the plurality of RF amplifiers.