Research On Generating Method Of Reference Power Source For Tracking Envelope Of RF Power Amplifier

The rapid development of communication modulation technology increases the rate of data transmission and the amount of information carried per unit signal.However,it also leads to higher peak-to-average ratio and bandwidth of RF envelope signal and greater amplitude variation.If the traditional constant voltage power supply mode is used,the efficiency of RF power amplifier will be reduced and a lot of energy will be wasted.The output voltage can be dynamically adjusted by using Envelope Tracking(ET)power supply to realize envelope tracking fitting of RF signal,thus greatly improving the efficiency of RF power amplifier.Currently,the composite architecture of switching converter and linear amplifier is the mainstream direction of ET power supply development.Multiple switching converters with different bandwidths have higher efficiency than single switching converters when processing highbandwidth envelope signals.In this paper,a novel generation method of RF power amplifier envelope tracking power source is proposed.Taking the combination of low bandwidth and high bandwidth switching converter ET power source as an example,a valley weighted average generation reference strategy is proposed for low bandwidth switching converter,which is used to track the energy of low bandwidth envelope reference signal.In this paper,the strategy of high bandwidth switching converter is proposed to track the energy of high bandwidth envelope signal.In order to improve the linearity of ET power supply,class AB linear power amplifier is used in this paper to supplement or release the energy provided by the switching converter,so that the voltage waveform can better track RF envelope signals.In this paper,FPGA is used to process the signal flow,and the peak and valley value information of envelope signal is used to generate the reference signal,which greatly reduces the memory occupation,reduces the total consumption of logical resources,and improves the computing processing speed of the reference generation.Finally,an experimental prototype with an envelope tracking bandwidth of 667 k Hz,a peak output power of 44 W and an output voltage range of 0-22.5V was built in the laboratory for experimental verification.The experimental results verified the correctness and effectiveness of the proposed research method and strategy.