Envelope Tracking Power Supply Based On Multiphase Switching Converter

The development of mobile communication industry is very fast, and a better performance requirement for the conventional RFPA with constant voltage supply is needed under the new modulation methods, while the envelope tracking technology can meet this demand and improve the efficiency of the RFPA. Switching converter used for envelope tracking can be very efficient, and multiphase interleaving technology can improve the switching frequency equivalently. This paper is mainly focused on the multiphase interleaved Buck circuits applied to envelope tracking.Simulation and analysis of the maximum shearing frequency when three different kinds of compensators are applied to Buck converter is finished. Buck converter using three different kinds of compensators is simulated for envelope tracking, and is analyzed for the maximum tracking bandwidth. The conclusion is that the higher shearing frequency can make the circuits’ dynamic performance better, and the converter can tracks higher frequency signal.Analyzing the relationship between the shearing frequency and the frequency of the multiphase buck converter. Simulating multiphase Buck converter applied to envelope tracking, verifying the tracking bandwidth improvement of the multiphase Buck converter.The application of high order filter in envelope tracking is studied. This thesis applies high order filter to the multiphase interleaved Buck, with the ripple cancellation effect of high order filter and multiphase interleaving technology, the system can achieve high tracking bandwidth. This paper designs the high order filter for a two phase Buck converter, and the design requirement for tracking bandwidth is validated by simulation. An modified closed-loop method is used for two phase buck converter with high order filter and the simulation is performed to verify its effectiveness.Finally, the circuits platform is designed, and the single Buck envelope tracking experiment, four-phase interleaved Buck envelope tracking experiment are performed. The tracking of several types envelope signals include OFDM signal are tested by the experiment platform, and the good tracking performance is verified by calculating the delay time and the normalized mean square error of the output signal.