Multiphase buck converter with minimum time control strategy for RF envelope modulation

P. M. Cheng, M. Vasic, O. Garcia, J. A. Oliver, P. Alou, J. A. Cobos
2011 2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)  
Power amplifier supplied with constant supply voltage has very low efficiency in the transmitter. A DC-DC converter in series with a linear regulator can be used to obtain voltage modulation. Since this converter should be able to change the output voltage very fast, a multiphase buck converter with a minimum time control strategy is proposed. To modulate supply voltage of the envelope amplifier, the multiphase converter works with some particular duty cycle (i/n, i=l, 2 ... n, n is the number
more » ... f phase) to generate discrete output voltages, and in these duty cycles the output current ripple can be completely cancelled. The transition times for the minimum time are pre-calculated and inserted in a look-up table. The theoretical background, the system model that is necessary in order to calculate the transition times and the experimental results obtained with a 4-phase buck prototype are given. I. input coupler phase reference ,. Non linear RF PA J ill ||i li Ml i •• Input detector ## Power Supply rr\ Envelope Amplifier Figure 1. Block schematic of a tranismitter based on Kahn's technique
doi:10.1109/apec.2011.5744702 fatcat:wnh6mfvnhvcrhoihasduq6av54