Load current estimation for control algorithms in buck converter

In this paper a switching load current estimator for a buck converter is introduced. By combining two estimation principles in a single estimator, both a fast response and a high accuracy of the load current estimation can be obtained. The controller of the buck converter then uses this estimated load current, enabling it to respond fast on load changes and regulate the output voltage with high accuracy. Detailed descriptions of both types of estimation, their behavior and their combination are given. The load current estimator and the state feedback control algorithm have been implemented in a FPGA device. Experimental results from a buck converter controlled by the state feedback algorithm using the proposed switching load current estimator are presented