A novel control design approach for average current-mode controlled bu
ck converters is presented. The buck converter large-signal averaged m
odel is shown to be easily large-signal linearisable, The linear model
is then examined as a multivariable system with no inner and outer lo
ops, using both the state-space and frequency domain descriptions, Tra
nsfer functions of the system are derived as a function of the desired
closed-loop poles, simplifying the design procedure and bringing forw
ard all the important characteristics of the closed-loop system, Sever
al advantages can be gained by the use of capacitor current instead of
inductor current feedback, Theoretical analysis is applied and confir
med with simulation and experimental results on a 250 W prototype, The
proposed approach can be used with all small-signal linear models of
DC-DC converters, offering simplicity and a better insight on system c
haracteristics.