New Deadbeat Criterion for the Peak Current-mode Controlled Buck Converter

A new criterion is derived for the amount of compensating ramp needed for the deadbeat response of the constant-frequency, trailing-edge modulated, peak current-mode controlled buck converter in continuous conduction mode. The criterion is derived using modified z-transforms and verified experimentally. It is shown that the use of the new criterion results in a faster step-response than when the compensating ramp is set equal to the falling slope of the inductor current scaled by the current sensor gain.