Improvements in switching regulator circuits

摘要

A current-mode switching regulator is disclosed, comprising at least: an inductor; a main switch for controlling the current flow through the inductor; and a feedback control circuit for operating the main switch cyclically and to vary a duty cycle of the main switch so as to substantially maintain an output voltage of the regulator at a desired level. The feedback control circuit further includes slope compensation circuitry adding slope compensation to a signal representing the inductor current prior to the slope compensated signal being compared to the fed-back output error voltage. Said regulator further comprising current limiting circuitry for controlling the main switch responsive to a current limit reference signal, said current limit circuitry comprising adjustment circuitry for adjusting the current limit reference signal in response to the duty cycle of more than one previous cycle so as to limit current in the inductor irrespective of said output voltage and to a value which, in the steady state, is substantially independent of the duty cycle.