Duty cycle generator for average model of buck converter with current-mode control-using analog behavioral modeling of PSpice

This paper presents a duty cycle generator for an average model of buck converter with current-mode control, which can simultaneously deal with both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). First, a duty cycle generator is mathematically derived, considering the transient-state of the current-loop. This technique plays an important role when the operating modes are changed under a considerable amount of step load change. Second, taking advantage of the analog behavioral modeling of PSpice, duty cycle generators for both the time and frequency domain analyses are built into a PSpice file. The accuracy of these models is verified through the computer simulations, which is compared to the actual circuit for the time domain analysis and the small signal model for the frequency analysis.