Feedback-loop computer aided design for PWM DC-DC converters operated in continuous conduction mode and its application for a buck converter

Dc and small-signal circuit models for the PWM buck converter operated in the continuous conduction mode (CCM) are given and applied to a buck converter. The model taking into account the parasitic components, such as the equivalent series resistance (ESR) of the filter inductor, the ESR of the filter capacitor, the transistor on-resistance, and the diode forward resistance and offset voltage. The dc voltage transfer function, the control-to-output transfer function, the input and the output impedance are automatically derived and plotted by means of a dedicated computer program. The main advantage of the proposed method is the application of a linear equivalent circuit of the converter considering the overall parasitic component to a simulation program, so that the feedback-loop is accurately designed with a computer aid.