CAD-based Capacitors Selection for Switching Regulators

This paper discusses a practical method to select filter capacitors for DC-DC power converters. The model adopted accounts for the correlation existing between the capacitance C and the equivalent series resistance (ESR) of real capacitors and provides a reliable design method for the choice of commercial components. The method relies on closed form solutions to evaluate capacitors peak to peak voltage ripple. Hence, it can be of great help for the development of computationally efficient CAD tools. The application of the method is illustrated for the design of capacitors in SEPIC topology complying with maximum acceptable steady-state voltage ripple. Experimental tests validate the method.