Steady-state analysis including parasitic components and switching losses of buck and boost DC-DC PWM converters under any operating condition

A detailed analysis of DC-DC buck and boost converters operated both in continuous and discontinuous current modes is reported. Expressions for the voltage transfer functions and efficiencies of these two basic topologies have been derived in a closed form. These equations describe the converter behaviour for both constant output voltage and constant input voltage operation. Voltage transfer functions are derived so that the load regulation characteristics of the converters are closely described, including those for continuous current mode operation. Because of this, they can be effectively used to design a converter circuit responding to any given design specification. Both the equations for the efficiencies and voltage transfer functions are general and the values of the parasitic parameters to be introduced can be found on the component data sheets or derived from simple measurements. Because of this, results of the analysis presented can be effectively used in the optimization of the converter circuit performances. The general approach to the analysis of power converters including parasitic components given in the paper can be applied to any power converter circuit. Theoretical derivations are in good agreement with the results of computer simulations performed by using the PSpice program.