Cascaded buck converter: A reexamination

Cascaded buck converter has been widely reported in the power electronics literature. The main features are a high voltage step-down ratio and large regulation range. Modeling of this converter has been also reported for a two and n stage cases. Continuous conduction mode (CCM), same switching commutation instant (D1= D2), and similar behavior than a single buck stage have been considered to size its parameters. In addition, it has been reported that once a duty cycle is close to 0 or 1, a degradation of the output voltage and inductor current take place. However, a little effort has been done to correctly size its parameters when they commutate at the same or different switching rates (D1= D2, D1<; D2, D1> D2), and it maintains a final voltage step-down ratio. Therefore, this paper reports the design stages to size its parameters in CCM for the overall cases (D1=D2, D1<; D2 and D1> D2). Numerical simulations for a two stage 100W buck converter are reported.