Fig. 5 shows the current ratio between two sources with
the duty-ratio. The input currents are equal to each other when
the duty-ratio is 50 %. Iin1 is larger than Iin2 when the dutyratio
is less than 50 %. Inversely, Iin1 is smaller than Iin2 when
the duty-ratio is higher than 50 %.
B. Discontinuous Conduction Mode
When the power converter is operated at the DCM, the
inductor current decreases from the peak to zero, during S has
been turned off. The duty-ratio for decreasing the inductor
current is denoted by d’. Then, the relationship between the
two input voltage and the output voltage can be obtained as