Note that the switching regulator operation can be continuous
or discontinuous. When operating in continuous conduction mode
(CCM), the inductor current never drops to zero; when operating
in discontinuous conduction mode (DCM), the inductor current can
drop to zero. Low-power buck converters rarely operate in DCM.
The current ripple, shown as ΔIL in Figure 2, is typically designed
to be 20% to 50% of the nominal load current.