SNVS715B March 2011 – June 2019 LM21212-2
PRODUCTION DATA.
The inductor (L) used in the application will influence the ripple current and the efficiency of the system. The first selection criteria is to define a ripple current, ΔIL. In a buck converter, it is typically selected to run between 20% to 30% of the maximum output current. Figure 25 shows the ripple current in a standard buck converter operating in continuous conduction mode. Larger ripple current results in a smaller inductance value, which will lead to lower inductor series resistance, and improved efficiency. However, larger ripple current will also cause the device to operate in discontinuous conduction mode at a higher average output current.
Once the ripple current has been determined, the appropriate inductor size can be calculated using the following equation: