Buck energy storage inductor

Why do buck regulators use double duty energy storage inductors?

The energy storage inductor in a buck regulator functions as both an energy conversion element and as an output ripple filter. This double duty often saves the cost of an additional output filter, but it complicates the process of finding a good compromise for the value of the inductor.

How do you choose a buck converter inductor?

Key considerations in inductor selection include: Inductance—the rated value of the inductor and its impact on the ripple current in the buck converter. DC current rating—translated from the output current needs of the buck converter, the DC current rating is linked directly to the temperature rise of the inductor and its DC resistance (DCR).

What is a high inductance Buck regulator?

A high inductance reduces ΔI and results in lower ‘r' (and lower RMS current in the output capacitor), but may result in a very large and impractical inductor. So typically, for most buck regulators, ‘r' is chosen to be in the range of 0.25–0.5 (at the maximum rated load). See Appendix A.

What is a peak inductor current in a buck regulator?

Peak inductor current in a buck regulator with continuous mode operation is: The core used for L1 must be able to handle 3.93A peak current without saturating. Peak inductor currents in discontinuous mode are much higher than output current: The 10μH inductor, at 1A output current, must be sized to handle 4.14A peak current.

How much energy does a buck boost inductor handle?

A Buck-Boost inductor has to handle all the energy coming toward it — 50 μJ as per Figure 5.4, corresponding to 50 W at a switching frequency of 1 MHz. Note: To be more precise for the general case of η≤1: the power converter has to handle P IN /f if we use the conservative model in Figure 5.1, but only P O /f if we use the optimistic model.

How does a buck converter regulated output voltage?

The output voltage on each isolated output would track the buck converter regulated output voltage scaled by the corresponding turns-ratio. The isolated rails are therefore only ‘indirectly’ regulated, and the parasitic elements of real components can easily degrade the voltage regulation of the isolated outputs.