MIC45205 Datasheet, PDF (16/31 Pages) Micrel Semiconductor – 26V/6A DC-to-DC Power Module

Micrel, Inc.
ΔI_L(PP) = Inductor current peak-to-peak, since the inductor
is integrated use Equation 4 to calculate the inductor
ripple current.
The peak-to-peak inductor current ripple is:
∆ I_L(PP)
=
V_OUT × (V_IN(max) − V_OUT )
V_IN(max) × f_sw × L
Eq. 4
The MIC45205 has a 1.0µH inductor integrated into the
module. In case of a hard short, the short limit is folded
down to allow an indefinite hard short on the output
without any destructive effect. It is mandatory to make
sure that the inductor current used to charge the output
capacitance during soft-start is under the folded short
limit; otherwise the supply will go in hiccup mode and
may not finish the soft-start successfully.
The MOSFET R_DS(ON) varies 30% to 40% with
temperature; therefore, it is recommended to add a 50%
margin to I_CLIM in Equation 3 to avoid false current limiting
due to increased MOSFET junction temperature rise.
With R15 = 1.37kΩ and C15 = 15pF, the typical output
current limit is 8A.
MIC45205
April 15, 2014
16
Revision 1.0