MB39A114 Datasheet, PDF (36/54 Pages) Fuji Electric – DC/DC Converter IC for Charging Li-ion Battery

MB39A114
To determine whether the current through the inductor is within rated values, it is necessary to determine the
peak value of the ripple current as well as the peak-to-peak values of the ripple current that affect the output
ripple voltage. The peak value and peak-to-peak value of the ripple current can be determined by the following
formulas.
Peak Value : IL
VIN − Vo
IL ≥ Io +
tON
2L
Peak-to-peak Value :
∆IL
VIN − Vo
∆IL =
tON
L
Example) Using the CDRH104R-150
15 µH (tolerance ± 30%) , rated current = 3.6 A
Peak Value
16.8 V output
VIN − Vo
IL ≥ Io +
tON
2L
25 − 16.8
1
≥ 3+
×
× 0.672
2 × 15 × 10^−6
300 × 10³
≥ 3.6 A
12.6 V output
VIN − Vo
IL ≥ Io +
tON
2L
22 − 12.6
≥ 3+
×
2 × 15 × 10^−6
≥ 3.6 A
1
300 × 10³
× 0.572
Peak-to-peak Value
16.8 V output
VIN − Vo
∆IL =
tON
L
25 − 16.8
1
=
×
× 0.672
15 × 10^−6
300 × 10³
=: 1.22 A
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