MB39A125 Datasheet, PDF (53/64 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging Li-ion Battery

MB39A125/126
12.6 V output
Vo
Io ≥
tOFF
2L
12.6
≥
2 × 15 × 10^−6
≥ 0.60 A
1
×
× (1 − 0.572)
300 × 10³
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 affects 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
≥ 3+
25−16.8
2 × 15 × 10^−6
≥ 3.6 A
1
×
× 0.672
300 × 10³
12.6 V output
VIN − Vo
IL ≥ Io +
tON
2L
≥ 3+
22 − 12.6
2 × 15 × 10^−6
≥ 3.6 A
1
×
× 0.572
300 × 10³
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