MB39A106 Datasheet, PDF (35/46 Pages) Fujitsu Component Limited. – 2-Channel DC/DC Converter IC with Overcurrent Protection Symmetrical-Phase Type

MB39A106
CH1
IO ≥
VO
2L
toff
≥
3.3
2 × 22 × 10^−6
×
1
300 × 10³
×
(1−0.22)
≥ 195 mA
CH2
IO ≥
VO
2L
toff
≥
5
2 × 22 × 10^−6
×
1
300 × 10³
×
(1−0.33)
≥ 254 mA
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
IL
≥ IO +
VIN − VO
2L
ton
Peak-to-peak value : ∆IL
∆IL
=
VIN −
L
VO
ton
Example: Using the SLF12565T-220M3R5
22 µH (allowable tolerance ±20%) , rated current = 3.5 A
Peak value
CH1
IL ≥ IO
+
VIN (Max) −VO
2L
ton
≥3
+
15−3.3
2 × 22 × 10^−6
×
1
300 × 10³
× 0.22
≥ 3.20 A
CH2
IL ≥ IO +
VIN (Max) −VO
2L
ton
≥3+
15−5
2 × 22 × 10^−6
×
1
300 × 10³
× 0.33
≥ 3.25 A
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