MB3875 Datasheet, PDF (16/27 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging

MB3875/MB3877
s METHOD OF SETTING THE CHARGING CURRENT
The charge current (output control current) value can be set with the voltage at the +INE2 terminal.
If a current exceeding the set value attempts to flow, the charge voltage drops according to the set current value.
Battery charge current setting voltage
+INE2 (V) = 25 × I1 (A) × RS (Ω)
s METHOD OF SETTING THE SOFT START TIME
Upon activation, the IC starts charging the capacitor (Cs) connected to the CS terminal (pin 22).
The error amplifier causes soft start operation to be performed with the output voltage in proportion to the CS
pin voltage regardless of the load current of the DC/DC converter.
Soft start time ts (Time taken for the output voltage to reach 100 %)
ts (s) =: 4.2 × CS (µF)
s METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATOR FREQUENCY SETTING
The trianguar wave oscillator frequency can be set by the timing resistor (RT) connected the RT terminal (pin 17).
Triangular wave oscillator frequency fOSC
fOSC (kHz) =: 14444 / RT (kΩ)
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