MB39A114 Datasheet, PDF (18/54 Pages) Fuji Electric – DC/DC Converter IC for Charging Li-ion Battery

MB39A114
(2) AC adapter detection block (UV Comp.)
This block detects that power-supply voltage (VCC) is lower than the battery voltage +0.2 V (Typ) , and OUT
terminal (pin 18) is fixed at the High level. The system restores voltage supply when the supply voltage reaches
the threshold voltage of the AC adapter detection block.
Protection circuit (UV Comp.) operation function table.
At UV Comp. operating (VCC voltage is lower than UV Comp. threshold voltage.)
OUT
CS
H
L
3. Soft start Function
Soft start block (SOFT)
Connecting a capacitor to the CS terminal (pin 22) prevents rush currents from flowing upon activation of the
power supply. Using the error amplifier to detect a soft start allows to soft-start at constant setting time intervals
independent of the output load of the DC/DC converter.
4. Detection Function
(1) Constant voltage control state detection block. (CV Comp.)
Error amplifier (Error Amp3) detects the voltage at FB3 terminal (pin 15) falling to or below 2.6 V (Typ) and
outputs the Low level to the constant voltage control state detection block output terminal (CVM, pin 5) .
(2) Overvoltage state detection block (OV Comp.)
Error amplifier (Error Amp3) detects the voltage at FB3 terminal (pin 15) falling to or below 1.3 V (Typ) and
outputs the High level to the overvoltage detection block output terminal (OVP, pin 18) .
5. Switching function
Output voltage switching function block (SEL)
The charge voltage is set in 16.8 V or 12.6 V by SEL terminal (pin 11) .
SEL function table
SEL
DC/DC output setting voltage
H
16.8 V
L
12.6 V
18