MB3887 Datasheet, PDF (20/33 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging Li-ion battery

MB3887
■ AC ADAPTOR VOLTAGE DETECTION
With an external resistor connected to the +INE2 terminal (pin 3) , the IC enters the dynamically-controlled
charging mode to reduce the charge current to keep AC adapter power constant when the partial potential point
A of the AC adapter voltage (VCC) becomes lower than the voltage at the −INE2 terminal.
AC adapter detection voltage setting : Vth
Vth (V) = (R1 + R2) / R2 × −INE2
VCC
−INE2
4
A
3
R1 +INE2
R2
<Error Amp2>
−
+
■ OPERATION TIMING DIAGRAM
Error Amp2 FB2
Error Amp1 FB1
Error Amp2 FB3
OUT
2.5 V
1.5 V
Constant voltage control
Constant current control
AC adapter dynamically-
controlled charging
20