Fujitsu MB3887 Datasheet page 20

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)
OPERATION TIMING DIAGRAM
Error Amp2 FB2
Error Amp1 FB1
Error Amp2 FB3
OUT
Constant voltage control
20
R2 INE2
INE2
4
A
VCC 3
R1 INE2
R2
<Error Amp2>
Constant current control
2.5 V
1.5 V
AC adapter dynamically-
controlled charging