MB3875_03 Datasheet, PDF (16/26 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging

MB3875/3877
s AC ADAPTER VOLTAGE DETECTION
With an external resistor connected to the +INE1 terminal, 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 -INE1 terminal.
AC adapter detected voltage setting Vth
Vth (V) = (R1 + R2) / R2 × − INE1
− INE1 setting voltage range : 1.176 V to 4.2 V (equivalent to 7 V to 25 V for Vcc)
−INE1
11
A
VCC
8
R1 +INE1
R2
<Error Amp.1>
−
+
s OPERATION TIMING DIAGRAM
Error Amp.2 FB2
Error Amp.3 FB3
Error Amp.1 FB1
OUT
AC adapter dynamically- Constant voltage
controlled charging
control
Constant current control
2.5 V
1.5 V
AC adapter dynamically-
controlled charging
16