MB3878 Fujitsu Media Devices, MB3878 Datasheet - Page 15

• Manufacturer Part Number: MB3878
• Description: DC/DC Converter IC for Charging
• Manufacturer: Fujitsu Media Devices

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 adaptor power constant when the partial potential point
A of the AC adaptor voltage (Vcc) becomes lower than the voltage at the -INE2 terminal.
AC adaptor detected voltage setting: Vth
Vth (V)
OPERATION TIMING DIAGRAM
Error Amp.1
Error Amp.3
Error Amp.2
OUT
INE2 setting voltage range : 1.176 V to 4.2 V (equivalent to 7 V to 25 V for Vcc)
controlled charging
AC adaptor dynamically-
FB1
FB3
FB2
(R1
R2)
V
CC
R2
R1
R2
INE2
Constant
voltage control
A
INE2
INE2
4
3
Constant current control
<Error Amp.2>
AC adaptor dynamically-
controlled charging
MB3878
2.5 V
1.5 V
15