MB39A119 Datasheet, PDF (25/53 Pages) Fujitsu Component Limited. – DC/DC Converter IC of Synchronous Rectification for charging Li-ion battery

MB39A119
(2) Automatic changing system power supply between AC adapter and battery
The AC adapter voltage is detected, and the external switch at input side and battery side is changed automat-
ically with the connection as follows. Connect CTL terminal (pin 21) to VCC terminal (pin 1) for this function.
OFF duty cycle becomes 100 % when CS terminal (pin 17) voltage is made to be 0 V, if it is needed after full
charge.
• Connection example of automatic changing system power supply between AC adapter and battery
System
AC adapter
ACIN
4
ACOK
XACOK
5
22
<AC Comp.>
+
−
MMiiccoonn
VCC
1
CTL
21
<SOFT>
VREF
CS
17
10 µA
Battery
(3) Battery selector function
When control signal from microcomputer etc. is input to ACIN terminal (pin 4) below, ACOK terminal (pin 5)
output voltage and XACOK terminal (pin 22) output voltage are controlled to select one of the two batteries for
charge. Connect CTL terminal (pin 21) to VCC terminal (pin 1) for this function. OFF duty cycle becomes 100
% when CS terminal (pin 17) voltage is made to be 0 V, if it is needed after full charge.
• Connection example of battery selector function
AC
adapter
ACIN
4
ACOK XACOK
5
22
<AC Comp.>
+
−
Micon
VCC ₁
CTL ₂₁
<SOFT>
VREF
CS
17
10 µA
System
AB
Ichg
RS1
Battery1 Battery2
25