Datasheet

16
LTC1479
APPLICATIONS INFORMATION
WUU
U
DCIN
DCIN
BAT1
BAT2
+
+
V
+
SW V
GG
1µF
50V
1µF
50V
1mH*
V
CC
+
R
SENSE

0.033Ω
SW A SW B
SW C SW D
SW E SW F
GA
330Ω
GB GC
GD GE GFSAB
SCD
SEF
SENSE
+
SENSE
–
2
5
+
V
CCP
2.2µF
16V
0.1µF
V
BAT
POWER
MANAGEMENT
µP
BDIV
V
BKUP
BACKUP
REGULATOR
LTC1538-AUX 
TRIPLE, HIGH EFFICIENCY,
SWITCHING REGULATOR
DCDIV
0.1µF
LTC1479
LT1510
Li-ION BATTERY
CHARGER
GG SG
GH SH
CHGMON
3.3V
5V
SW G
SW H
DCIN
Li-ION
BATTERY
PACK #1
Li-ION
BATTERY
PACK #2
1479 F08
BACKUP
NiCD
*COILCRAFT 1812LS-105 XKBC [phone]
12V AUX
R
B2
R
B1
R
DC2
R
DC1
cropower DC/DC converter. As shown in Figure 9, the
LT1304 monitors the input supply voltage and activates
when it drops below 6V.
Power for the DCIN and battery monitors and the logic
supply in the LTC1479 is then obtained from the output of
the LT1304 step-up regulator.
Charger System Interface
The LTC1479 is designed to work directly with constant-
voltage (CV), constant-current (CC) battery chargers such
as the LT1510 and LT1511.
LT1510 Battery Charger Interface
As illustrated in Figure 10, the LT1510 CV/CC battery
charger, takes power from the DC adapter input through
Schottky diode D1. The output of the charger is directed to
FROM 
PowerPath
CONTROLLER
BACKUP
NiCD
CELL
TO INPUT 
OF DC/DC 
CONVERTER
L1*
10µH
(BOLD LINES INDICATE HIGH CURRENT PATHS)
5V
CC

FROM 
DC/DC
D1 
MBR0530
R4
390k
1%
R5
100k
1%
SW
+
FB
SHDN
V
IN
GND
LT1304
C1
0.1µF
C3
0.1µF
I
LIM
R3
22k
LBI
R2
470k
4
8
7
3
5
1479 F09
C2
0.1µF
1
6
2
LBO
5V
CC

FROM
DC/DC
D2
BAS16LT1
Q1
2N7002
ROHM
DTA144E
R1
10k
Figure 9. LT1304 Micropower Backup Converter Circuit
Figure 8. Simplified Dual Li-Ion Battery Power Management System