LTC4060 Linear Integrated, LTC4060 Datasheet - Page 16

• Manufacturer Part Number: LTC4060
• Description: Standalone Linear NiMH/NiCd Fast Battery Charger
• Manufacturer: Linear Integrated

LTC4060
Full Featured 2A Charger Application
Figure 2 shows an application that utilizes the optional
temperature sensing and optional externally program-
mable automatic recharge features. It also has LEDs to
indicate charging status and the presence of sufficient
input supply voltage.
The PROG pin has a total resistance of 691Ω to ground
that programs the fast-charge current at the PNP’s emitter
to 2.02A (2A at the collector for beta of 100). The ARCT pin
voltage is programmed to 1.25V. When the battery cell
voltage falls below this automatic recharge will begin.
Optional capacitor C
This circuit can be modified to charge a 4A-Hr battery at a
C/2 rate simply by doubling the C
TYPICAL APPLICATIO S
16
BAT
“CHARGE”
filters excessive contact bounce.
1400Ω
R
330Ω
PROG
R
LED
“CHARGE”
R
4.42k
R
10k
HOT
NTC
TIMER
U
Figure 3. 1A Charger Application with Power Path Control
15
11
10
5
7
8
9
R
115Ω
R
576Ω
Figure 2. Full Featured 2A Charger Application
SHDN
CHRG
NTC
PROG
ARCT
SEL0
SEL1
PROG
ARCT
capacitance.
R
330Ω
LTC4060
V
LED
IN
GND
V
= 5V
CC
16
SENSE
PAUSE
TIMER
DRIVE
CHEM
15
11
10
5
7
8
9
ACP
BAT
SHDN
CHRG
NTC
PROG
ARCT
SEL0
SEL1
LTC4060
13
3
1
2
4
12
6
V
IN
GND
V
= 5V
CC
16
14
SENSE
PAUSE
TIMER
DRIVE
CHEM
FZT948
R
10k
ACP
BAT
AC
C
820pF
TIMER
ACP
13
3
1
2
4
12
6
Power Path Control
Proper power path control is an important consideration
when fast charging nickel cells. This control ensures the
system load remains powered at all times, but that normal
system operation and associated load transients do not
adversely affect the charging procedure. Figure 3 illus-
trates a 1A charger with power path control. When V
applied the forward biased Schottky diode will power the
load while the P-channel FET will disconnect the battery
from the load. When V
to provide a low loss switch from the battery to the load,
and the diode will isolate V
presense of V
MJD210
+
R
330Ω
*DRAIN SOURCE DIODE OF MOSFET
LED
2-CELL
NiMH
BATTERY
4060 F02
C
1.5nF
“AC”
TIMER
IN
C
10µF
*
.
FDG312P
BAT
B220A
+
2-CELL
NiMH
BATTERY
IN
4060 F03
C
10µF
LOAD
is removed, the FET will turn-on
IN
. The ACP output signals the
TO LOAD
IN
4060f
is