1
dc2133afa
DEMO MANUAL DC2133A
DESCRIPTION
LTC4079
60V, 250mA Linear Charger
with Low Quiescent Current
Demonstration circuit 2133A features a simple battery
charger circuit using the
LTC
®
4079
high-voltage mono-
lithic linear charger. The DC2133 has an input voltage
range from 2.7V to 60V and is capable of supplying up
to 250mA charge current. The charge voltage is jumper-
selectable to 4.2V or 8.4V. Charge current is adjustable
via the PROG pin and initially programmed for 99mA. In
shutdown or when unpowered, LTC4079 consumes only
10nA from the battery.
DC2133A is initially configured to enable charging from
application of V
IN
above the LTC4079 UVLO threshold.
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
The NTC input is connected to an on-board resistance to
enable charging with only a 2-wire battery connection;
however an external thermistor may be used with the
NTC test point.
Termination is accomplished by timer method. Charging
status is reflected by the
CHRG
LED.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2133A
Specifications are at T
A
= 25°C
Figure 1. Typical Battery Charge Cycle
PARAMETER
CONDITIONS
TYPICAL VALUE
Input Voltage Range
2.7V to 60V
Default Charging Voltage
V
BAT
= 4.2
4.2V
Default Charging Current
R
PROG
= 3.01k
99mA
PROG Pin Voltage
R
PROG
= 3.01k, I
CHG
= 99mA
2.5V
Input Regulation Voltage
EN = REG (JP1)
10.3V
Default Charge Timer
C
TMR
= 0.068μF
3h 45 min
TIME (HOURS)
0
100
80
60
40
20
90
70
50
30
10
0
1
dc2133a F01
5
3
2
4
I
BAT
(mA)
3.2
3.6
5.2
3.4
3.8
4.6
4.4
4.2
4
5.0
4.8
V
BAT
& V
CHRG
(V)
C/10
TERMINATION
CHRG
240mAh Li-Ion
V
IN
= 5V
R
PROG
= 3.01k
C
TMR
= 0.068µF
I
BAT
V
BAT
