QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 551
LITHIUM-ION BATTERY CHARGER WITH CHARGE TERMINATION
1
LTC4002-4.2
DESCRIPTION
Demonstration circuit 551 is a complete constant-
current/constant- voltage battery charger designed
to charge one Lithium-Ion cell. Programmed for 3A
charge current, this board features a 500kHz step
down switching regulator controller driving a P-
channel MOSFET. A fixed 3 hour timer is included
for charge termination in addition to a charge status
LED to indicate a near-full-charge condition and a
thermistor connection for battery temperature
charge qualification. Because of the heat generated
by the circuit, the thermistor must not be mounted
on this board. A 10k resistor (R3) is used instead of
a thermistor on this board.
The LTC
®
4002 on this board is in a tiny 3 X 3 mm
10 pin DFN package. All surface mount components
are used to minimize board space and height with
the circuitry occupying approximately 0.5 square
inches of board space although additional pc-board
copper is needed for heat dissipation.
Design files for this circuit board are available.
Call the LTC factory.
LTC is a registered trademark of Linear Technology Corporation
Other Features include:
•
Preset float voltages of 4.2V ±1%
•
3A Constant Current (can be programmed for other charge currents)
•
3 Hour charge termination timer
•
NTC Thermistor input for sensing battery temperature
•
Undervoltage Lockout
•
Manual Shutdown
•
Low battery drain current when input supply is removed
•
C/10 Trickle charge for deeply discharged batteries
•
Auto recharge when battery voltage drops below preset threshold
•
C/5 Charge LED indicator (CHRG)
