Linear LTC4050 Quick Start Manual

QUICK START GUIDE FOR DEMO CIRCUITS 530A-A AND 530A-B
DESCRIPTION
Demonstration circuit 530A-A and 530A-B are complete
constant-current/constant-voltage battery chargers de-
signed to charge one Lithium-Ion cell. Both feature the
LTC4050 Linear Battery Charger driving a P-channel
MOSFET in a series pass linear regulator configuration
for charging at a maximum current of 700mA (limited by
the power dissipation capabilities of the pass transistor).
Demo board LTC4050A-A features the LTC4050-4.1,
which has a recharge threshold voltage of 3.88V, making
it suitable for charging 4.1V cells.
Demo board LTC4050A-B features the LTC4050-4.2,
which is recommended only for charging a 4.2V cell,
due to its recharge threshold voltage of 3.98V.
Other Features include:
• Preset float voltages of 4.1 and 4.2V ±1%
• 700mA Constant Current (can be programmed for
other charge currents)
• 3-hour charge termination timer. This timer can be set
for other time periods through a capacitor change.
For instance, you may want to use a much shorter pe-
riod (on the order of 30 seconds) when evaluating the
Table 1. Performance Summary
PARAMETER
Input Voltage Range
Output Voltage V (constant voltage mode)
BAT
Output Current I (constant current mode)
BAT
Output Current I (trickle current mode)
BAT
C/10 CHRG LED Threshold Level
Trickle Charge Threshold Voltage
Battery Drain Current with V Removed
IN
board with a battery simulator instead of a Li-Ion bat-
tery.
• Manual Shutdown
• C/10 Trickle charge for deeply discharged batteries
• Auto recharge when battery voltage drops below pre-
set threshold (3.88V for DC530A-A and 3.98V for
DC530A-B).
• Low battery drain current when the input supply is
removed
• Input Power OK LED indicator (ACPR)
• C/10 Charge LED indicator (CHRG)
• NTC Input to prevent charging if the battery is too hot
or too cold
Small surface mount components are used to minimize
board space and height with the circuitry occupying ap-
proximately 0.15 square inches of board space with a
height of 0.054 inches (1.4mm).
Design files for this circuit board are available. Call
the LTC factory.
VALUE
4.5V to 6.0V (upper range limited by MOSFET dissipation)
4.1V ±1% DC530A-A
4.2V ±1% DC530A-B
700mA ±8%
70mA ±70%
35-140mA
2.49V
5µA
Note: If V is pulled down to 0V, the current drain from the battery will be higher due to the leak-
IN
age current of the input Schottky diode. A silicon diode could be used for the input diode if the
slightly greater forward voltage drop is not a problem.
LI-ION BATTERY CHARGER
LTC4050
1