QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 789
SINGLE CELL LI-ION BATTERY CHARGER WITH COMPARATOR
1
LTC4062
DESCRIPTION
Demonstration circuit 789 is a complete constant-
current, constant-voltage battery charger for one
Lithium-Ion cell and includes a comparator which can
be used to monitor battery voltage or other voltages.
The LTC4062EDD used on this demo circuit features
an internal P-Channel power MOSFET with a unique
thermal feedback loop that reduces the output current
under high ambient temperature and/or high power
dissipation conditions. This feature allows the charger
to provide higher charge currents under normal con-
ditions and still provide safe charging under abnormal
conditions such as high ambient temperature, high
input voltage or low battery voltage.
Jumpers on the board allow charge currents from
50mA to 1A to be programmed and several charge
termination methods to be used. A jumper also se-
lects either the battery voltage or an external voltage
for the comparator input. Terminals are provided for
the comparator input and output, shutting down the
charger, monitoring charge current and programming
the minimum charge current level for termination
(I
DETECT
). Two LEDs are included, one indicates
when the charge current has dropped below the
minimum charge current termination level and the
second indicates the comparator output state.
The IC is available in a 10-Pin 3mm x 3mm DFN
thermally enhanced package featuring an exposed
bottom-side metal pad for soldering to the PC board.
Design files for this circuit board are available. Call
the LTC factory.
LTC is a trademark of Linear Technology Corporation
Table 1. Typical Specifications (25°C)
Input Voltage Range V
IN
4.3 to 8V (upper range limited by PC board power
dissipation)
Input UnderVoltage Lockout 3.8V
Output Float Voltage V
BAT
(constant voltage mode) 4.2V ±0.5%
Output Current I
BAT
(constant current mode) From 50mA to 1A ± 8% (selected by jumpers)
Current Monitor Output 1V ±5% @ Full Current
Charge Termination Timer 3 Hours ±10%
Charge Termination Threshold Current (I
DETECT
) 25mA, 50mA, 100mA ± 10%
Comparator Threshold 2.910V ±3%
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