The LTC1732 is a complete constant-current/constantvoltage
linear charger controller for lithium-ion
(Li-Ion) batteries. Nickel-cadmium (NiCd) and nickel metalhydride
(NiMH) batteries can also be charged with constant
current using external termination. Charge current
can be programmed with 7% (max) accuracy using external
sense and program resistors. An internal resistor
divider and precision reference set the final float voltage
with 1% accuracy. The SEL pin allows users to charge
either 4.1V or 4.2V cells.
When the input supply is removed, the LTC1732 automatically
enters a low current sleep mode, dropping the battery
drain current to 7mA. An internal comparator detects the
end-of-charge (C/10) condition while a programmable
timer, using an external capacitor, sets the total charge
time. Fully discharged cells are automatically trickle charged
at 10% of the programmed current until cell voltage
exceeds 2.457V.