|
Linear Battery Charger
Linear Technology has introduced the LTC4062,
a compact stand-alone linear battery charger with
integrated micropower comparator. It offers advanced
features for charging safety, increased charge
termination flexibility, improved status reporting,
and prolonged battery life.
For safety, the LTC4062 is equipped with an adjustable
timer for charge termination and a precision float
voltage to prevent overcharging of the cell.
To eliminate the risk of overheating while charging
at a maximum rate, a patented thermal regulation
circuit keeps the LTC4062’s junction temperature
at a safe level. I/O pins report the state-of-charge
during trickle, normal and end-of-charge modes.
The LTC4062 includes an integrated precision,
micropower comparator with an undedicated comparator
with a general purpose input and open-drain output.
Potential uses include low battery detection or
precision input voltage detection.
The unit prolongs battery life by eliminating
unnecessary recharge cycles with its SmartStart
feature. Because frequent recharge cycles reduce
battery capacity and shorten battery life, SmartStart
operation prevents a new charge cycle from starting
if the battery voltage is above 4.1V when power
is first applied to the charger.
The IC also offers several methods of charge termination:
user adjustable current and charge time, external
digital control or automatic C/10.
The LTC4062 is housed in a 3 x 3mm DFN package
and is ideal for charging a battery from a wall
adapter or USB in MP3 players, digital cameras,
PDAs and cellphones. It can charge Li-ion batteries
to a 4.2V float voltage with +/-0.35% accuracy.
The device requires no external sense resistor,
MOSFET or blocking diode, greatly simplifying
design. In addition, the LTC4062 includes a soft-start
circuit to minimize in-rush current at the start
of a charge cycle.
For USB-powered charging, the logic PIN from a
USB controller can select low power or high power
compliant charge currents, eliminating dependence
on external discrete components.
At any point in the charge cycle, the LTC4062
can be shut down, limiting battery current drain
to less than 2uA; 1000-piece pricing starts at
$1.95 each.
For more information, visit www.linear-tech.com
|
