Active: In Production.
The MAX1737 is a switch-mode lithium-ion (Li+) battery
charger that charges one to four cells. It provides a
regulated charging current and a regulated voltage
with only a ±0.8% total voltage error at the battery terminals.
The external N-channel switch and synchronous
rectifier provide high efficiency over a wide input voltage
range. A built-in safety timer automatically terminates
charging once the adjustable time limit has been
The MAX1737 regulates the voltage set point and charging
current using two loops that work together to transition
smoothly between voltage and current regulation. An
additional control loop monitors the total current drawn
from the input source to prevent overload of the input
supply, allowing the use of a low-cost wall adapter.
The per-cell battery voltage regulation limit is set
between +4.0V and +4.4V and can be set from one to
four by pin strapping. Battery temperature is monitored
by an external thermistor to prevent charging if the battery
temperature is outside the acceptable range.
The MAX1737 is available in a space-saving 28-pin
QSOP package. Use the evaluation kit (MAX1737EVKIT)
to help reduce design time.