General Descriptions:
The CN3781 is a PWM switch-mode lithium ion battery charger controller for 1 cell li-ion battery in a small package using few external components.
The CN3781 is specially designed for charging lithium ion batteries with constant current and constant voltage mode. In constant voltage mode, the regulation voltage can be fixed at 4.2V with ± 1% accuracy, also can be adjusted upward with an external resistor.

FEATUREs:
● On-chip circuit block can automatically
   adjust charge current based on the output
   capability of input supply
● Suited for the applications powered by
   the supply with limited output capability,
   such as USB port, etc.
● Wide Input Voltage: 4.83V to 28V
● Complete Charge Controller for single
   cell Lithium-ion Battery
● Charge Current Up to 4A
● High PWM Switching Frequency:
   300KHz
● Regulation Voltage can be adjusted
   upward
● Constant Voltage Accuracy: ± 1%
● Charging Current is programmed with a
   current sense resistor
● Automatic Conditioning of Deeply
   Discharged Batteries
● Automatic Recharge
● Charging Status Indication
● Soft Start
● Battery Overvoltage Protection
● Operating Ambient Temperature
   － 40℃ to ＋85℃
● Available in 10 Pin SSOP Package
● Pb-free, Rohs-Compliant, Halogen Free

APPLICATIONs:
● Power Bank
● Hand-held Equipment
● Battery-Backup Systems
● Portable Industrial and Medical Equipment
● Standalone Battery Chargers