EC49017 is a complete constant-current & constant voltage linear charger for single cell lithium-ion and Lithium-Polymer batteries.
Its SOT23 package and low external component count make EC49017 ideally suited for portable applications. Furthermore, the EC49017 is specifically designed to work within USB power specification.
At the same time, EC49017 can also be used in the standalone lithium-ion and Lithium-polymer battery chargers.
No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture.
hermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.22V, and the charge current can be programmed externally with a single resistor.
The EC49017 automatically terminates the charge cycle when the charge current drops to 1/10th the programmed value after the final float voltage is reached.
When the input supply (wall adapter or USB supply) is removed, the EC49017 automatically enters a low current stage, dropping the battery drain current to less than 2uA. The EC49017 can be put into shutdown mode, reducing the supply current to 20uA.
Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. EC49017 is intentionally designed to have slightly negative Tempco.
This provides extra protection to Lithium battery during charging.