The PW4055 is a complete constant-current /constant-voltage linear charger for single cell lithiumion batteries.Its ThinSOT package and low external component count make the PW4055 ideally
suited for portable applications.Furthermore, the PW4055 is specifically designed to work within USB
power specifications.
The PW4055 No external sense resistor is needed, and no blocking diode is required due to the
internal MOSFET architecture.Thermal feedback regulates the charge current to limit the die
temperature during high power operation or high ambient temperature. The charge voltage is fixed
at 4.2V, and the charge current can be programmed externally with a single resistor. The PW4055
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 PW4055 automatically enters a low current state, dropping the battery drain current
to less than 2µA. The PW4055 can be put into shutdown mode, reducing the supply current to 25µA.
The BAT pin has a 7KV ESD(HBM) capability. 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
