Pulse charger with overcurrent protection function

TC4052 is a fully integrated pulse charger for single 4.2V lithium ion / lithium polymer batteries. When the input voltage is 5.25V and the 0.8A current is used for fast charging, the power consumption of LTC4052 is about 280mW, while the power consumption of the linear charger solution is as high as 1.8W. Unlike switch capacitors with high efficiency and low heat dissipation using inductors, the LTC4052 is designed with no inductor. The lithium ion / lithium polymer battery charger circuit designed by LTC4052 only accounts for the area of 70mm2 and the height is less than 1.7mm. The 700mA to 2A battery charger is designed. By reducing power to the lowest level, LTC4052 can relax the requirements of the terminal device for thermal design, allow smaller packages, smaller heat dissipation airflow and smaller PCB area, and eliminate hot spots, so that no heat sink or fan is needed.

LTC4052 needs a current limiting wall adapter to control the charging current. It also requires an overcurrent protection circuit to provide protection when a high current is used accidentally or when a wall adapter fails. LTC4052 is a fully integrated pulse charger without external MOSFET or blocking diode (see photo). The independent charger IC has the functions of C/10 detection, charging status indication, charging end timer, wall adapter detection and over current protection. The input power of LTC4052 can be 4.5V to 12V, and has a 1% drift voltage accuracy.