THE DESIGN OF A LI-ION BATTERY CHARGER BASED ON MULTIMODE LDO TECHNOLOGY

摘要

In this paper, we design a CMOS Li-Ion battery charger using the multimode low dropout (LDO) voltage regulator associated with a current sense to supply trickle current, constant current, and constant voltage for charging the battery in order. The protections from over charging and discharging are also considered by monitoring the charging current, reverse voltage, and battery temperature. The whole charger has been verified by HSPICE with TSMC 0.35 μm 2P4M CMOS process. The charger provides the trickle current of 150 mA, maximum charging current of 312 mA, and charging voltage of 4.2 V at the input voltage of 4.5 V. The power efficiency of 72.3% is acceptable under the power consumption of 1.28 W. The chip occupies an area of 1.78 mm × 1.77 mm including 2955rntransistors.