An area-efficient amplifier-less digitally-controlled li-ion battery charger in 0.35μm CMOS

In this paper, an amplifier-less digitally-controlled lithium-ion (Li-Ion) battery charger is presented. Owing to the digitally-controlled technique, the proposed charger eliminates all analog circuits and reduces the size of the power transistor. Hence, the proposed charger features a simple circuit structure and a small chip area. Additionally, this charger provides essential operations including constant-current (CC) and constant-voltage (CV) modes. The proposed charger is implemented in the TSMC 0.35-pm CMOS process with a 5-V power supply. The output voltage is 4.2 V, and the charging current in CC mode is 600 mA with an area of only 0.768 mm
²
.