The RY2231B1D4 is a Battery Management ICs with DFN-4-EP (1x1) packaging and RoHS compliance manufactured by RYCHIP. It is a low power CMOS chip designed for Li-Ion and Li-Po battery protection purposes. It has an integrated over-voltage and over-temperature protection, which helps to protect the cellular phone battery pack from overcharging, deep-discharge, and over-temperature events. It has an adjustable low voltage cutoff voltage for optimal Li-Ion and Li-Po battery protection. The RY2231B1D4 also has a low power consumption feature that helps to increase battery life and ensure safe operation. The chip also features a constant-current and constant-voltage regulation with an adjustable charge current up to 2.1A and adjustable end voltage up to 4.2V. It also has a charge status indicator.