Protection Circuit Safeguards Single-Cell Li-Ion Battery Packs

Sensitive lithium-ion cells are protected from overcharging and overdischarging by the UCC3958, a monolithic BiCMOS battery protection circuit. The device is particularly applicable to portable equipment using single-cell Li-ion battery packs, such as cell phones, pagers and PDAs.On the chip is a MOSFET with 50-milliohm on-resistance; the FET reduces external component counts. A charge pump reduces power losses while charging or discharging a battery pack with low cell voltage. The UCC3958 exhibits extremely low power drain. When the battery pack is in the undervoltage state, the chip enters an ultra low-power sleep mode that requires just1 µA of quiescent current. Cell protection features include precision internally trimmed charge and discharge voltage limits and discharge current limit with delayed shutdown. The chip comes in 16-pin power SOIC or 24-pin power TSSOP packages.