Features Protection for sensitive Li-Ion and Li-Polymer batteries, charging and over-discharging for dual battery packs Necessary integrity without external FETs trip short circuit current protection
3 Current capacity

The UCC3911 is a two-cell Li-Ion (Li-Ion) and Li-Polymer (Li-Polymer) battery pack protection device that integrates an on-chip series FET switch to reduce manufacturing cost and improve reliability. The main function of this device is to protect one or two lithium-ion batteries and lithium-polymer batteries from being overcharged (overvoltage) or overdischarged (undervoltage). It uses a precision bandgap which is used to detect the reference voltage when both cells are close to an overvoltage or undervoltage condition. When the on-board logic detects either condition, the series FET switch turns on the guard cell. A negative feedback loop controls the FET switch when the battery is either in an overvoltage or undervoltage condition. The action of the feedback loop in an overvoltage condition is to allow only the discharge current to pass through the FET switch. In an undervoltage condition, only charging current is allowed to flow. The op amp drive is loop powered only when the two states. In an undervoltage state the chip goes into sleep mode until it detects that the bank is charging. The FET switch drives the charge pump to the lowest possible RDS(ON) of the battery pack in the normal state of charge. In this state the op amp with negative feedback loop shuts down to save battery power. Nominal delay of 100µs before tripping for circuit protection of short battery packs. An external capacitor CDLY and B0 can be connected to increase the delay time and allow longer overcurrent transients. A chip enable (CE) pin is provided when held low, inhibiting the normal operation of the device to facilitate the assembly of the battery pack.