Multi-Cell Li-ion Battery Pack OCP/AnalogFront-EndThe ISL94200 is an overcurrent protection device andanalog front end for a microcontroller in a multi-cell Li-ionbattery pack. The ISL94200 supports battery packconfigurations consisting of 4-cells to 7-cells in series and1 or more cells in parallel. The ISL94200 provides integralovercurrent protection circuitry, short circuit protection, aninternal 3.3V voltage regulator, cell voltage monitor levelshifters, and drive circuitry for external FET devices forcontrol of pack charge and discharge.Selectable overcurrent and short circuit thresholds reside ininternal RAM registers. An external microcontroller sets thethresholds by setting register values through an I2C serialinterface. Internal registers also contain the detection delaysfor overcurrent and short circuit conditions.Using an internal analog multiplexer the ISL94200 providesmonitoring of each cell voltage plus internal and externaltemperature by a separate microcontroller with an A/Dconverter. Software on this microcontroller implements allbattery pack control functionality, except for overcurrent andshort circuit shutdown.