Multi-Cell Li-ion Battery Pack OCP/Analog
Front-End
The ISL94200 is an overcurrent protection device and
analog front end for a microcontroller in a multi-cell Li-ion
battery pack. The ISL94200 supports battery pack
configurations consisting of 4-cells to 7-cells in series and
1 or more cells in parallel. The ISL94200 provides integral
overcurrent protection circuitry, short circuit protection, an
internal 3.3V voltage regulator, cell voltage monitor level
shifters, and drive circuitry for external FET devices for
control of pack charge and discharge.
Selectable overcurrent and short circuit thresholds reside in
internal RAM registers. An external microcontroller sets the
thresholds by setting register values through an I2C serial
interface. Internal registers also contain the detection delays
for overcurrent and short circuit conditions.
Using an internal analog multiplexer the ISL94200 provides
monitoring of each cell voltage plus internal and external
temperature by a separate microcontroller with an A/D
converter. Software on this microcontroller implements all
battery pack control functionality, except for overcurrent and
short circuit shutdown.