The bq2941x is a
secondary overvoltage protection IC for 2-, 3-, or 4-cell lithium-ion battery packs that
incorporates a high-accuracy precision overvoltage detection circuit. It
includes a programmable delay circuit for overvoltage detection time.
Each cell in a multiple-cell pack is compared to an internal
reference voltage. If one cell reaches an overvoltage condition, the protection
sequence begins. The bq2941x device starts charging an external capacitor
through the CD pin. When the CD pin voltage reaches 1.2 V, the OUT pin changes
from a low level to a high level.