SLUSAX0E December 2012 – April 2021 BQ7716
PRODUCTION DATA
This terminal is connected to an external capacitor that is used for setting the delay timer during an overvoltage fault event.
The CD pin includes a timeout detection circuit to ensure that the output drives active even with a shorted or open capacitor during an overvoltage event.
The capacitor connected on the CD pin rapidly charges to a voltage if any one of the cell inputs exceeds the OV threshold. Then the delay circuit gradually discharges the capacitor on the CD pin. Once this capacitor discharges below a set voltage, the OUT transitions from an inactive to active state.
To calculate the delay, use the following equation:
Example: If CCD= 0.1 µF (typical), then the delay timer range is
tCD (s) = 10 × 0.1 = 1 s (Minimum)
tCD (s) = 20 × 0.1 = 2 s (Maximum)
The tolerance on the capacitor used for CCD increases the range of the tCD timer.