The BQ2461x monitors the charging current during the voltage regulation phase. When VTTC is valid, termination is detected while the voltage on the VFB pin is higher than the VRECH threshold AND the charge current is less than the ITERM threshold, as calculated in Equation 5:
The input voltage of ISET2 is from 0 V to 2 V. The minimum precharge/termination current is clamped to be around 125 mA with default 10-mΩ sensing resistor. As a safety backup, the BQ2461x also provides a programmable charge timer. The charge time is programmed by the capacitor connected between the TTC pin and GND, and is given by Equation 6
A new charge cycle is initiated and safety timer is reset when one of the following conditions occurs:
The TTC pin may be taken LOW to disable termination and to disable the safety timer. If TTC is pulled to VREF, the BQ2461x continues to allow termination, but disables the safety timer. TTC taken low resets the safety timer. When ACOV, VCCLOWV, and SLEEP mode resume normal, the safety timer is reset.