JAJSS91 November 2023 BQ25756E
PRODUCTION DATA
The device terminates a charge cycle when the battery voltage is above recharge threshold, and the current is below termination current. The termination current threshold is controlled by the lower option between 10% x ICHG pin setting or the ITERM register setting.
In standalone applications using the ICHG pin to program the current, the termination threshold is set at 10% of the ICHG pin value (10-A ICHG pin programming results in 1-A termination).
In host-controlled applications, the termination current can be programmed using the ITERM register bits. The ICHG pin can still be used to set a hardware limit for the charge current.
After the charging cycle is completed, the buck-boost converter turns off. When termination occurs, the status register CHARGE_STAT is set to 111, and an INT pulse is asserted to the host. Termination is temporarily disabled when the charger device is in input current, or input voltage regulation. Termination can be permanently disabled by writing 0 to EN_TERM.
At low termination currents, due to the comparator offset, the actual termination current may be up to 20% higher than the termination target. In order to compensate for comparator offset, a programmable top-off timer (default disabled) can be applied after termination is detected. The top-off timer follows safety timer constraints, such that if safety timer is suspended, so is the top-off timer. Similarly, if safety timer is doubled, so is the top-off timer. CHARGE_STAT reports whether the top off timer is active via the 110 code. Once the Top-Off timer expires, the CHARGE_STAT register is set to 111 and an INT pulse is asserted to the host.