SLUSE64 May 2021 BQ25723
PRODUCTION DATA
Usually adapter can supply current higher than DC rating for a few milliseconds to tens of milliseconds. The charger employs two-level input current limit, or peak power mode, to fully utilize the overloading capability and minimize battery discharge during system load transient. The level 1 current limit, or ILIM1, is the same as adapter DC current, set in IIN_DPM register. The level 2 overloading current, or ILIM2, is set in ILIM2_VTH, as a percentage of ILIM1.
When the charger detects input current surge and battery discharge due to load transient (both the adapter and battery support the system together), or when the charger detects the system voltage starts to drop below VSYS_MIN setting due to load transient (only the adapter supports the system), the charger will first apply ILIM2 for TOVLD (PKPWR_TOVLD_DEG register bits), and then ILIM1 for up to TMAX – TOVLD time. TMAX is programmed in PKPWR_TMAX register bits. After TMAX, if the load is still high, another peak power cycle starts. Charging is disabled during TMAX and TOVLD already expires; once TMAX, expires, a new cycle starts and resumes charging automatically.
To prepare entering peak power follow below steps:
Depends on the battery existence and charge status peak power mode can be finally enabled with two different approaches: