ZHCSO21 may 2021 BQ25720
PRODUCTION DATA
The device employs Narrow VDC architecture (NVDC) with BATFET separating the system from the battery. The minimum system voltage is set by VSYS_MIN register REG0x3E(). Even with a depleted battery, the system is regulated above the minimum system voltage.
When the battery is below minimum system voltage setting, the BATFET operates in linear mode (LDO mode), and the system is regulated at VSYS_MIN register value. As the battery voltage rises above the minimum system voltage, system voltage is regulated 150 mV above battery voltage when BATFET is turned off (no charging or no supplement current). When in charging or in supplement mode, the voltage difference between the system and battery is the VDS of the BATFET and the BATFET is fully on.