SLUSEK7 September 2024 BQ25773
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
When only battery is connected and adapter is removed, the system peak power pulse for a 2S or 3S system can be very high if the SoC and motherboard systems spikes coincide. These spikes are expected to be very rare, but possible. During these high power spikes, VSYS voltage could drop lower than minimum system voltage and crash the system considering the impedance of BATFET, charge sensing resistor and battery pack internal resistance. In VAP mode the charger first charges up the voltage of the input decoupling capacitors at VBUS to store a certain amount of energy. During these high system power spikes, the the energy stored in the input capacitors will supplement the system, to prevent the system voltage from dropping below the minimum system voltage and leading the system to black screen. The VAP mode can help to achieve much better Turbo performance for Intel CPU. Overall VAP mode is both a protection mechanism used to keep the system voltage from drooping below its minimum operational voltage and a method to boost Turbo performance by allowing Intel CPU to set a peak power higher than the capability of the battery.
To enter VAP mode follow the steps below:
When an adapter is plugged in or CPU goes to sleep mode, the host can follow below steps to exit VAP mode:
EN_OTG pin is used as multi-function pin to enable OTG, VAP and FRS mode. In order to enter VAP mode correctly, refer to Table 7-5 case 7 for reference, note OTG_VAP_MODE=0b should be configured before EN_OTG pin is pulled high. After EN_OTG pin is pulled up, it is not recommended to change OTG_VAP_MODE bit value.