SLUSEG4B December 2022 – February 2024 BQ25628 , BQ25629
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
In BQ25628 and BQ25629, accessory devices can be connected to charger PMID pin to get power either from the adapter through Q1 direct path or from battery boost mode. An optional external PMOS FET can be placed between the PMID pin and accessory input to disconnect the power path during over-current and over-voltage conditions. PMID_GD is used to drive this external PMOS FET through an inverter. PMID_GD HIGH turns on an inverter to pull the PMOS FET gate low to turn on PMOS FET, and PMID_GD LOW turns off the PMOS FET.
Upon adapter plug-in, PMID_GD goes from LOW to HIGH when VBUS rises above VBAT but below VPMID_OVP and passes poor source detection. An adapter voltage that is greater than VPMID_OVP but less than VVBUS_OVP will drive PMID_GD low, but will charge the battery if all other conditions are valid. In this state, the external PMOS FET will stay off to protect the accessory from over-voltage fault.
When the adapter is removed, PMID_GD goes LOW before battery boost mode starts. In battery boost mode, the device regulates PMID voltage to the VOTG register setting as a stable power supply to the accessory devices. PMID_GOOD goes from LOW to HIGH when PMID voltage rises above VOTG_UVPZ. Once PMID voltage is out of this range, PMID_GOOD goes LOW to disconnect the accessory device from PMID. During boost mode, any of the conditions to exit boost mode will also drive PMID_GD from HIGH to LOW. See Section 8.3.6.1 for a list of these conditions.
If the device enters bypass OTG mode, the PMID_GD goes from LOW to HIGH when HSFET (Q2) is enabled. During bypass OTG mode, any conditions to exit will also drive PMID_GD from HIGH to LOW. See Section 8.3.6.2 for a list of these conditions.