SLUSFK8 April 2024 BQ25770G
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
Fast Role Swap (FRS) means charger quickly swaps from power sink role to power source role to provide an OTG output voltage to accessories when the original power source is disconnected. This feature is defined to transfer the charger from forward mode to OTG mode quickly without dropping VBUS voltage per USB-C PD specification requirement.
To enable FRS feature, EN_FRS bit should be set to 1. When FRS is enabled (EN_FRS = 1), EN_OTG bit and converter OTG mode is only enabled after hardware EN_OTG pin is pulled up. Note when EN_FRS is reset to 0, EN_OTG bit will not be reset automatically, in order to fully exit the OTG mode operation EN_OTG bit need to be reset by the host. The steps for FRS feature operation are listed below.
The table below compares VAP, OTG and FRS feature configuration. It is recommended to configure charger into target mode correctly before the EN_OTG pin is pulled up. After the EN_OTG pin is pulled up, it is not recommended to change the OTG_VAP_MODE and EN_FRS bits.
CASE # | CONFIGURATION | CHARGER STATUS | ||||
---|---|---|---|---|---|---|
EN_OTG PIN | OTG_VAP_MODE BIT | EN_OTG BIT | EN_FRS BIT | BATTERY/ADAPTER CONFIG |
||
1 | 0 | X | X | X | Battery only | Battery only Discharge and converter off |
2 | 0 | 0 | X | X | Adapter+Battery | Forward mode (without FRS) |
3 | 0 | 1 | X | 0 | Adapter+Battery | Forward mode (without FRS) |
4 | 0 | 1 | X | 1 | Adapter+Battery | Forward mode (with FRS standby) |
5 | 1 | 1 | 0 | X | Battery only | Battery only Discharge and converter off |
6 | 1 | 1 | 1 | X | Battery only | OTG mode |
7 | 1 | 0 | X | X | Battery only | VAP mode |