ZHCSFL8C October 2016 – August 2021 TPS65983B
PRODUCTION DATA
The TPS65983B supports dead battery functionality to be able to power up from the Type-C port. This design supports dead battery using the PP_EXT path, where RPD_G1/2 and CC1/2 are connected respectively, and BUSPOWERZ is connected to GND to path 5-V VBUS into the system through the PP_EXT path. The TPS65983B will soft-start the PP_EXT (or PP_HV) path in order to comply with USB2.0 inrush current requirements. In order to enable PD functionality the TPS65983B must boot the application firmware from the flash. For the primary TPS65983B, once VBUS is detected at 5 V it will automatically start to load the application firmware from the flash. The TPS65983B will then be able communicate over PD and establish a power contract at the required 20 V. Figure 10-7 shows the boot up sequence of the primary TPS65983B.
When the TPS65983B that is not connected to the flash is connected in dead battery it will pass the 5 V from VBUS in to the battery charger where the battery would be able to generate the needed system 3.3-V rail to both of the TPS65983Bs. Once the primary TPS65983B has a valid 3.3-V supply (VBUS = 0 V on Primary TPS65983B) it will load the application firmware from the flash and pass it to the secondary TPS65983B that is connected. Once the secondary TPS65983B has loaded the application firmware over UART it will be able to negotiate a 20-V power contract. Figure 10-8 shows the dead battery sequence of the secondary TPS65983B.