The TPS65903x-Q1 device series integrates an embedded power controller (EPC) that fully manages the state of the device during power transitions. According to four defined types of requests (ON, OFF, WAKE, and SLEEP), the EPC executes one of the five predefined power sequences (OFF2ACT, ACT2OFF, SLP2OFF, ACT2SLP, and SLP2ACT) to control the state of the device resources. Any resource can be included in any power sequence. When a resource is not controlled or configured through a power sequence, the resource remains in the default state of the resource (from OTP).
Each resource is configured only through register bits. Therefore, a resource can be controlled statically by the user through the control interfaces (I2C or SPI) or controlled automatically by the EPC during power transitions (predefined sequences of registers accesses).
The EPC is powered by an internal LDO which is automatically enabled when VSYS is available to the device. It is important to ensure that VSYS (which is connected to VCC1, VCC_SENSE, and may also be connected to SMPSx_In and LODx_IN as suggested in the device block diagram) is the first supply available to the device to guarantee proper operation of all the power resources provided by the device. It is also important that VSYS is stable prior to VIO supply is available to ensure proper operation of the control interface and device IOs.