The TPS65981 controls two separate power paths making it a flexible option for Type-C and PD dock application that simultaneously charges a USB PD DisplayPort video source (for example, a notebook computer). The dock or monitor application of the TPS65981, shown in Figure 10-3, uses a GPIO to sense when a power supply is present on the system-side of the TPS65981. When external power is applied from an AC-DC power supply first, the TPS65981 shall be configured to automatically attempt to become the USB Type-C or PD power source. When a notebook computer or other USB PD source is connected first and the AC-DC supply is not present, the dock or monitor supports booting from VBUS in No Battery Mode, provides power to the SPI Flash to load application code, and can optionally power the entire system by enabling the PP_EXT path as a sink. If the AC-DC power supply is applied at a later time, the TPS65981 will detect the new power supply, automatically enable one of more Source PDOs, and initiate a Power Role Swap PD message to offer power to the system at the far-end of the Type-C cable. Refer to Figure 10-6 for a timing diagram of the GPIO-controlled variable buck regulator voltage output at PP_HV and the voltage at VBUS during a Type-C connection and throughout an intial USB PD power negotiation where the dock or monitor is the power source. The video receptacle can be DisplayPort, HDMI, or VGA although only DisplayPort is shown in Figure 10-3. The dock or monitor application uses a Type-C receptacle and an HD3SS460 SuperSpeed multiplexer that is controlled by the TPS65981. The CC1/2 pins of the TPS65981 will detect cable orientation and automatically configure the HD3SS460 SuperSpeed signal pairs for 2-lanes of USB3 data and 2-lanes of DisplayPort video or 4-lanes of DisplayPort video depending on the Alternate Mode configured by the downstream-facing port (DFP).

Figure 10-3 Type-C and PD Dock or Monitor Application