This example project has been developed to help designers who are working on dual port applications such as smart plugs, multi-port adapters, avionics seat backs, wall-sockets... which often require dynamic power sharing between ports. The highly configurable TPS65988 can implement dynamic power sharing without using an EC in the design. The simple to use GPIO App configuration event feature in TPS65988 makes this stand-alone solution possible.
The figure pictorially shows the control logic used for power sharing. In this example, lets assume that the total power available to the system is 60W. When no ports are connected, the total power available shall be delivered to the first device, getting connected to either of the ports. When the second device gets connected, the total power shall be split equally between the two ports.
The App Config events in the project file are configured to load PDOs in Transmit Source Capabilities register (0x32) dynamically (based on plug event) and execute SSrC PD message task (PD Send Source Capabilities). App Config input events are mapped to GPIO0 and GPIO2. App Config input GPIOs are connected to output plug event of the other port (GPIO1 and GPIO3). The plug event GPIO of a port will go high when the port makes connection, this will trigger App Config GPIO of the other port to scale down its power to half (Virtual address 6 and 1). Similarly, an unplug event will cause the other port to advertise full power (60W)
This project can be tested using TPS65988EVM. To know more about the application, please go through TPS65988DH: Integrated Type-C PD Dual-Port Wall Socket With Power Balancing.
