This reference design provides a
competitive and alternative design.
In a multiport PSE system, the
system-level software is the biggest challenge. The software handles complicated
situations and addresses the following challenges:
- The power supply is typically not able to support all ports with
a full load due to size and cost constraints. The system software manages the
port power with priority to keep the total power consumption below the power
budget.
- There are multiple power supplies in the system. These power
supplies can be in sharing mode or backup mode. The system software shuts down
low-priority ports fast enough to keep the total power consumption below the
remaining power budget.
- There are some legacy PD devices that do not present the
standard PoE PD signature. The system software finds a way to supply power to
these devices.
- System software limits the port power based on the PD class
levels or host configuration.
- When there are load-step changes on multiple ports, the system
software acts quickly enough to keep the power consumption below the power
budget.