JAJSHI3C March 2019 – October 2019 TPS23881
PRODUCTION DATA.
The Power Allocation settings in register 0x29 sets the maximum power level a port will power on. Settings for each Class level from 2-pair 4 W (Class 1) up to 4-pair 90 W (Class 8) have been provided to maximize system design flexibility.
NOTE
The Power Allocation settings in register 0x29 do not set the power limit for a given port. The port and channel power limiting is configured with the 2P (registers 0x1E- x 21) and 4P (0x2A - x2B) policing registers
During a turn on attempt, if a PD presents a classification level greater than the power allocation setting for a port, the TPS23881 limits the number of classification fingers presented to the PD prior to turn on based on the power allocation settings in register 0x29. This behavior is called Power Demotion as it is the number of fingers presented to the PD that sets the maximum level of power the PD is allowed to draw before the PSE is allowed to disable it.
NOTE
Power Demotion on a port is limited to the Type boundaries as the only means of communication from the PSE to the PD is the number of classification fingers prior to turn on.
1 finger = 15.4 W, 3 fingers = 30 W, 4 fingers = 60 W, and 5 fingers = 90W
Power Allocation
Register 0x29 |
Assigned Class Value (based on the PD connected at the port) | |||||
---|---|---|---|---|---|---|
Class 3 PD | Class 4 PD | Class 5 PD | Class 6 PD | Class 7 PD | Class 8 PD | |
4-Pair 15W | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 |
4-Pair 30W | Class 3 | Class 4 | Class 4 | Class 4 | Class 4 | Class 4 |
4-Pair 45W | Class 3 | Class 4 | Class 5 | Class 4 | Class 5 | Class 5 |
4-Pair 60W | Class 3 | Class 4 | Class 5 | Class 6 | Class 6 | Class 6 |
4-Pair 75W | Class 3 | Class 4 | Class 5 | Class 6 | Class 7 | Class 6 |
4-Pair 90W | Class 3 | Class 4 | Class 5 | Class 6 | Class 7 | Class 8 |
Power Allocation
Register 0x29 |
Assigned Class Value (based on the PD connected at the port) | |||||
---|---|---|---|---|---|---|
Class 3D PD | Class 4D PD | Class 5D PD | ||||
Odd Channel (Primary) | Even Channel (Secondary) | Odd Channel (Primary) | Even Channel (Secondary) | Odd Channel (Primary) | Even Channel (Secondary) | |
4-Pair 15W | Class 3 | Insufficient Power | Class 3 | Insufficient Power | Class 3 | Insufficient Power |
4-Pair 30W | Class 3 | Class 3 | Class 4 | Insufficient Power | Class 4 | Insufficient Power |
4-Pair 45W | Class 3 | Class 3 | Class 4 | Class 3 | Class 5D | Insufficient Power |
4-Pair 60W | Class 3 | Class 3 | Class 4 | Class 4 | Class 5D | Class 3 |
4-Pair 75W | Class 3 | Class 3 | Class 4 | Class 4 | Class 5D | Class 4 |
4-Pair 90W | Class 3 | Class 3 | Class 4 | Class 4 | Class 5D | Class 5D |
NOTE
Class "X-D" Dual Signature PDs present as Class "X" on each alterative pairset. For example: a "Class 4D" PD would present as Class 4 on both the Alterative A and Alternative B pairsets.