Texas Instruments BOOST-PSEMTHR-007, User Manual, Page: 8 / 38

TPS23881 Autonomous Operations
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8 SLVUBP0A – May 2019 – Revised August 2019
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TPS23881EVM: PoE, PSE, TPS23881 Evaluation Module
4 TPS23881 Autonomous Operations
The TPS23881 supports autonomous mode which means it can operate in standalone mode without any
host control. In order to enable this function, a pulldown resistor is needed on AUTO pin. During power up,
the resistance on the AUTO pin is measured, and the device is pre-configured according to
Table 6 and
all ports are configured with the same power application.
If AUTO pin resistor is selected for 2-pair operation, due to the hardware configuration on the mother
board, only 2-pair ports (J19, J20, J8, J7) are interoperable with PDs. If AUTO pin resistor is selected for
4-pair operation, only 4-pair ports (J21,J9) are interoperable with PDs.
Table 6. AUTO Pin Programming
AUTO PIN
AUTONOMOUS MODE
CONFIGURATION
RESULTING REGISTER CONFIGURATIONS
Register 0x12h Register 0x14h Register 0x29h
Open/Floating Disabled 0x00h 0x00h 0x00h
124 k
Ω
2-pair 15 W 0xFFh 0xFFh 0x00h
62 k
Ω
2-pair 30 W 0xFFh 0xFFh 0x33h
35.7 k Ω 4-pair 30 W 0xFFh 0xFFh 0xBBh
22.6 k Ω 4-pair 45 W 0xFFh 0xFFh 0xCCh
15.8 k Ω 4-pair 60 W 0xFFh 0xFFh 0xDDh
11 k
Ω
4-pair 75 W 0xFFh 0xFFh 0xEEh
7.7 k
Ω
4-pair 90 W 0xFFh 0xFFh 0xFFh
5 TPS23881EVM GUI Setup
5.1 TPS23881EVM GUI Installation
TI's TPS23881EVM GUI is used with the TPS23881EVM to control the port and provide real-time
feedback on port telemetry. Download the TPS23881EVM GUI from the
TPS23881 product folder page in
the Tools and software section.
Follow the onscreen instructions to complete the installation. The TPS23881 GUI uses the USB2ANY as
an interface between the PC USB port and the BOOST-PSEMTHR-007 J2 connector (I2C interface).
Before starting the TPS23881 GUI, make sure the USB2ANY is properly connected to TPS23881EVM and
the EVM is supplied with a 44-V to 57-V power supply as shown in
Figure 1 .
5.2 TPS23881EVM GUI Operation
Start the TPS23881EVM GUI by double clicking the GUI icon. A window similar to Figure 3 will come up.