Texas Instruments TIDA-050026-23882, Руководство по конструкции

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PSE Daughter Card
54 V to
PSE_3.3 V
Buck
PSE Ports
MSP430
Daughter Card
MSP430
54-V bus
PSE I2C bus
USB2ANY Connector
GPIOs
Edge
Connector
_signal
I2C
54 V to
ISO_3.3 V
Isolated
DC/DC
JTAG
14 pin
F
la
sh
/D
e
b
u
g
PSE Control Signals
Edge
Connector
_Power
Isolation
UART SPI
Power
Supply 1
Power
Supply 2
Sensing
PG2
GPIOs
PG1
USB2ANY Connector
I2C Repeater
(Optional)
PSE System Motherboard
24-Port RJ45 Connectors
Edge
Connector
_Power
Edge
Connector
_signal
(see NOTE A)
(see NOTE B)
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System Overview
3 TIDA032 – October 2019
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Copyright © 2019, Texas Instruments Incorporated
24-Port (2 pair) Power Sourcing Equipment Reference Design for Multi-port
Applications
2 System Overview
2.1 Block Diagram
Figure 1. TIDA-050026-23882 Block Diagram
A The 54-V to 3.3-V isolated DC/DC is for demonstration purposes only. It is not needed in a real system.
B Only connect a USB2ANY connector or JTAG to avoid GND loops.
2.2 Design Considerations
2.2.1 Input Power
2.2.1.1 Vpwr
DC input voltage is provided through J1 and J3. This board supports a dual power source in sharing mode
and redundant mode. If the power supplies are in redundant mode, make sure the main power supply is
connected to J1 and a backup power supply is connected to the J3 connector.
The minimum PSE port voltage is 44 VDC for Type 1, 50 V for Type 2 and Type 3, and 52 V for Type 4.
The maximum DC voltage at VPWR is 57 V for all types. During evaluation, choose the appropriate DC
power supply for the different type environment.
2.2.1.2 3.3 V
A local 3.3 V for local devices (labeled as 3.3 V) is provided by the onboard LM5017 buck converter. The
LM5017 device provides a basic power-on sequence and provides a well-controlled and consistent startup
to prevent erratic operation. In addition to 44 V to 57 V, the TPS238x requires 3.3 V for the digital circuitry
and each TPS2388x device consumes 6-mA typical and 12-mA maximum.
2.2.1.3 3.3 V_ISO
The reference design kit provides galvanic isolation between PoE power side and host side using digital
isolators. The host side power is provided by 3.3 V_ISO.