TPS23880EVM-008

User's Guide SLVUB84B – February 2018 – Revised October 2018 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module This user’s guide describes the evaluation modules (EVM) for the TPS23880 (TPS23880EVM-008 and BOOST-PSEMTHR-007). The EVM contains evaluation and reference circuitry for the TPS23880. The TPS23880 is a Power-over-Ethernet (PoE) device for power sourcing equipment (PSE). 1 2 3 4 5 6 Contents Description .................................................................................................................... 2 Quick Start .................................................................................................................... 2 General Use Features ....................................................................................................... 6 TPS23880EVM GUI Setup ................................................................................................. 8 EVM Schematic, Layout Guidelines and PCB Assembly, Layer Plots .............................................. 21 Bill of Materials ............................................................................................................. 32 List of Figures 25 ............................................................................................. 4 Advanced Setup Using LaunchPad™ .................................................................................... 5 TPS23880EVM GUI SRAM Loading Window ........................................................................... 8 TPS23880EVM GUI Startup Window ..................................................................................... 9 Device Configuration and Port Telemetry Page ....................................................................... 10 Register Map ............................................................................................................... 10 SRAM Code Load .......................................................................................................... 11 Program Started ............................................................................................................ 12 Terminal Response With Connected Ports ............................................................................. 13 Auto Mode System Software Structure.................................................................................. 15 Semi Auto Mode System Software Structure ........................................................................... 16 Power on Decision Flow Chart ........................................................................................... 19 System Power Monitor Flow Chart....................................................................................... 19 BOOST-PSEMTHR-007 (Motherboard) Schematic: Control ......................................................... 22 BOOST-PSEMTHR-007 (Motherboard) Schematic: Power Ports ................................................... 23 TPS23880EVM-008 (Daughterboard) Schematic ...................................................................... 24 BOOST-PSEMTHR-007 (Motherboard) Top Side Assembly ......................................................... 25 BOOST-PSEMTHR-007 (Motherboard) Top Side Routing ........................................................... 26 BOOST-PSEMTHR-007 (Motherboard) Layer 2 Routing ............................................................. 27 BOOST-PSEMTHR-007 (Motherboard) Layer 3 Routing ............................................................. 28 BOOST-PSEMTHR-007 (Motherboard) Bottom Side Routing ....................................................... 29 TPS23880EVM-008 (Daughterboard) Top Side Assembly ........................................................... 30 TPS23880EVM-008 (Daughterboard) Top Side Routing ............................................................. 30 TPS23880EVM-008 (Daughterboard) Bottom Side Routing ......................................................... 31 TPS23880EVM-008 (Daughterboard) Bottom Side Assembly ....................................................... 31 1 TPS23880EVM Voltage Rail Current Requirements 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Basic Setup Using USB2ANY List of Tables 2 3 ................................................................... EVM Input/Output Connectors ............................................................................................. EVM LEDs .................................................................................................................... SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 3 6 6 1 Description www.ti.com 4 EVM Test Points ............................................................................................................. 7 5 EVM Jumpers 6 Terminology ................................................................................................................. 17 7 State Definitions ............................................................................................................ 17 8 Function Definitions ........................................................................................................ 18 9 User Configurable Parameters ........................................................................................... 18 10 BOOST-PSEMTHR-007 Bill of Materials 32 11 TPS23880EVM-008 Bill of Materials 34 ............................................................................................................... ............................................................................... .................................................................................... 7 Trademarks LaunchPad, Code Composer Studio are trademarks of Texas Instruments. All other trademarks are the property of their respective owners. 1 Description The TPS23880EVM features the 8-channel, TPS23880, IEEE 802.3bt (draft) PoE PSE controller. The EVM consists of a motherboard (BOOST-PSEMTHR-007) and a daughterboard (TPS23880EVM-008) containing one TPS23880 device. The TPS23880EVM provides a multi-port base platform interface for TPS23880EVM-008, MSP-EXP430FR5969 (LaunchPad™), and USB2ANY (USB Interface Adapter). 1.1 Features The EVM supports the following features: • Four IEEE802.3bt (draft) 2-pair ports with 1000BASE-T (gigabit Ethernet data pass-through) • Two IEEE802.3bt (draft) 4-pair ports with 1000BASE-T (gigabit Ethernet data pass-through) • Single DC power supply input • Onboard 3.3-V regulator • Onboard I2C interface to both TPS23880 devices from either USB2ANY or MSP-EXP430FR5969. • Port ON status LEDs • User test points 1.2 Applications The EVM is used in the following applications: • Enterprise and SoHO switches and routers • Connected ceiling LED switches • PoE pass-through power modules • Network video recorders (NVRs) • Wireless backhaul and small-cell networking 2 Quick Start 2.1 Input Power 2.1.1 Input Power (Labeled VPWR) The DC input voltage is provided through J1 (screw jack). A DC power supply or wall adapter with sufficient current capacity can power the EVM. CAUTION Reverse voltage protection is not provided; ensure that the correct polarity is applied to J1. 2 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated Quick Start www.ti.com This DC input is labeled VPWR in the schematics and is used for port VBUS as well as for the TPS23880 devices. The VPWR connections to the PoE ports are not fused. Each two-pair port is capable of furnishing at least 30 W and each four-pair port can furnish 90 W. 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. During evaluation, choose the appropriate DC power supply for different environments. 2.1.2 Local 3.3 V (Labeled 3.3V) Local 3.3 V for local devices (labeled as 3.3V) is provided by the onboard LM5019 buck converter. The LM5019 provides a basic power-on sequence and provides a well-controlled and consistent startup. In addition to 54 V, the TPS23880 requires 3.3 V for the digital circuitry and this is routed up to TPS23880EVM-008 over the connector interface. The current consumption is 6-mA typical and 12-mA maximum. 2.1.3 External 3.3 V (Labeled 3.3V_USB) The BOOST-PSEMTHR-007 provides galvanic isolation between the PoE power side and host side using digital isolators (ISO7241CD). The host side power is provided either from J2 (from USB2ANY) or J5 (from MSP-EXP430FR5969 ). CAUTION Do not use USB2ANY and LaunchPad simultaneously. Table 1. TPS23880EVM Voltage Rail Current Requirements 2.2 Voltage Rail Typical (mA) 3.3V_USB 2.5 Maximum (mA) 3 3.3V 6 12 VPWR (Miscellaneous) 35 57 VPWR (4 × 2 Pair Ports and 2 × 4 pair Ports) 5556 5578 VPWR Total (4 × 2 Pair Ports and 2 × 4 pair Ports) 5591 5613 PoE Port Interfaces The TPS23880 device must be configured through the host to become operational. This EVM provides 2 ways to control the TPS23880: TPS23880EVM GUI (with USB2ANY) and MSP-EXP430FR5969 LaunchPad. 2.2.1 IEEE802.3bt (draft) 2-Pair Ports Four 2-pair ports are provided at J19, J20, J8, and J7 for 2-pair ports 1, 2, 3, and 4 respectively. The power furnished is according to alternative A with MDI-X polarity. 2.2.2 IEEE802.3bt (draft) 4-Pair Ports Two 4-pair high power ports are provided at J21 and J9 for 4-pair ports 1 and 2, respectively. The power furnished is according to alternative A with MDI-X polarity and alternative B with S polarity on a single port connector. A single- or dual-signature PD may be powered by the 4-pair ports with proper port configuration (enabling 4-pair mode). 2.3 I2C Interfaces Two I2C interfaces to the TPS23880 are provided on the EVM. SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 3 Quick Start 2.3.1 www.ti.com USB2ANY J2 provides an interface with the USB2ANY adapter when using a PC and GUI. 2.3.2 MSP-EXP430FR5969 J3, J4, and J5 provide an interface with the MSP-EXP430FR5969 when using a PC to develop custom system software. 2.4 Basic Test Setup Using USB2ANY for I2C Interface (Auto Mode or Semi-Auto Mode Operation with I2C Monitoring) An I2C interface is provided through J2 to the TPS23880 devices on the TPS23880EVM-008. The USB2ANY adapter (not included) can be used with any TI GUI which uses USB2ANY to read and write over an I2C bus. Figure 1 illustrates the basic setup using USB2ANY. TPS2373-4EVM-758 Class 3-4 J8 J19 J9 J21 J7 Ethernet Cable Ethernet Cable J20 TPS2373-4EVM-758 Class 5-8 BOOST-PSEMTHR-007 J2 J1 (+) (-) D1 TPS23880EVM-008 Ribbon Cable x x Positive Negative x USB2ANY Power Supply x x PC USB CABLE Figure 1. Basic Setup Using USB2ANY 4 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated Quick Start www.ti.com 2.5 Advanced Test Setup Using MSP-EX430FR5969 (LaunchPad™) The LaunchPad (not included) running a custom software program can communicate with the TPS23880 devices on the TPS23880EVM-008. Figure 2 shows the advanced setup using LaunchPad. TPS2373-4EVM-758 Class 3-4 J7 J8 J19 Ethernet Cable J9 J21 Ethernet Cable J20 TPS2373-4EVM-758 Class 5-8 BOOST-PSEMTHR-007 J2 (-) J1 (+) D1 TPS23880EVM-007 MSPEXP430FR5969 USB CABLE x x Positive Negative x Power Supply x x PC Figure 2. Advanced Setup Using LaunchPad™ SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 5 General Use Features www.ti.com 3 General Use Features 3.1 EVM Input/Output Connectors and Switches Table 2 lists the EVM input and output connectors. Table 2. EVM Input/Output Connectors 3.2 Connector or Switch Label J1 J1 DC power supply screw jack. (44–57 VDC). Use a 48 VDC (nominal) for type 1 and 54 VDC (nominal) for type 2, 3, and 4 PSE operation. J2 J2 Ribbon cable connection to USB2ANY adapter J3 J3 LaunchPad control (mates with LaunchPad J1) J4 J4 LaunchPad I2C (mates with LaunchPad J2) J5 J5 LaunchPad power (onboard, mates with LaunchPad J6) J6 J6 TPS23880EVM-008 control (mates with TPS23880EVM-008 J3) J17 J17 TPS23880EVM-008 Channel 5–8 (mates with TPS23880EVM-008 J2) J18 J18 TPS23880EVM-008 Channel 1–4 (mates with TPS23880EVM-008 J1) J22 J22 Two-pair port 1 data only J19 2 Pair Port 1 J23 J23 J20 2 Pair Port 2 J11 J11 J8 2 Pair Port 3 J10 J10 J7 2 Pair Port 4 J24 J24 J21 4 Pair Port 1 J12 J12 J9 4 Pair Port 2 J29 J29 Description Two-pair port 1 power and data Two-pair port 2 data only Two-pair port 2 power and data Two-pair port 3 data only Two-pair port 3 power and data Two-pair port 4 data only Two-pair port 4 power and data Four-pair port 1 data only Four-pair port 1 power and data Four-pair port 2 data only Four-pair port 2 power and data Chassis ground tie point EVM LEDs Table 3 lists the EVM LEDs and their descriptions. Table 3. EVM LEDs 6 LED Color Label D1 GREEN 48V 48-V ON indicator Description D16 BLUE D13 Two-pair port 1 power is ON. For J19 supplier #1 (see the bill of materials (BOM)), J19 internal port LED is active. For supplier #2, D16 is active. D17 BLUE D15 Two-pair port 2 power is ON. For J20 supplier #1 (see the BOM), J20 internal port LED is active. For supplier #2, D17 is active. D13 BLUE D14 Two-pair port 3 power is ON. For J8 supplier #1 (see the BOM), J8 internal port LED is active. For supplier #2, D13 is active. D12 BLUE D12 Two-pair port 4 power is ON. For J7 supplier #1 (see the BOM), J7 internal port LED is active. For supplier #2, D12 is active. TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated General Use Features www.ti.com 3.3 EVM Test Points Table 4 lists and describes the EVM test points. Table 4. EVM Test Points TP Color Label Description Motherboard: BOOST-PSEMTHR-007 TP1 RED VPWR Used for VPWR TP2 RED 3.3V Used for TPS23880 VDD TP3 SMT GND VPWR ground TP4 WHT SDA I2C Data from LaunchPad and USB-TO-GPIO TP5 WHT SCL I2C Clock from LaunchPad and USB-TO-GPIO TP6 WHT PSE_SDAO TP7 WHT PSE_SCL I2C clock to TPS23880 TP8 WHT PSE_SDAI I2C data in to TPS23880 I2C data out from TPS23880 TP9 BLK GND1 Ground from LaunchPad and USB2ANY TP11 SMT TP11 Chassis ground test point TP14 SMT GND VPWR ground test point TP15 SMT GND VPWR ground test point TP16 SMT GND VPWR ground test point Daughterboard: TPS23880EVM-008 3.4 TP2 RED 2P4D Two-pair port 4 DRAIN TP3 WHT 2P4G Two-pair port 4 GATE TP4 WHT 4P1AG Four-pair port 1A GATE TP5 RED 4P1AD Four-pair port 1A DRAIN TP7 WHT 4P1BG Four-pair port 1B GATE TP6 RED 4P1BD Four-pair port 1B DRAIN TP1 BLK GND VPWR ground TP8 SMT GND VPWR ground EVM Test Jumpers The EVM is equipped with shunts on the jumper positions identified in Table 5, in the Default Pin Position column. Shunts can be moved and removed, as required, during use. Table 5. EVM Jumpers Jumper Default Pin Position Label Description Motherboard: BOOST-PSEMTHR-007 J27 1-2 P1 Two-pair port 1 LED bias J28 1-2 P2 Two-pair port 2 LED bias J16 1-2 P3 Two-pair port 3 LED bias J15 1-2 P4 Two-pair port 4 LED bias J26 1-2 P5 Four-pair port 1A LED bias J25 1-2 P6 Four-pair port 1B LED bias J14 1-2 P7 Four-pair port 2A LED bias J13 1-2 P8 Four-pair port 2B LED bias Daughterboard: TPS23880EVM-008 J4 1-2;3-4;5-6;7-8 J5 Open A1;A2;A3;A I2C A1-A4 address lines 4 NA SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback AUTO pin selection (resistors are not populated) TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 7 TPS23880EVM GUI Setup www.ti.com 4 TPS23880EVM GUI Setup 4.1 TPS23880EVM GUI Installation TI's TPS23880EVM GUI is used with the TPS23880EVM to control the port and provide real-time feedback on port telemetry. Download the TPS23880EVM GUI from the TPS23880 product folder page in the Tools & software section. Follow the onscreen instructions to complete the installation. The TPS23880 GUI uses the USB2ANY as an interface between the PC USB port and the BOOST-PSEMTHR-007 J2 connector (I2C interface). Before starting the TPS23880 GUI, make sure the USB2ANY is properly connected to TPS23880EVM and the EVM is supplied with a 44- to 57-V power supply as Figure 1 shows. 4.2 TPS23880EVM GUI Operation Start the TPS23880EVM GUI by double clicking the GUI icon. A window similar to Figure 3 comes up. Figure 3. TPS23880EVM GUI SRAM Loading Window After the GUI is opened, it automatically loads the default SRAM and parity check code to the TPS23880. The default device address in the GUI is set to 0x20 which matches the default configuration of the EVM (J4 on the daughter card is installed with jumpers). The GUI sets the TPS23880 in configuration B mode (see the GENERAL MASK Register section of the data sheet for details). The address can be programed through the A1 to A4 pins and the I2C address setting in the GUI needs to match the hardware configuration. See the Pin Status Register section of the data sheet for details. The startup page contains links to the EVM user's guide, TPS23880 data sheet, E2E forum, and MSP430 reference code. Four popular PD end-equipment images are connected to the PSE switch. Links to the recommended PD device for each end equipment are also provided. Once Device Connected displays and port configuration type is selected , click Engineering View. 8 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com Figure 4. TPS23880EVM GUI Startup Window On the page displayed in Figure 4, each port can be configured separately by clicking each RJ45 connector. By default, the TPS23880 is configured in OFF Mode. Each port can be configured by clicking the RJ45 icon. Clicking the SET ALL PORTS TO STANDARD button sets all port to standard configurations (configuring ports in Semi-Auto mode, enabling OSS, power policing, and DC disconnect). Clicking the SET ALL PORTS TO AUTO MODE button enables Auto Mode for all ports. The status of each port is shown on the configuration and telemetry page. The configuration of the ports can also be edited on this page by clicking the RJ45 connector. If the port is configured in Auto Mode, the port will turn on automatically by the PSE device after connecting a valid PD. If not configured in Auto Mode, a port enable command is required (4P Enable for 4 pair ports and 2P Enable for 2 pair ports). The port can be turned on only when the PD has valid detection and classification results. SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 9 TPS23880EVM GUI Setup www.ti.com Figure 5. Device Configuration and Port Telemetry Page The GUI also provides access to every register of the device in the register map. Figure 6. Register Map 10 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com If wanting to reload a different version of SRAM code, click "Firmware" on the left corner and select the SRAM code file. Once that's done, the new SRAM code will be loaded to TPS23880 device. Figure 7. SRAM Code Load SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 11 TPS23880EVM GUI Setup 4.3 www.ti.com MSP-EXP430FR5969 Details The TPS23880EVM accepts the MSP-EXP430FR5969 evaluation module when the application requires management of the TPS23880 devices with an external controller. 1. Install MSP-EXP430FR5969 onto BOOST-PSEMTHR-007 and ensure that the USB2ANY ribbon cable is NOT installed into J2. 2. Connect the PC to the LaunchPad as shown in Figure 2. 3. The source code was developed for the MSP430 LaunchPad Development Kit (MSPEXP430GFR5969) using the Code Composer Studio™ (CCS) version 7.2.0 development environment. The target MSP430 can be programmed within this environment. 4. Once CCS is installed, use the basic set of instructions listed in Section 4.3.1 to import, build, and run the project. CCS version 7.2.0 is used in the following examples. Note that a terminal program such as HyperTerminal or Teraterm is required to view the output from the EVM when it is running. 4.3.1 Basic CCS and Terminal Setup Use the following steps for basic CCS and terminal setup: 1. Launch the CCS program on the PC: Start → Texas Instruments → Code Composer Studio 7.2.0 → Code Composer Studio 7.2.0. 2. OK the workspace location and CCS starts. 3. Import the project: Project→ Import CCS Projects (make sure you are in CCS Edit mode). 4. Navigate to the project location, then click the Finish button. 5. Build the project by clicking the hammer symbol. 6. Launch the debug session from CCS to activate the current project: Run, Debug (or F11). 7. Run the active project: Run, Resume (or play button, F8). 8. Determine the PC COM port connected to the LaunchPad by going into the Device Manager Ports (COM and LPT) section. Launch the terminal program. 9. Once the terminal program is properly connected to the LaunchPad running the PoE firmware, then text similar to the following image appears. Figure 8. Program Started 12 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com 10. The TPS23880EVM is now waiting for a PD load to be installed. As ports are installed, the system automatically detects, classifies, and powers up the port as shown in Figure 9. Port status is updated on the screen approximately every 10 seconds. Figure 9. Terminal Response With Connected Ports SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 13 TPS23880EVM GUI Setup 4.4 4.4.1 www.ti.com MSP430 Reference Code Overview There are two versions of MSP430 reference code published on ti.com. One is for basic applications and the other is focused on multi-port power management applications. The reference code for multiport power management applications will be discussed in detail since it has more flexibility and complexity. The system software supports the following features: • IEEE802.3bt (draft) PoE specification • Device detection, connection check, and classification • Automatic power on (standard 2-pair and 4-pair PDs) • DC disconnect • Port telemetry updates • Multi-port power management The reference code can support PSE systems with up to 48 ports. It keeps track of all system-level parameters as well as port-level parameters for each TPS23880 device within the system. The MSP430 communicates with the PC through UART, reporting the parameter and status of the port. CAUTION The parity programming is not available for current version of reference code. 14 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com 4.4.2 Auto Mode Auto mode operation is demonstrated in the MSP430 reference code and Figure 10 shows the flow chart. Basically, after configuration, the TPS23880 handles port detection, classification, turn on, and faults by itself and there is no control needed from the host. Start Initialize MSP430 (GPIO, I2C, UART) Every 10 seconds Print Input Voltage, Temperature, and Port Telemetry via UART Load SRAM Code Configure TPS23880 Interrupts Set Ports to Auto mode Enable DC Disconnect Configure 2 Pair/4 Pair Mode for Each RJ45 Port Power Off All Ports (QDEOH 3RUWV¶ 'HWHFWLRQ & Classification Figure 10. Auto Mode System Software Structure SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 15 TPS23880EVM GUI Setup 4.4.3 www.ti.com Semi Auto Mode OperationThe Semi Auto Mode reference code is interrupt based. When MSP430 receives an interrupt from PSE's INT pin,the code checks interrupt register and event registers to proceed with actions accordingly. The flowchart of semi auto mode code is shown as below. Start Classification Event Disconnection Event Fault Event Initialize MSP430 Get Classification Status Get Disconnect Status Get Fault Status Determine port(s) Determine port(s) Determine port(s) Load SRAM Code Print Status Configure TPS23880 Interrupts, Remapping, OSS,etc. Print Status Set Power Off to all ports. Set Ports to SEMI_AUTO mode Classification Valid? Every 10 seconds Print input voltage, temp, and port telemetry via UART Yes Enable DC Disconnect Power On Port/PPM v o W}Œš•[ detection& classification Figure 11. Semi Auto Mode System Software Structure 16 TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com 4.4.4 Multi-Port Power Management Module Multi-Port Power Management methods are used to manage the distribution and prioritization of PDs. Power Management itself is not defined by the IEEE specification. Instead, it is a policy that takes advantage of the POE specification as it defines such terms as port and system power. The goals of MultiPort Power Management in a POE enabled system are two-fold: • Power as many PDs as possible • Limit power cycling of PDs In many systems, the maximum system power available limits the total number of ports that may be powered. For example, each PD can draw a maximum of 30W, and a 48-port system can draw more than 1440W total system power. If the maximum system power available is less than 1440W then Power Management becomes necessary so that the available system power may be used in the most efficient manner while meeting the goals. 4.4.4.1 Definitions and Formulas Table 6 defines terms used in the Power Management algorithm. Table 6. Terminology TERM DEFINITION sysPower The current total power consumed by PDs The estimated power the current port(finished detection and classification) is going to consume portPowerEstimate 4.4.4.2 lowestPrioPort The lowest priority port among all turned on ports powerOffPort Port will be powered off powerOnPort Port will be turned on State Definitions The Power Management algorithm operates as a state machine, whereby the algorithm is a certain state at any given point in time. Table 7 shows the state definitions for the algorithm. Table 7. State Definitions STATE DEFINITION PM_CHECK Calculate existing ON ports’ total power, get current port estimate power, compare total power + port estimate power and Power budget PM_POWERUP Power up current port PM_OVERLIMIT Power demand has exceeded the power budget. Calculate whether the remaining power is enough to turn on current port after turning off all lower priority ports PM_POWERDOWN Power down the lowest priority port. Entered from PM_OVERLIMIT SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 17 TPS23880EVM GUI Setup 4.4.4.3 www.ti.com Function Definitions The power management function is called after a valid classification is performed. It includes the functions below to implement the algorithm. Table 8. Function Definitions FUNCTION 4.4.4.4 DEFINITION uint32_t PM_calSysPower(void) Calculate current total power consumed by PDs uint8_t PM_getActLowestPrioPort(void) Find lowest priority port among all turned on ports uint32_t PM_getPowerofPortsHigherPriority(uint8_t PM_sysPortNumber) Calculate total power of ports that have the same or higher priority uint32_t PM_getRequestPower(uint8_t PM_sysPortNumber) Get estimate power of current port(finished detection and classification) is going to consume based on classification results void PM_powerManagement(uint8_t PM_sysPortNumber) Power management function called in main function void PM_monitorSysPower(void) Note: running in background, timer interrupt triggered Real-time check if current total power consumed by PDs exceeds power budget (to prevent load step change on any ports). User Configurable Parameters The PPM module gives user some flexibility to configure. Table 9shows the user configurable parameters. Table 9. User Configurable Parameters TERM 18 DEFINITION LOCATION #define PM_EN Enable PPM feature. Enable=1, disable=0. power_manage.h #define PM_POWER_BUDGET Total system power budget. Unit: mW power_manage.h #define NUM_OF_TPS2388x Total number of TPS23880 in the system system_init.h #define PM_POWER_MONITOR_TIMER The timer that host monitor the actual system power system_init.h #define The timer that host restart detection/ classification of the PM_DETECT_CLASS_RESTART_TIMER ports which are turned off system_init.h uint8_t i2cAddList[] I2C address of TPS23880 system_init.c uint8_t PM_setPriority[] The port priority setting of each port system_init.c TPS238x_2P_Power_Allocation_t tps2388x_PA_2P[] Power allocation for 2 pair ports system_init.c TPS238x_4P_Power_Allocation_t tps2388x_PA_4P[] Power allocation for 4 pair ports system_init.c TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated TPS23880EVM GUI Setup www.ti.com 4.4.4.5 Design Flow The Power Management algorithm is shown in below figure in the form of a flow chart. Mode = PM_CHECK Is remaining power enough? Yes Mode = PM_POWERUP No Mode = PM_OVERLIMT Is remaining power enough after turning off lower priority ports? Yes Mode = PM_POWERDOWN No Figure 12. Power on Decision Flow Chart Real-time system power monitor to protect the system when step change happening on any ports. (100 ms timer triggered): Calculate total actual system power Is total system power over power budget? Yes Power down lowest priority port No Figure 13. System Power Monitor Flow Chart SLVUB84B – February 2018 – Revised October 2018 Submit Documentation Feedback TPS23880EVM: PoE, PSE, TPS23880 Evaluation Module Copyright © 2018, Texas Instruments Incorporated 19 TPS23880EVM GUI Setup 4.4.4.6 www.ti.com Pseudo-Code The Power Management algorithm can also be represented by the following pseudo-code. //This part is inserted after each port's successful classification if (Mode == Check) { Get RequesPortPower; Calculate SystemPower; if (SystemPower + RequesPortPower > PowerBudget) { Mode = OverLimit; } else { Mode = PowerUp; } } if (Mode == OverLimit) { //If the remaining power is enough to turn on current port after powering down all ports that have lower priority, //then turn off the lowest priority port; otherwise, wait for next cycle if (PowerofHigherPriorityPorts + RequesPortPower