AN4473 Application note PoE synchronous flyback, IEEE802.3at compliant, 5V - 4A PD converter based on the PM8803 controller Antonio Rotta Introduction This document describes a reference design for a POE+, high efficiency, 5 V - 4 A flyback converter based on the PM8803 PoE controller. The PM8803 is a highly integrated device embedding an IEEE802.3at compliant “Powered Device” (PD) interface together with a PWM controller and support for auxiliary sources. The STEVAL-TSP004V2 reference design is based on an isolated flyback topology CCM converter with synchronous rectification with a gate driver transformer. The same PCB can be populated in different ways to support various configurations and topologies (the flyback with diode rectification, synchronous flyback with or without an active clamp, self-driven synchronous flyback). Figure 1. STEVAL-TSP004V2 evaluation board photo May 2015 DocID026206 Rev 1 1/30 www.st.com Contents AN4473 Contents 1 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 3 2 Schematics for 5 V at 4 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 4 2.1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Measurements results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1 Efficiency comparison with three rectification bridge options . . . . . . . . . . 13 3.2 Converter efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.3 Voltage ripple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.4 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.5 Primary side waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.6 Secondary side waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.7 Load transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.8 PoE to auxiliary switchover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.9 Gloop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Supporting material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.1 PCB layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5 Electrical diagram general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2/30 DocID026206 Rev 1 AN4473 1 Main characteristics and circuit description Main characteristics and circuit description The main characteristics (reference and electrical specifications) of the converter are listed inTable 1 and Table 2. Table 1. Reference Reference code Device PM8803 Evaluation board STEVAL-TSP004V2 Table 2. Electrical specification Parameter Specifications Input voltage supplies VIN [VDC] From 40 to 60 V Auxiliary input voltage range From 30 to 60 V Output voltage Vout [VDC] 5 VDC ± 5% at 4 A Peak-to-peak output ripple < 30 mVpp Efficiency DC-DC at full load > 92% Efficiency overall at full load > 89% Transient response ΔVoutpk to 50% load step < 180 mV ΔVout in load line case < 0.5% GLOOP bandwidth > 3 kHz GLOOP phase margin at 0dB > 70 deg. GLOOP dB margin at 0 deg. > 10 dB This document details the characteristics and performances of the PM8803 evaluation kit STEVAL-TSP004V2, which has been designed to cover a broad range of Power over Ethernet (PoE) applications. The PM8803 is a highly integrated device embedding an IEEE802.3af/at compliant powered device (PD) interface together with a PWM controller and support for auxiliary sources. Even though the PM8803 device can be configured to work in several isolated topologies, self-driven or a transformer gate driven; this application note focuses on a high efficiency isolated flyback converter topology with synchronous rectification, 5 V output voltage with a 4 A output current capability. Auxiliary sources can be connected to the board on 2 different input connectors. One input (AUX II) allows prevalence of the auxiliary sources with respect to the PoE, while the other input (AUX I) allows the usage of a wall adaptor with voltage lower than the internal PoE UVLO threshold and still benefits from the inherent inrush and DC current limit. DocID026206 Rev 1 3/30 30 Main characteristics and circuit description AN4473 The possible configurations supported by the PM8803 demonstration kit as options on the same PCB are: • Alternative input bridge rectification: 4 possible options including standard diode bridges, discrete schottky diode bridges, half active bridges and full active bridges; schottky diode bridges are mounted on this eval board. • Optional 4 pairs detection circuit, to detect if power is provided on 2 pairs or on 4 pairs by a high power PSE source; this circuit is not used on this eval board. • Optional booster circuit, to increase the max. input current over 1 A; this circuit is not used on this eval board. • Diode or synchronous rectification; 4 package options for the diode and 2 package options for the MOSFET. • Primary side snubber; 3 options included an active clamp: a simple R-C snubber is used on this eval board. • Power transformer; 3 size options for transformer gate driven solutions and 2 size options for self-driven applications. The bill of material (BOM) in Table 3 provides the list of components to be mounted to obtain a flyback CCM converter with a gate transformer driven synchronous rectifier, with 5 V output at a 4 A evaluation board. 4/30 DocID026206 Rev 1 10 9 Chassis 1 2 3 R26 DocID026206 Rev 1 R37 0R0 R32 15K 0805 1206 1206 SMC STTH302S SP D7 SMA STPS2H100A D14 SMA STPS2H100A SMA STPS2H100A D9 SMA D13 SMA STPS2H100A SMA STPS2H100A D12 SMA STPS2H100A SMA STPS2H100A D17 D8 STPS2H100A D4 ETH1-460 24 23 0603 R7 0603 75R 75R 75R 75R 0603 0603 R5 R2 R1 Chassis TP23 BLACK Red C16 1nF 10% 0805 100V 0R0 1206 TP22 BLACK TP24 R125 C9 2.2nF 2KV 1812 R43 0R0 1206 1206 R17 0R0 VSS POE+F C18 0.1uF 10% 0805 100V Chassis SMA SMAJ58A D11 Chassis 1 2 3 4 5 6 7 8 J4 VSS C21 1nF 10% 0603 100V RTN C14 1nF 10% 0603 100V POE+F DATA OUTPUT Schematic 0R0 D1 2 1 22 21 20 19 18 17 16 15 14 13 2.1 TP3 BLACK TP2 Red Chassis C12 2.2nF 2KV 1812 C8 10nF 10% 0603 100V C7 75R 0603 R13 10nF 10% 0603 100V 75R 0603 R12 T1 Schematics for 5 V at 4 A Auxiliary input frontal or AUXI AUX 1 C6 10nF 10% 0603 100V 75R 0603 75R 0603 C5 10nF 10% 0603 100V R11 R10 3 4 5 6 8 7 9 10 11 12 2 SP J2 DATA & POWER INPUT J3 1 2 3 4 5 6 7 8 10 9 Chassis AN4473 Schematics for 5 V at 4 A Figure 2. STEVAL-TSP004V2 evaluation board: electrical schematic (1/2) 5/30 30 27k R27 C19 10nF R38 1k C69 10nF R101 24.9K 1% 1% R64 0R0 T2P R51 15K 0805 MMBT3904LT1 SOT23 Q18 R49 R9 1K 1% R0603 1% R0805 R72 120K 1% 1% R54 1206 0R0 0R0 1206 C23 470nF 10% 50V 0603 24.9K 1% R95 30R9 1% R131 TP8 BLACK TP7 Red NOTE The ARTN is a dedicated plane of signal ground that will be connected to the RTN power ground plane close to pin 4 and 9 of PM8803 NOTE for Resistors Where not indicated the body is 0603 and tolerance 5% NOTE for Capacitors Where not indicated the body is 0603 and the voltage is 50V VSS SP POE+F SA 1 2 3 TP11 BLACK 11 12 13 14 15 16 17 18 19 20 R70 10K 1% 1% VDD VDD DET SP CLS DCCL SA DT FRS T2P HTSSOP20-LARGE PM8803 SA Ex Pad 21 VC 0805 VSS RTN ARTN GAT2 100V C60 1nF RTN CS VB CTL U1 GAT1 R65 1K R58 27K SMC C41 1uF 25V 0603 L5 10uH R103 R66 10R ARTN SOD323 MM3Z15VT1 D32 RTN D57 R0805 R92 10R C39 1uF 25V 0603 2.2u 1210 100V 2.2u 1210 100V RTN C29 C28 TP9 Red 10 9 ARTN VC 510R RTN Power circuit SOD323 C54 470p R89 3.3K C40 1uF 25V 1206 Input Filter C26 33uF 20% 100V 10x10.2 2 BAT46J C53 1uF ARTN SOD323 BAT46J D52 2.2u 1210 100V C64 1 MSS7341-103ML 8 TP14 Red TP4 Red 7 6 5 4 3 2 1 10nF C38 STTH302S D21 D28 SOD323 BAT46J R107 10K 0R0 R84 10R R62 TP15 Red 1206 R21 220R C30 68pF 0805 100V TP19 BLACK RTN R108 0.30 ohm 1% 1206 TP18 Red 4 Red TP16 R23 100R 1206 Q17 RTN SO8 Si4848DY 0.1uF C45 VSS SP R109 0.30 ohm 1% 1206 5 6 7 8 1 2 3 J1 3 3 TBD 2KV 1812 T5 9 10 7 6 T8 Jumper-doppio JM2 Jumper-doppio JM1 6 4 1 1 3 1 COILCRAFT DA2319-AL COILCRAFT HA3691-AL 5 4 2 1 C22 2 DocID026206 Rev 1 2 R45 24.9K 0.1uF R80 20R 2 1 Fairchild FOD817AS U2 3 4 D36 BAT46J SOD323 BAT46J SOD323 D34 8 7 6 5 0805 C31 1.5nF NOTE for Jumpers JM1 and JM2 Move the short on both jumpers at the same time: - short between pin 1 and 2 when used AUX2 input - short between pin 2 and 3 when used AUX1 input. RTN SA R83 10K C44 TP10 Red TP5 Red Q12 R44 3K3 TP21 Red D20 Aux det Q16 MMBT3906LT1 SOT23 TP13 Red PowerFLAT™ 5x6 RTN C50 47nF R90 1k5 22uF 1206 16V C27 22uF 1206 16V C37 U3 22uF 1206 16V C67 22uF 1206 16V C68 C61 2 3 T2P VC 1812 2KV SOD323 BAT46J D39 1 4 2.2n Fairchild FOD817AS Auxiliary present ARTN STL60N3LLH5 3 2 1 0805 5R R53 1 L6 0.33uH 2 R117 C59 1uF 25V 0603 5.1K D40 2 4 1 R93 1K 22uF 1206 16V C33 C56 47nF 22uF 1206 16V C35 2 1 3 4 Fairchild FOD817AS U7 Feedback circuit SOT23-5 TS431AILT U4 SOD323 BAT46J 47K R99 C49 3.3nF Output Filter DO1813-331ML 3 6/30 5 48V AUX 2 100pF C55 R104 R91 10R C34 330uF 16V 8x10.2 Out det TP20 Red D44 T2P det R112 15K 1% 1% 4.7K 1% R119 3.3K 1% C48 1uF 25V 0603 R96 0R0 D26 R52 3K3 T2P present 0R0 R122 R111 12.4K 1% 1% R94 21K 1% 1% C36 0.1u 2 1 BLACK TP12 2 J5 Red TP6 1 Schematics for 5 V at 4 A AN4473 Figure 3. STEVAL-TSP004V2 evaluation board: electrical schematic (2/2) 4 AN4473 2.2 Schematics for 5 V at 4 A Bill of material Table 3. Bill of material Item Ref. Description Value PCB footprint Supplier Voltage 1 C5 Ceramic Capacitor 10 nF 10% C0603 TDK 100 V 2 C6 Ceramic Capacitor 10 nF 10% C0603 TDK 100 V 3 C7 Ceramic Capacitor 10 nF 10% C0603 TDK 100 V 4 C8 Ceramic Capacitor 10 nF 10% C0603 TDK 100 V 5 C9 Ceramic Capacitor 2.2 nF C1812 AVX 2 kV 6 C12 Ceramic Capacitor 2.2 nF C1812 AVX 2 kV 7 C14 Ceramic Capacitor 1 nF 10% C0603 TDK 100 V 8 C16 Ceramic Capacitor 1 nF 10% C0805 TDK 100 V 9 C18 Ceramic Capacitor 0.1 µF 10% C0805 TDK 100 V 10 C19 Ceramic Capacitor 10 nF C0603 Several 50 V 11 C21 Ceramic Capacitor 1 nF 10% C0603 TDK 100 V 12 C22 Ceramic Capacitor TBD C1812 AVX 2 kV 13 C23 Ceramic Capacitor 470 nF 10% C0603 Several 50 V 14 C26 Aluminium capacitor 33 µF 20% C-POL8-10 Panasonic EEEFK2A330P 100 V 15 C27 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V 16 C28 Ceramic Capacitor 2.2 µF C1210 Murata GRM32ER72A225 KA35L 100 V 17 C29 Ceramic Capacitor 2.2 µF C1210 Murata GRM32ER72A225 KA35L 100V 18 C30 Ceramic Capacitor 68 pF C0805 TDK 100 V 19 C31 Ceramic Capacitor 1.5 nF C0805 Several 50 V 20 C33 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V 21 C34 Aluminium capacitor 330 µF C-POL8-10 Panasonic EEEFK1C331P 16 V 22 C35 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V 23 C36 Ceramic Capacitor 0.1 µF C0603 Several 50 V 24 C37 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V DocID026206 Rev 1 7/30 30 Schematics for 5 V at 4 A AN4473 Table 3. Bill of material (continued) Item Ref. Description Value PCB footprint Supplier Voltage 25 C38 Ceramic Capacitor 10 nF C0603 Several 50 V 26 C39 Ceramic Capacitor 1 µF C0603 KEMET 25 V 27 C40 Ceramic Capacitor 1 µF C1206 KEMET 25 V 28 C41 Ceramic Capacitor 1 µF C0603 KEMET 25 V 29 C44 Ceramic Capacitor 0.1 µF C0603 Several 50 V 30 C45 Ceramic Capacitor 0.1 µF C0603 Several 50 V 31 C48 Ceramic Capacitor 1 µF C0603 KEMET 25 V 32 C49 Ceramic Capacitor 3.3 nF C0603 Several 50 V 33 C50 Ceramic Capacitor 47 nF C0603 Several 50 V 34 C53 Ceramic Capacitor 1 µF C0603 KEMET 25 V 35 C54 Ceramic Capacitor 470 pF C0603 Several 50 V 36 C55 Ceramic Capacitor 100 pF C0603 Several 50 V 37 C56 Ceramic Capacitor 47 nF C0603 Several 50 V 38 C59 Ceramic Capacitor 1 µF C0603 KEMET 25 V 39 C60 Ceramic Capacitor 1 nF C0805 TDK 100 V 40 C61 Ceramic Capacitor 2.2 nF C1812 AVX 2 kV 41 C64 Ceramic Capacitor 2.2 µF C1210 MURATA GRM32ER72A225 KA35L 100 V 42 C67 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V 43 C68 Ceramic Capacitor 22 µF C1206 Murata GRM31CR61C226 ME15L 16 V 44 C69 Ceramic Capacitor 10 nF C0603 Several 50 V 45 D1 Diode STTH302S SMC STMicroelectronics 46 D4 Schottky Diode STPS2H100A SMA STMicroelectronics 47 D7 Schottky Diode STPS2H100A SMA STMicroelectronics 48 D8 Schottky Diode STPS2H100A SMA STMicroelectronics 49 D9 Schottky Diode STPS2H100A SMA STMicroelectronics 50 D11 TVS diode SMAJ58A SMA STMicroelectronics 51 D12 Schottky Diode STPS2H100A SMA STMicroelectronics 52 D13 Schottky Diode STPS2H100A SMA STMicroelectronics 53 D14 Schottky Diode STPS2H100A SMA STMicroelectronics 54 D17 Schottky Diode STPS2H100A SMA STMicroelectronics 55 D20 Diode LED Aux det KA-3528SGT Kingbright 8/30 DocID026206 Rev 1 AN4473 Schematics for 5 V at 4 A Table 3. Bill of material (continued) Item Ref. Description Value PCB footprint Supplier 56 D21 Diode STTH302S SMC STMicroelectronics 57 D26 Diode LED Out det KA-3528SGT Kingbright 58 D28 Schottky Diode BAT46J SOD323 STMicroelectronics 59 D32 Zenere Diode MM3Z15VT1 SOD323 Onsemi 60 D34 Schottky Diode BAT46J SOD323 STMicroelectronics 61 D36 Schottky Diode BAT46J SOD323 STMicroelectronics 62 D39 Schottky Diode BAT46J SOD323 STMicroelectronics 63 D40 Schottky Diode BAT46J SOD323 STMicroelectronics 64 D44 Diode LED T2P det KA-3528SGT Kingbright 65 D52 Schottky Diode BAT46J SOD323 STMicroelectronics 66 D57 Schottky Diode BAT46J SOD323 STMicroelectronics 67 JM1 Connector Jumper-doppio 3PIN-P254 Several 68 JM2 Connector Jumper-doppio 3PIN-P254 Several 69 J1 Connector SA P-JACK-RAPC722 Several 70 J2 Connector SP P-JACK-RAPC722 Several 71 J3 Connector DATA & POWER INPUT RJ45-8PIN Molex 72 J4 Connector DATA OUTPUT RJ45-8PIN Molex 73 J5 Connector MOR-10X10.5-P5-2PIN MOR-2POLI-508 Several 74 L5 Inductor 10uH MSS7341-103ML Coilcraft 75 L6 Inductor 0.33uH DO1813H Coilcraft 76 Q12 Mosfet STL60N3LLH5 PowerFLAT™ 5x6 STMicroelectronics 77 Q16 Mosfet MMBT3906LT1 SOT23 Several 78 Q17 Mosfet Si4848DY so8pwrpak-SO8 VISHAY 79 Q18 Mosfet MMBT3904LT1 SOT23 Several 80 R1 Resistor 75R R0603 Several 81 R2 Resistor 75R R0603 Several 82 R5 Resistor 75R R0603 Several 83 R7 Resistor 75R R0603 Several 84 R9 Resistor 1K 1% R0603 Several 85 R10 Resistor 75R R0603 Several 86 R11 Resistor 75R R0603 Several 87 R12 Resistor 75R R0603 Several 88 R13 Resistor 75R R0603 Several 89 R17 Resistor 0R0 R0805 Several 90 R21 Resistor 220R R1206 Several DocID026206 Rev 1 Voltage 9/30 30 Schematics for 5 V at 4 A AN4473 Table 3. Bill of material (continued) Item Ref. Description Value PCB footprint Supplier 91 R23 Resistor 100R R1206 Several 92 R26 Resistor 0R0 R1206 Several 93 R27 Resistor 27k R0603 Several 94 R32 Resistor 15K R0805 Several 95 R37 Resistor 0R0 R1206 Several 96 R38 Resistor 1k R0603 Several 97 R43 Resistor 0R0 R0805 Several 98 R44 Resistor 3K3 R0603 Several 99 R45 Resistor 24.9K R0603 Several 100 R49 Resistor 0R0 R1206 Several 101 R51 Resistor 15K R0805 Several 102 R52 Resistor 3K3 R0603 Several 103 R53 Resistor 5R R1206 Several 104 R54 Resistor 0R0 R1206 Several 105 R58 Resistor 27K R0603 Several 106 R62 Resistor 10R R0603 Several 107 R64 Resistor 0R0 R0603 Several 108 R65 Resistor 1K R0603 Several 109 R66 Resistor 10R R0603 Several 110 R70 Resistor 10K 1% R0603 Several 111 R72 Resistor 120K 1% R0603 Several 112 R80 Resistor 20R R0805 Several 113 R83 Resistor 10K R0603 Several 114 R84 Resistor 0R0 R0603 Several 115 R89 Resistor 3.3K R0603 Several 116 R90 Resistor 1k5 R0603 Several 117 R91 Resistor 10R R0603 Several 118 R92 Resistor 10R R0805 Several 119 R93 Resistor 1K R0603 Several 120 R94 Resistor 21K 1% R0603 Several 121 R95 Resistor 24.9K 1% R0603 Several 122 R96 Resistor 0R0 R0603 Several 123 R99 Resistor 47K R0603 Several 124 R101 Resistor 24.9K 1% R0603 Several 125 R103 Resistor 510R R0603 Several 10/30 DocID026206 Rev 1 Voltage AN4473 Schematics for 5 V at 4 A Table 3. Bill of material (continued) Item Ref. Description Value PCB footprint Supplier 126 R104 Resistor 4.7K 1% R0603 Several 127 R107 Resistor 10K R0603 Several 128 R108 Resistor 0.30 ohm 1% R1206 Bourns 129 R109 Resistor 0.30 ohm 1% R1206 Bourns 130 R111 Resistor 12.4K 1% R0603 Several 131 R112 Resistor 15K 1% R0603 Several 132 R117 Resistor 5.1K R0603 Several 133 R119 Resistor 3.3K R0603 Several 134 R122 Resistor 0R0 R0603 Several 135 R125 Resistor 0R0 R1206 Several 136 R131 Resistor 30R9 1% R0805 Several 137 TP2 Test Point Red TH-5013 Keystone 138 TP3 Test Point BLACK TH-5013 Keystone 139 TP4 Test Point Red TH-5013 Keystone 140 TP5 Test Point Red TH-5013 Keystone 141 TP6 Test Point Red TH-5013 Keystone 142 TP7 Test Point Red TH-5013 Keystone 143 TP8 Test Point BLACK TH-5013 Keystone 144 TP9 Test Point Red TH-5013 Keystone 145 TP10 Test Point Red TH-5013 Keystone 146 TP11 Test Point BLACK TH-5013 Keystone 147 TP12 Test Point BLACK TH-5013 Keystone 148 TP13 Test Point Red TH-5013 Keystone 149 TP14 Test Point Red TH-5013 Keystone 150 TP15 Test Point Red TH-5013 Keystone 151 TP16 Test Point Red TH-5013 Keystone 152 TP18 Test Point Red TH-5013 Keystone 153 TP19 Test Point BLACK TH-5013 Keystone 154 TP20 Test Point Red TH-5013 Keystone 155 TP21 Test Point Red TH-5013 Keystone 156 TP22 Test Point Red TH-5013 Keystone 157 TP23 Test Point BLACK TH-5013 Keystone 158 TP24 Test Point BLACK TH-5013 Keystone 159 T1 Data Transfo ETH1-460 ETH1-460 Coilcraft 160 T5 Power Transfo COILCRAFT HA3691-AL PA2328NL Coilcraft DocID026206 Rev 1 Voltage 11/30 30 Schematics for 5 V at 4 A AN4473 Table 3. Bill of material (continued) Item Ref. Description Value PCB footprint Supplier DA2318-AL Coilcraft 161 T8 Power Transfo COILCRAFT DA2319-AL 162 U1 Controller IC PM8803 163 U2 Optocoupler Fairchild FOD817AS FOD817 Fairchild 164 U3 Optocoupler Fairchild FOD817AS FOD817 Fairchild 165 U4 Voltage Reference TS431AILT SOT23-5L STMicroelectronics 166 U7 Optocoupler Fairchild FOD817AS FOD817 Fairchild 12/30 HTSSOP20-LARGE STMicroelectronics DocID026206 Rev 1 Voltage AN4473 Measurements results 3 Measurements results 3.1 Efficiency comparison with three rectification bridge options STEVAL-TSP004V2 provides different rectification bridge options: single Schottky diode, half active bridge, full active bridge and diode bridge. They are alternatively usable thanks the options available on the STEVAL-TSP004V2 demo’s PCB. Efficiency measurements have been executed to compare the different characteristics cost/efficiency through three different rectification bridge options. Here below the schematics: Figure 4. Schematic Schottky bridge T1 pin.4 AUX 1 TP2 Red J2 T1 pin.1 SP 1 2 3 T1 pin.10 T1 pin.7 D1 R26 POE+F 0R0 1206 STTH302S SMC SP D4 D7 STPS2H100A STPS2H100A SMA SMA D8 D9 STPS2H100A STPS2H100A SMA SMA C15 NM 0805 R32 15K 0805 D14 D12 D17 STPS2H100A STPS2H100A STPS2H100A SMA SMA SMA D13 STPS2H100A SMA R37 VSS 0R0 1206 TP3 BLACK Figure 5. Schematic full active bridge AUX 1 TP2 Red SP D1 R26 1 2 3 T1 pin.1 T1 pin.7 T1 pin.4 T1 pin.10 POE+F STTH302S 0603 4 Q1 R30 1M 0603 P-Ch. 100V R29 1M 0603 SO8 D3 C15 1 2 3 4 Q4 Q3 P-Ch. 100V P-Ch. 100V SO8 D2 MM3Z15VT1 SOD323 MM3Z15VT1 SOD323 D5 MM3Z15VT1 SOD323 D15 MM3Z15VT1 SOD323 D16 MM3Z15VT1 SOD323 D18 MM3Z15VT1 SOD323 R31 1M 0603 SO8 D6 MM3Z15VT1 SOD323 NM 0805 R39 200K 0603 SO8 C77 NM R40 200K R36 1M 0603 Q8 N-Ch. 100V SO8 4 0603 C78 NM R41 200K 0603 5 6 7 8 Q7 N-Ch. 100V 4 4 C76 NM R35 1M 0603 4 C79 NM R42 200K 0603 1 2 3 SO8 5 6 7 8 Q6 N-Ch. 100V D19 MM3Z15VT1 SOD323 1 2 3 R34 1M 0603 SO8 5 6 7 8 Q5 N-Ch. 100V 1 2 3 R33 1M 0603 5 6 7 8 R32 15K 0805 C75 NM 5 6 7 8 SO8 R22 200K 0603 4 Q2 P-Ch. 100V 5 6 7 8 R28 1M 0603 C74 NM R25 200K 0603 5 6 7 8 C73 NM 4 1 2 3 C72 NM R20 200K 5 6 7 8 SP R19 200K 0603 1 2 3 SMC 1 2 3 0R0 1206 1 2 3 J2 R37 VSS TP3 BLACK 0R0 1206 DocID026206 Rev 1 13/30 30 Measurements results AN4473 Figure 6. Schematic half active bridge T1 pin.4 TP2 Red R26 1 2 3 T1 pin.1 T1 pin.7 T1 pin.10 SP D1 POE+F 0R0 1206 STTH302S SMC D4 D7 STPS2H100A SP D8 STPS2H100A D9 STPS2H100A SMA SMA STPS2H100A SMA SMA C15 NM 0805 R34 1M 0603 Q6 N-Ch. 100V SO8 SO8 Q7 C77 NM Q8 N-Ch. 100V SO8 SO8 4 4 1 2 3 R40 200K 0603 1 2 3 R39 200K 0603 R36 1M 0603 N-Ch. 100V 4 4 C76 NM R35 1M 0603 C78 NM 5 6 7 8 N-Ch. 100V R41 200K 0603 C79 NM R42 200K 0603 1 2 3 Q5 5 6 7 8 R33 1M 0603 D19 MM3Z15VT1 SOD323 D18 MM3Z15VT1 SOD323 D16 MM3Z15VT1 SOD323 5 6 7 8 D15 MM3Z15VT1 SOD323 5 6 7 8 R32 15K 0805 1 2 3 AUX 1 J2 R37 VSS TP3 BLACK 0R0 1206 The measurement has been executed providing a 48V on the RJ45 connector and connecting the Poe+/Vss (TP22 vs TP23) with external electronic load with different current values to cover around 40W of input power. Figure 7. Comparison efficiency bridge Efficiency Data Transfo + Bridge Efficiency [%] 100.0% 99.5% 99.0% 98.5% 98.0% 97.5% Schottky Diode Bridge 97.0% Full Active Bridge Half Active Bridge 96.5% 800 700 600 500 400 300 200 100 0 96.0% Input Current [mA] Figure 7 shows the input stage efficiency comparison with three different bridge rectification type. The green line shows the efficiency of the Schottky diode bridge option, the cheaper of them, populated with four Schottky diodes STPS2H100A of each bridge. The yellow line shows the efficiency of the full active bridge, the most efficient, using two 100 V- 240 mΩ Pchannel MOSFET on high side and two 100V 65 mΩ N-channel MOSFET on low side of each bridge. The red line shows the half active bridge solution, which represent a right compromise in term of cost vs. efficiency. 14/30 DocID026206 Rev 1 AN4473 Measurements results Changing the input bridge it is possible to gain up to 2% about on the overall converter efficiency. 3.2 Converter efficiency Figure 8. Overall and DC/DC efficiency 5 Vout Overall and DC/DC Efficiency Efficiency 94% 93% 92% 91% 90% 89% Overall with Schottky 88% Overall FAB 87% DC-DC Overall HAB 86% 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Iout [mA] Figure 8 shows overall and DC/DC efficiencies for the converter at 48Vindc. The dotted green line is the STEVAL-TSP004V2 DC-DC efficiency. The measurement has been executed supplying 48 V to the input RJ45 connector J1 and measuring the input voltage by TP22/TP23, input voltage of DC-DC converter stage. Figure 8 shows also the overall efficiency comparison measured with the same DC-DC converter stage connected to the three different rectification bridge stages previously mentioned. Please note that: • Overall efficiency includes all loss from RJ45 to the output voltage rail. • DC/DC efficiency is a figure of merit of the converter standalone and typically does not include the losses associated to the PoE interface section that are: the RJ45 connector, data transformer, bridges, power consumption of the I/F of the PM8803 device. On the STEVAL-TSP004V2 evaluation board is mounted the simple Schottky diodes bridge solution (green line). Thanks to the bridge rectification options foreseen on the pcb it is then possible to select the best compromise cost/efficiency depending on the target request. DocID026206 Rev 1 15/30 30 Measurements results AN4473 Figure 9. Output voltage drift Output Voltage 5 Vout changhe with load 5.170 drift 5V at 48V 5.165 5.160 5.155 0.0 1.0 2.0 Iout [mA] 16/30 DocID026206 Rev 1 3.0 4.0 AN4473 3.3 Measurements results Voltage ripple Figure 10. Ripple on 5 V at 0.4 A Figure 11. Ripple on 5 V at 4 A CH2: output current CH4: output voltage CH2: output current CH4: output voltage Above measurements are referred at the output voltage ripple. In Figure 12 and Figure 13 a measure of the ripple on the input voltage has been done, to give an indication of the noise at the input of the converter. Figure 12. Ripple before and after input filter with 5 V at 0.4 A (measured on C26 and C28) Figure 13. Ripple before and after input filter with 5 V at 4 A (measured on C26 and C28) CH1: ripple after input filter CH2: input current CH3: ripple before input filter CH4: primary Vgate CH1: ripple after input filter CH2: input current CH3: ripple before input filter CH4: primary Vgate DocID026206 Rev 1 17/30 30 Measurements results 3.4 AN4473 Startup Figure 14. Startup from Microsemi 9001G injector - 5 V at 0.4 A Figure 15. Startup from Microsemi 9001G injector - 5 V at 4 A CH1: VCC CH2: input current CH3: VSS - RTN CH4: output voltage CH1: VCC CH2: input current CH3: VSS - RTN CH4: output voltage Figure 16. Startup from Microsemi 9501G injector- 5 V at 0.4 A Figure 17. Startup from Microsemi 9501G injector- 5 V at 4 A CH1: Tx Rx input current CH2: spare input current CH3: VSS - RTN CH4: output voltage CH1: Tx Rx input current CH2: spare input current CH3: VSS - RTN CH4: output voltage 18/30 DocID026206 Rev 1 AN4473 Measurements results Figure 18. Detail of the output voltage at startup Figure 19. Detail of the output voltage at startup with no load with 4 A load CH2: input current CH4: output voltage CH2: input current CH4: output voltage DocID026206 Rev 1 19/30 30 Measurements results 3.5 AN4473 Primary side waveforms Figure 20. Primary steady state 0.4 A Figure 21. Primary steady state 4 A CH1: primary MOSFET drain CH2: input current CH4: primary MOSFET gate CH1: primary MOSFET drain CH2: input current CH4: primary MOSFET gate Figure 22. Detail of primary drain at 4 A load CH1: primary MOSFET drain CH2: input current CH4: primary MOSFET gate 20/30 DocID026206 Rev 1 AN4473 3.6 Measurements results Secondary side waveforms Figure 23. Secondary steady state 0.4 A Figure 24. Secondary steady state 4 A CH1: secondary MOSFET drain CH2: input current CH4: secondary MOSFET gate CH1: secondary MOSFET drain CH2: input current CH4: secondary MOSFET gate Figure 25. Detail of secondary drain at 4 A load CH1: secondary MOSFET drain CH2: input current CH4: secondary MOSFET gate DocID026206 Rev 1 21/30 30 Measurements results 3.7 3.8 AN4473 Load transients Figure 26. 2 A - 4 A load transient Figure 27. 0.4 A - 4 A load transient CH2: output current CH4: output voltage CH2: output current CH4: output voltage PoE to auxiliary switchover Figure 28. PoE to auxiliary switchover CH1:converter input voltage CH2: PoE input current CH3: T2P signal CH4: output voltage In Figure 28 is shown a smooth transition from a PoE line set to 54 V toward an auxiliary adapter at 44 V; the output voltage is maintained stable during the transition. 22/30 DocID026206 Rev 1 AN4473 3.9 Measurements results Gloop Figure 29. Gloop 48 V at 4 A Figure 30. Gloop 48 V at no load Bw: 3.2 KHz GM:10.6 dB PM: 70 deg. Bw: 4.0 KHz GM:12.2 dB PM: 77 deg. Figure 31. Gloop 40 V at 4 A Figure 32. Gloop 57 V at no load Bw: 3.2 KHz GM:10.6 dB PM: 70 deg. Bw: 4.2 KHz GM:11.7 dB PM: 78 deg. DocID026206 Rev 1 23/30 30 Supporting material AN4473 4 Supporting material 4.1 PCB layers Figure 33. PCB top assembly Figure 34. PCB bottom assembly 24/30 DocID026206 Rev 1 AN4473 Supporting material Figure 35. PCB layer 1 top Figure 36. PCB layer 2 DocID026206 Rev 1 25/30 30 Supporting material AN4473 Figure 37. PCB layer 3 Figure 38. PCB layer 4 bottom 26/30 DocID026206 Rev 1 Chassis 10 9 1 2 3 TP3 BLACK TP2 Red R26 R37 0R0 R32 15K 0805 0R0 Auxiliary input frontal or AUXI AUX 1 SP J2 1206 1206 D1 NM 0805 C15 SMC STTH302S SP C76 R33 0603 R28 0603 C72 SOD323 D15 R39 0603 SOD323 D2 R19 0603 SO8 Q5 4 Q1 SO8 4 1 2 3 5 6 7 8 5 6 7 8 C77 R34 0603 R29 0603 C73 D16 SOD323 D3 SOD323 4 R40 0603 4 Q6 SO8 Q2 SO8 R20 0603 0805 R16 NM C6 10nF 0603 100V 75R 0603 75R 0603 C5 10nF 0603 100V R11 R10 1 2 3 5 6 7 8 5 6 7 8 DATA & POWER INPUT Chassis <Description> D14 SMA STPS2H100A 3 D7 SMA STPS2H100A 10nF 0603 100V 10nF 0603 100V C12 2.2nF 2KV 1812 C8 75R 0603 75R 0603 C7 R13 R12 1 2 J3 D17 SMA STPS2H100A D24 4 D4 SMA STPS2H100A <Description> D12 SMA STPS2H100A 3 D8 SMA STPS2H100A 1 2 D13 SMA STPS2H100A D25 4 D9 SMA STPS2H100A C78 R35 0603 R30 0603 C74 D18 SOD323 D5 SOD323 R41 0603 Q7 SO8 Q3 SO8 R22 0603 4 4 SOD323 BAT46J D47 SOD323 BAT46J D33 SOD323 BAT46J D30 SOD323 BAT46J D29 4 pairs detection circuit Optional 2 1 3 4 5 6 8 7 9 10 1 2 3 5 6 7 8 5 6 7 8 C79 R36 0603 R31 0603 C75 ETH1-460 1M 0603 0603 D19 SOD323 D6 SOD323 R42 0603 R25 0603 SOD323 BAT46J D49 SOD323 BAT46J D48 R6 1M 24 23 22 21 20 19 18 17 16 15 14 13 R8 T1 4 Q8 SO8 Q4 SO8 4 1 2 3 5 6 7 8 5 6 7 8 11 75R NM R1000 0603 1M R24 0603 1M R55 0603 D56 MM3Z15VT1 SOD323 0805 R15 NM 0603 R7 0603 75R 75R 75R 0603 0603 R5 R2 R1 C16 1nF 0805 100V Chassis Red TP22 VSS C20 NM 0603 100V RTN C13 NM 0603 100V 47K R46 0R 1206 TP23 BLACK SMA NM D10 Q22 2N7002 BLACK TP24 R125 C9 2.2nF 2KV 1812 NM 0R T2 1206 R17 R43 1206 POE+F Red TP25 Chassis Vout Chassis 1 2 3 4 5 6 7 8 VSS T11 Pulse PE65855NL - NM C18 0.1uF 0805 100V 4 pairs detection signal D50 4P det R47 3K3 Input Common Mode Filter 0R Wurth 744226S - NM C17 NM 0805 100V 3 4 3 4 Sharp PC3H7 - NM U12 2 1 2 1 Fairchild FOD817AS U6 POE+F 1206 R14 1 2 12 4 1 2 3 4 5 6 7 8 3 Chassis - 1 2 3 + 1 2 3 - 1 2 3 + 1 2 3 4 3 DocID026206 Rev 1 1 10 9 C14 1nF 0603 100V SMA C21 1nF 0603 100V RTN SMAJ58A D11 J4 VSS POE+F DATA OUTPUT 5 2 AN4473 Electrical diagram general Electrical diagram general Figure 39. Schematic 1 of 2 (general) 27/30 30 SP NM R57 NM 100V 0805 NM C62 27k R27 C19 NM C25 NM R38 1k C69 10nF 1M R127 100K R126 NM Q19 MMBT3904LT1 SOT23 For PM8803C only NM C66 1 2 3 1 2 3 NOTE The ARTN is a dedicated plane of signal ground that will be connected to the RTN power ground plane close to pin 4 and 9 of PM8803 SO8 R9 1K 1% r0603 1% 5 6 7 8 R73 r0805 1206 0R 1206 0R Q23 11 12 13 14 15 16 17 18 19 R128 NM 100K R129 470pF 50V C71 D53 D42 HTSSOP20-LARGE PM8803 VDD VDD DET SP CLS DCCL SA DT FRS T2P R998 NM 1% R997 NM 1% SA BAT46J SOD323 R102 NM 1% 0805 R999 NM 1% 20 C24 NM 0805 R67 NM 1% 2 NM TP11 BLACK MMBTA92 SOT23 C23 470nF 10% 50V 0603 R95 24.9K STS4NF100 Q24 R131 R70 21K 1% R54 R49 30R9 1% T2P R51 15K 0805 R72 100k 1% TP8 BLACK TP7 Red MMBT3904LT1 SOT23 Q18 Booster C70 1 nF 50V 0603 D55 MM3Z15VT1 SOD323 R101 24.9K 1% R64 0R NOTE for Resistors Where not indicated the body is 0603 and tolerance 5% NOTE for Capacitors Where not indicated the body is 0603 and the voltage is 50V VSS VSS SOD323 BAT46J D51 NM R56 POE+F POE+F SA J1 48V AUX 2 3 1 Prevedere footprint 1206 e 1210 per C51 4 Ex Pad 21 RTN CS VB CTL U1 100K R130 NM SMA C60 VSS RTN ARTN GAT2 VC GAT1 R65 1K R58 27K 10 9 8 7 6 5 4 3 2 1 0805 TP14 Red TP4 Red BAT46J SOD323 D54 C32 NM 0805 1 SA 1 10uH Input Filter C26 33uF 100V 10x10.2 MSS7341-103ML L5 Q11 TBD SOT23 VAUX C53 1uF C46 R89 C40 NM 16V 0805 VC 3 510R R103 C54 470p NM 3.3K Q14 NM MMBT3904LT1 SOT23 R100 NM ARTN ARTN SOD323 C41 1uF 16V 0603 2.2u 1210 100V C64 BAT46J D52 Option Booster 100V 10nF C38 1nF SMC STTH302S D21 C43 NM 25V 4x6 2 R66 10R TSSOP6 SOT23-6L Q25 ARTN 0R 1 D37 SOD323 BAT46J D57 SOD323 SOD323 22R RTN 3TBD DPack 2 Q10 D45 TP15 Red 1 R107 10k D23 packages P_gate P_source Alternative mosfet VSS SP P_gate 3 P_source 3TBD SOT223 RTN R109 0.30 ohm 1206 Q17 SO8 2KV 1812 TBD 3 9 10 7 8 T7 T6 9 8 7 12 11 10 6 4 5 4 PA0184-Pulse T4 JM1 Jumper-doppio JM2 Jumper-doppio 1 1 D41 C57 0.1uF SA R106 10K TP17 Red R83 10K 0.1uF 1 NM 4 R45 33K RTN Vaux P Q20 Si2325DS SOT23 U2 Sharp PC3H7 U11 2 1 2 3 4 3 4 Q21 IRF6216PbF SO8 Q15 1nF D36 BAT46J SOD323 BAT46J SOD323 D34 Fairchild FOD817AS 1 8 7 6 5 0805 C31 MMBT3904LT1 NM SOT23 Vgate Kathode Q12 10R TP21 Red D20 Aux det R44 1K C47 NM Q16 MMBT3906LT1 SOT23 TP13 Red Power Flat 5x6 RTN C50 0.1uF R90 680R 10uF 1206 16V C27 8 7 11 12 10 9 10uF 1206 16V C37 U3 10uF 1206 16V C67 10uF 1206 16V C68 T2P VC 1812 2.2n 2KV SOD323 BAT46J D39 2 1206 0R L7 0.33uH 2 0.33uH DO3316P-103ML 1 L6 R59 DO1813-331ML 1 T10 R117 C59 1uF 16V 0603 NM 2 COILCRAFT FA2706-BL 1 2 5 6 3 4 5.1K D40 8 7 11 12 10 9 U4 C56 NM R97 2 SOT23-5 Sharp PC3H7 U10 2 1 2 1 3 4 3 4 Fairchild FOD817AS U7 C55 47nF 10uF 1206 16V C35 TS431AILT 2 R93 1K 10uF 1206 16V C33 Feedback circuit SOT23 TS2431AILT U5 SOD323 BAT46J 47K R99 C49 10nF Output Filter Opto :un footprint nell'altro C61 3 1 2 3 4 1 4 Sharp PC3H7 U9 Fairchild FOD817AS Auxiliary present ARTN Anode STL66N3LLH5 3 2 1 0805 R53 T9 NM COILCRAFT GA3278-BL 1 2 5 6 3 4 2 alternative power transformer Option Self Driven C51 47nF 200V 1206 10R C42 NM 16V 0603 R80 R71 Option Active Clamp C44 D31 SOD323 BAT46J NM TP10 Red TP5 Red Vo P_drain Vin NOTE for Jumpers JM1 and JM2 Move the short on both jumpers at the same time: - short between pin 1 and 3 when used AUX2 input - short between pin 2 and 3 when used AUX1 input. RTN SOD323 BAT46J 0R SOD323 BAT46J D38 T5 9 10 7 6 R98 3 1 8 1 Coilcraft HA3691-AL 5 4 2 1 COILCRAFT POE300F-50L 6 5 2 1 3 4 COILCRAFT POE13P 1 2 3 4 C22 T8 COILCRAFT DA2319-AL Vin P_drain Si4848DY 0.1uF C45 RTN 2 Q13 P_drain R108 0.30 ohm 1206 TP18 Red 4 Red TP19 BLACK SMA TP16 1206 220 1206 NM 220 Q9 MMBT3906LT1 NM SOT23 0R R84 10R R62 R23 R21 C30 100pF 0805 100V Kathode DPAK STPS15L45CB PowerFLAT 5x6 R18 NM 1206 BAT46J D28 RTN Vaux P BAT46J R0805 R92 2.2u 1210 100V C63 PowerFLAT 3x3 Power circuit R0805 R48 SOD323 D22 STPS15L30CDJF STPS8L30DEE SMB STPS2L30UF D46 RTN MM3Z15VT1 D32 C39 1uF 16V 0603 2.2u 1210 100V VAUX C29 2.2u 1210 100V TP9 Red C28 RTN Anode D43 A1 K A2 A1 K A2 5 6 7 8 1 2 3 packages 2 3 2 Alternative diode 1 2 3 4 per C40 3 2 5 6 7 8 Prevedere footprint 1206,0805 5 6 1 2 4 1 3 4 1 0R R96 0R 10 D26 TP20 Red C36 0.1u R111 12.4k 1% R94 21k 1% 2 1 Vgate 2 1 J5 Red TP6 BLACK TP12 Kathode Vo T2P present 0R R122 Vout R52 1K D44 T2P det R112 15K 1% 4.7K R119 1K 1% C48 1uF 16V 0603 R91 R104 100pF C34 330uF 6.3V 8x10.2 R60 BAT46J NM SOD323 D35 Out det I footprint devono esssere il piu' possibile sovrapposti, al fine di minimizzare lo spazio usato. 2 3 2 2 3 DocID026206 Rev 1 5 28/30 3 Electrical diagram general AN4473 Figure 40. Schematic 2 of 2 (general) AN4473 6 Revision history Revision history Table 4. Document revision history Date Revision 25-May-2015 1 Changes Initial release. DocID026206 Rev 1 29/30 30 AN4473 IMPORTANT NOTICE – PLEASE READ CAREFULLY STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgement. Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the design of Purchasers’ products. No license, express or implied, to any intellectual property right is granted by ST herein. Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product. ST and the ST logo are trademarks of ST. All other product or service names are the property of their respective owners. Information in this document supersedes and replaces information previously supplied in any prior versions of this document. © 2015 STMicroelectronics – All rights reserved 30/30 DocID026206 Rev 1