POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Triple Isolated Power Supply for POE Powered Device Application Using UC3844 and LX1752 Evaluation Board Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE CONTENTS INTRODUCTION………………………………………………………………………………………..3 KEY FEATURES………………………………………………………………………………………..3 APPLICATIONS………………………………………………………………………………………...3 ORDERING INFORMATION……………………………………………………………………………..3 OPERATION……………………………………………………………………………………………4 PERFORMANCE………………………………………………………...………………………………5-7 EVALUATION BOARD SCHEMATIC…………………………………………………………………….8-10 BILL OF MATERIALS…………………………………………………………………………………..11-13 PCB LAYOUT………………………………………………………………………………………….14-18 TEST SETUP & PROCEDURE…….……………………………………………………………………...19-20 Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Introduction to Product The multi-output power supply evaluation board is a fully assembled and tested printed circuit board (PCB) that provides three step-down regulated output voltages with a 36V to 57V input at 13W. The power supply is designed for Power Over Ethernet (POE) applications, specifically the Powered Device (PD) or the receiver end. Figure 1 shows a block diagram of the PD power supply. The power supply consists of the following sections: Input filter and rectifier, PD interface, EMI filter, 5V output isolated flyback converter, and 5V to 3.3V and 1.8V non-isolated step down converters. The UC3844 is designed as the isolated flyback converter and the LX1752 generates the step down dual outputs. The flyback converter is configured using 13W. The power capability of the design can be increased to 30W by changing the flyback transformer and output rectifier diode to a higher power rating. Note that the power supply circuitry (minus the PD interface) is not limited to POE applications and can be used in any application requiring a 36V to 57V input and step down output(s) adjusted for the required voltage(s). Figure 1 – Block Diagram 36V to 57V POE Input Input Filter and Rectifier PD Interface EMI Filter Isolated Flyback 5VDC 5V to 3.3V Step-Down 3.3VDC 5V to 1.8V Step-Down 1.8VDC Key Features: ● 36V to 57V Input Range ● Output Voltages 5V (Isolated Flyback Output) 3.3V (Step-down Switching Regulator) 1.8V (Step-down Switching Regulator) ● 13Watt Input ● Adjustable Output Voltages using External Resistors ● 70% Overall Efficiency ● Power Device Interface Applications: ● Power Over Ethernet Powered Device / Receiver End Supply ● Multi-output Power Supply Ordering Information: ● Part # LX1752-POE-PD13W Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Evaluation Board Operation: The evaluation board accepts a 36V to 57V input via a CAT-5 cable connected to the Ethernet connector port (J1). The connector J1 integrates an RF transformer for Ethernet data coupling and also an input filter that conducts RF interferences to chassis ground. Connector J2 routes and outputs the Ethernet data from port J1. The diode bridges (U1 and U2), which allow the positive and negative terminals of the input supply to be interchanged, are rated at 1.5A. The Powered Device (PD) interface consists of a detection, classification, and isolation circuits. The detection block supports two different detection schemes, which comprises of a 25kΩ resistor detection, as required by the IEEE 802.3a standard, and also an input capacitor detection. Classification is optionally performed by the Power Sourcing Equipment (PSE) to determine the level of power consumption by the PD. Isolation circuitry blocks power from the PSE to the flyback during detection and classification. For a detailed explanation of the Power Device interface, refer to Application Note AN-125. The isolated flyback converter uses the UC3844 current mode controller set to operate at 200kHz. The converter runs in a discontinuous mode. The isolated feedback is provided using an opto-isolator driven by an error amplifier made from a TL431. Additional compensation is provided using the error amplifier contained within the UC3844. The power transformer T1 has a primary side inductance of 27uH +/-15%. Note that upon initial power up, the flyback controller (U3) is kick-started by the energy stored in C13, which is charged up by the input voltage source. After startup, the auxiliary winding will generate the bootstrap voltage to keep U3 enabled. The power transformer also includes a reset winding via an ultra-fast rectifier diode (D8) to ground, to clamp leakage inductance overshoots when M2 turns off and also to provide a path that returns the leakage energy to the input for improving efficiency. To further prevent premature startup of the flyback converter, the circuitry consisting of Q6, Q7, and Q8 is a comparator used to hold off the UC3844 by providing a low impedance path from the COMP output through Q8 to ground until M1 is completely turned on. When M1 is turned off, the base voltage of Q6 will be less than the base voltage of Q7, driving the gate of Q8 high. When M1 is turned on and the input voltage rises to its nominal value, the base voltage of Q6 will be higher than the base voltage of Q7, pulling the gate of Q8 low to turn it off, allowing the COMP pin to rise to start the flyback circuit. A soft-start is implemented by adding D11, C18, and R30 to the COMP pin of the UC3844 since the COMP pin voltage directly controls the maximum current through the switch. Finally, note that since the flyback converter has a pulsed input current, an EMI filter is included to prevent the 200kHz current chop from becoming conducted emissions. The EMI filter consists of L4, C6, and C7. The final stage of the POE PD power supply consists of the LX1752 buck regulator configured to operate at a switching frequency of 800kHz, with output voltages set at 1.8V and 3.3V. The buck inputs, the input supply VIN to the LX1752, and VCCL of the LX1752 are powered by the 5V output of the flyback and are all tied to the same node. Feedback compensation of the LX1752 is provided externally using type 2. The current limit for both outputs is set at approximately 5A and can be externally adjusted. For more information regarding the LX1752, please refer to the device datasheet. Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Performance: Performance of the POE PD Power Supply is observed for 13W at the input under the following conditions: Nominal Output Voltage 1.8V 3.3V 5V Output Current 1A 1A 0.75A Overall Efficiency at Full Load Conditions The overall efficiency is the total output power of the 3 regulated outputs with respect to the input power applied at the Ethernet port connector. VIN=36V 70.5% Overall Efficiency (includes the diode bridges, PD interface, filters, Flyback, and Buck) 5V @ 0.75A VIN=48V 70% 1.8V @ 1A 3.3V @ 1A VIN=57V 69.7% LX1752 Buck Efficiency 1.8V @ 1A 3.3V @ 1A VIN=5V 92.6% Output Ripple Output Voltage 5V Flyback Output, VIN = 48V No Load 10mVpp Full Load 16mVpp 1.8V Step-Down Output, VIN = 48V 15mVpp 17mVpp 3.3V Step-Down Output, VIN=48V 20mVpp 22mVpp Line Regulation 5V @0.75A, VIN=36V, 57V <0.1% 1.8V @1A, VIN=36V, 57V <0.1% 3.3V @1A, VIN=36V, 57V <0.1% Load Regulation 5V @ no load and 0.75A, VIN=48V <0.1% 1.8V @ no load and 1A, VIN=48V <0.1% 3.3V @ no load and 1A, VIN=48V <0.1% Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE TYPICAL CHARACTERISTICS @ 25°C (REFER TO FIGURE 2) Hot Insertion Startup Under Full Load Conditions Hot Insertion Startup Under Full Load Conditions PowerDsine 3001 limits inrush currents CH1 – POE Input Source CH1 – POE Input Source CH4 – POE Input Current CH2 – 5V Flyback Output at 750mA CH2 – Flyback Input Voltage CH3 – 3.3V Buck Output at 1A CH3 – 5V Flyback Output Loaded at 750mA CH4 – 1.8V Buck Output at 1A Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE TYPICAL CHARACTERISTICS @ 25°C (REFER TO FIGURE 2) 3.3V Buck Output Step Load Response 1.8V Buck Output Step Load Response Output AC Coupled Output AC Coupled Post Filtered 5V Flyback Output Step Load Response 5V Flyback Switching Waveforms Output AC Coupled Note: Output ringing during step load due to LC filter (L1, C11, C12) resonance. LC filter attenuates flyback output ripple voltage. CH1 – Current into M2 External NFET CH2 – Current into Rectifier D9 CH3 – Extermal NFET Drain Voltage CH4 – Transformer Secondary Output Voltage Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Schematic J1 Isolation Block U1 4 - 3 + 48V 2 DF005M R3 24.9k 1 0813-1X1T-57F R2 10k R1 475k D4 BZX84C24 R6 511 U2 J2 4 - 3 + D5 1 2 3 4 5 6 7 8 S1 S2 DF005M 1SMA58A C2 47nF 100V R11 475k C3 100pF D3 BZX84C11 R7 511 Q2 MMBTA06 D7 BZX84C5V1 R4 475k R8 511 R5 51.1k R9 20k R13 49.9k Q3 KST92 C1 0.1uF 100V R10 422k R14 475k Q4 MMBTA06 Q5 2N7002 557484-1 D2 BZX84C30 D1 BZX84C12 Q1 KST92 R12 475k 2 TX+ TXRX+ NU NU RXNU NU SHLD SHLD Detection Block 1 1 2 3 4 5 6 7 8 9 10 11 12 S1 S2 RD+ TD+ NU NU VC1+ VC2+ CT RDTDVC1VC2NU SHLD SHLD D6 BZX84C10 C4 0.1uf M1 48VRTN STD16NF06 Classification Block is stuffed on the evaluation board and optionally performed by the PSE. RAWGND Note: For different levels of classification, R2 must be adjusted to the proper value. See AN-125 for details. J3 +5V +3.3V +1.8V 1 2 3 4 5 6 7 8 9 10 11 12 5V@3A MAX 5V@3A MAX GND GND 3.3V@4A MAX 3.3V@4A MAX GND GND 1.8V@5A MAX 1.8V@5A MAX GND GND CON12 Figure 2 – Ethernet Connectors, Diode Bridges, PD Interface Schematic Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Schematic C5 NU L4 48V 1 2 R17 118k 2N3906 C6 + R18 1M 48VRTN 180uF/63V C7 0.1uF 100V C8 330pF 2N3906 + 820uF/6.3V 3 Q6 Q7 Q8 2N7002 R22 221k R23 1M +5V C11 10uF 6.3V + C10 C12 10uF 6.3V 820uF/6.3V 6 D10 5 2 9 7 8 1 10 CDBA-140 C13 CMR1U-02M D8 47uF/35V 1M +5VA + HA3905-CL Coilcraf t R26 U3 8 4 R28 3.01k 2 1 C17 R30 1000pF 1M 2 4 R24 R25 16.2k T1 L1 1uH C9 R20 75 R19 11.5k R21 1 MBRS320 RAWGND 255k NU D9 100uH R16 1.0M C15 0.01uF R15 D11 VCC RT/CT VFB COMP FQD10N20 R27 2.7 VREF OUT ISNS GND C14 M2 7 6 1000p 2500V 1.0k C16 100pF 3 R29 0.43 5 UC3844 C18 4.7uF PMBD914 R31 R32 R34 NU C21 NU 2 118k 1k ISO1 SFH6156-2 R36 U4 TL431AIDR 1 1uF 3 R33 4 750 C19 R35 1.0k C20 NU 10k C22 R37 1.0k R38 1.0k NU Figure 3 – 48V to 5V Isolated Flyback Schematic Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 9 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Schematic R39 40.2K R40 C23 NU NU C24 R41 0.1uF R42 13.3k 21.0K +5VA +5VA R43 1K C26 R44 1K NU C29 NU C36 1uF 23 EO1 24 EA1- 26 25 SSEN1 PSET RFREQ LO1 CS2 PGND 21 20 R47 1 +1.8V 2.00K C30 C33 19 6 0.1uF Q9B FDS6911 17 C31 10uF 6.3V 820uF 6.3V 5 4 18 + 3 16 15 +5VA CR1 NU 9 R51 27 VIN 14 R49 R50 5.62K 8 13 NU 7 HR1 12 C37 1.2nF +5VA HO1 EO2 VS2 160K VC1 LX1752 EA2- 11 C35 R48 6 SSEN2 10 C34 VS1 U5 7 L2 3.3uH Q9A FDS6911 22 LO2 5 SHDN2 VCCL 4 SHDN1 HR2 0.22uF NU C28 10uF 2 CS1 HO2 3 C32 + C27 8 SY NC VC2 2 VREF 28 VIA GND 1.0uF R46 1K R45 160K 1.2nF 1 +5VA C25 +5VA CMDSH-3 C38 1.0uF 21.0K C39 C40 4.7uF 1.0uF 6.3V CR2 CMDSH-3 +5VA C41 1.0uF C43 + C42 R52 2.00K 6 5 NU 10uF 4 C44 0.1uF L3 3.3uH Q10B FDS6911 3 +3.3V 8 7 2 Q10A FDS6911 C46 820uF 6.3V + C45 10uF 6.3V 1 Figure 3 – 5V to 1.8V and 3.3V Dual Output Step-Down Converter Schematic Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 10 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Evaluation Board Build Of Materials Qty Reference Designators 13W POE PD Evaluation Board BOM Part Number Value Vendor Package Type 2 C1, 7 GCM21BR72A104 0.1uF, 100V Murata 805 1 C2 GRM21BR72A473 47nF, 100V Murata 805 2 C3,16 ECJ-1VC1H101K 100pF, 50V Panasonic 603 4 C4, 24, 33, 44 ECJ-1VB1E104K 0.1uF, 25V Panasonic 603 1 C6 UHE1J181MPD 180uF, 63V Nichicon 10x20 1 C8 ECJ-2VB2D331K 330pF, 200V Panasonic 805 4 C9, 10, 30, 46 6.3MCZ820M8X11.5 820uF, 6.3V Rubycon 8.0 x 11.5 6 C11, 12, 28, 31, 43, 45 JMK212BJ106M 10uF, 6.3V Taiyo Yuden 1 C13 ECA-1VHG470 47uF, 35V Panasonic 1 C14 62O102MQECS 1000pF, 2500V AVX 1 C15 ECJ-1VB1C103 0.01uF, 16V Panasonic 603 1 C17 ECJ-1VB1H102 1000pF, 50V Panasonic 603 2 C18, 40 JMK212BJ475M 4.7uF, 6.3V Taiyo Yuden 805 8 JMK212BJ105M 1uF, 16V Taiyo Yuden 805 3 C19, 25, 36, 38, 39, 41, 43, 45 C5, 27, 42 Not Used Through hole 7 C20, 21, 22, 23, 26, 34, 37 Not Used 603 2 C29, 35 ECJ-1VB1H122 1200pF, 50V Panasonic 603 1 C32 ECJ-1VB1E224K 0.22uF, 25V Panasonic 603 2 CR1, 2 CMDSH-3 30V, 100mA Central Semi 1 D1 BZX84C12 Zener, 12V, 5% Philips SOT-23 1 D2 BZX84C30 Zener, 30V, 5% Philips SOT-23 1 D3 BZX84C11 Zener, 11V, 5% Philips SOT-23 1 D4 BZX84C24 Zener, 24V, 5% Philips SOT-23 1 D5 1SMA58A 58V, 400W, TVS On Semi 1 D6 BZX84C10 Zener, 10V, 5% Philips Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 805 5.0 x 11 Through hole SOD-323 SMA SOT-23 Page 11 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE 1 D7 BZX84C5V1 Zener, 5.1V, 5% Philips 1 D8 CMR1U-02M 200V, 1A Central Semi SMA 1 D9 MBRS320 20V, 3A On Semi SMC 1 D10 CDBA140-G 40V, 1A Comchip SMA 1 D11 PMBD914 75V, 215mA Philips SOT-23 1 ISO1 SFH6156-2 Opto, CTR 100% Vishay SMD-4 1 J1 0813-1X1T-57F RJ-45 POE Bel Non std 1 J2 557484-1 RJ-45 Tyco Non std 1 J3 p/o PBC36SFCN 12 p x 0.1”ctr Sullins 16 pin header 1 L1 2643000801 1uH Fair-rite Ferrite bead 2 L2, 3 SPC-10049P-3R3 3.3uH 6A TMP 10x10 1 L4 SMI-0805-0101 100uH, 1.2A TMP 13.3 x 9.4 1 M1 STD16NF06L Nch, 60V, 24A ST Micro DPAK 1 M2 FQD10N20 Nch, 200V, 7.8A Fairchild DPAK 2 Q1, 3 KST92 PNP,300V, 0.5A Fairchild SOT-23 2 Q2, 4 MMBTA06 On Semi SC-70 2 Q6, Q7 SMBT3906 NPN,80V, 300mA Dual PNP, 40V Infineon SOT-363 2 Q5, 8 2N7002 Philips SOT-23 2 Q9, 10 FDS6911 Fairchild SOIC8 5 R1, 4, 11, 12, 14 ERJ-6ENF4753V Nch, 60V, 385mA Dual Nch 20V 7.5A 475k, 1/8W Panasonic 805 1 R2 ERJ-6ENF1002V 10.0k, 1/8W Panasonic 805 1 R3 ERJ-6ENF2492V 24.9k, 1/8W Panasonic 805 1 R5 ERJ-3EKF2492V 51.1, 1/10W Panasonic 603 3 R6, 7, 8 ERJ-6ENF5110V 511, 1/8W Panasonic 805 1 R9 ERJ-6ENF2002V 20k, 1/8W Panasonic 805 1 R10 ERJ-6EKF4223V 422k, 1/10W Panasonic 603 1 R13 ERJ-3EKF4992V 49.9k, 1/10W Panasonic 603 5 R16, 18, 23, 24, 30 ERJ-3EKF105V 1.0M, 1/10W Panasonic 603 Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 SOT-23 Page 12 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE 2 R17, R33 ERJ-3EKF1183V 118k, 1/10W Panasonic 603 1 R25 ERJ-6ENF1622V 16.2k, 1/8W Panasonic 805 1 R19 ERJ-6ENF1152V 11.5k, 1/8W Panasonic 805 1 R20 RMC1/875R01%G 75 1/4W SEI 1206 1 R21 ERJ-3EKF2553V 255k, 1/10W Panasonic 603 1 R22 ERJ-3EKF2213V 221k, 1/10W Panasonic 603 1 R26 ERJ-3GEYJ2R7V 2.7, 1/10W Panasonic 603 8 ERJ-3EKF1001V 1.00k, 1/10W Panasonic 603 1 R27, 32, 35, 37, 38, 43, 44, 46 R28 ERJ-3EKF3011V 3.01k, 1/10W Panasonic 603 1 R29 73L6R47J 0.47, 3/4W CTS 2010 1 R31 ERJ-3EKF7500V 750, 1/10W Panasonic 603 1 R36 ERJ-3EKF1002V 10k, 1/10W Panasonic 603 1 R39 ERJ-3EKF4022V 40.2k, 1/10W Panasonic 603 3 R34, 40, 49 Not Used 603 1 R15 Not Used 1206 1 R41 ERJ-3EKF1332V 13.3k, 1/10W Panasonic 603 2 R42, 51 ERJ-3EKF2102V 21.0k, 1/10W Panasonic 603 2 R45, 48 ERJ-3EKF1603V 160k, 1/10W Panasonic 603 2 R47, 52 ERJ-3EKF2001V 2.0k, 1/10W Panasonic 603 1 R50 ERJ-3EKF5621V 5.62k, 1/10W Panasonic 603 1 T1 HA3905-CL Flyback Tfmr Coilcraft 2 U1,2 DF005S Bridge Rect Fairchild 1 U3 UC3844ADM CMPS Controller Microsemi SOIC8 1 U4 TL431AIDR Shunt Regulator TI SOIC8 1 U5 LX1752CLQ Dual PWM Microsemi Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 SDIP MLPQ28 Page 13 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Evaluation Board PCB Layout Top Silkscreen and Solder Mask Top Layer Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 14 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Top Layer Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 15 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Inner Layer 2 Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 16 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Inner Layer 3 Bottom Layer Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 17 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Bottom Layer Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 18 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Test Setup: Test Procedure: The following is a demonstration scenario that can be used to evaluate the POE PD power supply: 1) The evaluation board can be powered over Ethernet via 48V, or by a regular external power supply for testing without network connectivity. 2) To verify the circuit operation over the full input range, use a bench top DC power supply capable of generating a voltage range of 36V to 57V and a current output of 1A for sourcing power via either node VC1+/VC1- or VC2+/VC2-. Set the power supply current limit to 500mA. Insure that the supply is shut off before connecting. 3) For power over Ethernet interface, use a POE source such as the PowerDsine 3001 Midspan from Microsemi and connect the Data & Power Out Port to the evaluation board port J1 via a CAT-5 cable. The evaluation board should now be powered by 48V. 4) If using an external power supply, set the supply voltage to 57V. Turn on the power supply. Without any output load currents, verify that the input current from the supply is below 30mA. 5) Using an oscilloscope, monitor the 5V output of the flyback at connector J3. Also monitor the step-down outputs of 1.8V and 3.3V at connector J3. 6) Using DMM (Digital Multi Meter), verify the nominal output DC voltages are stable at connector J3: +5VDC nominal +/-3%, +1.8VDC nominal +/-3%, +3.3VDC nominal +/-3% 7) Test load regulation. Using resistive load or electronic load, apply a 1A load at each of the 1.8V and 3.3V output, and a 750mA load at the 5V output. Monitor with DVM that the output voltages remain within 3% of the nominal. Note that the input current from the external power supply will be approximately 228mA at 57V or 270mA at 48V. 8) Test line regulation at full load conditions: Reduce the power supply voltage from 57V to 36V and verify that the output voltages remain within +/-3% of the nominal output voltages. Line regulation test is only applicable using external power supply to adjust the input voltage. 9) With power over Ethernet, connect another CAT-5 cable from port J2 to a computer for network connectivity. Actual setup using PowerDsine 3001 Midspan is shown below and can be used to verify actual network connectivity. Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 19 POE PD POWER SUPPLY EVALUATION BOARD USER GUIDE Power Over Ethernet Using PowerDsine 3001 Midspan for Network Connectivity POE PD Evaluation Board Port J2 Provides Data Interface to Computer CAT-5 Ethernet Connection (grey cable), Data In, No Power PowerDsine 3001 Midspan PowerDsine 3001 provides Data Out & Power Out via CAT-5 (blue cable) to port J1 of POE PD Evaluation Board Copyright © 2008 Rev. 1.0, 2008-12-18 Microsemi Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 20