LM5001ISOEVAL/NOPB

User's Guide SNVA221B – February 2007 – Revised April 2013 AN-1588 LM5001 Evaluation Board 1 Introduction The LM5001 evaluation board is designed to provide the design engineer with a fully functional isolated flyback power converter based on current mode control to evaluate the LM5001 switching regulator IC. The evaluation board provides a 5V output with 1A current capability. The input voltage ranges from 16V to 42V. The design operates at 250kHz, a good compromise between conversion efficiency and solution size. The printed circuit board consists of two layers of two ounce copper on FR4 material with a thickness of 0.062 inches. This application note contains the evaluation board schematic, Bill-of-Materials (BOM) and a quick setup procedure. Refer to the LM5001 High Voltage Switch Mode Regulator (SNVS484) data sheet for complete circuit design information. The performance of the evaluation board is as follows: Input Range: 16 to 42V Output Voltage: 5V, ±2% Output Current: 0 to 1A Frequency of Operation: 250 kHz Board Size: 2.75 X 1.75 X 0.6 inches Load Regulation: 0.1% Line Regulation: 0.1% Over Current Limiting All trademarks are the property of their respective owners. SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated AN-1588 LM5001 Evaluation Board 1 Evaluation Board Schematic 2 www.ti.com Evaluation Board Schematic T1 VCC VIN = 16V ± 42V J1 R5 20 D1 LPRI = 160 éH 5 8:3:2 R12 10 C11 470 pF VOUT = +5V IOUT = 1A J3 6,7 C1 2.2 éF C2 2.2 éF 4 3 J2 GND R6 8.06k R1 60.4k J7 ENABLE C4 0.01 éF D4 8,9 R13 49.9 C3 0.1 éF R14 560 C15 2.2 éF R15 10k C5 100 pF SYNC R3 6.04k R4 52.3k 2 VIN 8 EN 5 RT 4 GND LM5001 U1 J6 1 SW 7 COMP 6 FB 3 VCC C6 1 éF OPTIONAL SOFT-START 3 J4 C7 0.01 éF 2 D2 R2 10 C14 1 éF C12 100 éF VCC C9 1 éF R10 0 R8 249 4 U2 R17 0 R18 2.20k C16 R16 0.1 PF 4.99k 1 LM431 U3 3 R19 2.20k 2 R7 100k J5 C19 2200 pF J8 GND 2kV IGND D3 C8 10 éF Powering and Loading Considerations Read this entire page prior to attempting to power the evaluation board. 3.1 Quick Setup Procedure Step 1: Set the input source current limit to 1A. Turn off the input source. Connect the positive output of the input source to J1 and the negative output to J2. Step 2: Connect the load, with 1A capability, to J3 for the positive connection and J4 for the negative connection. Step 3: The ENABLE pin, J7, should be left open for normal operation. Step 4: Set the input source voltage to 28V and the load to 0.1A. The load voltage should be in regulation with a nominal 5V output. Step 5: Slowly increase the load while monitoring the load voltage at J3 and J4. It should remain in regulation with a nominal 5V output as the load is increased up to 1 Amp. Step 6: Slowly sweep the input source voltage from 16V to 42V. The load voltage should remain in regulation with a nominal 5V output. Step 7: Temporally short the ENABLE pin (J7) to GND (J5) to check the shutdown function. Step 8: Increase the load beyond the normal range to check current limiting while the input source is set to 28V. The output current should limit at approximately 1.9A. The input source current limit should be increased for this step. Fan cooling is critical during this step. 2 AN-1588 LM5001 Evaluation Board SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Performance Characteristics www.ti.com 3.2 Air Flow Prolonged operation at full power and high ambient temperature will cause the thermal shutdown circuit within the regulator IC to activate. A fan with a minimum of 200 LFM should always be provided. 3.3 Powering Up Using the ENABLE pin (J7) provided will allow powering up the input source with the current level set low. It is suggested that the load power be kept low during the first power up. Set the current limit of the input source to provide about 1.5 times the anticipated wattage of the load. As you remove the connection from the ENABLE pin to GND (J5), immediately check for 5 volts at the output. A quick efficiency check is the best way to confirm that everything is operating properly. If something is amiss you can be reasonably sure that it will affect the efficiency adversely. Few parameters can be incorrect in a switching power supply without creating losses and potentially damaging heat. 3.4 Over Current Protection The evaluation board is configured with cycle-by-cycle over-current protection. This function is completely contained in the LM5001. The Primary current is limited to approximately 1A. This equates to about 1.4A load current when the input voltage is 16V, and about 2.1A load current when the input is 42V. The thermal stress on various circuit components is quite severe while in an overloaded condition, therefore limit the duration of the overload and provide sufficient cooling (airflow). 3.5 Synchronization A SYNC pin (J6) has been provided on the evaluation board. This pin can be used to synchronize the regulator to an external clock or multiple evaluation boards can be synchronized together by connecting their SYNC pins together. Refer to the LM5001 High Voltage Switch Mode Regulator (SNVS484) data sheet for complete information. 3.6 Flyback Topology An excellent introduction to the isolated flyback converter is available on the Texas Instruments website. The Application Note AN-1095(SNVA005) discusses both loop compensation with a secondary side error amplifier and the phase-shift caused by opto-couplers. 4 Performance Characteristics Efficiency Plots Figure 1 shows the conversion efficiency versus output current for several input voltage conditions. Figure 1. Conversion Efficiency vs Output Current SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated AN-1588 LM5001 Evaluation Board 3 Performance Characteristics www.ti.com Turn-on Waveform When applying power to the LM5001 evaluation board a soft-start sequence occurs. Figure 2 shows the output voltage during a typical start-up sequence. Conditions: Input Voltage = 28VDC, Output Current = 1A Trace 1: Output Voltage Volts/div = 1V Horizontal Resolution = 5ms/div Figure 2. Voltage During a Typical Start-up Sequence Output Ripple Waveform Figure 3 shows the output voltage ripple. This measurement was taken with a very short ground clip and 20 MHz bandwidth limiting. Conditions: Input Voltage = 28VDC, Output Current = 1A, Bandwidth Limit = 20MHZ Trace 1: Output Ripple Voltage Volts/div = 50mV Horizontal Resolution = 2µs/div Figure 3. Output Voltage Ripple 4 AN-1588 LM5001 Evaluation Board SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated Performance Characteristics www.ti.com Primary Switchnode Waveform Figure 4 shows the typical primary voltage during continuous conduction mode (CCM). Conditions: Input Voltage = 28VDC, Output Current = 1A, Bandwidth Limit = 20MHZ Trace 1: LM5001 SW Pin Volts/div = 10V Horizontal Resolution = 2µs/div Figure 4. Primary Voltage During CCM SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated AN-1588 LM5001 Evaluation Board 5 Layout and Bill of Materials 5 www.ti.com Layout and Bill of Materials The bill of materials is shown in Table 1, including the manufacturer and part number. Table 1. Bill of Materials 6 DESIGNATO R QTY PART NUMBER DESCRIPTION VALUE C1,2 2 C3225X7R1H225K CAPACITOR, 1210 X7R CER, TDK 2.2µ, 50V C3,16 2 C2012X7R2A104K CAPACITOR, 0805 X7R CER, TDK 0.1µ, 100V C4, 7 2 C2012X7R2A103K CAPACITOR, 0805 X7R CER, TDK 0.01µ, 100V C5 1 C0805C101M5RAC CAPACITOR, 0805 COG CER, KEMET 100p, 50V C6, 9, 14 3 C2012X7R1A105K CAPACITOR, 0805 X7R CER, TDK 1µ, 10V C8 1 C2012Y5V1A106Z CAPACITOR, 0805 Y5V CER, TDK 10µ, 10V C11 1 C0805C471M5RAC CAPACITOR, 0805 COG CER, KEMET 470p, 50V C12 1 C1210C107M9PAC3810 CAPACITOR, 1210 X5R CER, KEMET 100µ,6.3V C15 1 C2012X7R1C225K CAPACITOR, 0805 X7R CER, TDK 2.2µ, 16V C19 1 C4532X7R3D222K CAPACITOR, 1812, X7R CER, TDK 2200p, 2000V D1 1 CMHSH-3 DIODE, SOD-123 SCHOTTKY, CENTRAL SEMI 200mA, 30V D2 1 CMMR1U-2 DIODE, SOD-123F, CENTRAL SEMI 1A, 200V D3 1 BAT54S DIODE, SOT-23 SCHOTTKY, VISHAY 200mA, 30V D4 1 CMSH5-40 DIODE, SMC SCHOTTKY, CENTRAL SEMI 5A, 40V R1 1 CRCW08056042F RESISTOR, 0805, VISHAY 60.4k R2,12 2 CRCW080510R0F RESISTOR, 0805, VISHAY 10 R3 1 CRCW08056041F RESISTOR, 0805, VISHAY 6.04k R4 1 CRCW08055232F RESISTOR, 0805, VISHAY 52.3k R5 1 CRCW080520R0F RESISTOR, 0805, VISHAY 20 R6 1 CRCW08058061F RESISTOR, 0805, VISHAY 8.06k R7 1 CRCW08051003F RESISTOR, 0805, VISHAY 100k R8 1 CRCW08052490F RESISTOR, 0805, VISHAY 249 R10,17 2 CRCW08050000Z0EA RESISTOR, 0805, VISHAY 0 R13 1 CRCW080549R9F RESISTOR, 0805, VISHAY 49.9 R14 1 CRCW08055600F RESISTOR, 0805, VISHAY 560 R15 1 CRCW08051002F RESISTOR, 0805, VISHAY 10.0k R16 1 CRCW08054991F RESISTOR, 0805, VISHAY 4.99k R18,19 2 CRCW08052201F RESISTOR, 0805, VISHAY 2.2k T1 1 FA2636-AL POWER XFR, COILCRAFT 160µH PRIMARY,8:3:2 U1 1 LM5001 REGULATOR, TEXAS INSTRUMENTS U2 1 PS2811-1M OPTO-COUPLER, NEC 100% - 200% CTR U3 1 LM431 REFERENCE, SOT23, TEXAS INSTRUMENTS 2.500V J1,2,3,4 4 7693 TERMINAL, 6-32 SCREW, 4 PIN, KEYSTONE SNAP IN, PC MOUNT J5,6,7,8 4 5002 TERMINAL, SINGLE PIN, KEYSTONE TESTPOINT, LOOP AN-1588 LM5001 Evaluation Board SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated PCB Layout www.ti.com 6 PCB Layout Figure 5. Component Side Figure 6. Solder Side SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated AN-1588 LM5001 Evaluation Board 7 PCB Layout www.ti.com Figure 7. Silkscreen 8 AN-1588 LM5001 Evaluation Board SNVA221B – February 2007 – Revised April 2013 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. 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