LM5001BSTEVAL/NOPB

User's Guide SNVA393B – March 2009 – Revised April 2013 AN-1956 LM5001 Boost Evaluation Board 1 Introduction The LM5001 boost evaluation board is designed to provide the design engineer with a fully functional power converter based on the boost topology to evaluate the LM5001 high voltage switch mode regulator. The performance of the evaluation board is as follows: Input Operating Range: 16 to 36V Output Voltage: 48V Output Current: 0 to 150 mA Measured Efficiency: 91% @ 150 mA, 86% @ 75 mA Frequency of Operation: 240 kHz Board Size: 1.75 X 1.75 inches Load Regulation: 1% Line Regulation: 0.1% The printed circuit board consists of 2 layers; 1 ounce copper layers FR4 material with a total thickness of 0.062 inches. When laying out the PCB note the proximity of the ground pin (pin 4) to the output capacitors (see the schematic in Section 2). Placing the ground pin near the output capacitor will minimize the ripple in the output by forcing a constant current to flow across the board for both the switch on and switch off portions of the cycle. If the board is laid out with the ground pin near the input capacitor then a high di/dt condition will occur due to the small conduction loop area during the switch on time and large loop conduction area during the switch off time. The output ripple and noise will be minimized if the conduction loop area and current both remain constant. Placing the ground pin near the output capacitor accomplishes this goal. All trademarks are the property of their respective owners. SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated 1 Schematic 2 www.ti.com Schematic 6.8 R6 L1 C8 470 pF D2 J1 J3 16V to 36V IN C1 2.2 PF 100 PH C2 2.2 PF CMSH2-60M C11 4.7 PF C9 4.7 PF C10 1 PF +48V, 150 mA J2 J4 R1 100k GND J7 GND R2 10.0 GND R8 0 J5 C3 0.1 PF ENABLE U1 2 8 5 R3 9.09k 4 C4 0.01 PF VIN EN VCC SW RT COMP GND FB C12 3 22 pF 1 R7 73.2k 7 C13 6 2200 pF LM5001M D1 R9 54.9k BAT54S R10 1.47k J6 SYNC R5 100k C5 100 pF R4 53.6k C6 1 PF C7 10 PF Softstart 2 AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback Powering and Loading Considerations www.ti.com 3 Powering and Loading Considerations When applying power to the LM5001 Boost evaluation board certain precautions need to be followed. A misconnection can damage the board. 3.1 Proper Connections When operated at low input voltages the evaluation board can draw up to 500mA of current at full load. The maximum rated output current is 150mA. Be sure to choose the correct connector and wire size when attaching the source supply and the load. Monitor the current into and out of the evaluation board. Monitor the voltage directly at the output terminals of the evaluation board. The voltage drop across the load connecting wires will give inaccurate measurements. This is especially true for accurate efficiency measurements. When measuring output ripple with an oscilloscope. Do not use the wire ground lead for the ground connection. The loop formed by the wire lead will pick up noise from the switching circuits and make the ripple voltage look larger then it actually is. Instead use a spring ground clip on the exposed ground ring on the scope probe to minimize the loop area of the ground lead. An alternative is to remove the shroud covering the scope probe. Then touch the exposed scope probe ground connection to the output ground terminal while simultaneously connecting the probe tip to the output terminal. 3.2 Source Power The power supply and cabling must look like a low impedance voltage source to the evaluation board. High inductance power supply leads like the type typically used for bench power supplies, could cause the LM5001 to become unstable or have poor response to load transients. This is due to the inductance of the power supply wiring interacting with the evaluation board input capacitor and causing a series resonant LC oscillation at a frequency defined by the inductance of the input wiring and the value of the input capacitor. In some cases it may be necessary to add an additional capacitor in parallel with input capacitor to move the resonate frequency away from the unity gain crossover frequency of the LM5001. Twisting the input supply lines together will reduce the inductance and potential for problems. Powering up at max rated voltage or close to this voltage can cause damage due to the inductance of the supply lines. Over shoot and ringing can be several volts under a sudden application of power. When operating near maximum input voltage slowly ramp up the voltage to avoid overshoot. 3.3 Loading An appropriate electronic load, with specified operation up to 48V maximum or more, is desirable. Monitor both current and voltage at all times. Ensure there is sufficient cooling provided for the load. 3.4 Over Current Protection The LM5001 monitors the peak current through the inductor on a cycle by cycle basis. If the inductor is sized large enough to not saturate when operating at peak current limit. Then the short circuit can be left on indefinitely with out damaging the device or causing it to go into thermal shutdown. Scope 36 Volt, 1 AmpPower Supply with Current Meter + Volt-meter - Volt-meter Evaluation Board Current-meter IN + + ON/OFF (SHUTDOWN) OUT - - + 10 Watt, 1 Amp Electronic Load Jumper Figure 1. Typical Evaluation Setup SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated 3 Performance Characteristics 4 www.ti.com Performance Characteristics Turn-on Waveforms Figure 2 shows the output voltage during a typical start-up with a 20V input and a load of 150 mA. There is no overshoot during startup. Output Ripple Waveforms Figure 3 shows the transient response for a load of change from 15 mA to 150 mA. The upper trace shows minimal output voltage droop and overshoot during the sudden change in output current shown by the lower trace. Conditions: Input Voltage = 20VDC Output Current = 150 mA Trace 1: Output Voltage Volts/div = 10V Horizontal Resolution = 4.0 ms/div Figure 2. Output Voltage During a Typical Start-Up With a 20V Input and a Load of 150 mA Conditions: Input Voltage = 20VDC Output Current = 15 mA to 150 mA Upper Trace: Output Voltage Volts/div = 500 mV Lower Trace: Output Current 150 mA to 15 mA to 150 mA Horizontal Resolution = 0.4 ms/div Figure 3. Transient Response for a Load of Change From 15 mA to 150 mA 4 AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback Performance Characteristics www.ti.com Conditions: Input Voltage = 20VDC Output Current = 150 mA Bandwidth Limit = 20 MHz Trace 1: Output Voltage Volts/div = 20 mV Horizontal Resolution = 1 µs/div Figure 4. Typical Output Ripple for an Input Voltage of 20V and a Load of 150 mA Figure 4 shows typical output ripple, seen directly across the output capacitor, for an input voltage of 20V and a load of 150 mA. This waveform is typical of most loads and input voltages. Figure 5 shows power efficiency over full input voltage and output current range. Peak efficiency is at full rated load and is greater then 90% across the input voltage range. Figure 6 shows the small signal closed loop response with 20V input and 150 mA load current into a resistive load. The gain curve starts at around 60dB the phase curve starts at around 45°. 0dB of crossover frequency is at 11 kHz with a phase margin of 70°. Conditions: Input Voltage = 16 - 36VDC Output Current = 10 mA - 150 mA Figure 5. Power Efficiency Over Full Input Voltage and Output Current Range SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated 5 Performance Characteristics www.ti.com Conditions: Input Voltage = 20VDC Output Current = 150 mA Figure 6. Small Signal Closed Loop Response With 20V Input and 150 mA Load 6 AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback Bill of Materials www.ti.com 5 Bill of Materials Table 1. Bill of Materials Designator Qty Part Number Description Value C1, C2 2 GRM31CR71H225KA88L CAPACITOR, 1206 X7R CER, Murata 2.2µF, 50V C3 1 C2012X7R1H104M CAPACITOR, 0805 X7R CER, TDK 0.1µF, 50V C4 1 C2012X7R1H103M CAPACITOR, 0805 X7R CER, TDK 0.01µF, 50V C5 1 C2012COG1H101J CAPACITOR, 0805 COG CER, TDK 100pF, 50V C6 1 C3216X7R1C105K CAPACITOR, 0805 X7R CER, TDK 1µF, 16V C7 1 GRM21BR61C106KE15L CAPACITOR, 0805 X7R CER, Murata 10µF, 16V C8 1 C2012COG1H471J CAPACITOR, 0805 COG CER, TDK 470pF, 100V C9, C11 2 C5750X7R2A475M CAPACITOR, 2220 X7R CER, TDK 4.7µF, 100V C10 1 C3225X7R2A105K CAPACITOR, 1210 X7R CER, TDK 1µF, 100V C12 1 C2012COG1H220J CAPACITOR, 0805 COG CER, TDK 22pF, 50V C13 1 C2012COG1H222J CAPACITOR, 0805 COG CER, TDK 2200pF, 50V D1 1 BAT54S DIODE, SOT-23, DUAL, SCHOTTKY, Fairchild Semiconductor 200mA, 30V CMSH2-60M DIODE, SMA, SCHOTTKY, Central Semiconductor Corp. 2A, 60V MSS1260 INDUCTOR, COILCRAFT 100µH, 1.8A 100K D2 L1 1 R1, R5 2 CRCW08051003F RESISTOR, 0805, VISHAY R2 1 CRCW080510R0F RESISTOR, 0805, VISHAY 10 R3 1 CRCW08059091F RESISTOR, 0805, VISHAY 9.09K R4 1 CRCW08055362F RESISTOR, 0805, VISHAY 53.6K R6 1 CRCW080568R1F RESISTOR, 0805, VISHAY 6.8 R7 1 CRCW08057322F RESISTOR, 0805, VISHAY 73.2K R8 1 CRCW08050000F RESISTOR, 0805, VISHAY 0 R9 1 CRCW08055492F RESISTOR, 0805, VISHAY 54.9K 1.47K CRCW08051471F RESISTOR, 0805, VISHAY J1, J2, J3, J4 R10 4 7693 Keystone Screw Terminal J5, J6, J7 Mar-36 PTC36SAAN 0.025" Sq post, 36 position, Sullins LM5001 High Voltage Switch Mode Regulator, Texas Instruments U1 1 SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback 3 posts used AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated 7 Printed Circuit Layout 6 www.ti.com Printed Circuit Layout Figure 7. Silkscreen Layer Figure 8. Top Layer 8 AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback Printed Circuit Layout www.ti.com Figure 9. Bottom Layer SNVA393B – March 2009 – Revised April 2013 Submit Documentation Feedback AN-1956 LM5001 Boost Evaluation Board Copyright © 2009–2013, Texas Instruments Incorporated 9 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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