DEMO MANUAL DC2061A LTC3784 High Efficiency PolyPhase® Synchronous Boost Converter DESCRIPTION Demonstration circuit DC2061 is a DC/DC synchronous boost converter featuring the LTC®3784 constant frequency current mode synchronous boost controller. The DC2061A operates over a 6V to 60V input, develops a 48V output and provides 3A to 12A of output current as shown in Figure 3. The 150kHz (2 • 150kHz at the output) constant frequency operation results in a small and efficient circuit. The converter provides high output voltage accuracy (typically ±3%) over wide load range with no minimum load requirement. The PERFORMANCE SUMMARY demonstration circuit can be easily modified to generate different output voltages. The DC2061 has a small circuit footprint. It is a high performance and cost effective solution for telecom, automotive and Power over Ethernet applications. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology, the Linear logo and PolyPhase are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Specifications are at TA = 25°C PARAMETER CONDITION VALUE Minimum Input Voltage IOUT = 0A to 3A 6V Maximum Input Voltage IOUT = 0A to 12A 60V VOUT VIN = 6V to 47V, IOUT = 0A to 3A 48V ±3% Typical Output Ripple VOUT VIN = 6V to 47V, IOUT = 3A 200mVP-P Nominal Switching Frequency 150kHz QUICK START PROCEDURE Demonstration circuit DC2061 is easy to set up to evaluate the performance of the LTC3784. For proper measurement equipment setup refer to Figure 1 and follow the procedure below: Note: When measuring the input or output voltage ripple, care must be taken to minimize the length of oscilloscope probe ground lead. Measure the input or output voltage ripple by connecting the probe tip directly across the VIN or VOUT and GND terminals as shown in Figure 2. 1.With power off, connect the input power supply to VIN and GND. 2.Keep the load set to 0A or disconnected. 3.Turn the input power source on and slowly increase the input voltage. Be careful not to exceed 60V. Note: Make sure that the input voltage, VIN, does not exceed 60V. If higher operating voltage is required, power components with higher voltage ratings should be used. When the input voltage is set higher than 48V the output voltage will follow the input voltage. 4.Set the input voltage to 6V and check for the proper output voltage of 48V. Set the output load to 2A. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 5.Once the proper output voltage is established, adjust the load and observe the output voltage regulation, ripple voltage, efficiency and other parameters. dc2061af 1 DEMO MANUAL DC2061A QUICK START PROCEDURE Figure 1. Proper Measurement Equipment Setup + VOUT – COUT GND Figure 2. Measuring Input or Output Ripple dc2061af 2 DEMO MANUAL DC2061A QUICK START PROCEDURE Changing The Output Voltage Output Load Step Response To set the output voltage lower than 48V, change the bottom voltage divider resistors connected to LTC3784 FB pin (see the Schematic Diagram). To get higher than a 48V output voltage, MOSFETs and capacitors with higher voltage ratings may be required. The load step response of DC2061A is very good even though relatively small amount of output capacitance is present at the output. If higher load steps need to be handled more output capacitance can be added in order to keep the voltage transients at the desired level. The load step transients are shown in Figure 4. Also, note that the load step response even from 0% load is excellent thanks to synchronous rectification. Note that the output voltage will start following the input voltage when input voltage is greater than the voltage set by the voltage divider. In this mode (wire mode) the synchronous output rectifier MOSFET is turned continuously ON. The only losses in this mode are due to the current sense resistors, inductors and output MOSFETs DC resistance. Converter Efficiency And Output Current The DC2061 output current capability depends on the input voltage and proper cooling. Typical performance of DC2061A is shown in Figure 3. As can be seen from Figure 3, the output current capability depends on the input voltage. Also, when input voltage is equal to, or higher than the output voltage setting (wire mode) the efficiency is very high (99%) since the converter is not really running and the output MOSFET is shorting VIN to VOUT. 98 Soft-Start Function 96 EFFICIENCY (%) 94 92 90 88 86 6VIN 9VIN 12VIN 24VIN 84 82 Figure 4. Fast Transient Response of DC2061 is Achieved with a Small Amount of Output Capacitance 0 2 4 6 8 10 12 IOUT (A) Figure 3. High Efficiency of DC2061 Allows the Board to Be Used in Thermally Critical Applications with Outputs Over 3A The DC2061 features soft-start circuit that controls the inrush current and output voltage ramp at start-up. The capacitor C15 (Figure 6) controls the start-up period. The start-up waveforms are shown in Figure 5. Please note the small output voltage step at about –2ms mark. The step is resulting from synchronous MOSFET being turned on. When the synchronous MOSFET is turned on the voltage drop across the synchronous MOSFET (body diode) is reduced from about 0.7V to IOUT • RDS(ON). While the synchronous MOSFET is in off state (prior to –2ms mark) the synchronous MOSFET body diodes are dissipating about 0.7V • IOUT or about 2.1W with 3A load. Please refer to the LTC3784 data sheet for details about proper handling of synchronous MOSFETs in your application. dc2061af 3 DEMO MANUAL DC2061A QUICK START PROCEDURE Bias Circuit The LTC3784 can operate with input voltages up to 65V. However, depending on input voltage, operating frequency and MOSFETs that are used the power dissipation in the part may become too high. In order to provide bias power at high input voltage the DC2061 circuit is equipped with high efficiency bias circuit LTC3630A. If the circuit is to be used with limited input voltage the bias power can be derived directly from input power source. Figure 5. The DC2061 Ramps the Output Slowly at Start-Up without Generating an Input Current Surge Options to power the LTC3784 from VIN or VOUT are provided on DC2061. Please remove the LTC3630A circuit in order to use these options. Also, refer to the data sheet for more information about bias power. PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 5 CIN1, COUT5, COUT10, COUT11, COUT12 CAP., 33µF, 63V, EP-CAP SUN ELECTRONICS, 63HVH33M 2 12 COUT1, COUT2, CIN2, COUT3, CIN3, COUT4, CIN4, CIN5, COUT6, COUT7, COUT8, COUT9 CAP., X7S, 4.7µF 100V,20% 3225/1210 TDK, C3225X7S2A475M 3 1 C2 CAP., NPO, 100pF, 25V,10%, 0603 AVX, 06033A101KAT 4 1 C3 CAP., X7R, 15nF, 25V, 10%, 0603 AVX, 06033C153KAT 5 5 C4, C9, C16, C17 CAP., X5R, 0.1µF, 25V, 10%, 0603 AVX, 06033D104KAT2A 6 2 C5, C10 CAP., NPO, 1000pF, 25V,10%, 0603 AVX, 06033A102KAT 7 1 C8 CAP., X5R, 4.7µF, 25V, 10%, 0805 TAIYO YUDEN, TMK212BJ475KG-T 8 1 C12 CAP., X7R, 0.1µF, 100V, 10%, 1206 AVX, 12061C104KAT 9 1 C13 CAP., X7R, 47nF, 25V, 10%, 0603 AVX, 06033C473KAT 10 1 C14 CAP., X5R, 22µF, 16V, 10%, 1206 AVX, 1206YD226KAT2A 11 1 C15 CAP., X5R, 1µF, 10V, 10%, 0603 AVX, 06033D104KAT2A 12 3 D1, D2 DIODE, BAS170W SOD323 INFINEON, BAS170W 13 1 D5 DIODE, PDZ6.8B SOD323 NXP, PDZ6.8B 14 2 L1, L2 IND, 10µH COILCRAFT, SER2918H-103KL 15 1 L3 IND, 220µH IND-744775222 WURTH ELEC., 744775222 16 4 Q2, Q4, Q6, Q8 MOSFET, N-Channel, LFPAK INFINEON, BSC028N06LS3 17 4 RSNS1, RSNS2, RSNS3, RSNS4 RES., Chip, 0.006Ω, 1%, 2010 VISHAY, WSL20106L000FEA 18 7 R2, R3, R7, R13, R15, R18, R21 RES., Chip, 0Ω, 1%, 0603 VISHAY, CRCW06030000Z0EA 19 1 R5 RES., Chip, 30.1k, 1%, 0603 VISHAY, CRCW060330K1FKEA 20 1 R6 RES., Chip, 475k, 1%, 0603 VISHAY, CRCW0603475KFKEA 21 2 R8 RES., Chip, 12.1k, 1%, 0603 VISHAY, CRCW060312K1FKEA 22 1 R9 RES., Chip, 15k, 1%, 0603 VISHAY, CRCW060315K0FKEA dc2061af 4 DEMO MANUAL DC2061A PARTS LIST ITEM QTY 23 2 REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER R17, R23 RES., Chip, 10Ω, 1%, 0603 VISHAY, CRCW060310R0FKEA 24 2 R26, R35 RES., Chip, 100k, 1%, 0603 VISHAY, CRCW0603100KFKEA 25 1 R29 RES., Chip, 47k, 1%, 0603 VISHAY, CRCW060347K0FKEA 26 1 R30 RES., Chip, 523k, 1%, 0603 VISHAY, CRCW0603523KFKEA 27 1 R33 RES., Chip, 150k ,1%, 0603 VISHAY, CRCW0603150KFKEA 28 1 R34 RES., Chip, 38.3k ,1%, 0603 VISHAY, CRCW060338K3FKEA 29 1 R36 RES., Chip, 80.6k, 1%, 0603 VISHAY, CRCW060380K6FKEA 30 1 U1 I.C. LTC3784IUFD QFN28–4 x 5 LINEAR TECH., LTC3784IUFD#PBF 31 1 U2 I.C. LTC3630AEMSE LINEAR TECH., LTC3630AEMSE Additional Demo Board Circuit Components 1 0 C1, C19, C20 OPT, 0603 OPT 2 0 D3, D4 DIODE, OPT PDS760 POWERID5-2P OPT 3 0 D6 DIODE, OPT SOD123 OPT 4 0 Q1, Q3, Q5, Q7 OPT, LFPAK OPT 5 0 R1, R4, R10, R11, R12, R14, R16, R27, R28, R31, R32, R37, R38 OPT, 0603 OPT Hardware-For Demo Board Only 1 11 E1, E5-E8, E11-E15, E21 TURRET, TESTPOINT , 091" MILL-MAX, 2501-2-00-80-00-00-07-0 2 2 E2, E4 JACK BANANA KEYSTONE, 575-4 3 2 E9, E10 STUD, TEST PIN PEM, KFH-032-10 4 4 (E9, E10) x 2 NUT, BRASS NUTS # 10-32 ANY, #10-32 5 2 E9, E10 RING, LUG RING # 10 KEYSTONE, 8205 6 2 E9, E10 WASHER, #10, TIN PLATED BRASS ANY, #10 EXT BZ TN 7 1 JP1 HEADER, 6 PINS 2 x 3 100 Ctrs. SAMTEC, TSW-106-07-L-D 8 2 JP2, JP4 HEADER, 3 Pins 2mm CTRS. SULLINS, NRPN031PAEN-RC 9 1 JP3 HEADER, 4 Pins 2mm CTRS. SULLINS, NRPN041PAEN-RC 10 3 XJP2, XJP3, XJP4 SHUNT, 2mm CTRS. SAMTEC, 2SN-BK-G 11 1 XJP1 SHUNT, 100 CTRS. SAMTEC SNT-100-BK-G 12 4 MTGS HEX STANDOFF 6-32 NYLON 3/4" KEYSTONE, 1903D MTGS 13 4 SCREW, PAN PHILLIPS 6-32 B & F, PMSSS 632 0038 PH 14 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 2061A 15 2 STENCILS TOP AND BOTTOM STENCIL DC2061A dc2061af 5 A B C - SEE QSG 5 4 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. 2. INSTALL SHUNTS AS SHOWN. * NOTES: D 3 3 SENSE1+ SENSE1- 4 2 * 1 + TECHNOLOGY + 1 2 6 5 A B C D DEMO MANUAL DC2061A SCHEMATIC DIAGRAM dc2061af Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C 5 4 3 3 4 2 2 D 5 TECHNOLOGY 1 1 A B C D DEMO MANUAL DC2061A SCHEMATIC DIAGRAM dc2061af 7 DEMO MANUAL DC2061A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc2061af 8 Linear Technology Corporation LT 0314 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014