DEMO MANUAL DC2013A LT3952EFE 60V LED Driver with Internal 4A Switch DESCRIPTION Demonstration Circuit DC2013A is a 60V LED driver with internal 4A switch featuring the LT®3952 monolithic LED driver. It accepts an input voltage from 5V to 36V (with transient to 42V) and boosts to a single string of LEDs up to 50V LEDs at 330mA. DC2013A features an integrated 4A switch, constant-current and constant-voltage output control as well as input current limit and monitoring. The LT3952 has a wide input voltage range down to 3V and up to 42V. It has adjustable switching frequency between 200kHz and 3MHz. It has an option for external frequency synchronization or spread spectrum frequency modulation. It has high PWM dimming capability from an external signal and can be PWM dimmed with an internally generated PWM oscillator and analog input signal. It can be analog dimmed with a control voltage on its control pin. LT3952 features both Open-LED and Short-LED (LED+ to GND) protection as well as fault output flags for each. Although DC2013A is assembled as a boost LED driver, it can be altered to be run as a buck mode, buck-boost mode or boost-buck LED driver. There is another demonstration circuit featuring LT3952 at 2.0MHz (DC2361A). DC2013A features an option to turn on spread spectrum by simply changing the position of a jumper from NO SPREAD to SPREAD or to EXTERNAL SYNC. Small ceramic input and output capacitors are used to save space and cost. The Open-LED overvoltage protection uses the IC’s constant-voltage regulation loop to regulate the output to approximately 55V if the LED string is opened although it may reach 59V peak during transient from running LEDs to open. There is a protection diode from LED+ to GND to prevent negative ringing during a shortcircuit with long wires. There is undervoltage and overvoltage lockout that can be adjusted on the circuit with a few simple resistor choices. There is an EMI filter on the input of DC2013A. This EMI filter has both an LC stage to reduce EMI below 20MHz and a ferrite bead to reduce higher frequency EMI. The PCB layout contains a small hot-loop for minimized high frequency EMI. The EMI filter can be used by connecting to the “EMI VIN” terminal. However, if the EMI filter is not needed, the input connection can be directly to the PVIN terminal. If the EMI filter is not used, it is recommended to remove the EMI filter if EMI measurements are being made from the PVIN terminal for base EMI testing. It can be replaced for EMI testing at the EMI VIN terminal. The LT3952 data sheet gives a complete description of the part, operation and applications information. The data sheet must be read in conjunction with this Demo Manual for Demonstration Circuit 2013A. The LT3952EFE is assembled in a 28-lead plastic TSSOP (FE) package with a thermally enhanced ground pad. Proper board layout is essential for maximum thermal performance. See the data sheet section “Layout Considerations”. Design files for this circuit board are available at http://www.linear.com/demo/DC2013A L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. dc2013af 1 DEMO MANUAL DC2013A PERFORMANCE SUMMARY PARAMETER CONDITION Input Voltage PVIN and EMI VIN Range Operating VIN = PVIN VLED > 36V MIN TYP Switching Frequency R1 = 287k 350 kHz 5 MAX 36 UNITS V ILED R1 = 0.75Ω 7.0V < PVIN < 36V VLED > 36V 333 mA Low PVIN ILED (CTRL Foldback) R1 = 0.75Ω PVIN = 5.0V R1 = 0.75Ω PVIN = 6.0V 270 320 mA mA VLED Range R4 = 1M, R5 = 22.6k Open-LED Voltage VOUT R4 = 1M, R5 = 22.6k 54.3 V PVIN 50 V Typical Efficiency (100% PWM DC) PVIN = 14V VLED = 50V ILED = 333mA 92.2 % Input Undervoltage Lockout (Falling Turn-Off) R7 = 499k, R8 = 196k, R9 = 24.3k 4.1 V Input Undervoltage Lockout (Rising Turn-On) R7 = 499k, R8 = 196k, R9 = 24.3k 5.4 V VISMON Operating ILED = 330mA 1.0 V Peak Switch Current Limit Operating 4 A QUICK START PROCEDURE Demonstration Circuit 2013A is easy to set up to evaluate the performance of the LT3952. Follow the procedure below: 1.Connect a string of LEDs that will run with forward voltage less than or equal to 50V (at 330mA), but greater than PVIN, to the LED+ and GND terminals on the PCB as shown in Figure 1. 2.Connect the EN/UVLO terminal to GND. 3.With power off, connect the input power supply to the EMI VIN (or PVIN) and GND terminals. Make sure that the DC input voltage will not exceed 42V (or VLED). 4.Turn the input power supply on and make sure the voltage is between 5V and 36V (or VLED) for proper operation. 5.Release the EN/UVLO-to-GND connection. 6.Observe the LED strings running at the programmed LED current. 7.To change the brightness with analog dimming, simply attach a voltage source to the CTRL terminal and set the voltage between 0V and 1.5V. See data sheet for details. 8.To change brightness with external PWM dimming, attach a 3V rectangular waveform with varying duty cycle to the PWM terminal. 9.To enable spread spectrum frequency modulation, simply change the position of the shunt on the SYNC/ SPRD jumper to the SPREAD SPECTRUM position. 2 DEMO CIRCUIT OPTIONS Demonstration Circuit 2013A can be adjusted for higher or lower output voltage, different LED current, or different topology. The following options are for simple changes to the demonstration circuit. The data sheet gives more information regarding designing with the LT3952. For more information, see the data sheet for details or contact Linear Tech customer support. MAXIMUM LED VOLTAGE DC2013A is set for 54.3V of overvoltage protection and the maximum LED string voltage used on the standard build should be 50V. Some margin is provided to limit the Open-LED overshoot above 55V in order to stay safely below the 60V limit. See data sheet for details. CURRENT OR VOLTAGE REGULATION The LT3952 can be used for constant-current or voltage regulation. If the load placed on the LED+ to GND terminals allows VOUT to climb high enough for V(ISP-ISN) = 1.2V, then the voltage regulation loop of the converter takes over. In this case, the compensation for a given channel should be adjusted for proper use as a constant-voltage regulator. The IC can be used as a boost or SEPIC constant-voltage regulator. Output voltage should remain below 60V when used as a constant-voltage device. dc2013af DEMO MANUAL DC2013A QUICK START PROCEDURE LED CURRENT LED current on DC2013A is set for 330mA with 0.75Ω resistor R1. For a different maximum LED current, change this resistor. 250mV/RLED = ILED. boost-buck see data sheet for details how to set the feedback resistors. Note that R19, R20, R21, and Q1 are provided as optional placeholders on the demonstration circuit for simple feedback resistor changes for these topologies. A change in LED current or input voltage may lead to higher or lower maximum switch current. The maximum switch current for this converter is 4A and is fixed internally. UNDERVOLTAGE AND OVERVOLTAGE LOCKOUT OVERVOLTAGE PROTECTION Resistors R13, R14, and R15 are available for setting UVLO and OVLO separately or for referring them to OUT for other topologies. Overvoltage protection is set with the resistor pair R4 and R5 for the boost topology. For buck mode, buck-boost mode, and UVLO and OVLO can be adjusted by changing the values of R7, R8 and R9. Figure 1. Test Procedure Setup Drawing for DC2013A dc2013af 3 DEMO MANUAL DC2013A QUICK START PROCEDURE Figure 2. DC2013A 12VIN 120Hz PWM Dimming Waveforms at Different PWM Duty Cycles with 1500:1 in Bold. ILED Waveform (200mA/DIV) Is on Top (with 50V LED String) and IL1 Waveform (1A/DIV) Is on the Bottom 0.35 0.30 ILED(A) 0.25 0.20 0.15 0.10 0.05 0 0 1 2 3 4 5 6 7 PVIN(V) 8 9 10 11 12 31 32 33 34 35 36 37 38 39 40 DC2013A F03 PVIN(V) Figure 3. DC2013A CTRL LED Current Foldback at Low Input with UVLO and OVLO Falling and Rising 4 dc2013af DEMO MANUAL DC2013A QUICK START PROCEDURE 100 EFFICIENCY (%) 95 90 85 80 75 70 0 5 10 15 20 25 PVIN (V) 30 35 40 DC2013A F04 Figure 4. DC2013A Efficiency at Maximum ILED vs PVIN with 50V LEDs (at 330mA) PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART # Required Electrical Components 1 1 C1 CAP., X5R, 10μF, 50V, 10% 1206 MURATA, GRM31CR61H106KA12L 2 1 C2 CAP., X7S, 4.7μF, 100V, 10% 1206 AVX, 12061Z475KAT2A 3 1 C3 CAP., X7R, 0.22μF, 10V, 10% 0603 MURATA, GRM188R71A224KA01J 4 1 C4 CAP., X7R, 4.7nF, 10V, 10% 0603 AVX, 0603ZC472KAT2A 5 1 C5 CAP., X5R, 2.2µF, 6.3V, 10% 0603 AVX, 06036D225KAT2A 6 1 C6 CAP., X7R, 1μF, 50V, 10% 0805 MURATA, GRM21BR71H105KA12L 7 1 D1 SCHOTTKY RECTIFIER DIODES INC., DFLS260-7 8 1 L1 INDUCTOR, 15μH WÜRTH ELEKTRONIK, 7447798151 9 1 M1 P-MOSFET, SI2307CDS, SOT23 VISHAY, SI2307CDS-T1-GE3 10 1 R1 RES., CHIP, 0.75Ω, 0.5W, 1% 1206 SUSUMU, RL1632R-R750-F 11 1 R2 RES., CHIP, 287k, 1/10W, 1% 0603 VISHAY, CRCW0603287KFKEA 12 1 R3 RES., CHIP, 3.0k, 1/10W, 5% 0603 VISHAY, CRCW06033K00JNEA 13 1 R4 RES., CHIP, 1M, 1/10W, 1% 0603 VISHAY, CRCW06031M00FKEA 14 1 R5 RES., CHIP, 22.6k, 1/10W, 1% 0603 VISHAY, CRCW060322K6FKEA 15 1 R6 RES., CHIP, 0.015Ω, 1W, 1% 1206 PANASONIC, ERJ-8BWFR015V 16 1 U1 I.C., LED Driver, TSSOP-28 LINEAR TECH., LT3952EFE#PBF dc2013af 5 DEMO MANUAL DC2013A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART # Optional Electrical Components 1 1 C7 CAP., X7R, 0.47μF, 25V, 10% 0603 MURATA, GRM188R71E474KA12D 2 1 C8 CAP., ALUM., 33µF, 50V, 6.3 × 7.7 PANASONIC, EEHZA1H330XP 3 1 C9 CAP., X5R, 2.2µF, 50V, 10% 1206 MURATA, GRM31CR71H225KA88L 4 1 C10 CAP., X5R, 0.1µF, 50V, 10% 0402 MURATA, GRM155R61H104KE14J 5 0 C11, C12, C17 (OPT) CAP., 0603 6 0 C13, C14 (OPT) CAP., 1206 7 0 C15, C16 (OPT) CAP., 1206 8 0 C18 (OPT) CAP., 0805 MURATA, GRM21BR71H105KA12L 9 1 D2 RECTIFIER, SMA DIODES INC., ES1B-13-F 10 1 FB1 BEAD, CHIP, 100Ω, 0805 TDK, MPZ2012S101AT000 11 1 L2 INDUCTOR, 4.7µH VISHAY, IHLP2020CZER4R7M11 12 0 Q1 (OPT) PNP SOT23 13 1 R7 RES., CHIP, 499k, 1/10W, 1% 0603 VISHAY, CRCW0603499KFKEA 14 1 R8 RES., CHIP, 196k, 1/10W, 1% 0603 VISHAY, CRCW0603196KFKEA VISHAY, CRCW060324K3FKEA 15 1 R9 RES., CHIP, 24.3k, 1/10W, 1% 0603 16 0 R10 (OPT) RES., 0402 17 2 R11, R12 RES., CHIP, 100k, 1/10W, 1% 0603 18 0 R13-R15, R18-R21, R24-R26 (OPT) RES., 0603 19 1 R16 RES., CHIP, 1M, 1/10W, 1% 0603 VISHAY, CRCW06031M00FKEA 20 1 R17 RES., CHIP, 249k, 1/10W, 1% 0603 VISHAY, CRCW0603249KFKEA 21 0 R22, R23 (OPT) RES., 0805 1 8 E1-E8 TESTPOINT, TURRET, 0.094" PBF 2 11 E9-E19 TESTPOINT, TURRET, 0.061" PBF MILL-MAX, 2308-2-00-80-00-00-07-0 3 1 JP1 HEADER 3-PIN 0.079" DOUBLE ROW WÜRTH ELEKTRONIK, 620 006 211 21 4 1 XJP1 SHUNT, 0.079" CENTER WÜRTH ELEKTRONIK, 608 002 134 21 VISHAY, CRCW0603100KFKEA Hardware 6 MILL-MAX, 2501-2-00-80-00-00-07-0 dc2013af DEMO MANUAL DC2013A SCHEMATIC DIAGRAM dc2013af 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. 7 DEMO MANUAL DC2013A 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 8 dc2013af Linear Technology Corporation LT 0415 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2015