LM3435EVAL/NOPB

User's Guide SNVA506A – October 2011 – Revised May 2013 AN-2196 LM3435 Evaluation Board 1 Introduction The Texas Instruments LM3435 Evaluation Board has been designed for evaluating the performance of the device in a typical pico projector application. The end user can interface his own system to the evaluation board to test out the performance of the system. With LM3435, the system requires only single DC-DC converter to drive three color LEDs instead of using three DC-DC converters with conventional design. The suggested approach not only saves components cost, but also releases invaluable PCB space to the system and enhances system reliability. Assuming the handy projector is powered by a single lithium battery cell or a 5Vdc wall mount adaptor, the key specifications of the evaluation board are: Supply voltage range, VIN = 2.7V to 5.5V Preset LED current per channel, ILED = 1.5A Minimum LED current per channel, ILED(MIN) = 600mA Maximum LED forward voltage drop, VLED = 3.5V @ 1.5A Flyback converter switching frequency, FSW = ~500kHz 2 Evaluation Board Schematic Diagram The complete schematic diagram of the evaluation board is shown in Figure 1. For the details of the design, please see LM3435 Compact Sequential Mode RGB LED Driver with I2C Control Interface (SNVS724). 3 Connecting the Evaluation Board to the System The LM3435 Evaluation Board is optimized to run with input voltages ranging from 2.7V to 5.5V and requires a supply current not less than 4.1A for full range operation. A connection diagram to show the configuration between the system and the evaluation board is shown in Figure 2. Proper connections to the I/Os must be confirmed before powering up the board. In order to avoid false triggering of the OPEN/SHORT fault detect of the device, the control pins GCTRL, BCTRL, and RCTRL must be kept in logic “LOW” during power-up. 4 Interfacing with the I2C Bus The current setting resistors only determine the nominal maximum LED current and the actual LED current can be further adjusted on-the-fly by the internal ten bits register for individual channel. The content of these registers are user programmable via standard I2C bus. The connection between the system MCU and the I2C bus is illustrated in Figure 2. The resolution is 1 out of 1024 part of the LED current setting. The user can program the registers in the range from full output, that is, 1023 (3FFH) to minimum LED current that is restricted by the inductor ripple current amplitude. For Projected On-Time (POT) scheme used in LM3435, a minimum inductor ripple current of 300mAPK-PK is required to maintain proper operation. For the details of the registers addresses and definitions, please see LM3435 Compact Sequential Mode RGB LED Driver with I2C Control Interface (SNVS724). All trademarks are the property of their respective owners. SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated AN-2196 LM3435 Evaluation Board 1 Interfacing with the GPIO Bus 5 www.ti.com Interfacing with the GPIO Bus The PWM control pins GCTRL, BCTRL, and RCTRL are internally pulled low, push-pull I/O ports are recommended to interface properly with the system MCU. The device enable, EN pin is internally pulled high, so an open drain I/O port is recommended. 6 Changing the Preset LED Current The factory preset LED current of the LM3435 evaluation board is 1.5A, In case the user need to make a change of the preset LED current, it can be done by simply replacing the LED current setting resistors R1, R2 and R3. The ILED(MIN) condition should not be violated for proper regulation, that is, the ILED current for all operation conditions must be no less than 600mA with this evaluation board. Some popular values for user's reference are listed in below. For details about the operation and calculations of the components, please see LM3435 Compact Sequential Mode RGB LED Driver with I2C Control Interface (SNVS724). Preset LED Current, ILED 2 R1, R2, R3 Value 1.5A 16.5kΩ 1.0A 24.75kΩ 0.75A 33.0kΩ AN-2196 LM3435 Evaluation Board SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Evaluation Board Schematic www.ti.com 7 Evaluation Board Schematic C3 VIN VOUT 10 PF L1 2.2 PH/6A C1 Power Input 47 PF C2 0.1 PF SD1 RB160M-60 GND H1 C4A 31 32 VOUT 33 34 RT 35 SW 36 SW 37 SW 38 VIN 39 PGND 3 CG EN C6 4 CB C7 5 CR R1 6 IREFG R2 7 IREFB BLED R3 8 IREFR BLED 9 GND RLED GLED RCTRL RLED 30 29 28 VOUT 27 26 GRN C10 25 24 To LEDs BLU 23 C11 22 21 C12 RED H2 3 x 0.47PF 20 BCTRL 19 GCTRL GLED 18 VIN VIN VIN SCLK VIN 17 16 C9 47 PF 15 C8 1 PF SGND 14 10 13 16.5k FAULT DAP (PGND) SDATA 16.5k 16.5k VOUT SGND SVDD 1 nF PGND 12 1 nF 2 x 10 PF 2 11 1 nF C5 VOUT 1 PGND PGND U1 PGND 40 R4 499k C4B SVDD *R5 10k 2 I C Bus *R6 10k R7 1k SDATA SCLK GND * R5, R6 - I2C Pull-high resistors FAULT CON2 GCTRL PWM Controls And GPIO Bus BCTRL RCTRL FAULT EN GND CON1 Figure 1. Evaluation Board Schematic Diagram SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated AN-2196 LM3435 Evaluation Board 3 Connection Diagrams 8 www.ti.com Connection Diagrams VOUT - VIN V 2.7V ± 5.5V 5A Power Supply + + VIN ** Use current probe to monitor the LED current + V - ILED IIN + A GRN LED RED LED GND SCLK SDA SVDD BLU LED 2 I C Bus &XVWRPHU¶V MCU Board GCTRL BCTRL RCTRL FAULT EN GND GPIO Bus Fault Indicator Figure 2. Evaluation Setup Connection Diagram 4 AN-2196 LM3435 Evaluation Board SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Typical Performance Waveforms www.ti.com 9 Typical Performance Waveforms All curves taken at VIN = 5V with configuration in typical application for driving one red (OSRAM LRW5AP-KZMX), one green (OSRAM LTW5AP-LZMY) and one blue (OSRAM LBW5AP-JYKX) LEDs with ILED per channel = 1.5A under TA = 25°C, unless otherwise specified. 2.5 90 2.0 BLUE ILEDx(A) LED EFFICIENCY, (%) 100 80 GREEN 70 1.5 1.0 RED 60 0.5 50 0.0 2 3 4 VIN(V) 5 6 5 15 25 35 RIREFx(k ) 45 55 Figure 3. LED Efficiency vs VIN@ TA=25°C Figure 4. ILEDx vs RIREFx Figure 5. Power Up Transient (10ms/DIV) Figure 6. RGB Sequential Mode Operation (1ms/DIV) SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated AN-2196 LM3435 Evaluation Board 5 Typical Performance Waveforms www.ti.com Figure 7. Color Transition Delay (100µs/DIV) 6 AN-2196 LM3435 Evaluation Board SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Bill of Materials www.ti.com 10 Bill of Materials In order to help customer shorten the design cycle of the target application system, a detailed list of all components used in this evaluation board is provided. ID Part Number Type Size Parameters Qty Su U1 LM3435 RGB LED Driver IC WQFN-40 1 Texas Instruments SD1 RB160M-60 Schottky Diode SOD-123 1A, 60V, Vf = 0.49V 1 Rohm L1 CDMC6D28NP-2R2MC Power Inductor 7mm x 7mm 2.2µH, 6A, 19mΩ 1 Sumida C1, C9 GRM31CR61A476M Ceramic Capacitor 1206 47µF, 10V, X5R 2 Murata C2 GRM188R61E104K Ceramic Capacitor 0603 0.1µH 25V, X5R 1 Murata C3, C4A, C4B GJ831CR61E106K Ceramic Capacitor 1206 10µF, 25V, X5R 3 Murata C5, C6, C7 GRM188R71H102K Ceramic Capacitor 0603 1nF, 50V, X7R 3 Murata C8 GRM188R71A105K Ceramic Capacitor 0603 1µF, 10V, X7R 1 Murata C10, C11. C12 GRM188R71E474K Ceramic Capacitor 0603 0.47µF, 25V, X7R 3 Murata R1, R2, R3 SMT Resistor 0603 16.5kΩ, ±1% 3 R4 SMT Resistor 0603 499kΩ, ±1% 1 R5, R6 SMT Resistor 0603 10kΩ, ±1% 2 R7 SMT Resistor 0603 1kΩ, ±1% 1 FAULT LTST-C170EKT SMT LED 0805 LED RED ORANGE 1 Lite-On VIN, VOUT 1593–2 Terminal Pin Φ2.35mm Turret DBL, 2.34mm 1 Keystone H1 B2PS-VH Connector Header 2 Position, Pitch 3.96mm 1 JST H2 B4PS-VH Connector Header 4 Position, Pitch 3.96mm 1 JST CON1 35363–0660 Connector Header 6 Position, Pitch 2mm 1 Molex CON2 35363–0460 Connector Header 4 Position, Pitch 2mm 1 Molex SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated AN-2196 LM3435 Evaluation Board 7 PCB Layout PCB Layout 58 mm 11 www.ti.com 50 mm Figure 8. Top Overlay 8 AN-2196 LM3435 Evaluation Board SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated PCB Layout 58 mm www.ti.com 50 mm 58 mm Figure 9. Top Layer 50 mm Figure 10. Bottom Layer SNVA506A – October 2011 – Revised May 2013 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated AN-2196 LM3435 Evaluation Board 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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