XRP7613EVB

XRP7613 1.2A 36V Step-Down High brightness LED Driver November 2012 Rev. 1.0.0 GENERAL DESCRIPTION EVALUATION BOARD MANUAL The Exar XRP7613 Evaluation board (EVB) is a fully assembled and tested surface-mount PCB that demonstrates the XRP7613 LED driver. The XRP7613 is a non-synchronous step-down converter with integrated FET optimized to drive high-power LEDs at up to 1.2A of continuous current. A wide 7.0V to 36V input voltage range allows for single supply operations from industry standard 12V, 18V or 24V power rails. Based on a hysteretic PFM control scheme, the XRP7613 can operate at switching frequency of up to 1MHz and allows for small external components selection while providing very fast transient response and achieving excellent efficiency. The output current is programmable from 150mA to 1.2A through an external sense resistor. FEATURES  1.2A Continuous Output LED Current  150mA to 1.2A Programmable Range  7V to 36V Single Rail Input Voltage  PWM & Analog Dimming Capability The XRP7613 is offered in RoHS compliant, “green”/halogen free 8-pin Exposed Pad SOIC package.  Up to 40kHz Frequency  LED Current Thermal Fold back Control  Selectable Linear Dimming of LED Current with temperature STANDARD CONFIGURATION  Shutdown Control The XRP2524EVB is configured to operate under the following conditions:  Input voltage range VIN:  LED current:  Built-in Soft Start  Open LED, LED Short Circuit and Over Temperature Protections 7V – 36V 769mA EVALUATION BOARD SCHEMATICS External LED + External LED - D1 SS14 C4 4.7uF 0.13 Ohm/ 1%/ 0805/ 0.25W RSET 4 C1 C2 1 10uF 0.1uF EN/DIM PGND GND ISEN VREF TH LX LED 2 R5 0k LED 3 3 6 5 8 RT 10k RTH L1 47uH 103KT1608 0 7 LED 1 VIN 0k t 2 GND PAD VIN GND R4 U1 XRP7613 PWM DIM ANALOG DIM R1 0k R2 DNP R3 DNP C3 DNP Fig. 1: XRP7613 Evaluation Board Schematics Exar Corporation 48720 Kato Road, Fremont CA 94538, USA www.exar.com Tel. +1 510 668-7000 – Fax. +1 510 668-7001 XRP7613 1.2A 36V Step-Down High brightness LED Driver PIN ASSIGNMENT PGND 1 VIN 2 8 LX 7 GND XRP7613 HSOIC-8 ISEN 3 6 VREF EN/DIM 4 5 TH Fig. 2: XRP7613 Pin Assignment PIN DESCRIPTION Name Pin PGND 1 Power ground pin. VIN 2 Power supply input pin. Place an input decoupling capacitor as close as possible to this pin. ISEN 3 LED current setting pin. Connect resistor RSET from this pin to VIN (pin 2) to define nominal average LED current. EN/DIM 4 Dimming and Enable pin. For automatic startup, leave pin floating. TH 5 LED temperature protection sense input. Connect temperature thermal sense resistors to turn off output current above a preset temperature threshold. VREF 6 Reference Voltage for thermal protection. GND 7 Ground pin. LX 8 Exposed Pad GND Description Connect to the output inductor. Power ground pin. ORDERING INFORMATION Refer to XRP7613’s datasheet and/or www.exar.com for exact and up to date ordering information. © 2012 Exar Corporation 2/7 Rev. 1.0.0 XRP7613 1.2A 36V Step-Down High brightness LED Driver USING THE EVALUATION BOARD current to ILED=0.1V/0.13Ω=0.769A. To program a different current use the above equation to select the appropriate resistor. POWERING UP THE BOARD Connect a power supply to the VIN and GND pins of the PCB. Upon powering up the XRP7613 will regulate the LED current at 769mA nominal. Nominal operating frequency is 200kHz at 12VIN. The input voltage can be varied from 7V to 36V. PWM DIMMING DRIVING EXTERNAL LEDS ANALOG DIMMING To drive an external LED or string of LEDs, remove resistor R4 or R5 from the PCB. Then connect the external LEDs to the posts marked “External LED+” and “External LED-” on the PCB. A DC voltage in the range of 0.4V to 1.25 volt can be applied to EN/DIM pin in order to achieve analog dimming. Populate R2/R3 as necessary and apply the dimming signal to the “ANALOG DIM” pin. A 0.1uF bypass capacitor is recommended (populate C3). The LED light, which is proportional to average LED current, can be dimmed using a logiclevel signal applied to the “PWM DIM” pin. Maximum dimming frequency is 40kHz. PROGRAMMING THE LED CURRENT The PCB is supplied with a 0.13Ω programming resistor “RSET”. This sets the © 2012 Exar Corporation 3/7 Rev. 1.0.0 XRP7613 1.2A 36V Step-Down High brightness LED Driver EVALUATION BOARD SCHEMATICS VIN GND PWM DIM ANALOG DIM C1 10uF C2 0.1uF R1 0k R2 DNP R3 DNP C3 DNP D1 SS14 GND PGND EN/DIM VIN U1 XRP7613 LX TH VREF ISEN 8 5 6 3 0.13 Ohm/ 1%/ 0805/ 0.25W RSET 2 4 1 7 RT 10k External LED + 103KT1608 0k LED 2 R4 C4 4.7uF LED 1 RTH t External LED - R5 0k LED 3 L1 47uH Rev. 1.0.0 4/7 © 2012 Exar Corporation GND PAD 0 XRP7613 1.2A 36V Step-Down High brightness LED Driver BILL OF MATERIAL Ref. Qty Manufacturer Part Number Size Component PCB 1 Exar XRP7613EVB 1.5"x2.2" XRP7613 Evaluation kit U1 1 Exar XRP7613 PSO-8 LED Driver D1 1 FAIRCHILD SS14 SMA Schottky Rectifier LED1 1 Philips/Lumileds LXA7-PW57 4.5x3.05mm Luxeon R SMT High Current LED LED2-LED3 0 DNP DNP DNP DNP L1 1 COOPERBussmann DR74-470-R 7.6x7.6mm 47uH shielded inductor C1 1 Murata Corp. GRM32ER61H106KA12L 1210 CER CAP 10uF, 50V, X5R C2 1 Murata Corp. GRM188R71H104KA93D 0603 CER CAP 0.1uF, 50V, X7R C3 0 DNP DNP DNP DNP C4 1 Murata Corp. GRM32ER71H475KA88L 1210 CAP CER 4.7uF, 50V, X7R R1,R4,R5 3 Panasonic ERJ-3GEY0R00V 0603 Resistor 0.00 Ohm, 1/10W R2,R3 0 DNP DNP DNP DNP RT 1 Panasonic ERJ-3EKF1002V 0603 Resistor 10K Ohm, 1/10W,1% RSET 1 Panasonic ERJ-S6SFR13V 0805 Resistor 0.13 Ohm,0.25W,1% RTH 1 Semitec 103KT1608T-1P 0603 Thermistor 10K Ohm, 1% Test Point 2 Mill-Max 0300-1-15-01-47-27-10 VIN, GND, PWM DIM, ANALOG DIM 4 Vector Electronic K24C/M © 2012 Exar Corporation 5/7 Pin RCPT .042 Dia Test Point Post Rev. 1.0.0 XRP7613 1.2A 36V Step-Down High brightness LED Driver EVALUATION BOARD LAYOUT Fig. 4: Layout – Top Side Fig. 3: Component Placement – Top Side Fig. 5: Layout - Bottom © 2012 Exar Corporation 6/7 Rev. 1.0.0 XRP7613 1.2A 36V Step-Down High brightness LED Driver DOCUMENT REVISION HISTORY Revision Date 1.0.0 11/09/2012 Description Initial release of document BOARD REVISION HISTORY Board Revision Date 146-6694-01 11/09/2012 Description Initial release of evaluation board FOR FURTHER ASSISTANCE Email: customersupport@exar.com Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx? EXAR CORPORATION HEADQUARTERS AND SALES OFFICES 48720 Kato Road Fremont, CA 94538 – USA Tel.: +1 (510) 668-7000 Fax: +1 (510) 668-7030 www.exar.com NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user’s specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. or its in all Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. © 2012 Exar Corporation 7/7 Rev. 1.0.0