ZXSC310EV5 EVALUATION BOARD USER GUIDE DESCRIPTION The ZXSC310 is a single or multi cell The ZXSC310EV5 is configured as a LED driver in an SOT23-5 package. The buck-boost converter to drive a 1W LED use of an external switching BJT or from 3 NiCd/NiMH or Alkaline batteries. Mosfet enables various circuit topologies. FEATURES • Drives a 1W white LED at 350mA • Typical efficiency of 75% ORDERING INFORMATION APPLICATIONS • LED torches • High Power LED driving TYPICAL APPLICATION CIRCUIT ORDER NUMBER ZXSC310EV5 Please note evaluation boards are subject to availability and qualified leads. ZXSC310EV5 EVALUATION BOARD Issue 1 – February 2009 © Diodes Incorporated, 2009 www.zetex.com www.diodes.com ZXSC310EV5 REFERENCE DESIGN The ZXSC310EV5 is configured to the reference design below. The use of buck-boost topology enables the input voltage to range from below to above the LED voltage. The target application is a 1W white LED being driven from a 3 NiCd/NiMH or alkaline battery input, for torches and high powered LED driving. R1,R2 and R3 form an input voltage feed-forward network, which lowers the effective Isense threshold when input voltage goes high. This provides flatter response of LED current against input voltage. Zener diode D3 causes Isense to be held high (above 20mV) when the output is over voltage. This acts as open circuit protection. The supply voltage for ZXSC310EV5 is: VIN=2.6V ~ 5V. For other reference designs or further applications information please refer to the ZXSC310 datasheet. WARNING: Exposed battery connections exist on the front and back of the board. Do not cause the batteries to short-circuit by placing it on a conductive surface or allowing other conductive materials to come into contact with it. Schematic Diagram Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 2 ZXSC310EV5 Parts List Ref Value Package Part Number Manufacturer U1 Q1 N/A N/A SOT23-5 SOT23 ZXSC310E5 ZXTN25012EFH Zetex / Diodes Inc Zetex / Diodes Inc D1 D2 LED1 L1 40V 2A SOT23-6 12V 0.25W SOT23 1W 350mA 22uH 2.5A N/A R1 R2 R3 C1,C2 0R018 4R7 2k4 4.7µF 10V 0805 0805 0805 1206 SW1 SK1 n/a n/a n/a 6 way DIL ZHCS2000 BZX84C12 n/a DO3316P-223 NPI31W220MTRF 7456122 C1206C475K8RAC GRM31CR71A475KA01 NMC1206X7R475K10 Notes Boost LED Driver Low sat. NPN transistor Zetex / Diodes Inc Schottky diode Zetex / Diodes Inc. Zener diode generic Not fitted Coilcraft SMT Inductor, NIC Components ~0.085R Wurth generic +/-1% tolerance generic +/-1% tolerance generic +/-1% tolerance Kemet X7R, Murata +/-10% tolerance NIC Components generic Slide switch generic 6 way connector Performance Graphs Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 3 ZXSC310EV5 ZXSC310EV5 OPERATION Connection diagram ZXSC310EV5 3 CELL BUCK / BOOST EVALUATION BOARD LED K SW1 SK1 OFF LED1 K L1 ON D2 R3 PO W ER D1 1 C2 Q1 C1 U1 A R2 R1 LED A ZXSC310EV5 Set-up and Test WARNING: Exposed battery connections exist on the front and back of the board. Do not cause the batteries to short-circuit by placing it on a conductive surface or allowing other conductive materials to come into contact with it. 1. Ensure that the ‘POWER’ switch is set to ‘OFF’ 2. Insert three ‘AA’ size alkaline or NiCd/NiMH batteries as depicted on the rear of the board, or connect a supply to the battery clips. (positive to BAT1 + and negative to BAT3 - ) 3. Set the PSU to 4.5V (if used). 4. Connect a suitable Lumileds™ Luxeon® emitter board to connector SK1. (The LED must be capable of handling 350mA) 5. Turn on the PSU (if used). 6. Turn the ‘POWER’ switch to ‘ON’ 7. The LED should illuminate, and the LED current should be regulated at 350mA +/-10%. 8. The input current should measure between 300mA ~ 400mA THIS IS A FUNCTIONAL BOARD. Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 4 ZXSC310EV5 Layout considerations PCB tracks should be kept as short as possible to minimise ground bounce, and the ground pin of the device should be soldered directly to the ground plane. It is particularly important to mount the inductor and the input/output capacitors close to the device to minimise parasitic resistance and inductance, which will degrade the efficiency. The FB pin is a high impedance input, so PCB track lengths to this should also be kept as short as possible to reduce noise pickup. Excess capacitance from the FB pin to ground should be avoided. Below (contained within the box), is the recommended layout of the ZXSC310 driver circuitry. ZXSC310EV5 3 CELL BUCK / BOOST EVALUATION BOARD LED K SW1 SK1 OFF LED1 K L1 D2 D1 R3 PO W ER 1 C2 ON Q1 C1 U1 R2 R1 A LED A Top Silk Top Copper Bottom Copper Drill File Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 5 ZXSC310EV5 INTENTIONALLY BLANK Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 6 ZXSC310EV5 INTENTIONALLY BLANK Issue 1 – February 2009 www.zetex.com www.diodes.com © Diodes Incorporated 2009 7 ZXSC310EV5 Definitions Product change Diodes Incorporated reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. Customers are solely responsible for obtaining the latest relevant information before placing orders. Applications disclaimer The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoever is assumed by Diodes Inc. with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Diodes Inc. does not assume any legal responsibility or will not be held legally liable (whether in contract, tort (including negligence), breach of statutory duty, restriction or otherwise) for any damages, loss of profit, business, contract, opportunity or consequential loss in the use of these circuit applications, under any circumstances. Life support Diodes Zetex products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Reproduction The product specifications contained in this publication are issued to provide outline information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. Terms and Conditions All products are sold subjects to Diodes Inc. terms and conditions of sale, and this disclaimer (save in the event of a conflict between the two when the terms of the contract shall prevail) according to region, supplied at the time of order acknowledgement. For the latest information on technology, delivery terms and conditions and prices, please contact your nearest Diodes sales office. Quality of product Diodes Zetex Semiconductors Limited is an ISO 9001 and TS16949 certified semiconductor manufacturer. To ensure quality of service and products we strongly advise the purchase of parts directly from Zetex Semiconductors or one of our regionally authorized distributors. For a complete listing of authorized distributors please visit: www.zetex.com or www.diodes.com. Diodes Zetex Semiconductors does not warrant or accept any liability whatsoever in respect of any parts purchased through unauthorized sales channels. ESD (Electrostatic discharge) Semiconductor devices are susceptible to damage by ESD. Suitable precautions should be taken when handling and transporting devices. The possible damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. The extent of damage can vary from immediate functional or parametric malfunction to degradation of function or performance in use over time. Devices suspected of being affected should be replaced. Green compliance Diodes Zetex Semiconductors is committed to environmental excellence in all aspects of its operations which includes meeting or exceeding regulatory requirements with respect to the use of hazardous substances. Numerous successful programs have been implemented to reduce the use of hazardous substances and/or emissions. All Diodes Zetex components are compliant with the RoHS directive, and through this it is supporting its customers in their compliance with WEEE and ELV directives. Product status key: “Preview” “Active” “Last time buy (LTB)” “Not recommended for new designs” “Obsolete” Datasheet status key: “Draft version” “Provisional version” “Issue” Future device intended for production at some point. Samples may be available Product status recommended for new designs Device will be discontinued and last time buy period and delivery is in effect Device is still in production to support existing designs and production Production has been discontinued This term denotes a very early datasheet version and contains highly provisional information, which may change in any manner without notice. This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance. However, changes to the test conditions and specifications may occur, at any time and without notice. This term denotes an issued datasheet containing finalized specifications. However, changes to specifications may occur, at any time and without notice. Sales offices The Americas Europe Taiwan Shanghai Shenzhen Korea 3050 E. 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