austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems application note is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: ams_sales@ams.com Please visit our website at www.ams.com AS3674 - AN01 - Demo Board Preliminary Application Note Application Note AS3492 Highly Efficient 2-10 LEDs Backlight Driver with 2 PWM Inputs * * 2 MHz DCDC Boost converter - Small 4.7H external coil - Very high application efficiency of up to 90% - Very low voltage changes on output to avoid acoustic noise on output capacitor even with PWM - Smooth startup even under low duty cycle PWM conditions Five Current sources up to 25mA - Low voltage compliance (150mV) - High side current source to simplify layout and thermal management of the LEDs - Automatically detect and disable failing or not used LEDs to keep efficiency high - Current matching <4% - Current accuracy <7.5% Excellent LED current output ripple <500A Support DLS (Dynamic Luminance Scaling or DBC) Undervoltage lockout and overcurrent protection Overtemperature protection Available in a tiny WL-CSP package - 3x4 balls, 0.4mm pitch, 1.7x1.4x0.5mm am lc s on A te G nt st il The output of the DCDC converter is used for five current sources connected to up to 10 LEDs. If a current source is not required, it shall be connteced to VOUT or GND - the AS3492 detects this condition and disables this current source automatically; this keep the efficiency of the system constantly high. The AS3492 is controlled by two enable inputs, ON13 and ON45. These inputs can also be used to connect a PWM input (like DLS or DBC). 2 Key Features lv The AS3492 is an inductive highly efficient DCDC boost converter. The DCDC converter operates at a fixed frequency of 2MHz and includes soft startup to allow easy integration into noise sensitive RF systems. A predictable startup is guaranteed even with very low duty cycle PWM input signals. The voltage on the output capacitor is controlled to minimize ripple and to avoid any acoustic effects for low frequency PWM input signals. al id 1 General Description The AS3492 includes several protection functions like undervoltage lockout, overcurrent and overtemperature. No microvias are required to assemble the AS3492 if only four channels are used and ON13=ON45. 3 Application Display backlight driver for mobile phones, digital cameras, PND and PMPs. Te ch ni ca The AS3492 is available in a space-saving WL-CSP package measuring only 1.7x1.4x0.5mm and operates over the -30C to +85C temperature range. * * * * * www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 1-8 AS3492 Demo Board 2V0 Preliminary Application Note Table of Contents GENERAL DESCRIPTION ................................................................................................................. 1 2 KEY FEATURES ............................................................................................................................... 1 3 APPLICATION .................................................................................................................................. 1 4 FURTHER APPLICATIONS ................................................................................................................ 3 5 REVISION STATUS ........................................................................................................................... 3 6 GENERAL DESCRIPTION ................................................................................................................. 3 7 GETTING STARTED .......................................................................................................................... 3 8 PCB: GET THE BOARD FUNCTIONAL .............................................................................................. 3 9 AS3492 DEMOBOARD 2V0 JUMPER AND DEVICE LOCATIONS ........................................................ 4 10 APPLICATION SCHEMATIC AS3492 DEMO BOARD 1V0 ................................................................... 5 11 AS3492 DEMOBOARD 1V0: LAYOUT (TOP VIEW) ............................................................................. 5 12 AS3492 DEMOBOARD 2V0: LAYOUT (BOTTOM VIEW) ..................................................................... 6 13 AS3492 DEMOBOARD 2V0: LAYOUT (MULTILAYER 1) ..................................................................... 6 14 AS3492 DEMOBOARD 2V0: LAYOUT (MULTILAYER 2) ..................................................................... 7 am lc s on A te G nt st il lv al id 1 Te ch ni ca COPYRIGHT ............................................................................................................................................. 8 www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 2-8 AS3492 Demo Board 2V0 Preliminary Application Note 4 Further Applications Visit our home-page: http: //www.austriamicrosystems.com 5 Revision status AS3492 - AN02 - Demoboard Rev.: 1V0 6 General description 7 Getting Started For this Application no Software is required 1 am lc s on A te G nt st il Connect the battery to VBAT and GND @ Point 1. lv al id Remark: all subsequent component numbering refers to the application schematics, shown in par"Application Schematic". 8 PCB: Get the board functional Te ch ni ca Push the switch SW1 and all LEDs of "group1" should be turned on. Push the switch SW2 and all LEDs of "group2" should be turned on www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 3-8 AS3492 Demo Board 2V0 Preliminary Application Note 9 AS3492 Demoboard 2v0 jumper and device locations Listed below are the various connectors and jumpers. Function Jumper setting comment Connection of all LEDs to GND Open LED5 string Short LED5 string GND Ground Connection Vbat Connection ON13 ON45 USB-BOX Interface Value U1 D1~D10 AS3492 CL120 High Efficient 2-10 LEDs Backlight Driver IC Citizen CL-120 LED SideLED C1 2.2F +/- 20% - X5R - 6V3 Semco CL05A225MQ5NNN C3 10F - X5R - 25V Semco CL10A106MA8NRNC L1 4.7H - 2x1,2x1mm Semco CIG21E4R7MNE am lc s on A te G nt st il Value comment ni ca Device Closed Useful for all LED current measurements, remove therefore R6 Closed Open open LED dectection open Connect Jumper to short led detection For GND connection of measurement probes PWM input for current source LED4 and LED5 Supply voltage input: apply 2.5V - 5.5V if pressed, ON13 is pulled to Vbat if pressed, ON45 is pulled to Vbat austriamicrosystems USB-BOX IF - not assembled comment al id J8 J5 J6 J3 GND VIN SW1 SW2 J9 Device lv Jumper Te ch Connector and Jumper locations of AS3492 Demo Board 2V0 www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 4-8 AS3492 Demo Board 2V0 Preliminary Application Note am lc s on A te G nt st il lv al id 10 Application Schematic AS3492 Demo Board 1V0 Application Schematic AS3492 Demo Board V2.0 Te ch ni ca 11 AS3492 Demoboard 2V0: Layout (top view) Layout (top view) www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 5-8 AS3492 Demo Board 2V0 Preliminary Application Note am lc s on A te G nt st il lv al id 12 AS3492 Demoboard 2V0: Layout (bottom view) Layout (bottom view) Te ch ni ca 13 AS3492 Demoboard 2V0: Layout (Multilayer 1) Layout (Multilayer 1) www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 6-8 AS3492 Demo Board 2V0 Preliminary Application Note am lc s on A te G nt st il lv al id 14 AS3492 Demoboard 2V0: Layout (Multilayer 2) Te ch ni ca Layout (Multilayer 2) www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 7-8 AS3492 Demo Board 2V0 Preliminary Application Note Copyright Copyright (c) 1997-2012, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, AustriaEurope. Trademarks Registered (R). All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. al id Diclaimer ni ca am lc s on A te G nt st il lv Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Te ch Headquarters austriamicrosystems AG A-8141 Tobelbaderstrasse 30, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 5692 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact www.austriamicrosystems.com (jen) Revision 1.0 / 4/18/2012 8-8 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: ams: AS3492 DB REV 2.0