AS3691

AS3691 Product Brief a ustria micro systems Product Brief AS3691 4 Precision 400mA Current Sources for RGB and Single Color Leds 1 General Description The AS3691 features four high precision current sources for driving up to four LED strings (RGB or single color leds). Each of the four currents sources can be controlled independently by PWM inputs. The full scale current value is set by external resistors. Very wide output voltage current source voltage compliance − Down to 0.41V 2) − Up to 15V Integrated overtemperature protection Separate sense pads (Rfb1-Rfb4) for easy and precise PCB Layout Package − DIE − QFN24 4x4mm 15V is sufficient for most applications as the AS3691 dose not switch off the LED current completely 2) 2 Key Features 4 x 400mA constant current outputs Programmable with external resistors 4 independent PWM inputs Absolute current accuracy +/-0.5% ’ Automatic Supply Regulation’ to reduce power 1) dissipation 1) 3 Applications General Lighting Backlighting RGB Backlighting for LCD TV/Monitors with White Color Balancing Patent Pending 4 Application Diagrams Figure 1 – Application Diagram of AS3691 for Single Color Lighting (Single Module shown) VDD Csup 100nF Rvdd Cvdd 100nF UV VREG 15 UV1 22 CURR1 1 Vc UV2 20 CURR2 17 Vc UV3 10 CURR3 13 Vc UV4 8 Vc CURR4 5 UV VDD AS3691 D1 Ref T1 I1 R1 23 ON1 2 24 RFB1 19 RES1 ON2 R2 16 18 RFB2 T2 I2 R3 11 RES2 ON3 14 12 RFB3 T3 I3 R4 7 RES3 ON4 4 RFB4 6 T4 I4 Overtemp 21,Pad VSS RES4 Ri1 V SS Ri2 Ri3 Ri4 VSS PWM PW M www.austriamicrosystems.com Revision 1.2 1-3 AS3691 Product Brief a ustria micro systems Figure 2 – Application Diagram of AS3691 for RGB Lighting (single Module shown) VDDG VDDB VDDR VDDG VDDB VDDR Rvdd Cvdd 100nF UVG UVB UVR VREG 15 UV1 22 CURR1 1 Vc UV2 20 CURR2 17 Vc UV3 10 CURR3 13 Vc UV4 8 CURR4 5 Vc UVG UVB UVR AS3691 D1 Ref T1 I1 R1 23 ON1 2 24 RFB1 19 RES1 ON2 R2 16 18 RFB2 T2 I2 R3 11 RES2 ON3 14 12 RFB3 T3 I3 R4 7 RES3 ON4 4 RFB4 6 T4 I4 Overtemp 21,Pad VSS RES4 Ri1 VSS PWMG PWMB PWMR Ri2 Ri3 Ri4 VSS PWMG PWMB PWMR Figure 3 – Complete AS3691 Application using White LEDs VDD Main supply DCDC Converter for VDD Voltage Feedback input for DCDC ... ... UV Vc Vc Vc Vc D1 ... 5V powered system (optional) D1 Overtemp ... Overtemp AS3691 AS3691 VSS PWM (optional) PWM www.austriamicrosystems.com Revision 1.2 2-3 AS3691 Product Brief a ustria micro systems Copyright Copyright © 1997-2005, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, AustriaEurope. Trademarks Registered ®. 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 of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent identification 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 life-sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. 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 Headquarters: austriamicrosystems AG Business Unit Communications A 8141 Schloss Premstätten, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 5692 info@austriamicrosystems.com For Sales Offices, Distributors and Representatives, please visit: www.austriamicrosystems.com austriamicrosystems www.austriamicrosystems.com Revision 1.2 – a leap ahead 3-3