Project Lighting - April 2008 - (Page 8)

CoveR stoRy sponsoR ADveRtIsement Analog Device’s ADP1653 Flash/Torch LED Driver The ADP1653 is a compact camera flash LED driver optimized for cellular phones. The high efficiency and dynamic LED current control of the device improve flash brightness and picture quality in dimly lit environments. Efficiency peaks at 92% and is higher than charge pump solutions over the Li-Ion battery range. The indicator and LED currents are programmable with resistors or through the I2C interface. The ADP1653 solution requires only four external components in I2C mode and fits in a 6.4 mm × 7.2 mm space. The part has integrated safety features such as soft start, thermal protection, and overvoltage protection. click here for more information at values specified by the LED manufacturers and chop the current at certain frequency and duty cycle. The dimming frequency should be over 100 Hz to prevent visual flicker. The dimming range is limited by the LED driver’s minimum duty cycle capability. Most of the LED drivers require a dimming signal from a microcontroller or an external timer. Selecting the appropriate HBLED driver requires LED lighting system understanding to make the best trade-offs. One needs to start with the basic electrical specification such as input voltage, LED current, LED forward voltage and their variations. The safety, EMI, thermal and mechanical specifications as well as available board space must also be considered. Linear drivers are used for low-cost, easy-to-implement, and low- Contents Viewpoint Selecting HBLED Drivers for Lighting Apps Simulation Technique for Optimizing White-LED Design An Analytical Approach to Cooling HBLEDs Lighting News Analog Devices Corporate Headquarters One Technology Way P. O. Box 9106 Norwood, MA 02062-9106 Phone: 1-800-262-5643 or 781-461-4482 http://www.analog.com/index.html Selecting the aPProPriate hBleD DriVer reQuireS leD lighting SyStem unDerStanDing to make the BeSt traDe-offS EMI applications. Switch-mode drivers are used for high-power, high-efficiency, or wide-input operating-voltage range, but they increase the parts cost and may add EMI concerns. Home Page Product Training Module Online Ordering Suppliers Catalog 8 | Project lighting | aPr 08 http://digikey.com/ http://ad.doubleclick.net/clk;198717884;26055153;t http://ad.doubleclick.net/clk;198717989;26055167;e http://www.analog.com/index.html http://ad.doubleclick.net/clk;198717988;26055168;e http://ad.doubleclick.net/clk;195096758;25485864;f http://ad.doubleclick.net/clk;198717986;26055170;v http://ad.doubleclick.net/clk;198717985;26055171;v

Table of Contents Feed for the Digital Edition of Project Lighting - April 2008

Project Lighting - April 2008 Contents Viewpoint About Project Lighting Sponsor Simulation Technique for Optimizing White-LED Design An Analytical Approach to Cooling HBLEDs LED Lighting Needs Smarts to be Competitive Lighting News Enter to Win an iPhone Refernce Materials Lighting Quick Links

Project Lighting - April 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.