Flickerless high-power LED drivers boost performance and cut size / costs

Dialog Semiconductor has announced two new driver controllers for high-power commercial LED lighting applications up to 90W. In these applications flicker-free operation is essential to avoid eye stress, particularly where there is long-term exposure to the light source. Dialog's patented Flickerless technology virtually eliminates flicker through digital control that achieves near-zero line frequency ripple, says the company. The iW3629 (non-dimmable) and iW3631 (dimmable) digital power controllers simplify the design of LED power supplies by replacing up to 45 discrete components. Both devices can be used with small input and output bulk capacitors, and small transformers. This cuts power supply size, bill of materials and costs while optimising performance. The controllers feature better than 0.95 power factor (PF), less than 15% total harmonic distortion (THD) and 85%+ efficiency over a wide load range, easily meeting the requirements of the Design Lights Consortium (DLC)1. The controllers comprise a two-stage design with a rectified AC-input (90 to 277 VAC), active start-up, and a boost circuit feeding a flyback converter. The latter provides a constant current drive to the LEDs. Quasi-resonant control in both stages maximizes power efficiency. Dialog's PrimAccurate(TM) primary side sensing technology produces tight line and load regulation while eliminating the need for secondary side feedback components. Fast, smooth start-up takes less than half a second and PF settling time is minimal. The iW3631 dimmable controller has a flicker- and shimmer-free dimming range of 1% to 100%. It has a built-in interface to industry-standard, 0-10V analog dimmers, so there's no need for an external driving source or microcontroller, and a dimming interface to support wireless solid state lighting applications, says the company. Davin Lee, senior vice president and general manager, Power Conversion Business Group, Dialog Semiconductor, said, "Commercial LED lighting customers are the most demanding in terms or LED lighting performance and reliability. However, the market is just as price sensitive as the consumer sector so we are constantly striving to help customers create lighting that combines leading-edge performance with the lowest possible cost. These two new high power LED driver controllers do exactly that using proven, patented technologies that produce visible competitive edge."