New-Tech Europe Magazine | July 2016 | Digital edition

Figure 3. 22W LED Driver Circuit with LF77944.

typically needs to be less than 20 percent. There are cur-rently no standards governing flicker. Most manufacturers and cus-tomers accept the US ENERGY STAR recommended spec for calculat-ing the flicker index. It suggests a figure of 0.15 or lower to be opti-mal since values below 0.15 are considered imperceptible. As a con-sequence, lighting manufacturers typically aim to achieve or improve on this limit. Direct AC Driver for Superior Performance All these problems are now being addressed, as Fairchild, a leading global supplier of high-performance semiconductor solutions, recently introduced its new FL77944 LED Direct AC Drive family of solid-state LED lighting solutions. The FL77944 and the IP provided by Fairchild enable a tunable flicker index below 0.10 while maintaining PF > 0.9 and THD

as well as analog and PWM dimming, which is key for wirelessly connected lighting. • Scaling for higher power applications. The Fairchild FL77944 can scale upwards to suit higher power applications well above 120W. This is simply done by wiring products in parallel. It also reduces the number of different ICs that lighting manufacturers need to keep in inventory. • Elimination of electrolytic capacitors. System designs with the FL77944 can eliminate the electrolytic caps, transformers and inductance coils. This reduces both the bill-of- materials (BOM) costs and the overall complexity compared to designs using SMPS. • Reduced board space. Locating the controller IC on the same PCBs as the LEDs, aided by the absence of electrolytic caps, transformers and inductance coils enables more

< 20%. LED lighting manufacturers can use these integrated driver circuits to easily scale power conditions. This will enable them to create smart and scalable LED systems that are smaller, have higher performance and reliability, offer size advantages and a lower component count as well as longer lifetimes compared to the traditional SMPS approach. The FL77944 is a cost-effective integrated circuit with everything manufacturers need for smart LED lighting products so they can accelerate time-to-market and focus on differentiating features, rather than spending precious time cobbling together disparate components. The new Fairchild FL77944 DACD solution offers: • Comprehensive dimming capabilities. It enables all the dimming capabilities required for smart lighting products, including phase-cut dimming

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