Innovative LED driver designed to solve transformer and dimmer compatibility issues

Dialog Semiconductor has announced its entrance into the MR16 dimmable solid state lighting (SSL) market with an innovative LED driver designed to solve transformer and dimmer compatibility issues in challenging, low-voltage lighting applications.


The iW3662 uses patent-pending digital control technology to optimise low-voltage SSL bulbs for compatibility with virtually any transformer (electronic or magnetic), even in lighting applications with output power as low as 4W.


The greatest challenge in designing low-voltage MR16 LED retrofit bulbs is the installed base of AC step-down electronic transformers, which are not a good match for LED lighting. MR16 halogen lamps require transformers to convert the standard electric line voltage down to 12VAC. Most low-voltage halogen lighting systems use small, inexpensive electronic transformers to perform this conversion. These transformers are designed to power resistive loads and can typically require a minimum load of 20W. While this load is easily provided by 50W halogen lamps, an equivalent LED MR16 lamp drawing 8W struggles to latch the transformer, with lower wattage bulb replacements often completely failing.

The iW3662 LED driver solves this MR16 transformer compatibility problem with patent-pending control technology that uses advanced digital analytics to detect installed electronic transformers and dynamically increases the peak loading to latch the transformer, even during low dimming ranges, while maintaining the high efficiency expected from SSL LED bulbs. The iW3662 includes detection for magnetic step-down transformers as well to automatically switch in a compatible loading mechanism for these older models.


The iW3662 dimmable MR16 SSL LED driver also uses digital technology to provide exceptional dimmer compatibility (both TRIAC and digital dimmers) and dimmer performance, with either electronic or magnetic transformers. It delivers smooth flicker and shimmer-free dimming down to 5% of measured light, says the company.


“Dialog is the definitive leader in digital control technology for SSL lighting, with LED driver solutions for applications ranging from small form-factor retrofit bulbs to commercial lighting ballasts,” said Davin Lee, senior vice president and general manager, Power Conversion Business Group, Dialog Semiconductor. “The one remaining portion of the market we had not addressed was the low-voltage, dimmable MR16 segment, where our customers experience transformer and dimmer compatibility issues with existing LED driver solutions. Our innovative iW3662 builds on our digital control expertise with new intellectual property developed specifically for the low-voltage SSL lighting market.”


The iW3662 is seeing broad industry adoption with Sengled Lighting being one of the first early adopters to offer a new generation of MR16 bulbs to the market.


“As a global leader in high quality, energy-saving green lighting solutions, Sengled is dedicated to bringing the most innovative SSL products to the market,” explains Johnson Shen, founder and president at Sengled Lighting. “The challenge with low-voltage, dimmable MR16 lighting is compatibility with the existing infrastructure of transformers and dimmers. Dialog’s new iW3662 LED driver enabled us to easily, elegantly and cost effectively solve these issues and enabled us to deliver the highest quality dimmable MR16 LED bulbs that allow consumers to seamlessly replace halogen bulbs today.”


Designed for low-voltage AC and DC inputs, the iW3662 offers either single-stage or two-stage operation. This simplifies design and reduces development time by allowing designers to specify one part across multiple low-voltage LED replacement bulb applications, as well as high-voltage chip-on-board (COB) LED modules up to 8W.


The advanced control circuitry in the iW3662 helps designers reduce their bill of materials (BOM) cost by enabling the use of low-cost, off-the-shelf inductors, while the high-frequency 1MHz switching supports the use of smaller, less-expensive external components.
The iW3662 integrates Dialog’s patented over-temperature protection (OTP) de-rating technology to address LED bulb lifetime issues caused by excessive heat. OTP technology monitors the temperature inside the sealed SSL bulb and seamlessly dims light output if the temperature rises above a safe operating threshold, then restores brightness as temperature falls. This results in cooler operation, avoids exceeding the temperature rating of the electrolytic capacitors, and helps ensure a predictable and safer bulb operating life, says the company.