Dimmable lighting-LED chip simplifies driver designs

February 06, 2015 // By Graham Prophet
The company’s first product in the MR16 dimmable solid state lighting (SSL) market is an LED driver designed to solve transformer and dimmer compatibility issues in low-voltage lighting applications.

The company’s first product in the MR16 dimmable solid state lighting (SSL) market is an LED driver designed to solve transformer and dimmer compatibility issues in low-voltage lighting applications.

The greatest challenge in designing low-voltage MR16 LED retrofit bulbs, Dialog asserts, 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 control technology that uses 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.

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