A new digital AC/DC SSL (solid state lighting) LED driver platform has been developed by iWatt Inc. that offers flickerless dimming in lighting applications.
The company’s iW3616 and iW3617 Flickerless LED drivers, can increase output power by more than 25W, which is said to lower the bill of materials (BOM) cost by some 10 to 20 percent. As a result they can be retrofitted to many already installed dimmers, including residential TRIAC dimmers as well as the more sophisticated digital dimmers.
Regulations around the world are placing huge demands on driver performance, in lighting efficiency. Quality is specified in terms of total harmonic distortion (THD) and power factor and the company’s iW3616 and iW3617 are said to match all these requirements, by achieving power factor greater than 0.95 and low total harmonic distortion (THD) of less than 15 percent.
Both devices are designed to meet, or exceed the 85 percent efficiency required for most new LED driver designs.
They are designed for 120V/230VAC offline LED lighting bulbs and fixtures and offer output power ratings up to 12W and 25W, respectively. They integrate a mix of the company’s PrimAccurate technology to reduce BOM cost and size, with Flickerless technology to eliminate flicker, along with digital dimming algorithms.
The devices follow on from the company’s 15W iW3614 LED driver, expanding dimmer compatibility and improving dimming and EMI performance. The reduction in BOM cost and a smaller overall solution size compared to the company's iW3614 is achieved by replacing FETs with lower cost BJTs, this is enabled by reducing the component count needed for the protection circuit and EMI filtering, and by using a smaller, lower-cost E-capacitor.
The drivers are capable of operating with dimming frequencies from 630Hz to 900Hz and are said to allow smooth, flicker-free dimming from 1 to 100 percent with tight +/-5 percent LED current regulation.
For added protection, safety features include: LED open/short circuit protection, input over-voltage protection, over-temperature thermal shutdown, and AC line over-voltage/frequency protection. An LED current de-rating at high temperatures also protects LEDs.
Other important key features of the drivers include:
• Output power: 12W (iW3616); 25W (iW3617)
• Digital dimming algorithms ensure wider compatibility with installed wall dimmers
• Flickerless technology eliminates LED flicker all the way down to the minimum light level
• PrimAccurate primary-side control reduces solution size, lowers BOM cost, increases reliability
• Power Factor > 0.95
• Total harmonic distortion (THD) < 15%
• Efficiency > 85%
• Meet global standards, including European Union IEC61000-3-2(1) requirement
• Complies with NEMA SSL 6(2) dimming standard for incandescent replacement screw-base lighting retrofit
• Compatible with Zhaga(3) hot-plug LED module for LED light interchangeability