TRIAC-dimmable LED driver ICs cut bill of materials by 40%
Single-stage, non-isolated, phase-cut or TRIAC-dimmable, buck topology LED driver ICs in the LYTSwitch-7 family reduce component count from 35 to 20 for typical dimmable LED driver boards.
The latest series from Power Integrations delivers up to 22W without a heatsink in a small, SO-8 footprint.
They do not require bleeders but use passive damping for TRIAC management and an off-the-shelf, single-winding inductor to reduce component count.
According to the company, the ICs deliver phase-cut dimming with a wide dimming range and monotonic dimming response. The LED drivers enable efficiency of greater than 86%; around 2% higher than conventional dimmable products, with high PF, accurate regulation and comprehensive protection. The ICs are suitable for bulbs, tubes and fixtures and suit low- or high-line input as well as wide-range universal-input designs for US commercial lighting applications, which operate from 90 to 305V AC with TRIAC dimming enabled in low-line installations.
Protection features including thermal foldback with end-stop shutdown, which protects the IC, driver and fixture at abnormally-high ambient temperatures by automatically reducing the current flow and dimming the lamp. Developers use thermal foldback to reduce costs associated with over-design of both electrical and mechanical components to meet reliability goals, as the IC automatically limits unusual temperature excursions without extinguishing the lamp. Devices are also protected from open- and short-circuit conditions, input and output over-voltage, over-current and safe operating area. The ICs meet international standards including DOE Level 6 (external power supply), CEC Titles 20 and 24, ENERGY STAR® Lamps Program Requirements Version 2.0, NEMA SSL-7A and EN61000-3-2 (C&D).
Key applications include low-cost A19 lamps, small-form-factor lamps such as candle-style and GU10 bulbs, commercial and industrial applications, ceiling lamps and downlight fixtures.
Two reference designs (DER-539 and DER-540) are available for download.