Active PFC driver design enables dimmable retrofit lamps (MAGAZINE)

Aug. 21, 2010
Designers of LED-based solid-state lighting (SSL) retrofit lamps face thermal and power challenges as well as the need to work with legacy dimmers, but new driver topologies enable reliable designs says Piero Bianco of Maxim.
Halogen and incandescent lamps, although popular, present some key concerns in today’s power conscious, green world. The lamps consume a lot of power and typically burn out after a few thousand hours of use. The latest high brightness LEDs (HB-LEDs) offer a great alternative – they use a lot less power and can last about ten times as long. However, designing LED-based solid-state lighting (SSL) replacements for popular halogen and incandescent lamps such as the MR16, PAR20, A19, and others presents several design challenges. The retrofit lamps must work with legacy triac dimmers and the driver electronics must fit in a tight space. But new driver designs with active PFC stages are enabling reliable and dimmable SSL retrofit lamps.

The primary challenges of designing an LED retrofit lamp include:

  • The retrofit lamps must fit in the same socket as the lamp they replace, and that means they should have the same form factor;
  • They have to manage the high amount of power generated by the LEDs, by having proper heat sinking, but also by working at high temperature while keeping high reliability and long lifetime;
  • They must be electrically compatible with the existing lighting infrastructure (wiring, dimmers, etc.).


This article was published in the July/August 2010 issue of LEDs Magazine. To read the full version of this article, please visit our magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine. You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter.