An alternate way of driving LEDs

May 15, 2008
Several lighting manufacturers have recently incorporated AC-driven LEDs into their lighting fixtures. Tim Whitaker looks at this emerging technology.
Most LEDs are designed to be driven by a DC current, and LED systems are built accordingly. However, with the correct design at the device or circuit level, it is also possible to drive certain LEDs with an alternating current.

One obvious advantage of this approach is the elimination of the otherwise essential AC-DC converter, which converts line (AC) voltage down to low (DC) voltage. (Note that LED replacement lamps, although plugged directly into an AC light socket, usually contain converter circuitry within the lamp so that the LEDs themselves are driven by a DC current.

AC-driven LEDs have been available for more than a year, and lighting manufacturers are now starting to take advantage. Nexxus Lighting recently introduced what it claims is the industry’s first LED floodlight for general illumination that operates directly from line voltage (i.e. 120V AC), without the need for an internal or external power supply. The SAVI™ SHO White floodlight is intended for interior and exterior applications, and contains a total of 17 Seoul Semiconductor 4-watt Acriche LEDs.

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This article was published in the April 2008 issue of LEDs Magazine.

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