DC-Level Dimmable LED Driver With Primary Side On-Time Control for DC Distribution

This paper proposes a light-emitting diode (LED) lighting system using a dc-level dimming technique. This new dimming method realizes LED lamp control by having the LED drivers in the same zone recognize the level of their input voltage as a dimming signal with a dc-level dimmer and minimum communication interfaces. The proposed dc LED system also achieves improved system efficiency by matching the variable input voltage to the LED load conditions. Practical design guidelines for the LED driver circuit are presented for system implementation. The prototype circuit for a 24-W LED lamp is designed following the guidelines for verification. The proposed dc-level dimming system and the conventional dimming LED lighting system, which dispatches communication modules to individual drivers to obtain dimming signal, are implemented for a two-story parking lot and their performance is compared and evaluated. The experimental results of the prototype system show 6.8% energy saving compared with conventional lighting, which results from the improved driver efficiency and reduced standby power consumption.