Abstract

The light-emitting diode (LED) technology is reaching a high penetration in commercial applications oriented to illumination. However, there are some problems associated when the application requires a high output power. The problems are related to the connection of several LED units to reach the voltage and current levels. The voltage-current characteristic of the LEDs is not always the same, specially when a failure occurs. Therefore, when some strings are connected in parallel, the illumination is not uniform if the same voltage is applied to all strings. For that reason, in this paper a multi-channel current balancing driver is proposed. The driver is based on a partial power DC-DC converter architecture. It performs current balancing handling only a portion of the total power delivered by the source, reaching an increased efficiency. Besides, due to the modularity of the architecture, it allows the parallel connection of as many strings as required to use for high power application. Simulations are performed in order to evaluate the converter performance.