A current compensator for mitigating the influence of long cable inductance between the LED driver and the light source

摘要

It is sometimes unavoidable to use a long cable to connect the light source to the driver when they are placed far apart in large scale LED lighting installation. Since LED driver typically delivers pulse-width-modulated current pulses, the long cable inductance will delay the rate of rise of the current pulses and will also cause negative off-state voltage across the light source, reducing luminous output and vitiating the life expectancy of the light source. This paper will present a current compensator, which can mitigate the distortion of the current pulses caused by the long cable. The concept is based on recycling the energy stored in the cable at the end of a current pulse and then driving the light source synchronously with the driver at the beginning of the next current pulse. A prototype for a 12V, 4.5A LED driver has been built and evaluated. Topological states, operations and experimental results will be given.