High-voltage LED-based efficient lighting using a hysteretic controlled boost converter

Car industries are especially interested on decreasing the power rating of the electrical sub-system to reduce wire weight and fuel consumption. Using LED devices, a typical 50W halogen-based car spot-light, could be replaced by a LED array of 8-12W. To improve the array life-time and simplify light dimming, all LED devices are series-connected to a high-voltage current-source driver. This driver, based on a single-stage boost converter has a very high voltage gain. Supplied from a 12 V car-battery, and limited only by the commercially-available switching devices, our prototype reaches 900V. Hysteretic control is decisive to achieve the required extremely high duty ratios, circa 98%, as well as to guarantee DCM-CCM border converter operation to reduce switching losses.