A new, simple, “universal”, low cost LED driver and controller

In this paper, a new LED driver and its controller are conceived, realized and experimentally validated. It presents several advantages compared with the existing counterparts: First it uses a single converter while most of the existing drivers are based on a two-converter architecture. In the proposed approach, the average current through the LED is directly regulated. The proposed driver is built around a “Sepic” converter because it allows lowering and raising of the battery voltage and, has the lowest number of components compared to “Inverter”, “Zeta” or “Flyback”, necessitating an input filter to meet the required disturbance standards. Compared to “Cuk”, with a Sepic, constraints on the voltage across the capacitor in series are weaker and, the implementation of detection of current through the LED requires fewer components. Moreover, in the proposed architecture the two inductor of the sepic are coupled which along with a very fast current mode control of the internal loop, results to a simpler transfer function. A PI controller is designed and its performance and robustness are experimentally verified for different converters.