DCM Integrated Double Buck-Boost led driver with reduced storage capacitance

This work proposes an approach for low frequency current ripple minimization in off-line light-emitting diode (LED) drivers. This strategy is based on the large signal modulation of the duty cycle of a LED converter so that the output ripple can be reduced and, consequently, the required filtering capacitances of the converter can be further decreased. The approach presented in this work is developed by defining a modulation function that allows for a reduction in the storage capacitance, and by analyzing the converter behavior when such function is applied to the driver. The design of the low-frequency filtering element of the converter is performed by using a graphical technique, which allows the designer to evaluate the behavior of the output current ripple and the input current distortion. The analysis is carried out for an Integrated Double Buck-Boost converter and experimental results are shown in order to demonstrate the validity of the proposal.