Comparative Study of Steady-State Performance of Voltage and Current Fed Dimmable LED Drivers

The paper focuses on electronic circuits for light regulation with arrays of light emitting diodes (LEDs) - dimmable LED drivers. Previously some well-known voltage fed (VF) topologies of such drivers (buck, boost and buck-boost) have been analyzed from the point of view of their non-linearity and accuracy achievable with practical control solutions in the static operation mode. It has been found that the volt-ampere curve of LEDs has a significant negative impact on the mentioned parameters in the case of VF drivers. The given paper extends this comparative study also to current fed (CF) dimmable drivers. The topologies of CF drivers are introduced, their static equations are obtained and then the CF drivers are tested experimentally. Conclusions about benefits of the CF drivers in the static operation mode compared with VF circuits are drawn in the final part of the paper.