LED lamp driving technology using variable series-parallel charge pump

Abstract

A novel high power light-emitting diode lamp driving technology that uses a reverse charge pump circuit and digital dimming method instead of a conventional DC-DC converter is proposed to obtain a high circuit efficiency at all dimming levels. In this method, the voltages of all capacitors are kept constant by the period in which the capacitors are connected in parallel. From the experimental results, the circuit efficiency was kept constant irrespective of the dimming level and lighting condition. In addition, an average circuit efficiency of 91.8% was obtained when all of the light-emitting diode lamps were turned on at the same dimming level.