A linear constant current LED driver without off-chip inductor and capacitor

A linear constant current light-emitting diode (LED) driver without off-chip inductor and capacitor is presented in this paper. The proposed driver consists of one resistor, one diode bridge and one controller integrated circuits (IC). The controller IC employs four LED strings and sequences their conduction to shape the output current in proportion to the input voltage. The controller IC was designed and implemented by using HHNEC 1μm 700V process. The experimental results show that high PF of 97.93% and efficiency of 90.41% under the input voltage of 220V|rms utility voltage were obtained.