The HV98100/HV98101 LED driver Integrated Circuit (IC) is an off-line, high-power factor, buck-boost controller targeted at general LED lighting products, such as LED lamps and LED lighting fixtures with a maximum power rating of about 15W. The IC is targeted at designs at single line voltages such as 110VAC or 230VAC. The HV98100/HV98101 uses a unique control scheme to achieve high-power factor and low THD simultaneously under all line and load conditions, while maximizing efficiency utilizing valley switching. The average LED current is also controlled in a closed-loop manner to achieve high-LED accuracy. Other unique features of the ICs are the bootstrap of the IC supply voltage from the output, as well as the unique valley-sensing scheme which allow the use of a standard off-the-shelf inductor to minimize the overall system cost.