PI's RDR-382 reference design describes a constant current, 43V (nominal), 150W reference power supply for 90-265 VAC solid-state lighting, using Power Integrations’ HiperPFS-2 PFC controller ICs and HiperLCS integrated LLC power stage ICs.
Traditional dual-stage drivers with separate PFC and LLC stages produce a constant-voltage (CV) output requiring multiple DC-DC converters to convert the output to constant current (CC). In contrast, RDR-382 uses a novel feedback and control scheme which enables the LLC to provide constant current directly at the output. As a result, component count is cut by approximately one-third, efficiency is increased to over 93%, and the elimination of the DC-DC converter stage significantly reduces size. The high nominal LLC switching frequency (250 kHz) reduces the size of the required magnetics, while the use of a continuous-conduction-mode, variable-frequency PFC stage reduces EMI compared to fixed-frequency alternatives. Driving single or multiple LED strings, the design allows analogue dimming to be implemented with a 0-10 VDC input.
Power Integrations; http://led-driver.power.com/sites/default/files/PDFFiles/rdr382.pdf