the order of 10 1 pf this can be accomplished if the on resistance of the second switch q 2 303 is chosen high enough and the current rating of the diode d 1 306 is chosen low enough as such in accordance with representative embodiments the current through the buck converter 301 is maintained at a comparatively low amplitude first e g 10 or less of the maximum current of the leds which allows the selection of the on resistance of the second switch q 2 303 to be comparatively high and which allows comparatively low current across the diode d 1 306 without significant conduction losses for example a diode with a current rating of 1 a might have a junction capacitance of 20 pf 50 pf whereas a diode e g diode d 1 306 with a current rating of 0 1 a might have a junction capacitance in the range of approximately 1 pf to approximately 5 pf which is comparatively low the switching losses are proportional to frequency so a factor of 10 reduction in capacitance translates to a factor of 10 reduction in switching losses which can be very significant at operating frequencies of 100 khz to 500 khz in accordance with representative embodiments the buck converter 301 is operated at a comparatively high switching frequency to allow low output current ripple into the leds i e substantially constant led current with a small value of the inductor 304 l 2 notably.