초록 ▼

An LED array circuit includes a number of series connected LED pairs, each pair including two parallel connected oppositely polarized LEDS. The array is coupled to a standard AC voltage source in series with an inductor L having Q>5 and a reactance which is equivalent to the resistance of a current

An LED array circuit includes a number of series connected LED pairs, each pair including two parallel connected oppositely polarized LEDS. The array is coupled to a standard AC voltage source in series with an inductor L having Q>5 and a reactance which is equivalent to the resistance of a current limiting resistor. The use of an inductor in place of a resistor increases the efficiency of the array to approximately 80%. The efficiency of the array is increased even further by coupling a capacitor parallel to the array and by tuning the inductor and capacitor to the frequency of the AC voltage source. According to one embodiment of the invention, a somg;e retro-fittable unit is provided wherein an inductor, a capacitor, and an array of LEDs are contained in a housing having substantially the same size and shape as a standard incandescent bulb or the lens/filter used in a traffic signal display. According to another embodiment of the invention, a single module is provided with a plurality of LED arrays, with each LED array having its own capacitor coupled in parallel thereto, and its own series coupled switch. The module is coupled to and across the AC voltage source, with one node of the module coupled to the AC voltage source by an inductor.

대표청구항 ▼

[ I claim:] [20.] An LED array circuit powered by a substantially sinusoidal AC voltage source, comprising:a) a first plurality of series connected LEDs having first and second terminal nodes, coupled to and across the substantially sinusoidal AC voltage source; andb) a current limiting inductor arr

[ I claim:] [20.] An LED array circuit powered by a substantially sinusoidal AC voltage source, comprising:a) a first plurality of series connected LEDs having first and second terminal nodes, coupled to and across the substantially sinusoidal AC voltage source; andb) a current limiting inductor arranged in series with and coupling one of said first and second terminal nodes to the substantially sinusoidal AC voltage source, said inductor having an inductance value chosen to provide a desired current through said LEDs, and having a Q value and reactance for improved power efficiency.