US Patent 7733032 OLED driver and lighting apparatus equipped with the same

An OLED driver for driving at least one organic electroluminescence element and lighting apparatus equipped with the driver. The driver has a direct-current power source and a dimmer. The source alternately applies first voltage and second voltage across the element. The first voltage is approximately equal to drive voltage of the element. The second voltage is lower than the first voltage and higher than barrier voltage of the element. The dimmer controls the source so as to change a ratio of a first term to a second term to dimm the element. The first term is a period of time for which the first voltage is applied across the element. The second term is a period of time for which the second voltage is applied across the element.