Universal method for driving LEDs using high voltage

An apparatus for driving a plurality of LEDs, comprising:

• first and second LED driving circuits, each LED driving circuit including:
• a plurality of LEDs divided into a plurality of LED segments connected in series including a leading LED segment and a trailing LED segment, each of said plurality LED segments having a positive end and a negative end;
• a plurality of voltage controlled current limiting devices, each of said plurality of voltage controlled current limiting devices being associated with one of said plurality of LED segments, and having a first terminal connected to the negative end of the associated LED segment, a second terminal being applied with a bias voltage and a third terminal being connected to a common node;
• a power-loss reduction circuit having a positive end connected to said common node;
• and
• a bottom voltage controlled current limiting device having a first terminal connected to a negative end of said power-loss reduction circuit, a second terminal connected to a control voltage, and a third terminal;
• a first switching device having a first end connected to the positive end of the leading LED segment of said first LED driving circuit, and a second end connected to the positive end of the leading LED segment of said second LED driving circuit;
• a second switching device having a first end connected to the negative end of the trailing LED segment of said first LED driving circuit, and a second end connected to the positive end of the leading LED segment of said second LED driving circuit;
• a current source having a first end connected to the third terminals of the bottom voltage controlled current limiting devices of said first and second LED driving circuits and a second end connected to ground;
• a universal controller controlling said first and second switching devices and said current source, and providing the control voltages of the bottom voltage controlled current limiting devices of said first and second LED driving circuits;
• and
• an input voltage connected to the positive end of the leading LED segment of said first LED driving circuit and said universal controller;
• wherein said first switching device is turned on, said second switching device is turned off, and the two control voltages are set identical when said input voltage is between rectified 90 volt AC to rectified 140 volt AC, and said first switching device is turned off, said second switching device is turned on and the control voltage of the bottom voltage controlled current limiting device of said second LED driving circuit is set greater than or equal to the control voltage of the bottom voltage controlled current limiting device of said first LED driving circuit when said input voltage is between rectified 180 volt AC to rectified 265 volt AC.