METHODS AND APPARATUS FOR DRIVING LIGHT EMITTING DIODES (LEDS) COMPRISING PARALLEL FLYBACK CONVERTER STAGES

1 . An apparatus for driving a light source, the apparatus, comprising:

a first flyback alternating current to direct current (AC/DC) converter stage comprising a first switch, a first switch controller and a comparator; and

a second flyback AC/DC converter stage comprising a second switch and a second switch controller, the second flyback AC/DC converter stage being electrically connected in parallel with the first flyback AC/DC converter stage.

2 . An apparatus as claimed in claim 1 , wherein the first switch comprises a first metal oxide semiconductor field effect transistor (MOSFET).

3 . An apparatus as claimed in claim 1 , wherein the second switch comprises a second MOSFET.

4 . An apparatus as claimed in claim 1 , wherein the first switch controller comprises a power factor controller (PFC).

5 . An apparatus as claimed in claim 3 , wherein the second controller comprises a gate controller.

6 . An apparatus as claimed in claim 4 , wherein the PFC controller comprises a memory comprising threshold limit data for an output power.

7 . An apparatus as claimed in claim 1 , further comprising:

a third flyback AC/DC converter stage comprising a third switch and a third switch controller, the third flyback AC/DC converter stage being electrically connected in parallel with the first flyback AC/DC converter stage and the second flyback AC/DC converter stage.

8 . An apparatus as claimed in claim 7 , further comprising:

a fourth flyback AC/DC converter stage comprising a fourth switch and a fourth switch controller, the fourth flyback AC/DC converter stage being electrically connected in parallel with the first flyback AC/DC converter stage, the second flyback AC/DC converter stage and the third flyback AC/DC converter stage.

9 . An apparatus as claimed in claim 7 , wherein the third switch comprises a third MOSFET and the third switch controller comprises a gate controller.

10 . An apparatus as claimed in claim 8 , wherein the fourth switch comprises a fourth MOSFET and the fourth switch controller comprises a gate controller.

11 . A method of driving a light source, the method comprising:

sensing a voltage over a sense resistor in a first flyback AC/DC converter stage;

comparing the voltage to a threshold voltage;

enabling a second flyback AC/DC converter stage if the voltage is greater than the threshold voltage.

12 . A method as claimed in claim 11 , further comprising:

enabling a third flyback AC/DC converter stage if the voltage is greater than the threshold voltage after the enabling of the second AC/DC converter stage.

13 . A method as claimed in claim 12 , further comprising enabling a fourth flyback AC/DC converter stage if the voltage is greater than the threshold voltage after the enabling of the third AC/DC converter stage.

14 . A method as claimed in claim 11 , further comprising:

not enabling the second stage if the voltage is less than the threshold voltage.

15 . A method as claimed in claim 13 , further comprising, after enabling the fourth flyback AC/DC converter stage, sensing the voltage over the sense resistor, and if the voltage is less than the threshold voltage, disabling the fourth flyback AC/DC converter stage.

16 . A method as claimed in claim 15 , further comprising, after disabling the fourth flyback AC/DC converter stage, sensing the voltage over the sense resistor, and if the voltage is less than the threshold voltage, disabling the third Flyback AC/DC converter stage.

17 . A method as claimed in claim 16 , further comprising, after disabling the third Flyback AC/DC converter stage, sensing the voltage over the sense resistor, and if the