Dimming and mixing light emitting diodes using reduced pulse widths

A method of mixing and dimming light emitting diodes (LEDs), comprising:

• providing a substantially constant amplitude of direct current to an LED load comprising a plurality of LED banks having a predetermined minimum rated current;
• capacitively storing a voltage across the LED load;
• passing the direct current selectively through the plurality of LED banks for durations during a mixing period, a combination of the durations being equal to the mixing period;
• receiving a dimming instruction indicative of a dimming current for the plurality of LED banks;
• in response to the dimming current being greater than or equal to the predetermined minimum rated current, decreasing the substantially constant amplitude of the direct current;
• and
• in response to the dimming current being less than the predetermined minimum rated current, decreasing the substantially constant amplitude of the direct current and decreasing the combination of the durations to be less than the mixing period.

A method, comprising:

• delivering, from a current source, a substantially constant direct current to a load, the load comprising a light emitting diode (LED) enabled by a switch and at least another LED connected in parallel with the LED;
• storing, with a capacitive element, a voltage level across the load;
• activating the switch for a mixing duration equal to a percentage of a mixing period;
• determining a dimming level for the LED and a selected minimum drive current for the LED as percentages of a rated current for the LED;
• comparing the dimming level and the selected minimum drive current;
• and
• in response to the dimming level being less than the selected minimum drive current, dimming the LED by decreasing the substantially constant direct current to equal the dimming level and activating the first switch for a mixing-dimming duration equal to (the mixing duration)*(the dimming level/the selected minimum drive current).