Time division modulation with average current regulation for independent control of arrays of light-emitting diodes
View Patent ↗Method and computer-readable medium embodiments provide for sourcing current to a series of light-emitting diodes in a plurality of series of light-emitting diodes. A method comprises generating a current, sequentially and separately switching the current to each of the series of light-emitting diodes in the plurality of series of light-emitting diodes for a corresponding period of time, and predicting an output voltage across a selected series of light-emitting diodes using a plurality of parameters stored in a memory.
1. A method of providing power to a series of light-emitting diodes in a plurality of series of light-emitting diodes, the method comprising:
generating an input DC current having an average current;
determining the average current of the input DC current based on a plurality of corresponding input DC currents through the plurality of series of light-emitting diodes;
determining a total period for switching the input DC current to all of the series of light-emitting diodes in the plurality of series of light-emitting diodes;
determining a corresponding period of time for switching the input DC current to a selected corresponding series of light-emitting diodes based on a ratio of the corresponding input DC current for the selected corresponding series of light-emitting diodes to the average current; and
sequentially and separately switching the input DC current to each of the series of light-emitting diodes in the plurality of series of light-emitting diodes for the determined corresponding period of time.
2. The method of claim 1 , further comprising:
switching no current to all remaining series of light-emitting diodes while switching the input DC current to a selected series of light-emitting diodes in the plurality of series of light-emitting diodes.
3. The method of claim 1 , wherein the average current of the input DC current is determined to be substantially equal to a sum of the plurality of corresponding input DC currents through the plurality of series of light-emitting diodes.
4. The method of claim 3 , wherein the corresponding time period for switching the input DC current to a selected corresponding series of light-emitting diodes is determined to be substantially equal to a proportion of the total period determined according to the ratio of the corresponding input DC current for the selected corresponding series of light-emitting diodes to the average current.
5. The method of claim 1 , further comprising:
storing, as a look-up table, a plurality of parameters corresponding to the plurality of series of light-emitting diodes.
6. The method of claim 5 , further comprising:
predicting an output voltage across a selected series of light-emitting diodes in the plurality of series of light-emitting diodes based on the stored plurality of parameters.
7. The method of claim 6 , further comprising:
measuring a corresponding output voltage for each series of light-emitting diodes in the plurality of series of light-emitting diodes.
8. The method of claim 7 , further comprising:
updating the predicted output voltage across a selected series of light-emitting diodes in the plurality of series of light-emitting diodes based on the corresponding measured output voltage.
9. The method of claim 1 , further comprising:
determining an input voltage.
10. The method of claim 1 , further comprising:
determining a peak input DC current.
11. The method of claim 1 , further comprising:
determining a corresponding output voltage for each series of light-emitting diodes in the plurality of series of light-emitting diodes.
12. The method of claim 1 , further comprising:
measuring a corresponding current through each series of light-emitting diodes in the plurality of series of light-emitting diodes.
13. The method of claim 12 , further comprising:
determining a corresponding period of time for switching the input DC current to a selected series of light-emitting diodes based on a comparison of the measured corresponding current to a predetermined current for the selected series of light-emitting diodes.
14. The method of claim 1 , further comprising:
determining a corresponding period of time for switching the input DC current to a selected series of light-emitting diodes based on an integer multiple of a period of switching.
15. The method of claim 1 , further comprising:
switching the input DC current to a selected series of light-emitting diodes in the plurality of series of light-emitting diodes if the input DC current is substantially zero.
16. The method of claim 1 , further comprising:
in response to a first input, adjusting an output brightness of the plurality of series of light-emitting diodes by modifying each corresponding period of time of current switching to each of the series of light-emitting diodes.
17. The method of claim 1 , further comprising:
in response to a second input, adjusting an output color of the plurality of series of light-emitting diodes by modifying a corresponding period of time of current switching to at least one of the series of light-emitting diodes in the plurality of series of light-emitting diodes.