Dimmable lighting devices and methods for dimming same

摘要

In a single lighting device including a large number of light-emitting elements (LEEs), the LEEs are divided into separately powered groups, and different combinations of the groups are fully energized to achieve the desired overall brightness. In some embodiments, the number of LEEs in each group has a binary relationship to the other groups. The resolution of the dimming is the brightness of the smallest group. In one example of five binary weighted groups of LEEs, 32 brightness levels can be achieved while the LEEs in the energized groups are fully ON. Thus, since there is no high frequency switching, there is substantially no power dissipation by the dimming control system, and there is limited noise or EMI created. The dimming control can be easily implemented with a logic circuit controlling a transistor switch for each group.

主权项

1. A lighting device comprising:
one or more substrates including electrical conductors; a plurality of groups of light-emitting elements (LEEs), each of the groups of LEEs comprising one or more LEEs disposed on the one or more substrates and in contact with the electrical conductors, the groups of LEEs being configured to provide a nominal light output when energized under nominal operating conditions, wherein the groups of LEEs are independently energizable and each of the nominal operating conditions associated with each of the groups of LEEs includes a corresponding nominal drive current; and a dimming control system operatively connected to the groups of LEEs via the electrical conductors and configured to
determine a binary dimming code based on a dimming signal, the binary dimming code having a plurality of bits, each of the groups of LEEs associated with a corresponding bit of the dimming code, andprovide the corresponding nominal drive current to each of the groups of LEEs, based on the bit value of the corresponding bit of the dimming code, to respectively energize each of the groups of LEEs.