Light fixture with dynamically controllable light distribution
A light engine is disclosed in which the light engine contains a core comprising an opening extending completely through the core and independently addressable LED segments. The opening defines an inner surface of the core. Each segment has multiple LEDs. A PCB contains a body adjacent to one of an inner or outer surface of the core and to which the LED segments are attached and legs extending from the body and bent to be adjacent and traverse to the other of the inner or outer surface. Each leg is associated with a different LED segment. Control circuitry is connected with the legs of the flexible PCB and independently controls parameters of the LED segments to provide a preset illumination distribution and intensity based on user input.
1. An apparatus of a light engine comprising:
a core comprising an opening extending completely through the core, the opening defining an inner surface of the core;
a plurality of independently addressable light emitting diode (LED) segments, each LED segment comprising a plurality of LEDs;
a flexible printed circuit board (PCB) comprising a body adjacent to one of an inner or outer surface of the core and to which the LED segments are attached and a plurality of legs extending from the body and bent to be adjacent and traverse to the other of the inner or outer surface, each leg associated with a different LED segment; and
control circuitry connected with the legs of the flexible PCB, the control circuitry configured to independently control parameters of the LED segments to provide a preset illumination distribution and intensity based on user input.
2. The apparatus of claim 1 , wherein:
the control circuitry comprises a first PCB having a first surface that opposes the LED segments, a second surface opposing the first surface, and an opening extending between the first and second surfaces, and
the legs of the flexible PCB extend through the opening and are soldered to control contacts of the first PCB on the second surface.
3. The apparatus of claim 2 , wherein:
the LED segments are configured in parallel, and
the control circuitry comprises:
a direct current (DC)/DC converter or low-dropout (LDO) regulator configured to convert a higher constant DC voltage to a lower constant DC voltage, the lower constant DC voltage used to adjust an LED voltage supplied to the LED segments,
a constant current regulator configured to provide a fixed peak current to the LED segments, and
a controller configured to control a duty cycle of the LED segments based on the user input to independently control light intensity from each of the LED segments.
4. The apparatus of claim 3 , wherein:
forward voltages of the LED segments are matched, and
an applied voltage to each of the LED segments is below the LED voltage by about 1-2 volts.
5. The apparatus of claim 2 , wherein:
the LED segments are configured in parallel, and
the control circuitry comprises:
a plurality of DC/DC converters each supplied with a constant voltage and configured to control a different LED segment, and
a controller configured to control at least one of a duty cycle or a peak current of the DC/DC converters independently based on the user input.
6. The apparatus of claim 2 , wherein:
the LED segments are configured in parallel, and
the control circuitry comprises:
a direct current (DC)/DC converter or low-dropout (LDO) regulator configured to convert a higher constant DC voltage to a lower constant DC voltage, the lower constant DC voltage used to adjust a constant current supplied to the LED segments, the LED segments sharing the constant current, and
a controller supplied with the lower constant DC voltage and configured to control, via a time-division multiplexer, at least one parameter of each of the DC/DC converters independently based on the user input, such that only one of the LED segments is conducting current at a particular time.
7. The apparatus of claim 6 , wherein:
the parameter is a duty cycle of the DC/DC converter.
8. The apparatus of claim 6 , wherein:
the parameter is the constant current supplied to the DC/DC converter.
9. The apparatus of claim 6 , wherein:
forward voltages of the LED segments are matched.
10. The apparatus of claim 2 , wherein:
the LED segments are configured in series, and a shunt switch is disposed between each LED segment, and
the control circuitry comprises:
a direct current (DC)/DC converter or low-dropout (LDO) regulator configured to convert a higher constant DC voltage to a lower constant DC voltage, the lower constant DC voltage used to adjust a constant current supplied to the LED segments, and
a controller supplied with the lower constant DC voltage and configured to control the constant current and a duty cycle of each LED segment independently.
11. The apparatus of claim 10 , wherein:
the controller is able to control the LED segments such that multiple LED segments are able to conduct current at the same time.
12. The apparatus of claim 2 , wherein:
a duty cycle associated with each of the LED segments is set by a lookup table in a memory of the control circuitry, the lookup table containing a correspondence between a light distribution indicted by a user equipment and the duty cycle associated with each of the LED segments.
13. The apparatus of claim 12 , wherein:
the lookup table further contains a correspondence between a constant current associated with each of the LED segments and the light distribution indicted by the user equipment.
14. The apparatus of claim 2 , wherein:
the control circuitry further comprises a second PCB that is detachable from the first PCB, and
the second PCB comprises communication circuitry configured to wirelessly communicate with a user interface via a supported communication protocol to control light output from each of the LED segments accordingly.
15. A method of controlling light distribution, the method comprising:
receiving a control signal from a user equipment;
determining a correspondence, between parameters of a plurality of independently controllable light emitting diode (LED) segments and an illumination distribution and intensity indicated by the control signal, the parameters comprising at least one of a duty cycle or current associated with each of the LED segments, each LED segment comprising a plurality of LEDs; and
controlling the LED segments through signaling supplied from control circuitry local to the LED segments through a plurality of legs of a flexible printed circuit board (PCB) comprising a body to which the LED segments are attached, each leg associated with a different LED segment.
16. The method of claim 15 , wherein controlling the LED segments comprises:
supplying each LED segment, connected in parallel and having matching forward voltages, with a constant voltage and a fixed peak current and varying the duty cycle of the LED segments independently, the fixed peak voltage supplied by a constant current regulator.
17. The method of claim 15 , wherein controlling the LED segments comprises:
varying at least one of a duty cycle or a peak current of a plurality of DC/DC converters independently, each DC/DC converter associated with a different LED segment, the LED segments connected in parallel.
18. The method of claim 15 , wherein controlling the LED segments comprises:
supplying all of the LED segments, which are connected in parallel and have matching forward voltages, with the same shared current, and
varying at least one of a duty cycle or a peak current of each LED segment such that only a single LED segment is conducting current at the same time.
19. The method of claim 15 , wherein controlling the LED segments comprises:
supplying all of the LED segments, which are connected in series and have matching bypass switch between each adjacent pair of LED segments, with a constant current, and
varying at least one of a duty cycle or a peak current of the LED segments independently, such that only multiple LED segments are able to conduct current at the same time.