The present invention relates to low voltage lighting systems, and more particularly, to a simplified control system and method for adjusting attributes of low voltage lighting, such as LED lighting.
LED systems for vehicles, such as boats and RVs, are known in the art. Industry trends have been to add multicolored, dimmable lighting in many areas, such as around cup holders, along steps and walk areas, as accent lighting, and as general and overhead lighting. Ideally, the range of full bright white to colored and dimmed lighting is desired to preserve night vision, such as for nighttime boating.
Current color LED systems comprise a four wire (red, blue, green, and a Return) or five wire (red, blue, green, white, and a Return) system with PWM (pulse width modulation) sent from a controller location to each of the controlled devices, requiring long wire runs. These systems inherently require substantial materials and labor to install, and thus high costs. Moreover, current systems can create unacceptable EMI (electromagnetic interference) and RFI (radio frequency interference) emissions. As described, for example, in U.S. Coast Guard Safety Alert 13-18, issued on Aug. 15, 2018, there is also an LED interference issue which must be obviated with respect to marine use.
Therefore, a need exists for an improved low voltage lighting control system which allows for multicolored, dimmable lighting as desired, with reduced wiring complexity, and which emits EMI and RFI within acceptable ranges.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide an improved control system for LED lighting or other low voltage lighting types, e.g., incandescent, which reduces materials and labor costs.
It is another object of the present invention to provide a simplified low voltage lighting control system which allows for both white and multicolored dimmable lighting as desired, with reduced wiring complexity.
It is still another object of the present invention to provide an improved low voltage lighting control system which minimizes both EMI and RFI emissions.
It is yet another object of the present invention to provide a low voltage lighting control system which addresses multiple devices, such that more than one zone of lighting can be controlled on one wire run.
It is still yet another object of the present invention to provide an improved method of controlling the attributes of low voltage lighting, including color and brightness.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The above and other objects, which will be apparent to those skilled in the art, are achieved in the present invention which is directed in an exemplary aspect to a simplified multi-colored, dimmable LED or other low voltage lighting control system comprising a pair of FETs (field-effect transistors) located at a lighting controller and adapted to send a pulse-controlled signal to multiple zones via a plurality of remotely-located receivers along a single long wire run, wherein each receiver is connected to an LED or other low voltage lighting device via a short, multi-wire run. The system comprises, in one embodiment, a transmitter having an input means for selecting lighting attributes such as color and brightness levels, optionally, an NMEA receiver, a TX microcontroller adapted to output an encoded data stream, a pulse shaping network, a plurality of field-effect transistors (FETS), a power output, one or more receivers, a data discriminator, an RX microcontroller, and one or more pulse-controllable LEDs or other low voltage lighting devices.
In another exemplary aspect, the present invention is directed to a method of controlling the attributes of low voltage lighting, such as LEDs, using a pulse-controlled PWM signal sent from a lighting controller to at least one of a plurality of receivers via a single wire run. In an embodiment, the method comprises selecting desired LED or other low voltage lighting attributes such as color and brightness levels via an input means at a lighting controller, serializing and encoding the selected data into a data stream output by a transmitter microcontroller, passing the data stream output to a pulse shaping network, propagating the signal through a power output to one or more remotely-located receivers in one or more lighting zones, decoding the data stream by a receiver microcontroller into device address and color data, comparing the decoded device address data with receiver address data, and responsive to the device address matching, sending the color values to pulse width modulation (PWM) registers within the receiver microcontroller. The method then comprises outputting the PWM by the receiver microcontroller, thus changing the duty cycle of LED driver field-effect transistors (FETS) which drive LEDs or other low voltage lighting, wherein the LEDs' brightness is proportional to the PWM values.
The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
In describing the embodiments of the present invention, reference will be made herein to
Certain terminology is used herein for convenience only and is not to be taken as a limitation of the invention. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,” “downward,” “clockwise,” and “counterclockwise” merely describe the configuration shown in the drawings. Indeed, the referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. For purposes of clarity, the same reference numbers may be used in the drawings to identify similar elements.
Additionally, in the subject description, the word “exemplary” is used to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” is not necessarily intended to be construed as preferred or advantageous over other aspects or design. Rather, the use of the word “exemplary” is merely intended to present concepts in a concrete fashion.
The present invention is directed to a control system and methods of control for low voltage lighting, wherein data and power is transmitted over a single wire run to control attributes of the lighting, such as color and brightness. Any reference to low voltage lighting herein should be understood to mean 48 VDC and below, and more particularly, in the range of 12 or 24 VDC. In the subject description below, reference to pulse width modulation (PWM) control of LED lighting is used for exemplary purposes only, and it should be understood by those skilled in the art that other methods of lighting control, e.g., analog or on/off, and other low voltage lighting types, such as incandescent lighting or high-intensity discharge (HID) lighting, are intended to fall within the scope of the present invention. As such, although the terms “LED” or “low voltage lighting” are used interchangeably herein, the terms should be understood to refer generally to any now-known or later developed form of lighting at 48 VDC and below.
Such systems also often create unacceptable EMI (electromagnetic interference) and RFI (radio frequency interference) emissions. For example, as described in U.S. Coast Guard Safety Alert 13-18, issued on Aug. 15, 2018, an LED interference issue has been reported where mariners have reported poor reception on VHF frequencies used for radiotelephone, digital selective calling (DSC) and automatic identification systems (AIS) when in the vicinity of LED lighting on-board ships. Such radio frequency interference caused by LEDs can create safety hazards.
The present invention remedies these deficiencies of prior art low voltage lighting control systems by providing an improved control system which allows for multicolored, dimmable lighting as desired, with reduced wiring complexity, and negligible EMI and RFI emissions.
Referring now to
The low voltage lighting control system of the present invention presents a solution to the long wire runs required in systems of the prior art. As shown in
As further shown in
It should be further understood by those skilled in the art that while the exemplary embodiment of the present invention shown in
Referring now to
The encoded data stream is then propagated through the POWER OUTPUT (11) stage to the TX-OUT (12) wire. This wire (12) or output line, now carrying both power and data, is then connected to one or more RECEIVER(s) (13), as shown in
A significant advantage of the lighting control system of the present invention is that the load is only pulsed when attributes of the lighting are changed, therefore if no change is made, there is no noise generated on the lines. Furthermore, because of the signal's low duty cycle, switching efficiency is not an issue, allowing the output to be ramped to further reduce EMI and RFI. Any PWM noise is generated only at the receiving nodes, which have lower overall current and greatly reduced lead lengths. The remaining reduced noise pulses are not synchronous and thus not adding or cumulative, rather temporarily spread, thus blending into the noise floor. As described above, another advantage of the control system of the present invention is that because the individual signal pulses are asynchronous, the system can address multiple devices, such that more than one zone of lighting can be controlled on one wire run.
An exemplary transmitter chip layout is shown in
As shown in
In the exemplary operations depicted in
Thus, the present invention provides one or more of the following advantages: the present invention provides an improved control system and methods of control for low voltage lighting, wherein data and power is transmitted over a single wire run to control attributes of the lighting, such as color and brightness. The simplified low voltage lighting control system of the present invention reduces materials and labor costs, while still allowing for both white and multicolored dimmable lighting as desired, with reduced wiring complexity. The low voltage lighting system of the present invention further provides for reduced noise generated on the lines due to the load only being pulsed when attributes of the lighting are changed, and minimizes EMI and RFI emissions, making it particularly conducive to marine applications. Moreover, the present invention provides a simplified low voltage lighting control system which addresses multiple devices, such that more than one zone of lighting can be controlled on one wire run.
While the present invention has been particularly described, in conjunction with one or more specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.
Thus, having described the invention,
Number | Date | Country | |
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62770282 | Nov 2018 | US |