EP3866570A1

EP3866570A1 - Low voltage track lamp with led module provided with integrated electronics

Info

Publication number: EP3866570A1
Application number: EP21156219.4A
Authority: EP
Inventors: Andrea GUIZZARDI; Alessandro Pasini
Original assignee: C Led Srl
Current assignee: C Led Srl
Priority date: 2020-02-14
Filing date: 2021-02-10
Publication date: 2021-08-18
Also published as: IT202000002968A1

Abstract

Track lamp (5) comprising just three building parts:- An electrified track (2) in its turn comprising electrical conductors, preferably four electrical conductors (24, 25, 26, 27),- A LED module (40);- Optionally a plurality of optical elements (6), or alternatively a closure screen of said electrified track provided with optical functions;characterized in thatsaid LED module (40) comprises a plurality of LEDs (47) and also all the electronic components needed for controlling them integrated in just one support which constitutes a single building part and in whichsaid LED module (40) with integrated electronics in its turnfurther comprises at least one of each following electronic components: inductor (42), capacitor (45), IC driver (43) for switching (buck step down), power diode (41), a microprocessor (46), wherein:- Said inductor (42) is provided with a low-loss, high frequency ferrite core, coil with low series resistance, lower than 200 mOhm;- Said capacitors (45) are provided in the form of ceramic capacitors with SMT technology and miniaturized package, preferably of the type identified by 0805 code;- Said IC driver (43) for switching is provided with a miniaturized package, in particular of the kind identified by the code SOT23-6, with an external MOSFET with low resistance RDS in On mode;- Said microprocessor (46) in the first embodiment a) provides a DALI protocol, while in the second embodiment b) manages a wireless Bluetooth® BLE (Bluetooth® Low Energy) connectivity.

Description

The present invention relates to the technical field of lighting, and in particular to a LED module with integrated electronics for low voltage (24/48 volt) tracks, which integrates the LED sources and the electronic components integrated on the same electronic board, electronic components that are normally mounted on the driver used to drive and control the LED sources.
In the art, using lighting systems provided with an electrified track is known. Such tracks are generally fixed to ceilings, and are used to electrically supply and control spot lights (luminaires) making use of LED light sources.
Typically, said electrified tracks comprise mechanical supports that are fitted inside the track fixed to ceilings. Said mechanical support is a mechanical element in the shape of a box, which acts as a mechanical interface between the electronic board (driver) and the electrified track that houses the electrical cables that supply LED light sources.
Up to now, the traditional low voltage light tracks comprised: an electrified track, an external driver housed inside a mechanical support to be fitted in said electrified track, a LED luminaire as light source, provided with a mechanical connector to connect it to said electrified track, so substantially the system used to comprise five elements.
In the limited space available on the electronic board, a plurality of electronic component must be assembled for controlling and electrically supplying said LED light sources. Typically, on the electronic boards of the known art there are provided the following electronic components: inductor, connector, capacitor, IC driver for switching (buck step down), power diode, power MOSFET, microprocessor.
It is worth mentioning that on the market there are provided different kinds of electronic components. E.g.:

Said inductor can be chosen among the following type: its core can be chosen in standard ferrite, or high frequency ferrite, or composite material, while its coil can be provided with different sections and series impedance; finally the inductors can be shielded or non-shielded;
Said connector can be chosen among the following possibilities: Surface Mount Technology (SMT), or Plated Through Hole (PTH) mounting.
Said capacitors can be chosen among the following possibilities: ceramic capacitors, electrolytic capacitors, polyester capacitors, tantalum capacitors; all these are provided with different working voltage and different package dimensions;
Said IC driver for switching (buck step down) can be chosen among the following possibilities: integrated versions with integrated power MOSFET or with external power MOSFET; its package can be provided with different dimensions;
Said power diodes: input supply diodes and diode of the switching section (buck step down);
Power MOSFET: there are provided packages having different dimensions and power;
Microprocessor: there are provided different architectures: e.g. 8, 16, 32 bit with PWM peripherals or not.

A disadvantage of the known art is that lighting systems comprise several components (shown in Figures 1A and 1B).
Another disadvantage of the known art is that up to now, the maximum current which could be supplied to said LEDs through the known art electronic boards having dimensions suitable for being housed in standard electrified tracks was indicatively limited to about 700 mA.
US20170074471 discloses a modular LED line light comprising at least one line light module. The at least one line light module comprising a U-shaped body comprising a base and two opposing side walls extending from the base, the base comprising an interior surface and an exterior surface; At least one LED array is destined to be secured to the interior surface of the U-shaped body. To the said U-shaped body and to the LED array a rail for receiving at least some light modules is provided. The said rail comprising a first surface and a second surface, wherein the first surface is configured to receive the exterior surface of the base of the U-shaped body of the at least one light module. Cooling tubes for receiving a cooling fluid for removing heat from the at least one line light module, the cooling tube being disposed between the exterior surface of the base of the U-shaped body and the first surface of the rail. The LED line light further comprising a common bus bar which delivers electrical power to the plurality of line light modules, wherein the common bus bar comprises two copper rods, wherein each of the copper rods is electrically connected to each of the plurality of line light modules using a clip, wherein each of the clips is longitudinally and rotatably adjustable relative to the copper rod, and wherein the two copper rods are disposed outboard of the side walls of the U-shaped bodies of the plurality of line light modules. The LED line light module comprises further a macro lens for receiving the optical output of the at least micro lens arrays associated to the Led array. At the external side of the U-shaped body a LED driver board for controlling operation of the plurality of line light modules, The LED array is a separate construction part as the Led driver board ad the LED array and the controller board are secured at different parts of the U-shaped body.
A GUI, a CPU, a controller board and a power supply are provided as different constructive parts of the LED light line and are not integrated on the LED array board and neither on the LED driver board.
In the said disclosed LED light line the different constructive parts which cam be provided as separated integrated parts to be assembled together consist in a rail, at least one U-shaped body, Cooling tubes, a LED array module, a LED driver board, macro and/or micro lenses, and a board comprising a CPU a controller and a power supply and a device for displaying a GUI. Each of these parts needs furthermore securing elements for being secured to the rail and/or to the U-shaped body. As it appears from the above constructing such a LED light line needs to have the availability of many different constructive parts and obliges to carry out long and complex manufacturing operations.
The electronic components of the LED driver board and of the controller board, of the power supply and of the CPU and GUI are generic and not optimized in order to obtain a dimensional reduction and a low heat generation. Indeed, a cooling system operating with cooling liquid is provided.
In relation to the LED line light of the state of the art and particularly of the kind of document US20170074471 , the present invention aims in reducing the number of constructive parts to be assembled for producing the said line light, limiting the dimension of the said line light and avoiding having excessive heat generation despite increased integration and dimensional reduction. Furthermore, in combination with the above features the LED line light according to the present invention should allow operating LED arrays generating an higher light intensity and thus a higher power consumption.
WO2013128339 discloses a LED lighting arrangement comprising a digital bus of the kind denominated DALI. The DALI bus is not integrated together with the controllers, the drivers and the LED on a same circuit board.
Document GB2526440 discloses a LED lamp combined with a sensor arrangement comprising a Bluetooth communication unit.
EP2882263 discloses a diver circuit for controlling a dimmable LED light line using amplitude control and/or PWM-modulation control depending on the dimming ranges.
Aim of the present invention is providing a LED module with integrated electronics suitable for housing said LEDs, but also capable of controlling the LEDs integrated on said module, at the same time improving the performances with respect to the known art.
This object is achieved by an apparatus having the features of the independent claim. Advantageous embodiments and refinements are specified in claims dependent thereon.
With the present invention, both the driver with its mechanical support as distinct components, and the LED luminaire with its mechanical conductor are eliminated, while the resulting track lamp contains all the functions of the eliminated components, with a marked saving of space and components. Even spatially and aesthetically, the encumbrance is markedly reduced with respect to known art solution. Finally, there is a strong saving in cost.
Moreover, the LED modules with integrated electronics according to the present invention are provided with cutting-edge performances. In fact, power levels are markedly higher than those of the known art: indicatively, the apparatus according to the present invention provides a maximum current of 1000 mA.
The LED module with integrated electronics according to the present invention comprises the same electronic components (inductor, capacitor, IC driver for switching (buck step down), power diode, optionally a microprocessor) as in the known art electronic boards, but some of said components were specifically chosen in order to allow the miniaturization of said electronic board. In particular, the components determining at the same time miniaturization and increase in maximum current are: inductor, IC driver for switching (buck step down), capacitors, microprocessor.
In particular:

Said inductor was chosen according to its building technology, providing a low-loss, high frequency ferrite core. Said core develops less heat than standard ferrite core inductors or composite material core inductors, which are typically used for this kind of electronic board. Moreover, the coil provided with low series impedance, lower than 200 mOhm, contributes to develop less heat. The specific inductor was chosen by individuating the models with a working temperature that is higher than in the lighting technology, and in particular using an inductor that is normally used in automotive, where components working at higher temperatures are mandatory.
Said IC driver for switching was chosen with a particularly small package (SOT23-6). The chosen IC driver is provided with an external MOSFET with low RDS (series resistance) in On mode, so as to be more efficient and develop less heat.
Said ceramic capacitors were chosen with SMT technology and with a miniaturized package (0805). These components are particularly small.
The chosen microprocessor provides a 32-bit architecture, suitable for performing the calculations and functions necessary for the working of the electronic board, the possibility to have up to 6 PWM 16-bit peripherals, and the presence on board of a Bluetooth® BLE module and a NFC module.

The present invention is provided in two different embodiments:

a) A first embodiment, which allows to dimmer said LED light sources thanks to the presence of a DALI (Digital Addressable Lighting Interface) bus on said LED module with integrated electronics.
b) A second, more complex, embodiment, which comprises a driver provided with a Bluetooth® BLE (Bluetooth® Low Energy) protocol uploaded on said LED module with integrated electronics. This embodiment allows to electrically supply and control LED light sources, and at the same time allows the module to work as a beacon, which can be used for geolocation and to send information (consumption, temperature, diagnostic information, etc.) concerning the luminaire working. It also allows said LED module with integrated electronics, and consequently the LED light sources, to be wirelessly controlled through portable electronic devices, therefore without the need of connecting cables between light sources and switches.

On the market, there are provided different models of commercial electronic modules known as beacons. A Bluetooth® beacon transmits with a pre-determined periodicity a 2.4 GHz radio signal according to the Bluetooth® Low Energy standard, containing in a codified way according to the Bluetooth® standard different unique identifiers specific for each device.
In an embodiment provided for the use of DALI digital protocol, the electrical connection between the LED module with integrated electronics and low-voltage electric supply is realized through cables soldered to pads provided on said LED module with integrated electronics.
In an alternative embodiment provided for the use of the Bluetooth® BLE protocol, the electrical connection between the LED module with integrated electronics and low-voltage electric supply, together with the digital signal of DALI protocol, is realized through finger spring contacts, which realize a snap fit connection with the mechanical support.
A first advantage of the present invention consists in the elimination of the external LED driver with its mechanical support, by integrating the necessary components on said LED module with integrated electronics.
A second advantage of the present invention is the elimination of LED luminaires and their mechanical connector, by integrating said light source in the electrified track, with a saving in terms of components, costs and encumbrance.
A third advantage of the present invention consists in the possibility of supplying, with equal dimensions and tracks, more powerful LED light sources than those supplied with the state of the art LED drivers, and therefore providing a higher light flux.
A fourth advantage is the replacement of the soldered electrical cables placed between the electronic board and the LED light source with spring electrical contacts. This eases and hastens the assembling, and contacts are more reliable.
A fifth advantage consists in the possibility to control the LED light sources using an APP installed on a portable electronic device like a smartphone or a tablet.
A sixth advantage is the possibility to control a single luminaire with a single electronic board, obtaining tunable white effects or light of different colours, when the luminaire is provided with LEDs having different features (different colour temperature, warm or cold, or LEDs of different colours).
Further advantages and properties of the present invention are disclosed in the following description, in which exemplary embodiments of the present invention are explained in detail based on the drawings:

Figures 1A, 1B: Typical lighting system with electrified track according to the known art, to which a luminaire is connected, inside which there is provided a LED light source, in an assembled and exploded axonometric view;
Figure 2: Exploded axonometric view of the mechanical support aimed at housing the driver (electronic board) according to the known art;
Figure 3: Electrified track, transversal section and axonometric view;
Figure 4: LED module with integrated electronics, top view;
Figure 5: Track lamp, assembled axonometric view;
Figures 6A, 6B: Track lamp, exploded axonometric and transversal section view.

Figures 1A, 1B show in an assembled and exploded axonometric view a typical lighting system 1, provided with an electrified track 2 according to the known art, carrying a luminaire 3 comprising a LED light source. For each luminaire 3 mounted on an electrified track 2, a driver (electronic board) must be provided, housed inside its mechanical support 4, which is better visible in Figure 2.
Figure 2 shows an exploded axonometric view of the mechanical support 4 aimed at housing the electronic board (not shown). Said mechanical support, in the shape of a box, is provided typically with a bottom portion 21 for housing the control electronic board (driver), a lid 22 which closes the bottom portion 21, and a mechanical connector 23 which is placed on the bottom of the portion 21 to allow the passage of the stem of luminaires 3. Obviously, said mechanical support 4 is provided with plan sizes that are compatible with those of the electronic board to be housed, and of the electrified track 2 housing it.
Figure 3 shows a typical electrified track 2 according to the known art in an axonometric view and in a transversal section. It is worth mentioning that the inside of said electrified tracks according to the known art is of standard dimensions, while the portion oriented toward the wall can vary according to their type of use. E.g., the electrified track 2 shown in Figures 1 and 3 is made for an at sight use, while the electrified track 2 shown in Figures 5 and 6 is made for in grade integrated use in a ceiling or wall.
Said electrified track is substantially a profile with a rectangular transversal section. Inside said profile there are provided two, optionally four, electrical conductors 24, 25, 26, 27. In particular, the conductors 25, 27 are used to electrically supply the light sources of luminaires, while the conductors 24, 26 are used to carry a DALI signal. Inside said profile, in correspondence of each LED luminaire 3, its mechanical support 4 is placed, as shown in Figure 1B. Said mechanical support in its turn houses the electronic board (driver) intended to electrically supply and control the LED light sources.
In the present invention, said electrified track 2, which is known art, remains unchanged in its internal configuration, which allows an optimization of the already-used components.
Figure 4 shows a LED module 40 with integrated electronics according to the present invention. Said LED module 40 with integrated electronics in fact comprises both the LEDs housed in the luminaire 3 according to the known art, and the electronic components mounted on the driver housed in the mechanical support of the known art.
The mounting of said electronic components is performed on just one side of said LED module 40 with integrated electronics through SMT technology (Surface Mount Technology).
Said LED module 40 with integrated electronics is provided with a non-polarized 24/48 V power supply. It comprises a power diode bridge consisting of four diodes 41. Said diodes are realized with Schottky technology, which allows to enhance the board efficiency.
Said LED module 40 with integrated electronics comprises an inductor 42 that is provided with a low loss, high frequency ferrite core. Moreover, it is provided with a coil with low series resistance, lower than 200 mOhm, which develops a lower heat. The inductor 42 is of the shielded type.
Said LED module 40 with integrated electronics further comprises an IC driver 43. The IC driver for the switching was chosen with a particularly miniaturized package (SOT23-6). The chosen IC driver provides a low RDS (Series Resistance) external MOSFET 44 in On mode, so as to be more efficient and develop less heat.
Said LED module 40 with integrated electronics comprises a plurality of ceramic capacitors 45, with SMT technology and miniaturized package (0805). These components are particularly small.
Said LED module 40 with integrated electronics comprises an integrated circuit microprocessor 46, which manages the working of the electronic board through suitable firmware.
Said LED module 40 with integrated electronics further comprises a plurality of LEDs 47 in a variable configuration, which may be provided all of the same type or may emit different light fluxes and different white hues or different colours.
At an end of said LED module 40 with integrated electronics there are provided two pads 48 designed for the contact with either (not shown) finger spring connectors or for soldering a conductor cable (not shown). Said LED module 40 with integrated electronics comprises two pads 48 at a first end designed for 48 volt supply, and other two pads 49 at the opposed end for the digital bus DALI (Digital Addressable Lighting Interface), in order to allow the dimming of LEDs 47.
On said LED module 40 with integrated electronics there are provided four connectors 50 and 51 placed at its two ends, two for the fast connection to 48-volt supply and for DALI bus. This mode prevents electric wire soldering.
In an embodiment, said LED module 40 with integrated electronics comprises a plurality of couples of holes 52 placed in correspondence of each LED 47, which are used to fix single optical elements 6 (visible in Figures 5 and 6) placed in front of each LED. Said optical element 6 is a single lens, preferably made of PMMA, e.g. with a cone beam angle of 5° to 150°, with steps of 15°, roto-symmetrical or oval or asymmetric lenses. Obviously, said known optical elements are chosen according to the desired performances.
In the first embodiment a), for the functioning of DALI bus some specific components are needed, e.g. two optocouplers 53 and a diode bridge 54, which allows the connection of the non-polarized DALI bus.
In said LED module 40 with integrated electronics, the constant current control of the LED light source is hybrid: AM (Amplitude Mode) and PWM (Pulse Width Modulation). The AM mode is activated in the dimming range 100% to 5% of the light flux. The PWM mode is activated in the dimming range 5% to 1%.
The adoption of a hybrid control mode allows obtaining a minimal or non-existent optical flicker with respect to the known art. In fact, in the known art, the light flux is not constant. The human eye cannot perceive the flicker of light, which can nonetheless cause damage to health, and in extreme cases trigger epileptic seizures. With the hybrid control (AM+PWM) the emitted light is more constant in the whole adjustment range from 100% to 5% with respect to the known art control, which is performed with just PWM
The second embodiment b) provides that said microprocessor 46 can manage a wireless Bluetooth® BLE (Bluetooth® Low Energy) protocol. Said embodiment allows to electrically supply and control LED light sources 47 integrated in said LED module with integrated electronics, and at the same time allows the module to work as a beacon, which can be used for geolocation and to transmit information (consumption, temperature, diagnostic information, etc.) on the working of track lamps 5 (shown in Figures 5 and 6). The advantage of Bluetooth® is the possibility to control the LED sources 47 housed in said LED module 40 with integrated electronics through an application (APP) installed on a portable smartphone or a tablet.
Said microprocessor 46 manages the functioning of the electronic board through a specific firmware, and in particular a Bluetooth® BLE radio module, a NFC (Near field Communication) connectivity, a DALI (Digital Addressable Lighting Interface) bus and signals for LEDs control. Through this connectivity, programming and setting the different wireless operative modes of the electronic board is possible. This possibility is particularly useful in order to perform updates, post-sale service, and obtaining diagnostic information. All this is performed through a portable electronic device (tablet, smartphone), thanks to a suitable APP.
If in the same environment there are provided at least two track lamps 5 provided with a Bluetooth® module, the mesh connectivity function is activated. The mesh connectivity provides the interchange of information about colour temperature, dimming level and environmental information (e.g. environment lighting) coming from optional sensors between said LED modules 40 with integrated electronics of each track lamp 5. In other words, the commands transmitted by a portable electronic device to the nearest track lamp 5 are transmitted to the first immediately adjacent track lamp 5, so as to share the transmitted commands and make the environmental lighting homogeneous.
With the mesh Bluetooth® technology, up to 250 track lamps 5 can be interconnected.
Figure 5 shows a track lamp 5 according to the present invention in an assembled axonometric view. Said track lamp 5 comprises:

An electrified track 2 according to the known art;
A LED module 40 with integrated electronics according to the present invention;
Optionally, a plurality of optical elements 6.

Figure 6A shows a track lamp 5 according to the present invention in an exploded axonometric view, while Figure 6B shows the same track lamp 5 in an exploded transversal section.
As already specified, the optional single optical elements 6, preferably made of PMMA, can be fixed on said LED module 40 with integrated electronics thanks to holes 52. Obviously, said known optical elements are chosen according to the desired performances.
In a not shown embodiment, said optional optical elements 6 are replaced by a closure screen of said electrified track 2, wherein optical elements are embedded, which are placed in front of each LEDs 47 provided on said LED module 40 with integrated electronics.
In order to have a visual impression of the differences between the known art and the present invention, compare the Figures 1 with Figures 6. The track lamp 5 totally replaces the lighting system 1, evidently with markedly lower encumbrance and number of components, to which lower costs correspond. All this with markedly higher performances than those of the traditional lighting system 1.

The following comparison table shows the reduction in the number of components.

Lighting system according to the known art	Track lamp according to the present invention
Electrified track 2	Electrified track 2
External driver (electronic board) (not shown)	--
Mechanical support for external driver 4	--
Mechanical connector for luminaire 23	--
LED luminaire 3 optionally comprising an electronic board on which they are mounted	LED module 40 with integrated electronics comprising LEDs 47 optionally optical elements 6

1: lighting system with electrified track
2: electrified track
3: luminaire
4: mechanical support
5: track lamp
6: optical elements
21: bottom portion
22: lid
23: mechanical connector
24: electrical conductor
25: electrical conductor
26: electrical conductor
27: electrical conductor
40: LED module with integrated electronics
41: diodes
42: inductor
43: IC driver
44: external MOSFET
45: capacitor
46: microprocessor
47: LED
48: pad
49: pad
50: connector
51: connector
52: hole
53: optocoupler
54: diode bridge

Claims

Track lamp (5) comprising three building parts:
- An electrified track (2) comprising four electrical conductors (24, 25, 26, 27),

- A LED module (40);

- A plurality of optical elements (6), or alternatively a closure screen of said electrified track provided with optical functions;
characterized in that
said LED module (40) comprises a plurality of LEDs (47) and also the electronic components needed for controlling them said LED and said electronic components being integrated in one support which constitutes a single building part and
wherein said LED module (40) with integrated electronics further comprises at least one of each following electronic components: inductor (42), capacitor (45), IC driver (43) for switching (buck step down), power diode (41), a microprocessor (46), wherein:
- Said inductor (42) is provided with a low-loss, high frequency ferrite core, coil with low series resistance, lower than 200 mOhm;

- Said capacitors (45) are provided in the form of ceramic capacitors with SMT technology and miniaturized package, preferably of the type identified by 0805 code;

- Said IC driver (43) for switching is provided with a miniaturized package, in particular of the kind identified by the code SOT23-6, with an external MOSFET with low resistance RDS in On mode;

- Said microprocessor (46) in the first embodiment a) provides a DALI protocol, while in the second embodiment b) manages a wireless Bluetooth® BLE (Bluetooth® Low Energy) connectivity.
Track lamp (5) according to claim 1, wherein there is provided a digital bus of the kind identified by the denomination DALI to allow the dimming of the said plurality of LED (47) integrated in said LED module (40) with integrated electronics.
Track lamp (5) according to claim 1 or 2, further provided a Bluetooth® connectivity of the kind identified by the denomination BLE to allow the control of LED light sources (47) integrated in said LED module (40) with integrated electronics through an application (APP) installed on a portable device like a smartphone or a tablet.
Track lamp (5) according to claim 3, wherein said Bluetooth® BLE module works in a mesh mode, interconnecting up to 250 track lamps (5).
Track lamp (5) according to one or more of the preceding claims, wherein the constant current control of LED light sources is obtained through a hybrid control: Amplitude Mode and Pulse Width Modulation.
Track lamp (5) according to one or more of the preceding claims, capable of providing 1000 mA of maximum current.
Track lamp (5) according to one or more of the preceding claims, wherein an electrical connection between electrified track (2) and LED module (40) with integrated electronics is realized through "finger" spring contacts that realize a snap-fit connection.
Track lamp (5) according to claim 6, wherein an electrical connection between electrified track (2) and LED module (40) with integrated electronics is realized through four pads (48 and 49) and cables soldered on them.