Lighting module, system with the module and control method

Abstract

A controllable lighting module (11) comprises an input (12) for electric powering thereof, one or more light sources (16) which can be activated upon command, a control unit (15) for receiving external commands and for controlling the one or more light sources (16) depending on these commands. The module also comprises an output (13) and a switch element (14) connected to the control unit (15) for interrupting or allowing electrical continuity between the said input (12) and the said output (13) upon command of the control unit (15). The control unit (15) is also able to receive the commands as modulation of the voltage applied to the said input (12) and to remain operative also during the variations of the power supply to the input (12) produced by the said modulation of the voltage at the input (12). A system with such modules (11) and an operating method are also described.

Description

[0001] The present invention relates to a controllable lighting module, to a system composed of one or more such modules, and to a control method.

[0002] In recent years, in the sector of controlled lighting modules, LED-based technology has become established as the state of the art, both because of its electrical efficiency and its flexibility in providing flexible controlled systems.

[0003] For example, in the market there exist numerous lighting devices which have replaced also from the regulatory point of view the more conventional incandescent lamps. A very common type of LED-based device consists of so-called "LED strips", namely flexible strips, which are typically powered with a low voltage (12 or 24V) and which have, mounted thereon, the single LEDs, suitably grouped together and connected in parallel.

[0004] An LED strip is usually characterized in that it is flexible, may be easily sold in reel form and may be easily adapted to the dimensions of the support on which it must be mounted, for example for the production of lamps.

[0005] The strips are usually obtained by arranging in parallel groups of LEDs (normally, but not exclusively, from 3 to 8 depending on the supply voltage used). In this way the strip may be cut along the joint between two groups so that it can be adapted to the length of the support and to the total amount of light required. Furthermore, the parallel arrangement normally ensures that breakage of one group of LEDs does not affect the operation of the other groups.

[0006] With LED technology the colour and intensity of the single light sources may be easily varied. The luminous intensity may in fact be easily adjusted using a PWM type power supply, while by combining together two or more differently coloured LEDs it is possible to recreate different colours or shades of white.

[0007] The normal LED strips have, however, all the LEDs connected together and unable to be controlled singly or in groups and therefore any variation in the luminosity or colour will affect the entire strip.

[0008] In order to address the need for being able to control the lighting elements in a varied manner, lighting modules have been proposed, also in the form of strips or groups of several differently arranged LEDs which may be selectively controlled by means of suitable command lines so as to obtain the possibility of creating lighting effects and selectively switching on the light sources singly or in suitable groups.

[0009] Several modules may then be grouped together in order to provide complex and extensive lighting effects by means of control commands which are selectively sent to the various modules and / or to the LEDs of the various modules.

[0010] The presence of several light sources which can be directed in different ways has for example made it possible in various sectors (e.g. the automobile sector) to provide lighting effects by temporally varying the switching on of the light sources in a suitable manner.

[0011] The selective control of the light sources is performed by using data lines, i.e. electrical connections transporting the signals which convey the command information. Between the various modules and between the modules and any central control device there is therefore a connection bus formed by one or more data lines and at least two lines for powering the modules. A suitable protocol transports the commands along the data lines such that they may be correctly received and interpreted by all the modules connected on the bus.

[0012] However, these known solutions pose various problems, including mainly the cost, the availability and the performance.

[0013] In fact, the presence of one or more command lines multiplies the wiring costs of the modules and complicates the structure thereof.

[0014] For solutions other than simple lighting modules (for example for peripheral home automaton devices) systems have been proposed where the data is conveyed along the same lines which transport the power supply, so as to provide buses with only two conductors. These two-wire systems, however, are generally relatively complex both in terms of the additional hardware which must be included in the modules and which is required in order to introduce and extract the data, separating it from the power supply, and in terms of the communication protocol. The known solutions in fact require that the power supply of the interconnected modules should not be altered by the data transmission and therefore the signal which conveys the data is superimposed on the power supply. For example, hardware for modulating and demodulating relatively high frequency alternating signals, which are superimposed on the normal supply voltage, are used in order to convey the data suitably modulated on these signals without at the same time altering the power supply of the devices which is kept stable.

[0015] These systems are therefore relatively costly and complex to manage, while also trying to limit as far as possible their sensitivity to external disturbances, and are generally difficult to apply to lighting systems, in particular of the LED type, which desirably should have a relatively low cost and complexity.

[0016] A further problem of the command communication systems on buses with two or more lines is that, irrespective as to the transmission mode, the modules connected to the bus receive simultaneously all the commands sent on the bus and it is therefore necessary to provide each module connected on the bus with a unique address or identifier such that each command sent on the bus may have, associated with it, the specific address of the module for which it is intended. In this way, all the connected modules simultaneously receive the commands sent on the bus, but only the module with the associated address will recognize the commands as being intended for it and will execute them.

[0017] A solution which is usually employed in the technical sector is that of associating beforehand with each module a unique address by means of a suitable hardware arrangement. This arrangement may be realized for example by suitably adjusting the electrical connections inside each module which encode the address for that module. This procedure, however, requires a prior operation by the user or the producer, who must encode addresses for each single module (for example by means of encoding switches or welds). In addition to being a time-consuming operation, especially if there are a large number of modules, it may easily give rise to errors and result in several modules having the same address on the same bus and therefore malfunctioning during the working operation of the system. Another solution proposed by the prior art is that of producing directly modules already with their own fixed preset address, but this solution can only be used when a small number of modules undoubtedly of a different type are used on the same bus.

[0018] The known solutions are therefore unsatisfactory for the connection of lighting modules which may be all identical to each other and which may be connected together in an undefined and also relatively high number.

[0019] The general object of the present invention is to provide an innovative lighting module which can be controlled in a simple and efficient manner using only two supply conductors.

[0020] A further object is to provide an innovative lighting module which can be easily used in order to make up assemblies consisting of several lighting modules which can be controlled and connected by means of only two conductors.

[0021] A further object is to provide a lighting module system which is easy to use and assemble.

[0022] A further object is to provide a method for assigning addresses and for transmitting commands to lighting modules connected using only two supply conductors.

[0023] These and other objects of the invention will become clear from the description below.

[0024] In view of the predefined objects, the idea which has occurred, according to the invention, is to provide a controllable lighting module comprising an input for electric powering thereof, one or more light sources which can be activated upon command, and a control unit for receiving external commands and for controlling the one or more light sources depending on these commands, characterized in that it comprises an output and a switch element connected to the control unit for interrupting or allowing electrical continuity between the said input and the said output upon command of the control unit, the control unit being able to receive the commands such as modulation of the voltage applied to the said input and there also being provided a temporary electronic supply circuit which is situated between the input and the control unit and which is able to keep the control unit operative also during variations of the power supply at the input produced by the said modulation of the voltage at the input.

[0025] Preferably, a module of this type according to the invention may have the control unit which, upon activation of the module, initially maintains uninterrupted the electrical continuity between input and output by means of the switch element and waits to receive at the input a command assigning an associated identification address for the subsequent commands.

[0026] In this way, several lighting modules connected in series according to the invention may receive an associated identification address as will become clear from the description below of a possible embodiment of a system according to the invention.

[0027] According to a communication method of a module according to the invention, upon switching on of the module, there is a first step of assigning an identification address to the module and a second step of receiving and interpreting commands at the module input. The step of assigning an identification address to the module may in turn comprise the steps, performed by the control unit of the module, of waiting for a first command for assigning an identification address, storing the identification address of said command as an identification address of the module, activating the switch element of the module so as to allow the electrical continuity between the input and the output of the module and remain on standby for subsequent commands associated with the stored identification address. This advantageously allows propagation of the assignment of unique identification addresses to various modules connected in series.

[0028] As will become clear below, it is possible for example to provide a lighting system which comprises a master unit, with an output designed to emit a power supply and modulate said power supply for control of the lighting modules according to the invention, and at least one lighting module according to the invention which is connected with its input to the output of the master unit and is the only one or the first module of a series of lighting modules which each have, except for the last one in the series, their output connected to the input of the next lighting module in the series.

[0029] The innovative structure of the module according to the invention allows implementation of an efficient and simple algorithm for two-wire communication with the module also when it is inserted in a series of modules, each with its output connected using only two wires to the input of the next module in the series. Moreover, according to the principles of the present invention, upon activation, an automatic procedure for assigning a unique address to the module or to each module in a series of modules interconnected with only two wires may be easily and rapidly performed.

[0030] In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, an example of an embodiment applying these principles will be described below with the aid of the accompanying drawings. In the drawings: Figure 1 shows a schematic view of a lighting module provided according to the invention; Figure 2 shows in schematic form diagrams of command and switching-on signals for the light sources of the module according to Figure 1; Figure 3 shows a schematic view of a lighting system provided according to the invention with a plurality of modules according to Figure 1 connected together in series by means of the two sole power supply conductors which pass from one module to another; Figure 4 shows a schematic view of the system according to the invention with activation sensors; Figure 5 shows in schematic form a possible physical embodiment of a lighting module according to the invention in the form of an elongated strip. With reference to the Figures, Figure 1 shows in schematic form, indicated overall by 11, a lighting module provided in accordance with the invention.

[0031] The module 11 comprises an electric power supply input 12 and an electric power supply output 13 to which the supply present at the input 12 is transferred upon command. The supply voltage to be normally applied to the input 12 may be for example preferably 12V or 24V.

[0032] Between the input 12 and output 13 the module 11 comprises a controlled switch element 14 which allows the passage of the power supply from the input 12 to the output 13 to be enabled or interrupted. For example, the switch element 14 may be realized by means of an electronic switch, for example a MOSFET or other known electronic element for controlled interruption of the current flow, chosen with suitable electrical characteristics such as a low voltage drop between input and output, a suitable interruption speed and a suitable flow current, as will be clear below for the person skilled in the art.

[0033] The electric power supply of the module 11 is advantageously bipolar with the input 12 which has input terminals 12a and 12b which correspond to output terminals 13a and 13b of the output 13. The power supply may preferably consist of a low voltage, for example 12 or 24 volts, and a direct current.

[0034] The switch element 14 may be present on both the power supply terminals between the input 12 and the output 13, or preferably only on a single terminal 12a, 13a, as shown by way of example in Figures 1 and 2.

[0035] The module 11 comprises a control unit 15 which commands the activation or not of the switch element 14 and which for example is realized by means of a suitable microprocessor circuit suitably programmed and of a type known per se, as may be easily imagined by the person skilled in the art on the basis of the description of the invention provided here.

[0036] The module 11 also comprises one or more light sources 16, which are also connected to the control unit 15 in order to be controlled by it. Control of each source (or group of sources) may be performed for example by means of a corresponding controlled electronic switch element 19 connected in series to the source (or to the group of sources) so as to supply it upon command of the control unit 15. The switch elements 19 may be elements outside or inside the control unit 15 and may be realized by means of electronic switches, for example MOSFETs or other known electronic elements for controlled switching of the current flow, chosen with suitable electrical characteristics such as a low voltage drop, a suitable switching speed and a suitable flow current, as will be clear to the person skilled in the art.

[0037] As will become clear below, the control of the light sources may consist of simple switching on and off or also modification of the colour or luminosity. Advantageously, the light sources may be chosen so as to have an overall luminous power of more than 14W / min.

[0038] Below for simpler description reference will be made to the light sources 16 as LEDs, which are a preferred light source owing to the high efficiency in converting electric power into light. However, it is understood that these light sources may be realized using any technology for light emission by means of an electric current. The invention will therefore also include lighting devices with light sources consisting for example of incandescent lamps, neon lamps or other known electric light sources. The control systems may therefore also vary in a manner known per se depending on the specific technology of the light sources used.

[0039] The module 11 is provided with a suitable filter or electronic temporary power supply circuit 18 which is located between the supply input 12 and the control unit 15 and allows the control unit 15 to be kept operative also during short interruptions or variations in the supply to the input 12 for the reasons which will be clarified below. In particular, the temporary power supply device 18 receives the voltage from the input 12 and maintains it during the variations or temporary interruptions for a short, predefined, communication time period.

[0040] This filter or circuit 18 may for example comprise an electric capacitor of suitable capacity for keeping stable the supply voltage of the control unit 15 during short interruptions or variations in the input supply voltage.

[0041] The control unit 15 is also provided with an input 17 connected to the input 12 of the module and designed to allow the control unit 15 to monitor the supply voltage at the input 12 so as to detect predetermined rapid variations or modulations of the supply at the input 12.

[0042] These variations in the supply at the input 12 may thus transmit information to the input of the module and to the control unit 15 by means of a suitable code based on variations or interruptions. It is thus possible to communicate information to the input of the module using the same two wires which convey the power supply to the module 11.

[0043] The code based on the variations may comprise a binary code with two different voltage levels at the input 12 representing the logic values "0" and "1" of a binary serial communication.

[0044] Advantageously, the two different voltage levels may correspond respectively to the full supply voltage (Vmax) of the module and the lack of voltage or "zero" voltage. In this way the voltage difference between the logic value "1" and the logic value "0" is maximized for improved and safer communication and less sensitivity to external disturbances, also in the case of relatively long lengths of the power supply conductors.

[0045] All the information to be transmitted to the module 11 and therefore to its internal control unit 15 may therefore be encoded by means of a serial binary code on the power supply line by means of variation of the power supply at the supply input 12 between the two set voltage levels corresponding to the bit "0" and the bit "1".

[0046] Any serial binary code of the type known per se may thus be used, as at this point may be easily imagined by the person skilled in the art.

[0047] For example, a simple asynchronous transmission mode with bit packets defined by a start bit, the serial bit to be transmitted, an optional parity bit, and an optional stop bit of suitable duration may be used.

[0048] The number of bits of the packet may also be a predefined number of bits which depends on how much different data is to be transmitted to the module and will preferably be established during the design of the particular system. For example, using 8 bits, 256 different combinations of bits (from 0 to 255, expressed in decimals) may be sent.

[0049] The bits of each packet may also be divided into parts representing different correlated information.

[0050] For example, the data received by the module may easily comprise information packets containing an address of the module for which the commands are intended, the commands directed to the module and any parameters associated with these commands.

[0051] It is thus possible to send easily to the module 11 commands which may be for switching on or off all the LEDs of the module, switching on or off only some specific LEDs of the module, or also varying the luminous intensity emitted by all or some specific LEDs of the module. In the case of differently coloured LEDs grouped together or LEDs of the composite type for the emission of lights consisting of several colours (e.g. RGB LEDs) the commands may also comprise information about the variation in the colour of the light emitted.

[0052] The commands may also be composite commands, for example formed by a command code and information associated with this command code. For example a command code may be a command code for switching on an LED, associated with the information about the luminosity at which said LED must be switched on (for example by means of PWM control of the LED).

[0053] Figure 2 shows in a) an example of a possible progression of the supply voltage over time, with highlighted a period T1 for transmission of information to the module and a period T2 of normal continuous supply of the module.

[0054] In a preferred solution, the periods T1 and T2 may for example be repeated at regular intervals.

[0055] During data reception in the period T1 there are rapid variations (in this case, interruptions) of the input supply to the module owing to modulation thereof for transport of the commands. The temporary power supply circuit 18, however, is able to keep the control unit 15 operative also during the interruptions or variations in the power supply to the input 12, produced by the modulation of the supply voltage for sending commands to the module. The power supply of the control unit 15 is thus guaranteed to be sufficiently stable so that the control unit may, via its input 17, at least continue to interpret the data and commands arriving at the supply input 12 and then execute them.

[0056] Preferably the temporary power supply circuit 18 is simple (for example provided with a relatively small capacity capacitor) and suitable only for low current consumption levels of the electronic module circuits. In this case, the temporary power supply circuit 18 is not suitable for supplying also the light sources, which may consume also a significant amount of current, and the supply to these sources is therefore obtained solely from the supply at the input 12 of the module and not from the circuit for temporarily supplying the electronic circuits of the module.

[0057] The LEDs 16 of the module could therefore be subject to bothersome flickering of the light emitted during the rapid fluctuations of the supply conveying the information to the input 12.

[0058] The control unit 15, in a preferred embodiment, therefore deactivates the switching on of all the LEDs of the module 11 during the data reception periods T1, so as to prevent the rapid variations in the supply from causing bothersome flickering of the light emitted by the LEDs.

[0059] For example, each lighting module 11, upon reception of the first trailing edge of the supply voltage which indicates the start of data reception, disables control of the LEDs for the entire duration of the digital transmission of the data and then restores it at the end of transmission for the period T2 of normal powering of the modules.

[0060] This is shown by way of example in Figure 2, where the line b) represents the progression of enabling of the control of the LEDs in relation to the progression of the line - indicated by a) - which represents the power supply of the module 11 at the input 12.

[0061] Consequently, with this solution the rapid flickering of the LEDs is avoided and the control of the LEDs will take place with PWM, with a maximum duty cycle determined by the duration T1 of the digital transmission.

[0062] The loss of luminosity due to the use of a maximum duty cycle not equal to 100% may be suitably compensated for by means of suitable dimensioning of the current in the LEDs 16, namely by supplying the LEDs with a current sufficient to increase their average luminosity so as to compensate for the PWM supply with maximum duty cycle.

[0063] With the PWM supply the intensity of the LEDs may also be reduced upon command with respect to the maximum intensity permitted, by sending a suitable digital command to the module, which will prolong the switching off period beyond the period T1 required by data transmission (therefore suitably reducing the power supply duty cycle of the LED), thus resulting in the possibility of controlling the light intensity emitted.

[0064] In this embodiment, the frequency of the PWM for controlling the LEDs is determined by the periodic frequency of data reception by the module 11. This frequency is generally necessarily conditioned in the lower range by the fact that it must not be perceivable to the human eye and in upper range usually by the PWM circuit used.

[0065] In order to prevent the light emitted by the LEDs from causing flickering which is perceivable to the human eye owing to the interruptions of the LED supply for the entire period T1, the period T1 must be sufficiently short and, if the data is to be sent periodically to the module, the repetition frequency of the period T1 must be sufficiently high for it to be not perceivable to the human eye. In general, this frequency may be set to around or above 500 Hz. The frequency selected must be preferably maintained also when there no real commands to be transmitted to the module 11 and, in such cases, an "empty command" may be sent to the module 11.

[0066] So as not to lower excessively the command duty cycle of the LEDs, conveniently the transmission duration T1 of a single data packet should not be too long. For this reason, the communication protocol may envisage, if necessary, breaking up the information into several packets, each with a sufficiently limited duration.

[0067] The packets may, for example, comprise a start bit which identifies the start of the transmission and allows synchronization of the module 11 with transmission, followed by a certain number of bits which identify as binary numbers possible types of packet, while the remaining bits of the packet contain data associated with each packet (for example addresses, commands and / or values associated with the commands).

[0068] A communication protocol according to the invention may, for example, comprises packets of seven bits, with a start bit, two bits which define four possible types of packet and the remaining four bits which contain the packet data.

[0069] The types of packet identified by two bits may be for example: ENUM, DIMMER, SWITCH ON, DATA With a greater number of bits a greater number of types of data may also be provided.

[0070] ENUM identifies a packet which contains in the data an "address" code which must be stored by the module 11 as its unique address.

[0071] The number of address bits will depend on the maximum number of modules 11 which it has been pre-established may be connected in series in the system, for example five bits for a maximum of 32 modules or eight bits for a maximum of 256 modules, etc.

[0072] A packet of the DIMMER type may cause a variation in the luminosity of the module LEDs, while a SWITCH ON packet may cause switching on (or switching off) of the module LEDs.

[0073] Both the DIMMER packet and the SWITCH ON packet may also contain in their data part the aforementioned address assigned to the module 11, so that it may recognize as its own the information which it receives at the input 12.

[0074] The DIMMER and SWITCH ON packets may be followed by one or more packets of the DATA type so as to communicate to the module or modules 11 addressed in the DIMMER or SWITCH ON command the data relating to the light intensity, the desired colour, or the switching on or off of the LEDS or groups of LEDs of the module. The DATA type packets therefore contain in the data part the information which completes the last DIMMER or SWITCH ON packet received.

[0075] Basically, the DATA packet type identifies a packet which contains data associated with, or forming a continuation of, a preceding packet.

[0076] By way of example, let us consider an embodiment of the module 11 comprising eight groups of LEDs.

[0077] The SWITCH ON packet, which may contain the address of the module 11 to which the command is addressed, will be followed by two DATA packets which will communicate a total of 8 bits, each bit corresponding to the state (for example, 0 = ON, 1 = OFF) which is required for each group of LEDs, with for example the first bit of the 8 bits which is associated with the first group of LEDs, the second bit of the 8 bits which is associated with the second group of LEDs, and so on.

[0078] In a simple form of the system, the DIMMER packet will be followed by two DATA packets which will communicate a total of 8 bits (one byte) containing for example in bit 7 the selection of one of two LED colours (e.g. 0 = "warm white", 1 = "cold white") and in bits 0-16 the desired light intensity (0 = minimum light, 127 = maximum light).

[0079] In a more complex variant, the DIMMER packet may be associated with more extensive information and therefore followed by several DATA packets. For example, it may be followed by four DATA packets (= a total of 8+8 bits) which transmit the light and colour intensity with a greater number of levels of light intensity and / or colours. For example, the first two DATA packets (8 bits) may define 255 levels of luminosity and the second two DATA packets (8 bits) may define 255 colours.

[0080] In even more complex forms of the system, the DIMMER packet may be followed by a series of DATA packets which detail the luminosity and / or colour separately for each LED or groups of LEDs of the module 11, as may now be easily imagined by the person skilled in the art.

[0081] In any case, the switch element 14 of the module may be controlled by the control unit of the module so as to propagate or not at the output 13 not only the normal supply at the input 12 but also data packets which modulate said supply.

[0082] Upon switching on of a module 11 (namely when a normal initial supply is provided at the input 12), the control unit 15 is activated and waits to receive the first transmission of data at the input 12, while keeping the switch element 14 deactivated so that no supply, or subsequently, no data is initially propagated at the output 13.

[0083] Upon reception of the first command, the module 11 checks whether this command is a command for assigning an identification address of the module 11 (for example because it contains the ENUM packet type) and, if so, stores this address as its own identification address. This address may be kept stored in the module (for example in a suitable and per se known electronic memory associated with or contained in the control unit of the module) until it is switched off and be used by the control unit of the module in order to recognize the following commands which will be sent to the input 12. Only after an identification address has been received and stored, will the control unit 15 activate the switch element 14 in order to connect the input 12 to the output 13. From that moment, the module 11 will respond only to the commands directed to it and identified by the address which it has stored, but propagating at the output 13 that which it receives (supply and commands) at the input 12.

[0084] In an alternative solution, upon switch-on of a module 11, the control unit 15 activates and waits to receive the first transmission of data on the input 12, while keeping deactivated the switch element 14, as in the previous solution.

[0085] Upon reception of the first command, the module 11 checks whether this command is a command for assigning an identification address of the module 11 (for example because it contains the ENUM packet type) and, if so, stores it as its own identification address, so as to keep it in its memory and use it until the next total switch-off. However, the control unit of the module instead simply activates the switch element 14 so as to connect the input 12 to the output 13, will command the switch element 14 (preferably after stable activation of the switch element 14 for a short period - for reasons which will become clear below) so as to modulate the supply at the output 13 on the basis of the transmission algorithm in order to transmit from the output 13 an address packet with a new address. This new address may advantageously be the address received by the module 11, increased by 1. After emission of this new address, the control unit of the module 11 will command the switch element 14 so as to connect the input 12 to the output 12 in a stable manner, as in the previous solution. From that moment, the module 11 will thus respond to the commands directed to it and identified by the address which it has stored and will propagate at the output 13 that which it receives (supply and commands) at the input 12. Both the above-described variations in the behaviour of the module 11 upon switch-on allow for example the series connection of several modules 11 according to the invention in a simple and rapid manner and using only two conductors, while allowing the separate control of each module 11 and automatic setting of the modules 11 so as to distinguish between each module 11 during reception of the commands directed to it.

[0086] This may be understood by referring to Figure 3.

[0087] Figure 3 shows in schematic form an example of a controlled lighting system - denoted overall by 10 - provided in accordance with the present invention by arranging in series several modules 11, each module 11 having its own output 13 which is connected to the input 12 of the next module 11.

[0088] In the system shown in Figure 3 there is a master unit 20 which has a command output 21 designed to provide the power supply and commands to the series of modules 11. The output 21 is connected to the input 12 of the first module 11 in the series.

[0089] The master unit 20 may be of any type suitable for powering the modules and implementing the protocol chosen for communication with the modules 11 as described above and for providing the commands to the modules autonomously or following an external command.

[0090] For example, the master unit 20 may comprise a command unit 22, (for example a suitably programmed microprocessor system) which receives the power supply for itself and for the modules 11 from a per se known power supply circuit 23 which obtains it from a suitable electric power supply source 24 (for example electricity network).

[0091] A modulator circuit 25 of the master unit may vary upon command the voltage at the output 21 between two voltage levels chosen to represent the logic values "0" and "1" of the serial communication with the modules, so as to allow the unit to send commands to the modules 11.

[0092] By suitably choosing these two voltage levels respectively as level 0V (no voltage) and Vmax equal to the normal supply voltage of the modules, the modulator circuit 25 may be a simple electronic controlled switch, known per se to the person skilled in the art, connected between the power supply 23 and the output 21 of the master unit.

[0093] Advantageously, the master unit 20 may also detect the value of the current consumed by the modules 11 connected to its output 21.

[0094] For example, the master unit may be provided with a suitable current sensor 26, known per se, placed in series with the output 21. The sensor 26 may for example be formed by means of an electrical resistance crossed by the current directed towards the output 21 and by a meter for measuring the voltage drop on the resistance.

[0095] As will be explained further below, by knowing the current consumption at its output 21, the master unit 20 is able to establish when a module 11 is connected to the power supply or how many modules 11 are connected to the power supply, for the purposes which will become clear below.

[0096] Once the series of modules 11 has been created and connected to the master unit 20, the master unit may emit a normal supply voltage for the modules at its output 21. Said supply voltage will thus be received by the input 12 of the first module in the series.

[0097] As described above, a module 11 according to the invention, when it is initially supplied with power, awaits the first command at its input 12 and keeps its output 13 deactivated. In this way, only the first module 11 in the series is active, while the other modules remain switched off.

[0098] The master unit 20 detects the current consumption of the first module and sends as a command the address assignment command (e.g. address = 0). The first module therefore detects the arrival of this command and stores it as its own address sent to it.

[0099] According to the first mode of operation of the module 11 described above, the module 11, after storing the address assigned to it, activates its first switch element 14 so as to transmit the power supply from its first input 12 to its output 13 and, from here, to the second module 11 in the series which (having just been switched on) is awaiting commands on its input 12, while it keeps its output 13 switched off.

[0100] The master unit 20 detects the increase in the current consumption caused by switching on of the new module 11 and sends a new command for assigning an address (for example the address previously sent and stored by the first module, but increased by one). The first module 11 in the series, having already an assigned address, will ignore the address assignment command, which will instead be interpreted and stored by the second module 11 which has just been switched on. The second module 11, once it has stored the address assigned to it, will therefore activate its output 13. The procedure of activating and assigning addresses to the modules will thus continue, being automatically propagated between one module 11 and the next module 11, until the master unit, after assigning an address to a module 11, will detect no further increase in the current consumption at its output 21. This will indicate that the address has been assigned to the last module in the series and the procedure for assigning unique addresses may terminate.

[0101] As an alternative to monitoring the increase in current occurring with each address assignment, the master unit may also be preset to send all the addresses up to the highest address which can be used in the system for the maximum number of modules which may be used. Obviously, when the number of modules actually present is reached, the subsequent addresses will not be stored by any module. The speed of execution of the procedure is in any case sufficiently high that the time lost in sending the subsequent addresses may in any case be negligible and not be noticed.

[0102] Once all the possible addresses have been sent, the master unit may measure the current consumption of the modules 11 at its output 21, determine the number thereof by dividing said consumption by the preset standard consumption of a module 11, and then use only the addresses corresponding to the number of modules 11 which are actually used.

[0103] In any case, at the end of the address assignment procedure, the master unit knows how many modules 11 are connected in the series and the address to which each of them will respond.

[0104] As an alternative to the complete assignment of the addresses by the master unit, the modules 11 may be designed to implement the second mode of operation described above.

[0105] According to said alternative, the first module 11, after storing the address sent to it by the master, advantageously activates only briefly its switch element 14 so as to send the supply from its input 12 to its output 13 and from here to the second module 11 in the series, which (having just been switched on) awaits commands at its input 12 while it keeps its output 13 switched off.

[0106] Thereafter, it is the first module 11 which autonomously sends a command for assignment of a new address (for example the address previously received and stored, but increased by one). This new address instead will be thus received and stored by the second module 11 which has just been switched on. This second module 11, once it has stored the address assigned to it, will therefore activate its output 13 so as to send a new address to the next module.

[0107] The procedure for activating and assigning addresses to the modules will thus continue, being automatically propagated between one module 11 and the next module 11, as far as the last module in series, which will simply send a new empty address.

[0108] The modules in the series will thus all have their own assigned address and will thus all become operative and connected to the power supply line. During the procedure for assignment and propagation of the addresses, the master unit, upon each activation of a new module 11 in the series, will detect the increase in the current consumption at its output 13 and remain on standby.

[0109] After the last module 11 has received its own address and emitted a last new empty address, the master unit will not detect any further increase in the current consumption at its output 21 and will establish in this way that the address assignment and propagation procedure has ended and that the system may enter its normal operating phase.

[0110] Moreover, at the end of the address assignment procedure, the master unit may easily determine the number of modules 11 connected in series on the basis of the total consumption which it detects at its output 21 divided by the predefined standard consumption of a module 11. Knowing the number of modules 11 connected in series, the master unit may determine automatically the addresses of each module 11 from the address which it sent to the first modules in the series, since each module 11 following the first module will have that address increased by a predetermined amount depending on the position of the module along the series. For example, if each module during the address assignment procedure emits on its own output 13 its address increased by 1, the addresses of the modules along the series will be respectively the address of the first module, assigned by the master unit, plus 1, 2, 3, 4, etc.

[0111] In any case, once the assignment step has ended (it may last for a very short time after switching on of the system, depending basically only on the duration of transmission or propagation of all the module addresses), the master unit may send to each module 11 in the series the desired commands for controlling the LEDs of each module.

[0112] Owing to the innovative structure of the modules 11 and the system associated with them, it is in fact possible to have correct communication between the master unit and the modules 11 whatever the number of modules 11 which are connected in series, up to the maximum number of modules provided for that system and without the need for external manual operations in order to assign the addresses to the modules 11.

[0113] This allows, for example, light effects and play produced by the series of modules 11 to be produced automatically and independently of the number of lighting modules 11 used.

[0114] The master unit is in fact able to know the number of lighting modules present and their addresses in order to apply correctly any required effect, transmitting to the correct modules the commands containing the information as to which LEDs to switch on, as well as the duration, colour and intensity.

[0115] Said sending of the commands will always be performed by means of serial communication on the supply line, as already described above, each command having associated with it the address of the module for which it is intended. The modules 11, all being supplied with power, detect the data on the supply line, but only the module for which the data is intended will recognize its address and use said data.

[0116] Obviously, as may be now easily imagined by the person skilled in the art, it is possible to provide special addresses (for example "0", if not specifically assigned to a module 11) or commands without an address, so as to communicate the same command to all the modules 11 simultaneously, or to some of them.

[0117] The master unit may obviously send commands for providing lighting effects and controlling the LEDs on the basis of programs stored in it or also on the basis of signals or commands which it receives from outside (for example from home automation systems, computers, manual control systems, etc.), by means of suitable known interfaces or one or more communication lines 27, or two-way lines (for example a USB connection, Ethernet connection, etc.).

[0118] By way of example, Figure 4 shows in schematic form a system according to the invention where a series of modules 11 form a strip of LEDs 28 with at the ends two known distance sensors, denoted by 29 and 30 and arranged so as to detect the distance from each sensor of one or two objects (for example hands) introduced between the sensors in order to know the position of these objects along the LED strip. The sensors are connected to the master unit 20 which is programmed to send commands to the modules 11 of the strip for example in order to switch on (or switch off) only the LEDs in the vicinity of the object or between two objects, etc. The modules 11 may basically be made using any form and arrangement of the LEDs on them. The low complexity of the circuitry facilitates the deposition of the LEDs also on modules with a physically small area.

[0119] By way of example, Figure 5 shows a possible physical embodiment of a module 11 with a substantially linear (thin and long rectangular) form, with LEDs arranged along the main extension thereof and with the input 12 and output 13 at the opposite ends for easy connection of several modules so as to form a strip of any length.

[0120] The module may have a total length of less than 30 cm and in particular in the region of 26 cm or less.

[0121] At this point it is clear how the objects of the invention have been achieved. Owing to the innovative structure of the modules 11 described here, communication with each module is facilitated and several modules may be easily connected together. All of which with a low complexity of the circuitry and at a low cost. Several modules 11 may be easily connected together in series in any number by means of only two wires and receive the power supply and be controlled by exchanging messages with each other or receiving commands from any external device connected to the input 12 of the first module 11 in the series.

[0122] Owing to the presence of the switch element 14 in each module 11, each module may propagate or not at its output 13 the power supply and the digital information which it receives at its input 12. Moreover, also when there is continuous power supply at the input 12 of the module, the modules may, if necessary or desirable, send its serial encoded information to the output 13 so as to communicate with modules 11 downstream thereof.

[0123] Any numbers of lighting modules 11 may be easily used by simply connecting in series the desired number of modules. Also the addition of a module 11 to an already constructed system will be automatically detected upon switching on of the system, and assignment of the addresses will occur in any case in a manner which is automatic, rapid and completely transparent for the user.

[0124] The number of LEDs of each lighting module 11 may obviously be chosen depending on the specific practical requirements and the LEDs of the module may be differently arranged and / or grouped together depending on the desired luminous intensity and the lighting forms to be realized with the controlled switching on and off of the LEDs.

[0125] For example a module 11 may comprise eight groups of four LEDs each. Such a grouping allows for example optimum use of a 12V power supply since it results in a low heat dissipation of the module with the use of white LEDs which are widely available and which normally have a voltage drop of 2.5 - 2.7V. For a 24V power supply, instead, it will be preferable to use a group of eight LEDs or again four LEDs, but with a lower light output. Obviously, suitable known solutions may be used to allow a suitable heat dissipation. For example, the LEDs may be mounted on heat-conducting substrates and with heat dissipating elements (such as dissipator fins),

[0126] In the system according to the invention, commands may be easily sent to the various modules 11 so as to provide for example desired lighting effects, such as lighting programs, light play, etc. If desired, the system may also adapt automatically the lighting effects to the number of modules 11 which are connected, this number being able to be automatically detected by the system.

[0127] The programming of the lighting effects produced by the system may obviously be stored in the system or be obtained from further per se known devices such as command units, computers, Internet connections, etc. The effects may also be realized as cyclical lighting effects on a time basis. The master unit may also consist of the first module 11 in the series of modules, if necessary by also integrating in the module 11 some of the functions described here for the master unit. For example, the module 11 may comprise a sensor element for sensing the current consumption at its output 13 so as to detect the number of any other modules 11 situated downstream in the series. The unit 19 of the system may also consist of a simple known power supplier designed to the provide the appropriate continuous voltage required to power normally the series of modules 11. The system according to the invention may also comprise or be easily combined with further accessories for managing, starting or stopping the light effects which can be controlled by means of the modules 11.

[0128] For example, it may be connected to sensors in order to signal the need to send commands for complete or partial activation of the light sources or for producing the start or end of the lighting effects.

[0129] In particular, presence sensors may be provided where the sensors activate lighting effects when they detect the presence of objects or persons within their activation range.

[0130] The encoding of the data transmitted by means of interruption of the supply voltage of the modules may be different from that described above and comprise other known types of encoding and serial protocol systems.

[0131] For example, the information may be transmitted still with division of the supply voltage, but using frequency modulation instead of asynchronous serial transmission. In this mode the master unit encodes the bits with the duration of the PWM period. The lighting modules 11 will measure in this case the PWM period and obtain the necessary information.

[0132] By suitably varying the duty cycle, the controller could directly set the level of the light emitted, without the need to send specific level messages.

[0133] The colour (for example warm or cold effect) of all the light sources, in particular LEDs, could also be determined by the polarity of the supply voltage. In this case, the modules 11 will contain a circuitry, which may now be easily imagined by the person skilled in the art, for suitably managing the power supply of the electronics present inside the modules. For example a known diode rectifier circuit may be used in order to obtain always the correct polarity of the power supply of the circuits despite the inversion in polarity of the voltage at the input of the modules.

[0134] The modules 11 may be provided with other further accessory functions, in addition to that described above. For example, in addition to the step for automatically assigning the addresses, upon switch-on the module 11 may also carry out a preliminary operational check, known per se, for example for an internal operational auto test.

Claims

1. Controllable lighting module (11) comprising an input (12) for electric powering thereof, one or more light sources (16) which can be activated upon command, and a control unit (15) able to receive commands from the outside and to control the one or more light sources (16) depending on these commands, characterized in that it comprises an output (13) and a switch element (14) connected to the control unit (15) for interrupting or allowing electrical continuity between the said input (12) and the said output (13) upon command of the control unit (15), the control unit (15) being able to receive the commands such as modulation of the voltage applied to the said input (12) and there also being provided an electronic temporary power supply circuit (18) which is located between the input (12) and the control unit (15) and which is designed to keep the control unit (15) operative also during variations of the power supply at the input (12) produced by the said modulation of the voltage at the input (12) .

2. Controllable lighting module (11) according to Claim 1, characterized in that the light sources (16) are of the LED type.

3. Controllable lighting module (11) according to one or more of the preceding claims, characterized in that the control unit (15) upon switching-on of the module initially maintains interrupted the electrical continuity between input and output by means of the switch element (14) and waits to receive at the input (12) a command for assignment of its identification address for the subsequent commands.

4. Controllable lighting module (11) according to one or more of the preceding claims, characterized in that the control unit (15) is designed to receive the commands as modulation of a voltage applied to the said input (12) in the form of a binary serial code with the bits of the code which are represented with variations in the supply voltage between two predefined voltage levels.

5. Controllable lighting module (11) according to Claim 4, characterized in that the two voltage levels are, respectively, the supply voltage of the module and zero.

6. Controllable lighting module (11) according to one or more of the preceding claims, characterized in that the control unit (15) deactivates switching-on of its light sources (16) during variations of the power supply at the input (12) which are produced by the said modulation of the voltage at the input (12).

7. Communication method for a module (11) according to any one of the preceding claims, characterized, upon switching-on of the module (11), by a first step of assigning an identification address to the module (11) and by a second step of receiving and interpreting commands at the input (12), the step of assigning an identification address to the module (11) comprising in turn the steps, carried out by the control unit (15) of the module (11), of waiting for a first command for assignment of an identification address, storing the identification address of this command as the identification address of the module (11), activating the switch element (14) of the module (1) so as to allow the electrical continuity between the input (12) and the output (13) of the module and remaining on standby for subsequent commands associated with the stored identification address.

8. Communication method according to Claim 7, characterized in that, upon detection of a modulation of the voltage at the input (12), the control unit (15) deactivates the light source (16) for the entire duration of the voltage modulation, recognizes whether the modulation at the input contains a command associated with the identification address stored during the step of assignment of an identification address to the module (11), interprets this command and executes it.

9. Communication method according to Claim 7, characterized in that at least some commands are switching on / off commands and / or commands for varying the colour and / or the luminosity of the light source (16).

10. Lighting system comprising a master unit (20), with an output (21) designed to emit a power supply and to modulate said power supply for controlling the lighting modules (11) according to any one of the preceding claims, and at least one lighting module (11) according to any one of the preceding claims, said at least one lighting module (11) being connected with its own input (12) to the output (21) of the master unit (20) and being the only one or the first module (11) of a series of said lighting modules (11) which each have, except for the last one in the series, its output (13) connected to the input (12) of a following lighting module (11) in the series.

11. Lighting system according to Claim 7, characterized in that the master unit (20) comprises a command unit (22) and a modulator circuit (25) designed to vary upon command of the associated command unit (22) the voltage at the output (21) between two voltage levels chosen to represent the logic values "0" and "1" of a serial communication with the lighting modules (11).

12. Lighting system according to Claim 8, characterized in that the master unit (20) comprises a current sensor (26) which is connected to its output (21) so as to measure the current consumption at this output (21) and which is connected to the command unit (22) so as to signal to the command unit (22) when a module (11) is connected to the power supply present at the output (21) of the master unit (20).

13. Method of communication between modules (11) and a master unit (20) for a system according to any one of Claims 10 to 12, comprising a step of assigning identification addresses to the modules (11) during which initially all the modules (11) connected in series have their switch element (44) open so as to interrupt the power supply between their input (12) and their output (13), the master unit (20) modulates the power supply at its output (21) with a command for assigning an identification address, such that only the first module (11) of the series receives this identification address and stores it as its own, after storage of the identification address said first module (11) activates its switch element (14) so as to have electrical continuity between its input (12) and its output (13) and the master unit modulates again the power supply at its output (21) with a command for assigning a new identification address which is thus received and stored by the following module (11) in the series, which in turn activates its switch element (14) so as to have electrical continuity between its input (12) and its output (13) and the master unit modulates again the power supply at its output (21) with a command for assigning a new identification address which is thus received and stored by the next module (11) in the series, and so on, until the master unit detects that there are no further modules (11) in the series which must store an identification address.

14. Method according to the preceding claim, characterized in that the master unit detects that there are no further modules (11) in the series which must store an identification address by means of verification that there is no further increase in the current consumption at its output (21) and terminates the step of assigning the addresses to the modules.

15. Method of communication between modules (11) and a master unit (20) for a system according to any one of Claims 10 to 12, comprising a step of assigning identification addresses to the modules (11) during which initially all the modules (11) connected in series have their switch element (44) open so as to interrupt the power supply between their input (12) and their output (13), the master unit (20) modulates the power supply at its output (21) with a command for assigning an identification address, such that only the first module (11) of the series receives this identification address and stores it as its own, after storage of the identification address the module (11) activates its switch element (14) so as to modulate the power supply at its output (13) with a command for assigning an identification address following that stored by it such that said command for assigning an identification address following that stored by it is received and stored by the following module (11) in the series, which in turn activates its switch element (14) so as to modulate the power supply at its output (13) with a command for assigning an identification address following that stored by it, and so on, until the last module in the series has received and stored its own identification address.

Images