WO2011123963A2

WO2011123963A2 - Electronic circuit for measuring the light of light-emitting diodes used in an emergency lamp

Info

Publication number: WO2011123963A2
Application number: PCT/CH2011/000073
Authority: WO
Inventors: Michel Noe; Pierre Schneider
Original assignee: Polynom Ag
Priority date: 2010-04-07
Filing date: 2011-04-06
Publication date: 2011-10-13
Also published as: EP2375858A1; WO2011123963A3

Abstract

In an electronic circuit (2) for measuring the light of light-emitting diodes (3) used in an emergency lamp, the circuit (2) is fed by a supply (14) of the light-emitting diodes (3) and comprises: a light sensor (4) for producing an electrical signal (17) according to a luminous flux of the light-emitting diodes, an electronic controller (6) for processing said signal (17), and an electronic switch (5) for interrupting or short-circuiting the supply (14) of the light-emitting diodes (3). The electronic controller (6) is constructed as a digital controller and comprises: a storage circuit (10, 11) for supplying the electronic controller (6), wherein during the processing of the electrical signal (17), the circuit (2) switches the electronic switch (5) off and on in a certain sequence, which digitally encodes the value of the electrical signal (17) as a feedback signal, in order to transmit the value of the electrical signal (17).

Description

ELECTRONIC CIRCUIT FOR THE LIGHT MEASUREMENT OF LUMINAIRE DIODES USED IN A EMERGENCY LIGHT

The invention relates to the field of electric emergency lights. It relates to an electronic circuit for the light measurement of light-emitting diodes used in an emergency light, as well as to a skin-tone module for powering light-emitting diodes, each according to the preamble of the corresponding independent patent claims.

PRIOR ART In so-called single-battery LED emergency lights, light-emitting diodes (LEDs) are used as lighting means. Since such emergency lights are considered as emergency lights, such lights must be checked regularly. In the emergency lighting of a building, there are standards that precisely determine the minimum light intensity of the rescue route lighting or markings.

In emergency lighting, LEDs are used more and more frequently. In today's LED technology, the light intensity decreases depending on the temperature constantly. This means that from a certain period of operation, the light intensity is too low or the standard is no longer met. Because the light emitting diodes still produce light, it is difficult for the operator to know from when the standard is no longer met. This means that a regular measurement of the light intensity supplied by the LEDs is required. Since the LEDs, unlike other light sources, draw the same electrical power from their supply (ie same voltage x same current), whether they are new or provide a lot of light or worn out or provide too little light, it is difficult Luminous intensity of the LED or its wear derive from electrical measurements.

In a single-battery LED emergency light, there is a main module, with which all the necessary functions are performed. To measure the luminous intensity of the LEDs, standard light sensors (photo diodes, photo transistors or special integrated circuits) are installed next to the LEDs. The measurement is transmitted to the main module as a digital or analogue signal. In the main module, this measurement is compared with a minimum value, and if necessary the light is switched off and / or the faulty state is signaled locally or reported remotely.

With this conventional solution, there is an additional connection in the luminaire which the light sensor connects to the main module. The main module must be adapted so that the signal transmitted by the light sensor can be processed. This means that there is a constructive or hardware difference between a normal main module without light measurement and one with light measurement.

There are solutions in which the supply voltage is used for feedback. This can be dispensed with an additional connection.

DE 10 2008 034 524 A1 describes a circuit in which a transistor is inserted in the light sensor circuit, so that if the light measurement is too low, the transistor can separate the LED from the main module. The main module can then detect the undershooting of a minimum illuminance by detecting this interruption. In EP 1 000 806 A2, a circuit is described in which a diagnostic circuit, which is located next to the LED or the LED arrangement, increases the current consumption in the event of a fault, so that the main module is informed of the faulty state by means of a current measurement.

In these two inventions, there is an important drawback which makes their use for emergency lighting impossible. The problem lies in the independence of the monitoring. In both cases, the LED sensor is disconnected or more loaded by the light sensor or the diagnostic circuit in the event of a faulty condition, without any possibility for the main module to influence or prevent these changes. The main module is only able to detect such changes.

For an emergency light, an independent separation of the LED arrangement in the case of a lower light intensity (DE 10 2008 034 524 AI) is not possible because the light intensity in emergency mode is usually much lower than that in network operation. With such a separation, the emergency light would automatically switch off in emergency mode. Even if the light intensity in emergency as well as in the network operation would be identical, for safety reasons the LED light must illuminate in emergency mode, regardless of whether the light intensity is high enough or not.

In the second document (EP 1 000 806 A2) more power is required from the energy source in the event of a faulty condition. If this faulty condition arises because of a too low light intensity, and the light intensity in emergency operation is much lower than that in the network operation, then automatically more power from the energy source, ie from the battery in emergency operation is required. Such a solution is of course excluded for emergency lighting, since all the energy stored in the battery must be consumed for emergency lighting. PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide an electronic circuit for the light measurement of light emitting diodes used in an emergency, and a Hautptmodul for feeding light emitting diodes of the aforementioned type, which overcomes the disadvantages mentioned above.

This object is achieved by an electronic circuit for the light measurement of light-emitting diodes used in an emergency luminaire, as well as a skin-type module for supplying light-emitting diodes with the features of the corresponding independent patent claims.

In such an electronic circuit for the light measurement of light emitting diodes used in an emergency light,

Thus, the circuit is powered by a supply of light emitting diodes, and has the following elements:

► a light sensor which measures a part of the luminous flux of the LEDs and generates a corresponding electrical signal,

»An electronic control that processes and evaluates this electrical signal,

either an electronic switch, with which the supply of the light-emitting diodes can be interrupted, or an electronic switch with which the supply of the light-emitting diodes can be short-circuited,

a memory circuit which stores energy from the supply for a certain time and supplies it to the power supply of the electronic control,

wherein the circuit is adapted, in the processing of the electrical signal by the digital electronic control, the electronic switch in a specific sequence, which as Feedback signal digitally encoded the value of the electrical signal, for switching the value of the electrical signal off and on.

Thus, the circuit can store energy from the supply by means of a storage circuit for a certain time and use it to supply the electronic control, which circuit can detect the voltage of the supply, and the circuit is able to produce a sequence of on and off operations Receive supply as signals and convert it into one of several control signals. In order to use the LED supply as a communication line in this way, the circuit preferably has a monitoring device with which the LED power supply is monitored in order to decode signals transmitted from a main module to the circuit.

With the energy storage, short interruptions of the LED supply can be bridged, so that the circuit can continue to function when the LED supply is used as a communication line, that is, when the LED supply is either from the main module or from the photometric circuit In this case, the circuit is designed to control the electronic switch in an evaluation of the electrical signal according to a predetermined criterion by the electronic control and thereby interrupt the supply of light-emitting diodes respectively short-circuit. For example, a rating associates the signal with a particular state corresponding to the value of the signal. For example, the state expresses that the value is within a certain range between two limits.

In a preferred embodiment of the invention, the electronic switch, typically a transistor or other semiconductor switch, is arranged in the circuit such that it can interrupt the supply of the light emitting diodes, preferably by being connected in series with the light-emitting diodes. This interruption is detectable in a main supply module, so that a coded signal can be transmitted to the main module by means of a series of pulsed interruptions. It may thereby, in another embodiment of the invention, be responded to by the main module for a permanent interruption (for example, by an alarm or a display).

In another preferred embodiment of the invention, the electronic switch is arranged to short-circuit the supply (possibly also via a resistor of known size). In this embodiment too, signals or information can be transmitted to the main module as a result of the short-circuiting. The following explanations therefore apply mutatis mutandis to this embodiment. The invention thus relates to an automatic self-diagnosis of the light intensity, which is supplied by the built-in lights in the emergency light emitting diodes.

With an intelligent light sensor module, which is mounted in the emergency light next to the LEDs, the light intensity is measured. There are then two embodiments of the invention:

In a first embodiment of the invention, this light intensity is evaluated by the light sensor module. If this light intensity is too low, the LED feed is interrupted with the same module, preferably pulsed breaks, with a sequence of interrupts digitally encoding the state. With the main module controlling the emergency light in both mains and emergency mode , this line break or these pulsed interrupts will be registered and interpreted as the "low light level" state. With a preprogrammed strategy, a corresponding behavior is triggered via the main module, such as the activation of a local acoustic or optical signal or feedback regarding the too low light intensity to a control center (for example, wirelessly or via a bus line).

In a second embodiment of the invention, this light intensity is only measured by the light sensor module and evaluated by the main module. In this case, the measured value of the luminous intensity is transmitted by the light sensor module via the LED supply by pulsed interruptions to the main module, the sequence of interruptions digitally encoding this value. The evaluation of this measurement or the triggering of a corresponding behavior is then carried out by the main module.

The light sensor module is supplied with the same voltage parallel to the LEDs. The communication between the main and the light sensor module via this single two-pole LED power supply. In a selectable operating state, the light sensor module can measure the light and transmit the measurement or its evaluation if necessary, or the light measurement in another operating state with a simple communication protocol in which the LED supply is switched on and off Do not perform or interrupt the LED cable. In this protocol, it is also possible to retrieve a transmission of a measured value of the light intensity. In this case, the light sensor module turns off the LED power in a particular sequence and on, which sequence replicates the measured light intensity value digitally encoded so that this value is transmitted to the main module.

With the invention it is possible to use the same main module hardware for luminaires with or without light sensor. The difference is then only in the programming of the main module, ie in the software. With the invention, the light sensor is located on an intelligent light sensor module, with which the light measurement is evaluated and, in the case of too small a value, the connection from the main module to the light emitting diodes can be interrupted and with which the light measurement and / or their evaluation to the main module transferable is.

It is thus very easy to convert an emergency light without light measurement into an emergency light with light measurement:

• The intelligent light sensor module must first be mounted next to the LEDs (so that the light can be measured).

• The 2-pin connection from the main module to the LEDs, which is intended to supply the LEDs, is then connected to the light sensor module instead of the LEDs. The LEDs are only connected to the light sensor module.

In a preferred embodiment of the invention, when the electronic controller is switched on, the electronic switch is switched on by the supply, preferably via a current source connected to the supply. Thus, a quick turn on is possible without having to wait for the startup of a digital processor unit, which ultimately controls the electronic switch.

In a preferred embodiment of the invention, the electronic circuit is adapted, in the processing of the electrical signal by a digital electronic control, the electronic switch in a particular sequence, which digitally encodes the value of the electrical signal as a feedback signal for transmitting the value of the electrical signal turn off and on. Thus, a value for the brightness of the LEDs can be transmitted via the supply line. In a preferred embodiment of the invention, the electronic circuit is designed, during the processing of the electrical signal by the digital electronic controller, to send out the state of processing to the electronic switch in a specific sequence which digitally codes the state of processing as a feedback signal. and turn it on. Thus, a state such as "first threshold for brightness undershot"'can be transmitted.

In a preferred embodiment of the invention, the circuit uses limit values in the evaluation of the electrical signal, wherein these limits are generated or can be generated by means of a calibration. Thus, the limit values, for example during production or commissioning, can be adapted to the light intensity of the LED arrangement used and / or to possible variances of the measuring device.

In a preferred embodiment of the invention, the circuit uses limits in the evaluation of the electrical signal, these limits being preprogrammed in the digital controller. This allows standardized limits to be used across a series of luminaires.

In a preferred embodiment of the invention, the circuit may be selectively switched to at least one of the following states with one of the plurality of control signals:

A waiting state in which, regardless of the light measurement, the current flowing in the light-emitting diodes is not interrupted.

A test state in which, depending on the light measurement, the current flowing in the light-emitting diodes can be interrupted. This interruption is preferably done by the circuit itself, for example by switching the arranged in series or parallel to the LEDs electronic switch. a measuring state in which, depending on the light measurement, the electronic switch for transmitting the value of the electrical signal to the main module is switched on and off, ie pulsed interruptions are transmitted to the main module,

a communication state in which depending on the light measurement of the electronic switch for transmitting the state of the processing is switched on and off to the main module, or vice versa information is transmitted from the main module to the circuit. It can be distinguished:

o a communication state in which thresholds to be used for the evaluation of the light measurement to be performed are transmitted to the circuit by pulsed breaks generated by the main module, o a communication state in which information from the circuit transmitted to the main module by pulsed interruptions generated by the circuit. Such information may be, for example, stored light measurements made in the past, but also general information about the circuit itself, such as "software version", "production date" or "cumulative operating time", etc.

In the Hautptmodul for feeding light emitting diodes by means of a supply, this is also designed to power an electronic circuit according to one of the preceding claims by means of the supply. In this case, the main module is configured to detect a sequence of interruptions or short circuits of the supply, this sequence digitally encoding a feedback signal from the electronic circuit and decoding the feedback signal therefrom. In a method of operating an electronic circuit for the light measurement of light emitting diodes used in an emergency light, the supply of light emitting diodes in the electronic circuit is intermittently interrupted (or, in another preferred embodiment of the invention, shorted) to transmit coded feedback signals to the main module , Conversely, the supply can be intermittently turned off by the main module to transmit control signals to the electronic circuit. Further preferred embodiments emerge from the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the subject invention will be explained in more detail with reference to preferred embodiments, which are illustrated in the accompanying drawings. In each case: FIG. 1 shows an electronic circuit according to the invention;

FIG. 2 shows a variant of a part of the circuit;

Figure 3 shows a time course of signals for communication with the

Circuit; and

Figure 4 shows another variant of the circuit. ,

Basically, the same parts are provided with the same reference numerals in the figures. WAYS FOR CARRYING OUT THE INVENTION

On the Fig.1 the invention is outlined. In an LED light there is a converter in a main module 1 and some built in an LED array light emitting diodes 3. The converter operates in a known manner either as a power source or as a voltage source. Since the current flowing in each LED must be limited to a maximum value, it is sometimes necessary to insert into each LED branch of the LED array 3 circuits that limit the current or divide the current. Such circuits can be active or passive (pure resistors).

On the one hand, the invention relates to the light sensor module 2, which is installed between the main module 1 and the light-emitting diodes 3, and, on the other hand, the main module 1, as well as the communication between the light sensor module 2 and the main module. This communication is done by turning on and off the voltage of the supply 14 in one direction or via the switching on and off of the transistor 5 as an electronic switch in the other direction.

Description of the Light Sensor Module 2:

The light sensor module 2 consists of the following components:

Light sensor 4: This light sensor is a conventional light sensor which can measure the light with a photodiode, a phototransistor or other component. With this light sensor, the luminous flux (or a part thereof) of the LEDs 3 is measured. This light sensor is either populated on the light sensor module or located in the LED array, where it is connected with wires to the light sensor module. When it is on or in the light sensor module, it is also possible to guide the light (or a part thereof) of the light-emitting diodes 3 to the light sensor with a light guide. The light sensor provides an electrical signal 17, which simulates the measured luminous flux analog or digital, to the controller 6.

Controller 6: This controller 6 is a digital electronic controller with which the light sensor module 2 is controlled. This electronic control is preferably built with a microcontroller. The following tasks are controlled by this microcontroller:

• Edit the light measurement or signal 17. This light intensity measurement may first be amplified. In a simple implementation, this is compared to a limit value. In a further embodiment, this is transmitted by the control of the transistor 5.

• Calibration. By an input signal 15, the current light intensity measurement can be stored to compare later measurements with this stored value or to calibrate based on this measurement. This calibration is used, for example, in the manufacture of the LED

Light made when the LEDs are new. The threshold may then be e.g. be calculated as 50% or 70% of the reading stored during calibration. The input signal 15 can via a test button (with a connection to 0V and a pull-up resistor or on the supply voltage 16 of the controller 6 or a pull-down

Resistance). Of course, it is also possible to define the time of calibration via an infrared or radio interface, or to receive and store calibration values from the main module at any time.

· Monitoring of the LED voltage of the supply 14. This monitoring takes place by measuring the voltage, if necessary by dividing by means of a resistance bridge (resistors 7 and 8). When the main module 1 cuts off the voltage of the supply 14 for a short time, this interruption is registered by the controller 6. Such interruptions, whose duration is short enough not to be noticed by human eyes, Simple commands can be transmitted from the main module 1 to the light sensor module 2.

Control of the transistor 5 connected in series with the light-emitting diodes 3 in order to disconnect the connection from the main module 1 to the light-emitting diodes 3 or to switch off the LED light, as shown in FIG. 1, or control of the transistor 5 connected in parallel with the light-emitting diodes 5 in order to short-circuit this connection or supply of the light emitting diodes 3, as shown in FIG. 4. In both cases, therefore, the current flowing in the light-emitting diodes 3 is interrupted by switching the transistor 5. When the controller 6 turns the transistor 5 on and off in certain sequences, it is able to transmit messages or measured values to the main module. Such interruptions are preferably, like that of the voltage of the supply 14, also short enough not to be perceived by human eyes.

Transistor 5: This transistor 5 is preferably shown as a MOSFET transistor. Of course, bipolar or IGBT transistors can also be used instead of a MOSFET transistor. As shown in Fig. 1, the LEDs 3 can be turned on or off with this transistor, because the current, which is generated by the main module and flows through the light-emitting diodes, flows through the transistor 5. Although a very simple direct control can be realized by the controller 6, a preferred controller is shown in Fig. 2 (as part of the circuit of Fig. 1). With this preferred variant of the control, the MOSFET transistor 5 is turned on via the pull-up resistor 21, as soon as a positive voltage of the supply 14 is applied. Thus, it is possible to avoid the time delay at start-up. Such a time delay arises when the controller 6 must first start to turn on the transistor 5. With this preferred control, the transistor 5 is controlled by the controller 6 via the additional transistor 22. Depending on the voltage of the supply 14 vzw is provided to protect the gate of the transistor 5 with a Zener diode 23. If the line length of the connection to the LEDs 3 is too long, it may also be necessary to protect the transistor 5 with the freewheeling diode 24 of overvoltages.

As shown in Fig. 4, the light emitting diodes 3 can also be turned on or off with the transistor 5 by this transistor 5 short-circuits the supply 14 and the LED current dissipates. With this variant of the control, the transistor 5 should be switched off when starting. For this, the pull-down resistor 50 can be used.

Supply of the controller 6:

When the LED array or LEDs 3 are powered by the main module, the current flows through the light sensor module into the light emitting diodes 3. Through the diode 10 and the resistor 13 (which can also be replaced by a current source or a short circuit, if the voltage of the Supply 14 is too high or too small) then flows a current with which the capacitor 1 1 is loaded and the controller 6 and the light intensity sensor 4 are supplied via the voltage regulator 9. The supply voltage 16 can also be regulated with a Zener diode instead of the voltage regulator 9. If necessary, the capacitor 12 may be provided as a smoothing capacitor for the controller 6. This capacitor is then considered as a storage capacitor for the supply of the controller 6. With the capacitors 1 1 and 12 as memory capacitors preferably the supply voltage 16 will remain supported supported, even if the voltage of the supply 14 for communication during a short period to zero is set. Description of the communication and the resulting states: A possible communication is shown on the drawing Fig.3. The following description is based on the circuit shown in FIG. The same communication is also possible with the circuit shown in FIG. 4, in that the transistor 5 is switched on instead of switched on instead of switched on.

At the time of starting (time t0), the light sensor module 2 is in a waiting state in which the light meter 17 is not processed although it can be made. That is, the transistor 5 is turned on, for example, with the control shown in Fig. 2, and that the transistor 5 is always kept on, regardless of the light measurement 17. This wait state is indicated by the time Tl in the drawing Fig.3 ,

When the light measurement 17 is judged, it is necessary to get the corresponding command from the main module 1. This command consists of a certain series of turning off and on the voltage of the supply 14, which are decoded as digital "0" and "1" bits, respectively, from the controller 6 via the resistors 7 and 8. Such a series of turning off and on takes place within a period of time T. The time period T, while the communication is taking place or the commands are sent from the main module 1 to the light sensor module 2, is preferably short enough so that the human eye does not perceive it, since the light emitting diodes 3 are switched off at each "0" or "0". to be switched every "1". The total capacitance of the capacitors 11 and 12 must be high enough to protect the supply voltage 16 of the controller 6 during the time period T. The state in which the light measurement 17 is evaluated is the so-called test state, and is denoted by the time T2 in the drawing Fig.3. In this test state T2, the transistor 5 is turned off when the light measurement 17 is below a certain predetermined limit. Such a possibility is exemplified at time t4, when the transistor 5 whose gate voltage is drawn is turned off. When the transistor 5 is turned off, no current flows from the main module 1 into the LEDs 3. When the main module is constructed as a power source, the main module 1 can measure this current to register that the LEDs 3 provide little light. When the main module is constructed as a power source, the voltage of the supply 14 will increase when the transistor 5 is turned off. In this variant, the main module 1 can thus measure the voltage of the supply 14 in order to register that the light-emitting diodes 3 supply too little light. The time at which the light sensor module 2 changes from the waiting to the test state, with the time delay T, at which the communication takes place and must be interpreted, after the starting point tl.

In an emergency, in which possibly the light intensity in emergency mode is smaller than that in the network operation, the emergency operation is always controlled for safety reasons by means of a corresponding control signal in the waiting state. That is, the emergency operation in the standby circuit as drawn at time tO starts or at time t2 in the permanent circuit. Preferably, there is another control signal, in which the light sensor module 2 changes from the test state T2 to the waiting state T1. The return to the waiting state is drawn from time t2. In this command, the transistor 5 is turned on again and will remain so, regardless of the light measurement 17. Another possibility is to transmit with the shutdown of the transistor 5, a kind of feedback to the main module, since the main module as a current as well as a voltage source can measure the interruption - as described above. With a certain sequence of switching off and on of the transistor 5, the light sensor module can also send signals or messages to the main module. With such messages it is also possible to measure the measured Digitally transmitting the value of the light measurement, and for example, leaving the evaluation of the light measurement, for example by comparison with one or more limit values, to the main module. In this preferred embodiment of the invention, the light sensor module 2, for example after receiving a corresponding control signal, in a so-called measurement state in which the value of the measurement is requested by the main module. This process starts, for example, at time t3 on the drawing Fig.3. The measurement state is shown as T3.

If the message requested by the main module relates only to the state of the light sensor module, the light sensor module 2 is in a so-called communication state, for example after receiving a corresponding control signal.

When data such as calibration values are transmitted from the main module to the light sensor module, the light sensor module 2 is in a so-called communication reception state, for example after receiving a corresponding control signal.

In so-called self-test emergency lights, a self-diagnosis is regularly carried out. The LEDs are controlled. In such luminaires, it is possible to control the light sensor module 2 with appropriate control signals in the test state T2 or in the measuring state T3, as shown as an example on the drawing Figure 3 at the times tl and t3.

Claims

Electronic circuit (2) for the light measurement of light-emitting diodes (3) used in an emergency light,

wherein the circuit (2) is powered by a supply (14) of the light-emitting diodes (3)

and the following elements:

A light sensor (4) which measures part of the light flow of the light-emitting diodes (3) and generates a corresponding electrical signal (17),

An electronic controller (6) which processes and evaluates this electrical signal (17),

Either an electronic switch (5) with which the supply (14) of the light-emitting diodes (3) can be interrupted, or an electronic switch with which the supply (14) of the light-emitting diodes (3) can be short-circuited,

characterized in that the electronic controller (6) is constructed as a digital controller, and that the circuit comprises:

A memory circuit (10, 11) which can store energy from the supply (14) for a specific time (T) and deliver it to the power supply of the electronic controller (6),

Wherein the circuit (2) is adapted, in the processing of the electrical signal (17) by the digital electronic control (6), the electronic switch (5) in a specific sequence, which as a feedback signal the value of the electrical signal (17) digitally coded to turn off and on to transmit the value of the electrical signal (17).

Electronic circuit according to claim 1, wherein the electronic switch (5) is arranged in the circuit (2) such that it can interrupt the supply (14) of the light emitting diodes (3), preferably by connecting in series with the light emitting diodes (3) is. Electronic circuit (2) according to claim 2, wherein the electronic switch (5) is switched on by the supply (14) when the electronic control is switched on, preferably via a current source (21) connected to the supply (14).

An electronic circuit (2) according to claim 1, 2 or 3, wherein the circuit (2) is adapted to evaluate the electrical signal (17) and the electronic switch (5) in a sequence which as a feedback signal the state of the evaluation digitally encoded, to turn on and off to communicate the status of the rating.

Electronic circuit (2) according to claim 4, wherein the circuit (2) uses limit values in the evaluation of the electrical signal (17), and these limit values are generated by means of a calibration (15).

Electronic circuit (2) according to claim 4, wherein the circuit (2) uses limit values in the evaluation of the electrical signal (17), and these limit values are already preprogrammed in the digital controller (6).

An electronic circuit (2) according to any one of claims 4 to 6, wherein the circuit (2) is adapted to sense the voltage of the supply (14) and the circuit (2) is capable of providing a sequence of supply turns on and off (14) as signals to receive and convert into one of a plurality of control signals.

Electronic circuit according to claim 7, wherein the circuit is in a waiting state in which regardless of the light measurement of the electronic switch (5) does not flow in the light-emitting diodes (3) current interrupts, can be, and the circuit (2) with one of the plurality of control signals in the wait state is switchable.

Electronic circuit (2) according to claim 7 or 8, wherein the circuit (2) can be in a test state in which the electronic switch (5) can interrupt the current flowing in the light-emitting diodes (3) as a function of the light measurement , and the circuit (2) with one of the plurality of control signals in the test state is switchable. 10. Electronic circuit according to one of claims 7 to 9, wherein the circuit (2) in a measuring state, in which depending on the light measurement of the electronic switch (5) for transmitting the value of the electrical signal (17) on and is turned off, and the circuit (2) with one of the plurality of control signals in the measurement state is switchable.

An electronic circuit (2) according to any one of claims 7 to 10, wherein the circuit (2) is switched on and off in a communication transmission state in which the electronic switch (5) is switched on and off depending on the light measurement for transmitting the state of the evaluation, can be located, and the circuit (2) with one of the plurality of control signals in the communication transmission state is switchable.

12. Electronic circuit (2) according to claim 1 1, in which by means of the circuit (2) in the communication transmission state, a cumulative period of operation of the emergency light is transmitted.

13. Electronic circuit (2) according to one of claims 7 to 12, in which the circuit (2) is in a communication receiving state, in which values for evaluating the light measurement via a sequence of output signals and switch-ons of the supply from the main module (1) can be transmitted to the circuit (2),

and the circuit (2) is switchable with one of the plurality of control signals in the communication reception state.

An electronic circuit (2) according to claim 13, which is adapted to receive calibration values in the communication reception state.

15. Hautptmodul (1) for supplying light emitting diodes (3) by means of a supply (14),

characterized in that the main module (1) is also designed to supply an electronic circuit (2) according to one of the preceding claims by means of the supply (14), and the main module (1) is adapted to

· A sequence of power interruptions or short circuits

(14), said sequence digitally encoding a feedback signal from the electronic circuit (2),

• and to decode the feedback signal.

16. Hautptmodul (1) according to claim 15, wherein the main module (14) for interrupting the supply (14) in the form of a sequence of off and on the supply (14) is formed, this sequence is a control signal for the electronic circuit ( 2) digitally coded.