AU2011201614B2

AU2011201614B2 - Electronic ballast with interface device

Info

Publication number: AU2011201614B2
Application number: AU2011201614A
Authority: AU
Inventors: Stefan Honerkamp; Otto Meyer; Andreas Rehburg; Frank Westermann
Original assignee: Optotronic GmbH
Current assignee: Optotronic GmbH
Priority date: 2010-04-09
Filing date: 2011-04-08
Publication date: 2013-08-29
Anticipated expiration: 2031-04-08
Also published as: DE102010014442A1; EP2375868B1; EP2375868A3; EP2375868A2; BRPI1101876A2; AU2011201614A1

Abstract

Electronic Ballast with Interface Device Abstract 5 An electronic ballast (EB) for operating a lamp, the ballast comprising an interface device (50,50') including on the input side thereof a connecting means (51) for receiving externally supplied brightness control information in the form of external control signals, and comprising a control device (30) which is connected to the said interface device (50,50') for receiving externally supplied brightness control information and is designed 10 for controlling the brightness of the lamp (40) in dependence of the received brightness control information, wherein the interface device (50,50') comprises a fist signal path (51,70,71,72,75,52',51,70,90,72,75,52) for transmitting brightness control information that is attached to external digital control signals to a first input signal terminal (31) of the control device (30), and a second signal path (51,70,80,81,82,53) that is different from 15 the first signal path at least in some sections, for transmitting brightness control information that is attached to external control signals which are formed as switching signals to an input signal which are formed as switching signals to an input signal terminal (32) of the control device (30) which is different from the first input signal terminal, and that the interface device (50,50') includes a means (80) for identifying the 20 control signal structure of the externally supplied control signal and for opening the signal path that is assigned to the identified signal structure and/or for blocking a signal path that is not assigned to the identified signal structure. (Figure 1a) -E

Description

S&F Ref: 992131 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address BAG electronics GmbH, of Kleinbahnstr. 27, 59759, of Applicant: Arnsberg, Germany Actual Inventor(s): Otto Meyer Frank Westermann Stefan Honerkamp Andreas Rehburg Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Electronic ballast with interface device The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(3571798_1) 1 10 Electronic.ballast with interface device The invention relates to an electronic ballast for operating a lamp, the ballast comprising an interface 15 device including on the input side thereof a connecting means for receiving externally supplied brightness control information in the form of external control signals, and comprising a control device which is connected to the said interface device for receiving externally supplied 20 brightness control information and is designed for controlling the brightness of the lamp in dependence of the received brightness control information. The invention also relates to a process for operating such a ballast. 25 Such electronic ballasts (EB) are particularly suitable for the operation of gas discharge lamps, high pressure discharge lamps or light emitting diodes (LED), and due to the provision of the interface device, these ballasts are flexible in use. By the fact that they are configured for 30 receiving external control signals that can be produced by switches or key switches as well as for receiving external digital control signals, such EBs can be used as a self- 2 contained light controller and also as a ballast being a single component of a light technical system for operating one more lamps. In the first-mentioned use, the brightness control information is formally genierated by iieans of a switch 6r a key switch and is transmitted to the EB; in the second-mentioned use, the EB can receive 5 digital control signals, for instance from a central system control unit, particularly signals according to the DALI standard (digital addressable lighting interface), and control the brightness of the lamp in dependence of this brightness control information. A known EB of this kind is described for example in German patent application DE 197 1o 57 295 Al. In the known EB, the interface device is designed for supplying both control signals produced by a switch or a key switch and digital control signals as brightness control information to the same terminals of the control device. But this increases the demands concerning the functionality of the employed control devices of the EB, and even an increased functionality of the control device cannot guarantee in any case that 15 the respective control signal is correctly assigned and processed within the control device. Thus, a need exists to remove some of the existing drawbacks of conventional electronic ballasts. 20 SUMMARY According to an aspect of the present disclosure, there is provided an electronic ballast for operating a lamp, the ballast comprising: an interface device including on the input side thereof a connecting means for 25 receiving externally supplied brightness control information in the form of external control signals; and a control device which is connected to the said interface device for receiving brightness control information and which is designed for controlling the brightness of the lamp in dependence of the received brightness control information, wherein the interface device includes a first signal path for passing brightness 30 control information that is attached to external digital control signals to a first input signal terminal of the control device, and a second signal path that is different from the first signal part at least in sections, for passing brightness control information attached to control signals which are formed as switching signals to a signal terminal of the control device different from the first signal terminal, and that the interface device includes a 3s means for identifying the control signal structure of an externally supplied control signal 3 and for opening the signal path which is assigned to the identified signal structure, or for blocking a signal path which is not assigned to the identified signal structure, or both for opening the signal path which is assigned -t-Me id-ntifiedsig-Ne structure and for blocking a signal path which is not assigned to the identified signal structure. 5 According to another aspect of the present disclosure, there is provided a process for operating an electronic ballast for operating a lamp, the ballast comprising: an interface device receiving on its input side externally supplied brightness control information in the form of external control signals; and a control device to which brightness control information is transmitted and which controls the brightness of the 10 lamp in dependence of the received brightness control information, the process comprising: receiving at the control device a first signal input terminal thereof brightness control information attached to external digital control signals via a first signal path of the interface device for processing, and 15 receiving at the control device a second input terminal thereof brightness control information via a second signal path of the interface device for processing, wherein said brightness control information being attached to external control signals formed as switching signals, wherein within the interface device the signal structure of the available external 20 control signal is identified and the signal path assigned to this signal structure is opened or a signal path that is not assigned to the identified signal structure is blocked in dependence of the identified signal structure or the signal path assigned to this signal structure is opened and the signal path that is not assigned to the identified signal structure is blocked. 25 OTHER DISCLOSURE With the described construction of the EB according to the invention it is achieved on one side that the received external control signal that is attached to brightness control information, i.e. constitutes such information, is applied to an associated input port of the 30 control device and that thereafter processing of the attached control information can be performed based on the knowledge of the signal structure of the available control signal. Control signals having a particular signal structure are thus supplied to the associated input port of the control device, so that the control device needs not be configured for the differentiation of the various signal structures. The interface device includes means for 35 identifying the various control signal structures of the externally 4 su-pplied control signal, because -one- signa-l--structure-is assigned to a respective particular signal path within the interface device. After the signal structure has been identified, the respective control signal can be 5 transmitted in a targeted manner to the assigned, predetermined signal path and can thus be supplied to the associated, predetermined input signal terminal of the control device. 10 It should be noted that the interface device of the EB according to the invention is not limited to two signal paths for external control signals which are each assigned to one signal structure. Additional signal paths of this kind for the differentiation of various structures of 15 external control signals can be also comprised, in which case the control device may have control inputs in a number corresponding to the number of signal paths. The attachment of brightness control information to the 20 respective external control signals can be implemented for instance by this control information being encoded in a predetermined manner in the associated external control signal. In a corresponding manner, the attached brightness control information can be decoded from such a control 25 signal or the control information can be derived from the control signal. Preferably, the brightness control information content of the signal is fully preserved while the signal is carried on the assigned, i.e. associated signal path within the interface device, but it also 30 possible to perform for instance a conversion of the signal on this signal path.

5 It is particularly useful for the input-side terminal device of the interface device to be designed as a dual wire connection for receiving externally supplied 5 brightness control information, i.e. for receiving the externally supplied control signal, which simplifies the connection to the external signal supply. In this connection, it is particularly useful if both the control signals generated by a switch or a key switch and the 10 digital control signals can be applied to the EB via the same input terminals of the connecting device, particularly via said dual wire connection. Normally, the control signals generated by a switch or key switch and thus designed as switching signals or the digital signals are .15 applied to the dual wire connection, depending on whether the EB according to the invention is employed for instance as a self-contained light controller or as a component within a light-technical system. 20 The control signal received from the interface device is examined for its structure within the device and is allocated to one of the possible structures. To this end, the interface device includes the said means for identifying the control signal structure of the externally 25 supplied control signal. This means is suitable for detecting and differentiating a generally arbitrary parameter of the signal, for instance the frequency behavior and/or the amplitude of the signal. In this respect, it can be useful for the means for identifying the 30 control signal structure of the externally supplied control signal and for enabling the signal path that is assigned to 6 the identified signal structure to include an ar-ra-ngement-- for threshold detection with an associated switch, a micro controller arrangement for signal evaluation with a switch device associated to and controlled by this arrangement 5 and/or a frequency crossover, whereby the control signal can be passed to the corresponding input signal terminal of the control means via the assigned signal path. In a particularly inexpensive embodiment, the means for 10 identifying the control signal structure of the externally supplied control signal and for opening the signal path assigned to the control signal can comprise a Zener diode which becomes conductive if a predetermined threshold voltage exists. Such an embodiment is particularly useful 15 if the control signal structures to be differentiated particularly differ in their voltage amplitude so that, if a Zener diode is provided, it can be determined that the corresponding signal path is opened if the existing voltage exceeds the threshold voltage of the Zener diode. Such a 20 signal path including a Zener diode remains blocked to a control signal structure having a low voltage amplitude or to a control signal having such a signal structure. For opening the respective signal path that has been 25 assigned to the identified signal structure, the interface device can comprise at least one switch that connects the respective signal path to the associated input port of the control device. As with the described example of the Zener diode, such a switch can be self-controlled. But it is also 30 possible to use a switch having a control input, said switch being controllable particularly through the 7 -external control -input signal of the interface._device _ -r. through a signal derived from this control input signal. It is particularly useful to provide at least one switch 5 for each of the first and second signal paths, both switches being non-conducting in the passive state, particularly after initializing the operation of the ballast. This guarantees that no signal path is opened prior to the identification of the signal structure, which 10 in turn guarantees that an external control signal is not unintentionally applied to the wrong control signal input of the.control device. To avoid such misrouting of the external control signal via 15 a signal path which is not assigned to this signal or to its signal structure and hence the transmission to a control signal input of the control device which is not assigned to this signal, it can be further advantageous if a switch of a signal path can be selected via a delay 20 element, especially if time-variable control signals such as a key switch signal having a modulation of e.g. 50 Hz, 60 Hz or 100 Hz exists, wherein the external control signal or a signal derived from this external control signal is most expediently available at the delay element. This 25 avoids short-term misrouting which otherwise occurs of the external control signal or of the control information attached to this signal, thus preventing misinterpretation in the control device. With this embodiment, the delay element can be an RC member, the capacitor being charged 30 through the applied external control signal or through a signal derived from the external control signal and the 8 vl6tage Ycfoss ~the capacitor being used as-a- switching - voltage for opening a signal path. To avoid an undesired state at the input signal terminal of 5 the control device, it can be expedient for the ballast according to the invention to be designed in such a manner that after opening one of the two signal paths the other signal path is automatically blocked. 10 Advantageously, it can be provided that at least one of the signal paths in the interface device comprises electronic components for the conversion of the control signal carried on this signal path. An optocoupler and/or a DC/DC converter can be provided for instance for galvanic 15 uncoupling. Moreover, it is also possible to use signal conversion components such as an A/D converter or a U/f converter with subsequent digitalization in one of the signal paths, so that for instance an analogous key switch signal which is received from the interface device and 20 which, due to its signal structure, is allocated and supplied to one of the two signal paths in the interface device and thus to a particular input signal terminal of the interface device, is converted into a digital signal during its signal transmission through the interface 25 device, but still corresponds to the key switch signal of the switch concerning its control information. In this manner it is possible for example that both input signal terminals are arranged at the control device for receiving control signals, the digitalized control signal being 30 applied to the second input signal terminal of the control device via the second signal path. Such a conversion 9 - -enables the external -signals to be adapted -to -the respective control device. Preferably, within the scope of the invention, the switches 5 which are used can be semi-conductor switches such as transistors. On part of the process, the invention achieves the object by a process for operating an electronic ballast for 10 driving a lamp, said ballast comprising an interface device receiving on the input side externally supplied brightness control information in the form of control signals, and comprising a control device to which the brightness control information is transmitted and which controls the 15 brightness of the lamp in dependence of the received control information. The process according to the invention is characterized in that the control device receives at a first input signal terminal brightness control information that is attached to external digital control signals via a 20 first signal path of the interfaces device for processing, and further receives at a second input signal terminal brightness control information attached to control signals formed as external switching signals via a second signal path of the interface device for processing, wherein in the 25 interface device the signal structure of an external control signal is identified and the signal path allocated to this signal structure is openend and/or a signal path that is not allocated to this signal structure is blocked in dependence of the identified signal structure. 30 10 As far as in the---present application--the expression "control signal via a first signal path" is used, this is understood to mean not only the original external digital control signal received from the interface device but also 5 a signal which is derived or converted from this external digital control signal. Such a conversion can be performed for example via an A/D converter, D/A converter, DC/DC converter and/or an optocoupler. In the same manner, the expression "control signal via a second signal path" not 10 only describes the control signal that is formed as a switching signal and is received at the input side of the interface device but also a control signal that is possibly derived from this signal while being transmitted via the second signal path, said control signal being passed to the 15 associated second input signal terminal of the control device via the second signal path. Moreover, it should be noted that the terms "first" or "second" used in this context merely serve the purpose of differentiation and shall not be understood as any limitation concerning the 20 order or the like. In the following, several embodiments and further features of the invention will be described with reference to the attached drawings wherein it is shown by: .25 Figure la a schematic diagram of the electronic ballast designed in accordance with the invention; 30 Figure lb a schematic diagram symbolizing two different external control signals; 11 Figure 2 a detailed view of an interface device and a micro controller connected to it of one embodiment of an electronic ballast in 5 accordance with the invention; Figure 3 a detailed view of an interface device and a micro controller connected to it of another embodiment of an electronic ballast in 10 accordance with the invention. Figure la shows a schematic diagram of an electronic ballast 1 designed in accordance with the invention. In this schematic diagram, the electronic ballast includes a 15 mains-operated rectifier 10 that converts the mains voltage into a rectified intermediate circuit voltage and delivers this voltage to an alternating-current converter 20. The alternating-current converter 20 can be designed for example as a half bridge with two switches connected in .20 series between a positive supply voltage and the ground. The switches can be alternately selected via the control device 30 designed as a micro controller,- for opening and closing via the control line S. The load circle connected to the alternating-current converter 20 includes a 25 discharge lamp 40 through which a lamp current iL flows after the ignition process. For the sake of clarity, possible additional components comprised by the EB, e.g an ignition device or a preheating device, are omitted from the schematic diagram, since these devices are known to a 30 person skilled in the art and need not be separately explained. The same applies especially to possible 12 additional -measuring devices, e.g. for detecting -the lamp current and/or lamp voltage, the signals from these devices being used by the micro controller 30 for operating the lamp. 5 Essential for the present invention is the transmission of external brightness control information via an interface device 50 to the micro controller 30. To this end, the interface device 50 includes an input port 51 that is 10 designed as a dual wire connection in the described embodiment and comprises terminals 51a, 51b. In an embodiment which is not illustrated, an input port can be provided with more than two terminals. According to the invention, the interface device 50 is configured in such a 15 manner that to the input port 51 brightness control information both in the form of control signals that are generated through a switch or a key switch and in the form of external digital control signals can be applied. 20 Figure lb shows a schematic diagram symbolizing two examples for the provision of such external control signals that can be applied to the port 51. In the example shown to the left, external control signals 25 are generated by means of a switch 60 that is connected to the mains voltage N, L, i.e. for the duration of the closing operation of the switch 60 a sinusoidal mains current is delivered. In a different embodiment, a key switch can be employed instead of a switch, and the key 30 switch or the switch are capable of switching a different voltage such as a constant voltage for example. In the EB 13 according to the invention, the external control signal thus produced is normally used in cases where the EB is employed as a self-contained light control device. The supplied external control signals are interpreted by the 5 micro controller 30 as brightness control information, e.g. for turning the lamp on or off and also for dimming the lamp. In Figure lb, to the right, the application of an external 10 control signal in the form of a DALI (digitally addressable lighting interface) signal is symbolized, through which the micro controller 30 receives control information for instance from a central light control system in cases where the EB is integrated as a single component in a light 15 technical system. These DALI signals can comprise for example the information for turning on or dimming the lamp or lamps connected to the EB. The interface device 50 of the EB 10 according to the 20 invention is configured in such a manner that the control information attached to the external digital control signals is supplied to an input port 31 having corresponding input signal terminals 31a, b and the control information attached to the external switching signals is 25 supplied to a different input port having different input signal terminals 32a, b of the control device 30. To this end, the interface device 50 comprises a first signal path for supplying control information attached to the external digital signals from the input port 51 to a first output 30 port 52 having output terminals 52a, b, and further comprises a second signal path for supplying control 14 -information attached to the external switching signals from the input port 51 to a second output port 53 having output terminals 53a, b. Each of these output ports 52, 53 is connected to an associated input port or input terminal 31, 5 32 of the micro controller. This guarantees that control information which corresponds to the external digital control signals is available for further processing at said one input port 31, and that control information which is attached to the external switching signals, i.e. which 10 corresponds to the external switching signals, is available at the other input signal port 32 of the micro controller 30. To provide for a separation of the various control signals 15 within the interface device 50, the interface device comprises in the illustrated embodiment a means for identifying the control signal structure of the externally supplied control signal and for opening one of the two signal paths that is assigned to the identified control 20 signal structure. Corresponding embodiments will be described in the following with reference to the Figures 2 and 3 which for reasons of clarity illustrate the EB according to the invention in a detailed view in which only the micro controller 30 and the interface device 50, 50' 25 are shown. In this connection it is assumed that the external control signals that have been described with reference to Figure lb can be available at the input port 51 of the interface 30 device 50, which signals represent brightness control information for the micro controller 30. First of all it 15 shall be assumed with -reference to the embodiment according to Figure 2, that the EB is integrated in a light-t:echnical system and that a digital DALI signal is accordingly available at the input port 51 having the input terminals 5 51a, 51b. This signal passes the bridge rectifier 70 that serves to prevent mispoling and passes via the self conducting MOSFET transistor 71, the photodiode of the optocoupler 72, the Zener diode 73 and the resistor 74. The signal attached to the external DALI signal passes via the 10 photo transistor of the optocoupler 72 after being subject to signal matching that is implemented by the two resistors 75, 76, the transistor 77 and the diode 78 to the associated input port 31 of the micro controller 30. The described signal progression corresponds to the signal path .15 within the interface device 50 carrying the control signal which corresponds to the external digital control signal which is available at the input port 51. The Zener diode 80 is configured in such a manner that its threshold voltage is higher than the maximum voltage amplitude of the digital 20 signal available at the input port 51, so that the diode blocks the other signal path for control signals. In the described example, the threshold voltage of the Zener diode amounts to 24V. 25 However, if the switch signal described above with reference to Figure lb is available at the input port with a sequence of 50 Hz mains oscillations, this signal is rectified via the component 70 and opens the second signal path on reaching the threshold voltage at the Zener diode 30 80, which second signal path continues via the resistor 81, the photodiode of the optocoupler 82 and the resistor 74.

16 The signal attached to the external control signal passes via the photo transistor of the optocoupler 82 to the input port 32 of the micro controller 30. The control information that is attached to the external control signal and that is 5 available at the input port 51 of the interface device 50 is thus transmitted to the associated input port 32 of the controller. To avoid that the available external control signal passes 10 to a signal at the input port 31 of the micro controller, the transistor 29 is switched conducting with opening the second signal path, whereby the transistor 71 is cut off so that the first-described signal path is interrupted. If the external control signal exhibits a sequence of rectangular 15 voltage pulses having an amplitude which is higher than the threshold voltage of the Zener diode 80, it is guaranteed at any point of time that only a respective one of two described signal paths is open to the input port 32 or to the input port 31. 20 To guarantee simultaneous opening of both signal paths even in such cases in which the external control signal is formed as a switching signal with a sequence of especially sinusoidal voltage pulses, the embodiment of an EB 25 according to the invention as illustrated in Figure 3 can be used. For reasons of clarity, also Figure 3 only shows the components micro controller 30 and interface device 50'. Components in Figure 3 which are similar to components in Figure 2 are identified by the same reference numbers. 30 .17 The' essential difference between the- interface device -50 according to Figure 2 and 50' according to Figure 3 is that instead of a self-conducting transistor 71 a self-blocking transistor 90 is arranged in the current path which carries 5 the signal that is attached to the external digital control signal. This transistor 90 is switched by a delay element arranged parallel to the input port 51 and comprising the resistor 92, the diode 93 as well as the integrator capacitor 94 which is capable of making the self-blocking 10 transistor 90 conducting after corresponding charging. If at the input port 51 of the interface device 50', at the terminals 51a, b thereof, a digital signal is available with a voltage amplitude lower than the threshold voltage of the Zener diode 80, both signal paths of the interface 15 device 50 are initially blocked. The signal path for the signal that is attached to a switching signal again runs via the components 70, 80, 81, 82 and 74, 79 or from the optocoupler 82 to the associated input signal port 32 of the micro controller 30. Here, the latter designates the 20 relevant signal path to the micro controller for the brightness control information that is attached to the external switching signals. In the micro controller, the input signal received at the port 32 is transmitted via corresponding components to the reference ground. The 25 signal path for the signal that is attached to an external digital control signal runs via the components 70, 90, 72, 73 and 74 or from the photo transistor of the optocoupler 72 via the level matching implemented by the components 75 78 to the first input port 31 of the micro controller 30. 30 The latter designates the here relevant signal path to the micro controller for brightness control information that is 18 attached to the external control signals. In this case, too the signal available at the first input port 31 is internally passed to the reference ground via corresponding components within the controller. 5 If an external digital control signal, for example a DALI signal, is applied to the input port 51 of the interface device 50', both signal paths are blocked initially with regard to the above explanation. The Zener diode 80 blocks 10 because the input voltage is lower than the threshold voltage. The self-conducting switch is cut off, since there is initially no voltage across capacitor Cl. Independently of whether the available digital control signal has a monopolar or bipolar structure, the bridge rectifier 70 15 delivers an average positive voltage with which the capacitor Cl is charged. After a voltage is achieved at the capacitor which is sufficient for triggering the transistor 90 to become conducting, the signal path for the digital signal is enabled, i.e. open and is thus available at the .20 input port 31 of the micro controller 30. The time duration which is necessary for through-connecting the self-blocking transistor 90 is dependent of the time constant of the RC member and of the structure of the digital signal itself. Even in the embodiment illustrated in Figure 3 and as 25 explained with reference to Figure 2, the threshold of the Zener diode 80 is set in such a manner that if an external digital signal is applied to the input port 51, said threshold cannot be achieved and the signal path assigned to a switching signal is accordingly not open. 30 19 On the other hand, if the EB is used as an independent device, the control signals input in the EB at its input port 51 are switching signals. If these switching signals are generated by switching the mains voltage, as described 5 with reference to Figure 1b, a mains pulse sequence with a frequency of 50 Hz is available at the input port 51. This pulse sequence is rectified by means of the bridge 70. As long as the voltage at the Zener diode 80 is lower than the threshold voltage of 24 V, the associated signal path is 10 blocked. During this time, the capacitor 94 is charged via the resistor 92 and the diode 93. To avoid that the capacitor 94 is charged for through-connecting the self blocking switch 90 if brightness control information in the form of an external switching signal is available at port 15 51, the time constant of the delay element is correspondingly set. It is determined by the resistor 92 and the capacitance 94 and is adjusted in such a manner that the switch 90 cannot become conducting before the threshold voltage of the Zener diode 80 is reached and the 20 signal path for the signal attached to the external control signal is open. Due to current flowing through the resistor 74, the transistor 79 becomes conducting and thus discharges the capacitor 94, so that the transistor 90 cannot become conducting. It is guaranteed in the described 25 manner that the switch 90 remains in any case cut-off if the described external switching signal is available at the input port 51. It can thus be achieved that a signal is available at no time at the input port 31 of the micro controller, thus avoiding indefinite conditions in the 30 controller.

20 According to embodiments which are not illustrated, also other signal forms can be provided in both signal paths. For example, in the signal path that comprises the optocoupler 82 also an A/D converter can be provided so that in this case the input port 32 of the micro controller 30 is designed for processing digital signals. 5 The foregoing describes only some embodiments of the present invention, and modifications and/or changes can be made thereto without departing from the scope and spirit of the invention the embodiments being illustrated and not restrictive.

21 Electronic ballast-with interface device List of refernce numbers 5 1 electronic ballast EB 10 rectifier 20 alternating-current inverter 30 micro controller 31 first input port of micro controller / input 10 terminal 31a, 31b input signal terminals of first input port 32 second input port of micro controller / input terminal 32a, 32b input terminal / input signal terminal of second 15 input port 40 discharge lamp / lamp 50 interface device 50' interface device 51 input port of interface device 20 51a, 51b input signal terminals of interface device 52 first output port 52a output terminal 52b output terminal 53 second output port 25 53a output terminal 53b output terminal 60 switch 70 bridge rectifier 71 self-conducting transistor 30 72 optocoupler 73 Zener diode 22 74 resistor 75 resistor 76 resistor 77 transistor 5 78 Zener diode 79 transistor 80 Zener diode 81 resistor 82 optocoupler 10 90 self-blocking transistor 91 resistor 92 resistor 93 diode 94 capacitor 15 iL lamp voltage (N, L) mains voltage S control line

Claims

1. An electronic ballast for operating a lamp, the ballast comprising: an interface device including on the input side thereof a connecting means for 5 receiving externally supplied brightness control information in the form of external control signals; and a control device which is connected to the said interface device for receiving brightness control information and which is designed for controlling the brightness of the lamp in dependence of the received brightness control information, 10 wherein the interface device includes a first signal path for passing brightness control information that is attached to external digital control signals to a first input signal terminal of the control device, and a second signal path that is different from the first signal part at least in sections, for passing brightness control information attached to control signals which are formed as switching signals to a signal terminal of the control is device different from the first signal terminal, and wherein the interface device includes a means for identifying the control signal structure of an externally supplied control signal and for opening the signal path which is assigned to the identified signal structure, or for blocking a signal path which is not assigned to the identified signal structure, or both for opening the signal path which is assigned to the identified signal structure and for 20 blocking a signal path which is not assigned to the identified signal structure.

2. The electronic ballast according to claim 1, wherein the input-side terminal of the interface device for receiving externally supplied brightness control information is designed as a dual-wire connection. 25

3. The electronic ballast according to either claim 1 or 2, wherein the means for identifying the signal structure of the externally supplied control signal and for opening or blocking a signal path comprises a device selected from the group of devices consisting of: 30 a device for threshold detection with an associated switch; a micro controller device for signal evaluation with an associated switch means controlled by the micro controller device; a frequency crossover; and any combination of the foregoing devices. 35 24

4. The electronic ballast according to claim 3 wherein the means for identifying the signal structure of the externally supplied control signal and for opening of the signal path assigned to the control signal comprises a Zener diode which becomes conducting if a 5 threshold voltage is achieved.

5. The electronic ballast according to any one of the claims 1 to 4, wherein the interface device comprises at least one switch connecting the respective signal path with the associated input terminal of the control device. 10

6. The electronic ballast according to any one of the claims 1 to 5, wherein a switch of a signal path is controlled through the external control signal of the interface device. 1s

7. The electronic ballast according to either claim 5 or 6, wherein at least one switch is provided for each of the first and second signal paths, both switches being in a non-conducting state after the initialization of the operation of the ballast.

8. The electronic ballast according to any one of the claims 5 to 7, wherein a 20 switch is controllable through a delay element at which the external control signal is available.

9. The electronic ballast according to any one of the claims 4 to 7, wherein after opening one of the two signal paths the other one of the signal paths can be blocked. 25

10. The electronic ballast according to any one of the claims 1 to 9, wherein at least one of the signal paths comprising electronic components for the conversion of the external control signal. 30

11. A process for operating an electronic ballast for operating a lamp, the ballast comprising: an interface device receiving on its input side externally supplied brightness control information in the form of external control signals; and 25 a control device to which brightness control information is transmitted and which controls the brightness of the lamp in dependence of the received brightness control information, the process comprising: 5 receiving by the control device at a first signal input terminal thereof brightness control information attached to external digital control signals via a first signal path of the interface device for processing, and receiving by the control device at a second input terminal thereof brightness control information via a second signal path of the interface device for processing, i wherein said brightness control information being attached to external control signals formed as switching signals, further wherein within the interface device the signal structure of the available external control signal is identified and the signal path assigned to the signal structure is opened, or is a signal path that is not assigned to the identified signal structure is blocked in dependence of the identified signal structure, or a signal path assigned to the signal structure is opened and a signal path that is not assigned to the identified signal structure is blocked in dependence of the identified signal structure. 20

12. The process according to claim 11, wherein both signal paths are blocked prior to the identification of the signal structure of the external control signals.

13. The process according to either claim 11 or 12, wherein the identification of the 25 control signal structure of the externally supplied control signal is performed by means of threshold detection, signal evaluation within a micro controller device, frequency separation, or a combination of any one of the foregoing means.

14. The process according to any one of the claims 11 to 13, wherein the signal 30 path is opened by selecting a switch, said switch being closed in a self-controlled manner by the external control signal.

15. The process according to any one of the claims 11 to 14, wherein after opening one signal path the other one of the two signal parts is automatically blocked. 35 26

16. The process according to any one of the claims 11 to 15, wherein one of the two signal paths is open time-delayed. 5 DATED this Eighth Day of April, 2011 BAG electronics GmbH Patent Attorneys for the Applicant SPRUSON & FERGUSON