DE10121380A1 - Monitoring of LED type displays to ensure they are operating correctly, e.g. for signal displays used with railway switching and control, by monitoring the current drawn by individual display units and the whole unit - Google Patents

Abstract

An electronically protected power supply to a circuit assemblies (21-25) and sequential comparators (31-35) in which a supply current (IR) is monitored to determine if it falls below or above threshold values. An overall comparator (4) is provided to determine if the total current exceeds or falls below reference thresholds. Dependent on the individual and group comparisons corresponding result values ER and EG are generated. According to their valves power supply can be reduced or increased. The invention also relates to a corresponding display for display of time-varying information made up of an array of LEDs.

Description

The invention relates to an electronically protected circuit group power supply according to claim 1 and a display device for changing information according to the preamble of claim 12, in particular for use in a system for ver Traffic regulation, control, or monitoring for vehicles, for example in a ver traffic traffic light.

For display devices that are used in safety-relevant and critical applications Secure operation and defined failure are of great importance. Such a safety-critical application is, for example, in the case of lamps in the signal traffic systems - here are traffic lights in traffic and signals in rail traffic called - or given with system monitoring equipment (indicator lights). Here, more and more come in parallel or in place of incandescent or gas discharge lamps Series connected light emitting diodes (LEDs) are used. The still curling towards incandescent lamps Lower luminosity is compensated for by the operation of several LEDs. The LEDs have here in addition to a lower power loss, it also has the advantage of being significantly higher Reliability and durability.

Such a display device designed for the longest possible service life placed and tested, however, like all other lighting devices, is subject to failures that can lead to impairment of the use of the display device. Especially here particularly relevant cases in which the display device to prevent damage on people or vehicles or objects, i.e. used as a safety signal, there must be a monitoring device assigned to the display device, which recognize a defect in the display device and corresponding immediate Measures should activate.

A malfunction of the LEDs and thus the display device must be caused by a (for glow lamps) standardized control device or function monitoring device that can. These control units are designed so that they burn out an incandescent lamp can recognize with certainty.  

The monitoring of incandescent lamp arrangements is simple in terms of circuitry and therefore also mostly kept simple: incandescent lamps only have the two operating states intact (Filament in order) and defective (filament burned out), but no intermediary would be in the characteristics of a display device based on incandescent lamps. Therefore their monitoring devices (control units) are extremely simple in terms of circuitry and are essentially limited to determining a binary yes-no state. For example, widely used in traffic lights with incandescent lamp signals dete, structurally and circuit-wise extremely simple monitoring device lines are, however, in such display devices in which the lighting elements through Semiconductor components are formed, so far not usable.

A malfunction of an LED differs from that of an incandescent lamp. a. as a result of that instead of an interrupted current flow through the LED, there is also an increased current flow can kick. In the case of strongly aged LEDs, the light yield also increases with increasing Be number of operating hours. Thus, with a display made up of many individual LEDs device failure of several LEDs remain undetected. The reliable detection of mistakes function is no longer guaranteed by the standardized control units.

As is well known, one has trained in semiconductor components compared to those in incandescent lamps expanded light fields in addition to a more homogeneous one over the entire surface and thus also farther away clearer recognition above all the advantage that very many de perfect LEDs lead to a noticeable loss of information. By a suitable one Wiring of the light emitting diodes and formation of the circuit controlling this can even Several defects in the light emitting diodes prevent a decrease in the overall light intensity the. Thanks to the decentralized arrangement of the rows of LEDs connected in groups it can also be avoided that partial areas of the illuminated field become dark. It can For example, each individual row of LEDs is individually monitored for failure, and if a certain limit is exceeded, for example if more than 20% are defective LEDs completely switch off the display device via an automatic shutdown become.

Therefore, in a generic display device with multiple lighting elements, the lighting elements by semiconductor components and in particular by light diodes who are trained, additional design and circuitry for one Monitoring device necessary.  

The failure characteristics of previously known display devices with semiconductor components ten as lighting elements is much more complex than a simple failure character ristics of incandescent lamp arrangements. With the well-known, existing on-site and simple Monitoring options can be held without a special, substantial scarf effort, not conclusively concluded on the lighting status of one of the LEDs become. Because the control required for the function of LEDs, the light circuit itself as well as any other modules or modules of the monitoring direction inevitably also have their own power consumption, which is undefi in the event of a defect is niert and can generate a current flow that interpre as (proper) glow can be tiert, although one or more LEDs have already failed. At be certain applications, such as traffic lights in particular, it is also necessary ensure that a minimum radiation intensity and a minimum uniformity of the Illuminated field are maintained. However, the current flow changes are usually relatively small, so that the residual light intensity and the uniformity of the illuminated field below Not exactly determined under certain circumstances and thus possibly not a safety shutdown can be carried out reliably.

The known display devices based on semiconductor components are taken into account usually only so-called high-resistance failures, in which the defective semiconductor construction element becomes high-resistance, d. H. the current flowing through the defective semiconductor component becomes zero. Low-resistance failures in which the resistance value of the defective semiconductor component becomes zero, are usually compared with known display devices relaxed, since these are less common in relation to high-resistance failures. Nevertheless, it is desirable, also the less common low-resistance failures of semiconductor devices can also be considered to ensure the safety of the An pointing device continues to improve.

From DE-OS 29 25 692 a light emission diode display device has become known the one in which a light emission diode field is supplied with a current stabilizing circuit, which diode array in a parallel connection of individual series connections from Light emission diodes, which series circuits each have a current limiting component included in the form of an ohmic resistor.

The object of the invention is an electronically protected circuit group current Supply and a display device for changing information available to provide reliable detection of partial or total failures of the circuit group Power supply and especially the LEDs grouped in circuit groups  ensures, which in particular in a plant for traffic regulation, control, or - Monitoring for vehicles, for example a traffic light in connection with the there, conventional, structurally simpler monitoring devices for detection a total failure of the display device can be used, d. H. the display Direction according to the invention should have a failure characteristic that largely the off case characteristics of incandescent lamp arrangements.

The problem is solved with the features of claim 1 and the character nenden features of claim 12.

According to the invention it is provided that an electronically protected circuit group power supply is assigned at least two circuit groups connected in parallel, the total current NI _{R of} which is composed of the individual currents I _R during operation, is combined at a point V (N corresponds to the number of circuit groups), each assigned to a circuit group Series comparators which, when the current I _Rmax through the circuit group or the voltage across the circuit group exceed or fall below, deliver a result value E _R with respect to a preset value, with a total comparator which exceeds or falls below a normal value below the composite total current NI _R at point V with respect to a preset value NI _Rnom delivers a result value E _{G which is} different from a normal value, with a result _{monitoring device} which monitors the results E _R and E _G , whereby at a result value E _G , E _R which is different from the normal value and which switches the circuit groups with current or voltage source supplying current on or off.

The series comparators in particular ensure that a low-resistance fault lfall in a circuit group (for example in the case of a series connection of lights diodes as a circuit group or in the case of heating elements as a circuit group, the not individually over a certain temperature - by means of the flowing through them owing current - may) be reliably recognized, this may result in a Circuit groups harmful overload - and associated risks such as over heating or destruction of the circuit groups - prevented.

The current or voltage source is particularly connected to an energy store, which feeds the energy store with a charging current I _L. This enables energy to be temporarily stored to supply the circuit groups.

According to a further advantageous embodiment of the invention, the energy store is made of formed a capacitor.

The circuit groups are preferably permanently connected to the energy store the, whereby these are supplied with electricity by the energy store. Is an advantage this means that the circuit groups even when the current or voltage source is switched off are supplied with electricity from the energy store.

The charging current I _L is particularly advantageously chosen so large that after the energy store has been charged and the current I _{R has} subsequently risen in the circuit groups connected to the energy store, the overall comparator by exceeding the preset combined total current NI _{Rnom is} the current or Turns off the voltage source by supplying a result value E _G that differs from the normal value by means of the result monitoring device. This ensures that the energy storage device is first discharged and that the current does not rise above a harmful level. After the energy store is discharged, the current I _R flowing out into the circuit groups drops again, as a result of which the individual currents fall below the value I _Rnom - and the total current thus falls below the value NI _Rnom -, which has the consequence that the result _values E _G assumes its normal value and the power source is switched on again to charge the energy store. Another very great advantage in this arrangement is that an error in the series comparators, the overall comparator and the result monitoring device can be reliably detected, since constantly changing states are assumed. A static behavior of a module would result in the power source being permanently switched on or off, which enables reliable error detection.

According to a particularly preferred embodiment of the invention, the series comparators assigned to a circuit group are set such that when the maximum current I _Rmax in a circuit group is exceeded, the current or voltage source is switched on by supplying a result value E _R that differs from the normal value by means of the result monitoring device hold. As a result, the current I _R is no longer reduced by the circuit groups. The advantage here is that an occasionally dangerous (fire hazard) or difficult to detect low-resistance fault can be reliably detected, since an interval-like switching on and off, which would otherwise be continued by the overall comparator, would not be ended, since the overall comparator only the total current recognizes all circuit groups. This enables reliable fault detection of a low-resistance fault in a circuit group.

The charging current I _L is advantageously greater than the total current NI _R defined via the preset value.

A further particularly preferred embodiment of the invention provides that a slow- _{moving fuse element} is provided that disconnects all circuit groups and / or the current or voltage source from the power supply if a maximum permissible current value I _{Smax has been reached} by the current or voltage source , The advantage here is in particular that in the event of errors in the series comparators, the overall comparator and the result monitoring device, which, as said, would result in a static behavior, which would have the power source permanently switched on, the entire arrangement is switched off by switching off the current - Or voltage source through the fuse element. In the event of a "permanently connected power supply" fault, the current would therefore become zero, as in the "permanently switched on power supply" fault case. I.e. all circuit groups are deactivated in quick succession. Even the low-resistance fault, which leads to the sharp rise in a single current I _R and thus to the switched-on supply of the current or voltage source through the associated series comparator, can thus be reliably recognized from the outside. In this way, the circuit group power supply according to the invention has a failure characteristic that is comparable to a failure characteristic known in the case of incandescent lamps. Of particular advantage, the circuit group power supply according to the invention with this assigned circuit groups can therefore be used in an environment in which yes-no monitoring - in the sense of defective / not defective - the operability as the sole monitoring means is possible or provided, that is to say simple without there are other constructive or circuit-technical measures and monitoring devices that use expenditure. Accordingly, the fuse element can be formed by a simple fuse with a predetermined breakdown current value.

The result monitoring device is advantageously a linking device which links the result values E _G , E _{R to} one another, the result values also being digital and the linking device being an OR gate.

A particularly preferred embodiment of the invention provides that the circuit group are LED rows, the individual LEDs of which are connected in series.  

Advantageously, the circuit groups form a light emission element, which in a a further advantageous embodiment of the invention is a display element, in particular a Signal indicator.

The series comparators, the overall comparator, the circuit groups, the result monitoring device, the energy store and the current or voltage source structurally a unit advantageously form a unit structurally. This enables the light emission unit or the circuit groups together with the circuit group Power supply as a unit, for example in the form of a light bulb replacing one Unit can be replaced.

Another aspect of the invention relates to a display device for changing information, the information being represented by the selection or combination of individual light-emitting elements arranged on a carrier, the light-emitting elements being formed by semiconductor components, in particular comprising light-emitting diodes or other integrated semiconductor circuits Components for light emission, and the semiconductor devices are connected in several circuit groups, and each circuit group forms a secondary branch of a main branch. In this case, a control circuit device assigned to the circuit groups is provided which, when a partial current I _R flowing in a secondary branch is exceeded or undershot, in particular by a predetermined current threshold value, controls blocking or deactivation of the main branch and thus all circuit groups in immediate succession, and that the control circuit device when the current flowing in the main branch NI _{R is} exceeded or undershot, in particular in particular by a predetermined current threshold value, in immediate succession a blocking or deactivation of the main branch and thus all circuit groups and / or if the current flowing in the main branch is undershot, in particular by a predetermined current threshold, controls the activation of the main branch and thus all circuit groups in immediate succession.

The circuit groups are advantageously formed by at least one lighting element.

The light-emitting elements are advantageously made of semiconductor components, in particular LEDs, or other integrated semiconductor circuits with components for Light emission trained.

A particularly preferred embodiment of the invention provides that the control circuit device each has a series comparator assigned to a circuit group, which in each case has a result value E different from a normal value when the current I _R through the circuit group exceeds or falls below the preset value I _{Rmax R} deliver.

A no less advantageous embodiment provides that the control _{circuit device has} an overall comparator which, when the combined total current NI _R exceeds or _{falls below} the point V at point V with respect to a preset value I _{Rnom, supplies} a result value E _{G which is} different from a normal value.

According to an advantageous embodiment of the invention, the control circuit device has a result monitoring device which monitors the results E _R and E _G , wherein if there is a result value E _G , E _R different from the normal value, the main branch is blocked or deactivated by switching off the circuit groups with current supplying current or voltage source.

A current source is advantageously provided which feeds an energy store with a charge current I _L.

The circuit groups are advantageously permanently connected to the energy store and this is connected in parallel to the current source supplying the circuit groups.

The charging current I _L is chosen so large according to a particularly preferred and advantageous embodiment of the invention that after charging the energy storage device and the subsequent increase in the current in the circuit groups connected to the energy storage device, at least one series comparator assigned to a circuit group by exceeding the maximum current I _Rmax and / or the total comparator by _exceeding the preset combined total current NI _{Rnom switches off} the current or voltage source by supplying a result value E _G , E _R different from the normal value by means of the result _{monitoring device} .

Advantageously, the series comparators assigned to a circuit group are set such that they keep the current or voltage source switched on by supplying a result value E _R different from the normal value by means of the result _{monitoring device} in a circuit group when the maximum current I _{Rmax is} exceeded. This again enables the reliable detection of a low-resistance fault in a circuit group.

Preferably, a slow-acting fuse element is provided that separates all circuit groups and / or the voltage or current source from the same supplying power supply if a maximum permissible current value I _{Smax is reached} by the voltage or current source.

The display device in an installation for traffic regulation, control, or monitoring used for road vehicles, especially in a traffic light.

The system for traffic regulation, control or monitoring also has an advantage a monitoring device downstream of the display device, which a Total failure of the display device detected.

Advantageously, the display device provides on the output side a monitoring signal for the monitoring device ( 2 ) which has two different electrical states, the one state, operating state, correct operation of the display device and the other state, fault state, corresponding to a total failure of the display device.

A comparator which is monitored by the voltage and power supply is advantageously provided, which compares the voltage supplied by the voltage and power supply with a minimum value and, when the minimum value is exceeded, supplies a voltage detection signal E _S.

According to an advantageous embodiment, the comparator has an oscillator that is only at a voltage above the minimum value begins to oscillate, and the oscillation Provides signal at its output.

According to an equally advantageous embodiment, the comparator has a high pass filtering the oscillation signal of the oscillator and then rectifying it to the voltage detection signal E _S.

A result adding device is advantageously provided, which is connected between the result monitoring device and the current or voltage source and only switches on the current or voltage source when the switch-on / switch-off signal E _E and the voltage detect signal E _{S are present} . In this way, operating states that are not fault-free are avoided if the voltage supply is insufficient.

An advantageous embodiment of the invention provides that a recording power reduction device is provided which, in the presence of an external reduction signal S _A , reduces the power consumption of the circuit groups and thus the entire display device by temporarily switching off the current or voltage source, regardless of the switch-on - On / off signal E _E controls.

The input power reduction device preferably has an oscillator which, when the lowering signal S _{A is} present, supplies a square-wave signal which is linked to the switch-on / switch-off signal E _{E in} such a way that the current or voltage source is only present when a positive pulse is present Rectangular signal and the on / off signal E _{E is} turned on. As a result, the circuit groups are not supplied with current during the pulse breaks, which results in a reduction in the power consumption.

With the circuit arrangement of the display device according to the invention it is possible to One that is safe in operation due to the failure of individual lighting elements loss of luminosity, which is questionable in terms of technical equipment. Traps on the other side in the Individual lighting elements over time due to high-resistance interruption, so the total luminosity of the display device is hardly weakened, because it is still in Operation branch branches (circuit groups) of lighting elements with a large ßer partial flow, whereby compensation for the loss of luminosity is achieved becomes. Even the failure of one or more secondary branches (circuit groups) still leads not to a total failure of the display device, since the partial flows in the remaining, still intact secondary branches (circuit groups) are automatically raised so far that the light intensity emitted by the still intact lighting elements is increased and the due to the failure of one or more secondary branches (circuit groups) Luminosity weakening is compensated. Only after several branch branches have failed (scarf groups) and a concomitant considerable increase in the remaining branches distributing total current are now in one of the remaining branches of excessive partial flow through the entire display device speak of the series comparators switched off. Then the display device delivers Failure signal, which can be detected by a monitoring device. To this The display device according to the invention has a failure characteristic which is associated with a failure characteristic known in the case of an incandescent lamp arrangement is comparable. By beson therefore, the display device according to the invention is immediate and without further design or circuitry measures and expenses with a previously used in systems for traffic regulation, control or monitoring  Monitoring device can be coupled, which a total failure of the display device via a simple current evaluation like a "filament break".

The invention eliminates the need for regular checks of the current lighting state of the display device by measuring current flow changes. With the invent The display device according to the invention creates a safe and unambiguous situation when of which only two conditions have to be determined, namely whether current flows in the main branch and thus a safe overall lighting defined uniformly in brightness and luminance signal exists, or no current flows in the main branch or that the display device is not more shines. Small current changes that are difficult to measure do not have to be monitored as is the case with the prior art.

Another advantage is that the display device according to the invention is flexible can be handled by the design of the control circuit device and the individual maximum partial currents in each circuit group and the individual switching times of the comparators can be determined exactly at which light field decay the display device device should switch off automatically.

By monitoring the current in the individual circuit groups from the half Circuit components formed circuit is achieved that after failure of a predetermined Percentage of circuit groups due to current overloading the series comparators current paths still functioning (through the remaining circuit groups) the entire Display device automatically switched off and thus the situation in a safe closed is brought up. The failure in be signaled in the usual way to cause the display device to be replaced to be able to.

With the display device according to the invention, not only high-resistance failures can occur of semiconductor components, but now also takes into account low-resistance failures be, whereby the security of the display device is further increased. A blast failure of a light element causes the total electrical resistance of the be affected branch becomes infinite and correspondingly the partial current flowing therein becomes zero. The partial flows in the remaining secondary branches rise accordingly, accompanying this with the increase in light intensity, etc. as described above. With one down ohmic failure, however, the branch in question remains intact overall; it flows in Partial current that is only slightly lower than before the low-resistance failure. Only with meh  In the case of other low-resistance failures, the partial current in the relevant branch is so large that the display device completely. disabled.

Any direct or alternating voltages are suitable in accordance with the principle of the invention which cause a sufficient current through the circuit groups for the operation of the display device. By quickly switching the current or voltage source is always ensured that the correct amount of current through the scarf tion groups flows. For example, the display device is in the 220 V network and 110 V network can be operated without adjustments or changes.

Advantageous developments of the invention result from the further subclaims and from their sub-combinations.

Further features, advantages and expediencies of the invention result from the following description of an embodiment of the invention with reference to the drawing. It shows:

Fig. 1 is a schematic diagram of a display device and an electronically secured circuit group power supply realized therein according to a preferred embodiment of the invention;

Fig. 2 realized a schematic diagram of a display device and a secured therein electronic circuit group Stromver supply of FIG. 1 in addition, a the input voltage is realized in the monitoring circuit,

Fig. 3 is a schematic diagram of a display device and a secured therein realized electronically circuit group Stromver supply of FIG. 1 in which in addition a Recordin meleistungsverminderungseinrichtung invention is implemented,

FIGS. 4 and 5 is a schematic representation of the loss characteristic of a display device according to the embodiment, and

Fig. 6 is a schematic representation of a display device according to the invention according to a preferred embodiment.

Elements provided with the same reference symbols in the figures of the exemplary embodiment are the same or have the same effect.

The embodiment shown in the figures shows an inventive display device 1 for changing information with an electronically secured circuit group power supply 31 to 35 , 4 , 5 , 6 , 7 , the information by selection or combination of individual, on a carrier T arranged lighting elements L is provided, and the lighting elements L are formed by semiconductor components, in particular from light emitting diodes 2 a or other integrated light sources.

In Fig. 1 is a schematic diagram of an electronically secured th circuit group power supply 31 to 35 , 4 , 5 , 6 , 7 integrated into an LED module as a display device 1 , in which the circuit groups 21 to 25 by series circuits of LEDs 2 a are formed.

The display device 1 is connected to a DC voltage power supply 9 . This DC voltage does not have to be stabilized and its amount can be freely selected within wide limits. The DC voltage can be obtained directly from the mains AC voltage by rectification. In particular, it can also be an AC voltage power supply, but here the comparators 31 to 35 and 4 as well as the result monitoring device 5 and possibly the current or voltage source 6 would have to be supplied with a DC voltage obtained in a conventional manner from the AC voltage. The control unit (not shown here) monitors the current consumed by the entire display device 1 like an incandescent lamp.

The display device 1 consists of any number of circuit groups 21 to 25 connected in parallel in the form of LEDs 2 a in series, each of which consists of any number of LEDs. The current I _R through the circuit groups 21 to 25 is compared in each case by a series comparator 31 to 35 with an adjustable threshold value I _Rmax . In normal operation, all series comparators supply a digital low level (normal value) at their output. If the current through a series exceeds the triggering threshold value, the corresponding comparator delivers a digital H level at its output (result value E _R ).

The current through all LED rows is brought together in node V and the total current NI _R , which is composed of the individual _currents I _R , is compared by a total comparator 4 with its nominal value NI _Rnom . N is the number of circuit groups and I _R is the current through a series. If the total current NI _{R falls} below the setpoint NI _Rnom , the overall comparator delivers a digital high level at its output (result value E _G ), if the setpoint is exceeded, a digital low level.

The output signals E _R, E _R the row comparators 31 to 35 and the total Compa rators 4 are a trained result monitoring device 5 connected by a as OR gate 5, the output of the turn-on / off signal E _E for a controlled current source 6 provides. The controlled current source 6 feeds an energy store 7 , which is formed by a capacitor 7 a, with a charging current I _L when the switch-on / switch-off signal E _{E is} at a high level. The charging current I _L is such that it is greater than the desired combined current NI _Rnom through all circuit groups. As a result, the voltage at the energy store 7 increases and the total current NI _R increases. If the total current reaches or exceeds the desired current NI _Rnom , the overall comparator 4 delivers logic low as the result value E _G. In fault-free operation, the current through each circuit group 21 to 25 has the desired current I _R = I _Rnom at this moment, so that the triggering threshold current I _R = I _{Rmax of} the series comparators has not yet been reached and all series comparators have a low level deliver. As a result, the switch-on / switch-off signal E _E goes low and the power source switches off. The circuit groups are now fed by the energy store 7 , the voltage of which decreases in the process. As a result, the total current NI _R also drops and the overall comparator switches the current source back on when the total current falls below the value NI _Rnom .

This process is repeated periodically, so that the total current NI _{R is kept} at its desired value NI _Rnom (leveling it). The switching frequency is determined without further measures by the delay times of the components involved (comparators, result monitoring device, current source). By installing a hysteresis in the characteristic curve of the overall comparator 4 , the switching frequency can be set to a smaller value than this maximum value.

This dynamic control of the total current is at the same time a safeguard against errors in the comparators, the result monitoring device and the current source. If one of these components fails, it provides an arbitrary but constant level at the output. As a result, the energy store 7 is either no longer charged or always charged. Since continuous charging of the energy store leads to such a high total current that the fuse 8 blows, in both cases no current is taken up by the display device 1 .

If one or more circuit groups 21 to 25 fail and no longer carry current (customary failure mechanism of an LED), the current through the remaining intact circuit groups increases because the total current NI _R is kept constant (to NI _Rnom ) by the sum comparator , If a certain number of circuit groups has failed, the triggering threshold current I _{Rmax of} the series comparators in the remaining circuit groups is exceeded. Due to the high level of the result value E _R at the output of these comparators, the switch-on / switch-off signal E _{E is} permanently set to high, so that the current source 6 no longer switches off and the fuse 8 blows. Failures of the series comparators 31 to 35 are safeguarded in that a faulty high signal leading series comparator is sufficient to set the switch-on / switch-off signal E _E to a high level, which in turn leads to the fuse 8 blowing. So all series comparators 31 to 35 of the still intact circuit groups would have to deliver erroneously low levels so that an error remains undetected. This can be ruled out with a sufficiently large number of circuit groups and thus series comparators. The threshold I _{Rmax of} the row comparators can determine how many rows may fail before the module switches off.

A situation over time t is simulated in FIGS. 4 and 5, in which circuit group 21 fails at simulation time t1 (high-resistance failure). In FIG. 5, the current I _R is represented by the circuit group 21 and 22 I I _R21 + _R22. If circuit group 21 fails, current I _R22 through circuit group 22 increases by 25%. As a result, the threshold I _Rmax , which is also shown, is exceeded and the switch-on / switch-off signal E _E assumes a permanently high level ( FIG. 4). As can be seen, the current through the intact circuit groups increases very quickly, which causes the fuse 8 to blow (not shown in the current profile).

Often, signal devices also require that the display device only work at a certain minimum voltage of the voltage and power supply 9 - and thus light up - to prevent the information signal of the display device from being barely visible. This can be achieved by expanding the circuit as shown in FIG. 2.

The voltage applied to the display device 1 by means of voltage and power supply 9 is compared by a comparator 10 with a minimum value (for example at a supply voltage of approximately 115 V). If this minimum value is exceeded, an oscillator 11 becomes oscillatable, which supplies a square-wave signal 13 with an adjustable frequency. The square-wave signal 13 is filtered by a high-pass filter 12 and then rectified to the voltage detection signal E _S. The voltage detection signal E _S is linked to the switch-on / switch-off signal E _E by a result adding device 14 designed as an AND gate. The current or voltage source 6 is only switched on when both signals E _E and E _S are present. As a result, the current or voltage source 6 can only switch on when the minimum voltage is reached by the voltage and power supply 9 . If there are errors in the comparator 10 and in particular in the oscillator 11 , the oscillation breaks down and any DC voltage is present at the output of the oscillator 11 . Because of the high-pass filter 12 , the voltage detection signal E _S thereby assumes a low level and switches off the current or voltage source 6 and thus the entire display device, which in turn enables detection of the malfunction.

A reduction in intensity is also realized according to a similar principle the control unit (not shown) located in the signaling system can be triggered; beispielswei se for a night reduction in which only a reduced power consumption is desired.

In Fig. 3, a realization of a power reduction device 15 ge is shown, in this case a Os in the power reduction device Os zillator is turned on directly by the control unit by a lowering signal S _A. The square wave voltage then supplied by the oscillator is used as a clock signal for a loadable down counter. The counter's overflow signal is a pulse voltage with a pulse duty factor that can be set by the meter's load word. The pulse voltage is evaluated directly as a switch-on signal E _A to one of the current or voltage source 6 and the switch-on signal with the switch-on / switch-off signal E _E linking AND gate 16 . The current or voltage source 6 is switched on only when both signals are present. The period of the pulse voltage is selected in the millisecond range in this application, so that the LED module works normally during the pulse and is switched off during the pulse pause. Because of the inertia of the eye, an average intensity is perceived which corresponds to the intensity set by the overall comparator, but multiplied by the pulse pulse duty factor. In the event of errors in the oscillator / counter, the module is either switched off or operated at maximum intensity, depending on the duty cycle.

The embodiment shown in FIG. 6 shows a display device 1 according to the invention for changing information, the information being represented by selection or combination of individual lighting elements L arranged on a carrier T, and the lighting elements L being formed by semiconductor components, in particular from Light-emitting diodes 2 a or other integrated semiconductor circuits with components for light emission. The semiconductor components are connected in several circuit groups.

Via connecting lines 23 , the display device 1 according to the invention is connected to the potential of a mains supply voltage Ne and to a monitoring device 22 previously used in systems for traffic regulation, control or monitoring, the monitoring device 22 is coupled with the circuit according to the invention. The peculiarity of the display device 1 according to the invention is precisely that it can be coupled to a monitoring circuit 22 which has hitherto been used in traffic lights and which detects a total failure of the display device 1 via a simple current evaluation, as in a "filament breakage".

This state can be registered and reported to a control center by means of a monitoring device 22 customary in the art. The staff is then requested to replace the relevant display device.

The advantages of an LED are fully apparent, long service life, little loss performance, mechanical stability, temperature insensitivity and finally saving of otherwise usual transformers in the display device.  

LIST OF REFERENCE NUMBERS

1

display element

21

to

25

circuit groups

2

a LEDs

3

Control circuit means

31

to

35

Rows comparators

4

Total comparator

5

Result monitoring device

5

a OR gate

6

Current or voltage source

7

energy storage

7

a capacitor

8th

fuse element

9

power supply

10

comparator

11

oscillator

12

highpass

13

square wave

14

Result adding device, AND gate

15

Power consumption reducing means

16

AND gate

22

monitoring device

23

connecting cables
Ne mains supply voltage
I _R

, I _Rnom

, I _Rmax

Individual flows, desired, maximum
NI _R

composite total current
V common point
I _L

charging current
I _smax

maximum permissible current value
E _G

, E _R

result values
E _E

On / switch-off signal
E _S

Spannungsdetekt signal
E _A

On-signal
S _A

Drawdown signal
L light elements
T carrier

Claims (37)

1. Electronically protected circuit group power supply ( 31 to 35 , 4 , 5 , 6 , 7 ), of which at least two circuit groups ( 21 to 25 ) are connected in parallel, the total current NI _{R of} which is composed of the individual currents I _R during operation in one Point V is merged (N corresponds to the number of circuit groups),
each with a circuit group ( 21 to 25 ) assigned series comparators ( 31 to 35 ) which, when the current I _Rmax through the circuit group or the voltage across the circuit group exceeds or falls below, with respect to a preset value, each one different from a normal value Deliver the result value E _R ,
with a total comparator ( 4 ) which, when the combined total current NI _R exceeds or _{falls below} the point V with respect to a preset value NI _{Rnom, supplies} a result value E _{G which is} different from a normal value,
with a result monitoring device ( 5 ), which monitors the results E _R and E _G , wherein if there is a result value E _G , E _R which is different from the normal value, the current or voltage source ( 6 ) which supplies the circuit groups with power is switched off or on. 2. Electronically secured circuit group power supply according to claim 1, characterized in that the current or voltage source ( 6 ) supplies an energy store ( 7 ), which is in particular formed by a capacitor ( 7 a), with a charging current I _L. 3. Electronically secured circuit group power supply according to claim 2, characterized in that the circuit groups ( 21 to 25 ) are permanently connected to the energy store ( 7 ). 4. Electronically secured circuit group power supply according to claim 3, characterized in that the charging current I _L is chosen so large that after charging the energy store ( 7 ) and the subsequent increase in the current I _R in the circuit groups connected to the energy store ( 21 to 25 ) the total comparator ( 4 ) _{switches off} the current or voltage source ( 6 ) by supplying a result value E _G which differs from the normal value by means of the result monitoring device ( 5 ) by exceeding the preset combined total current NI _Rnom . 5. Electronically protected circuit group power supply according to one of claims 1 to 4, characterized in that the series comparators ( 31 to 35 ) assigned to a circuit group ( 21 to 25 ) are set such that they exceed the maximum current I _Rmax in a circuit group keep the current or voltage source ( 6 ) switched on by supplying a result value different from the normal value E _R by means of the result monitoring device ( 5 ). 6. Electronically protected circuit group power supply according to one of claims 2 to 5, characterized in that the charging current I _{L is} greater than the pre-set total current NI _Rnom . 7. Electronically secured circuit group power supply according to one of claims 1 to 6, characterized in that a slow responding fuse element ( 8 ) is provided that all circuit groups ( 21 to 25 ) from the current or voltage source ( 6 ) disconnects if a maximum permissible current value I _{Smax has been reached} by the voltage or current source ( 6 ). 8. Electronically protected circuit group power supply according to one of claims 1 to 7, characterized in that a slow responding fuse element ( 8 ) is provided that the current or voltage source ( 6 ) from the power supply ( 9 ), if a maximum permissible , _Current value I _{Smax is reached} by the voltage or current source ( 6 ). That the result monitoring device (5) is secured 9. Electronic circuit group power supply according to one of claims 1 to 8, characterized in that a result of the values of E _G, E _R linking each linking device (5 a). 10. Electronically secured circuit group power supply according to claim 9, characterized in that the result values are digital and the logic device is an OR gate ( 5 a). 11. Electronically secured circuit group power supply according to one of claims 1 to 10, characterized in that the circuit groups ( 21 to 25 ) are LED rows, the individual LEDs ( 2 a) of which are connected in series. 12. Electronically secured circuit group power supply according to one of claims 1 to 11, characterized in that the circuit groups ( 21 to 25 ) form a light emission element. 13. Electronically protected circuit group power supply according to claim 12, characterized, that the light emission element is a display element, in particular a signal Display element. 14. Electronically secured circuit group power supply according to one of claims 1 to 13, characterized in that the series comparators ( 31 to 35 ), the overall comparator ( 4 ), the circuit groups ( 21 to 25 ), the result monitoring device ( 5 ), the energy store ( 7 ) and the current or voltage source ( 6 ) structurally form a unit. 15. display device ( 1 ) for changing information,
the information being represented by the selection or combination of individual lighting elements (L) arranged on a carrier (T),
wherein the luminous elements are formed by semiconductor components, in particular light emitting diodes (2a), or other semiconductor integrated circuits with components for light emission,
and the semiconductor components are connected in a plurality of circuit groups ( 21 to 25 ), and each circuit group in terms of current forms a secondary branch (Ni) of a main branch,
characterized,
that a control circuit device ( 3 ) assigned to the circuit groups is provided which, when a partial current I _R flowing in a secondary branch (Ni) is exceeded or undershot, in particular by a predetermined current threshold value, results in a blocking or deactivation of the main branch (H) in immediate succession and thus all circuit groups ( 21 to 25 ), and that the control circuit device blocks or deactivates the main branch (H.) in immediate succession if the current NI _R flowing in the main branch (H) is exceeded or undershot, in particular by a predetermined current threshold value ) and thus all circuit groups and / or if the current flowing in the main branch (H) is undershot, in particular by a predetermined current threshold value, controls the activation of the main branch (H) and thus all circuit groups in immediate succession. 16. Display device according to claim 15, characterized in that the circuit groups ( 21 to 25 ) are formed by at least one lighting element. 17. The display device according to claim 16, characterized in that the lighting elements are formed by semiconductor components, in particular from light-emitting diodes ( 2 a), or other integrated semiconductor circuits with components for light emission. 18. Display device according to claim 15, characterized in that the circuit groups ( 21 to 25 ) are ausgebil det by at least one semiconductor device. 19. Display device according to claim 18, characterized in that the semiconductor components are light-emitting elements, in particular light-emitting diodes ( 2 a), or other integrated semiconductor circuits with components for light emission. 20. Display device according to one of claims 15 to 19, characterized in that the control circuit device ( 3 ) each has a circuit group ( 21 to 25 ) assigned series comparators ( 31 to 35 ), which exceed or fall below the current I _R by the circuit group with respect to the preset value I _Rmax each deliver a result value E _{R that is} different from a normal value. 21. Display device according to one of claims 15 to 20, characterized in that the control _{circuit device} ( 3 ) has an overall comparator ( 4 ) which, when the combined total current NI _R exceeds or _{falls below} a point V with respect to a preset value I _Rnom results value E _{G that} differs from a normal value 22. Display device according to one of claims 15 to 21, characterized in that the control circuit device ( 3 ) has a result monitoring device ( 5 ) which monitors the results E _R and E _G , wherein if there is a result value E _G , E different from the normal value _{R is} a blocking or deactivation of the main branch (H) by switching off one of the circuit groups supplying current or voltage source ( 6 ). 23. Display device according to claim 22, characterized in that the current or voltage source ( 6 ) feeds an energy store ( 7 ) with a charging current I _L. 24. Display device according to claim 23, characterized in that the circuit groups ( 21 to 25 ) are permanently connected to the energy store ( 7 ) and this is connected in parallel to the current or voltage source ( 6 ) supplying the circuit groups. 25. Display device according to one of claims 23 or 24, characterized in that the charging current I _L is chosen so large that after the energy store ( 7 ) has been charged and the subsequent rise in the current in the circuit groups connected to the energy store ( 21 to 25 ) at least one series comparator ( 31 to 35 ) assigned to a circuit group by exceeding the maximum current I _Rmax and / or the total comparator ( 4 ) by exceeding the preset combined total current NI _{Rnom through} the current or voltage source ( 6 ) Delivery of a result value E _G , E _R different from the normal value switches off by means of the result monitoring device ( 5 ). 26. A display device according to one of claims 22 to 25, characterized in that the series comparators ( 31 to 35 ) assigned to a circuit group ( 21 to 25 ) are set such that they in a circuit group when the maximum current I _{Rmax is} exceeded Keep the current or voltage source ( 6 ) switched on by supplying a result value E _R different from the normal value by means of the result monitoring device ( 5 ). 27. Display device according to one of claims 15 to 26, characterized in that a slow responding securing element ( 8 ) is provided that all circuit groups ( 21 to 25 ) and / or the voltage or current source ( 6 ) supply from the same disconnects the power supply ( 9 ) if a maximum permissible current value I _{Smax is reached} by the voltage or current source ( 6 ). 28. Display device according to one of claims 15 to 27, characterized in that the control circuit device ( 3 ) is an electronically secured circuit group power supply ( 31 to 35 , 4 , 5 , 6 , 7 , 8 ) according to one of claims 1 to 14. 29. Display device according to one of claims 15 to 28, characterized, that they are in a plant for traffic regulation, control, or monitoring for roads vehicles, especially in a traffic light. 30. Display device according to claim 29, characterized in that the system for traffic regulation, control or monitoring has a monitoring device ( 22 ) which is connected downstream of the display device and which detects a total failure of the display device. 31. Display device according to claim 30, characterized in that it provides on the output side a monitoring signal for the monitoring device ( 22 ) which has two different electrical states, one state, operating state, proper operation of the display device ( 1 ) and the other Zu stood, fault condition, a total failure of the display device ( 1 ) corresponds. 32. The display device according to any one of claims 15 to 31, characterized in that the supervising by the voltage and current supply (9), comparator (10) is provided, which compares the delivered by the voltage and current supply (9) voltage to a minimum value , and delivers a voltage detection signal E _S when the minimum value is exceeded. 33. Display device according to claim 32, characterized in that the comparator ( 10 ) has an oscillator ( 11 ) which begins to oscillate only when the voltage is above the minimum value, and provides the oscillation signal at its output. 34. Display device according to claim 33, characterized in that the comparator ( 10 ) has a high pass filter ( 12 ) which filters the oscillation signal of the oscillator ( 11 ) and then rectified to the voltage detection signal E _S. 35. Display device according to claim 34, characterized in that a result adding device ( 14 ) is provided which is connected between the result monitoring device ( 5 ) and the current or voltage source ( 6 ) and the current or voltage source ( 6 ) only when the The on / off signal E _E and the voltage detection signal E _S turn on. 36. Display device according to one of claims 15 to 35, characterized in that a power reduction device ( 15 ) is provided which, in the presence of an external lowering signal S _A, a reduction in the power consumption of the circuit groups and thus the entire display device by temporarily switching off the current or voltage source ( 6 ), independently of the switch-on / switch-off signal E _E control. 37. Display device according to claim 36, characterized in that the absorption power reduction device ( 15 ) has an oscillator which, when the lowering signal S _{A is} present, supplies a square-wave signal which is linked to the switch-on / switch-off signal E _{E in} such a way that the The current or voltage source ( 6 ) is only switched on when there is a positive pulse of the square-wave signal and the switch-on / switch-off signal E _E.