EP3075212B1 - Led converter for an led module - Google Patents

Description

The present invention relates to an LED module, an LED converter and a method which make it possible to transmit operating parameters of the LED module to the LED converter without a specific communication line between the LED module and the LED converter.

Several approaches are already known from the prior art for specifying operating parameters for a connected LED module to an LED converter. This is necessary, for example, because different forward currents are necessary for different LED modules in order to make the LED sections of the LED modules glow. Operating parameters are, for example, a required forward current or a setpoint or forward voltage to be applied.

One approach known from the prior art is to set the operating parameters to be set for the connected LED module on the LED converter via DIP switches or resistors. However, this requires interaction with the LED converter.

In another approach, configuration resistors are used on the LED module to specify the required operating parameters for the LED converter. For this, however, additional connections are required on the one hand, and interaction is required on the other.

It is also known to transmit the necessary operating parameters to the LED converter via a separate digital signal channel. However, additional components have to be installed for this and an interaction is again necessary.

Finally, it is also known to assign an EPROM, for example, to the LED module, from which the LED converter can determine information regarding the operating parameters to be set on the LED module.

From the WO 2010/092504 A1 an LED system with an associated driver is known, the driver reading out the impedance of a circuit of the LED system by applying an AC voltage. Furthermore, the US 2010/0214082 A1 to a system in which a service and data are provided via the same line. The power signal can be controlled by means of PWM and the data signal can be controlled by means of frequency modulation.

However, the approaches known from the prior art all require either an interaction with the LED converter or the LED module, or require additional connections or components. This increases the costs of the LED module and / or the LED converter. In addition, more space is required for the components, which prevents a more compact design.

The object of the present invention is to improve the known prior art, particularly with regard to the disadvantages mentioned above. In particular, it is the object of the present invention to transmit (report back) information to an LED converter, for example with regard to the operating parameters of an LED module, without additional components or connections or interaction being necessary. It is therefore the object of the present invention to produce an LED module and an LED converter more cost-effectively and to build them more compactly.

The objects of the present invention are achieved by the features of independent claims 1 and 5. The dependent claims advantageously develop the core concept of the invention further.

Fig. 1

zeigt schematisch das Grundprinzip der vorliegenden Erfindung anhand einer erfindungsgemäßen LED-Leuchte (bestehend aus einem erfindungsgemäßen LED-Modul und einem erfindungsgemäßen LED-Konverters).

Fig. 2

zeigt eine Stromspannungskennlinie einer LED-Strecke und das erfindungsgemäße Auslesefenster.

Fig. 3

zeigt einen Schaltkreis, der eine automatische Deaktivierung der Schaltung auf dem erfindungsgemäßen LED-Modul ermöglicht.

Fig. 4

zeigt ein Beispiel der Schaltung auf dem erfindungsgemäßen LED-Modul, die eine stromkonstante Last darstellt.

Fig. 5

zeigt schematisch die Erfassung einer stromkonstanten Last auf dem erfindungsgemäßen LED-Modul durch den erfindungsgemäßen LED-Konverter.

Fig. 6

zeigt eine Schaltung auf dem erfindungsgemäßen LED-Modul, die eine stromveränderliche Last darstellt und insbesondere eine Frequenz der Änderung der Leistungsaufnahme des erfindungsgemäßen LED-Moduls einstellt.

Fig. 7

zeigt wie eine Änderung der Leistungsaufnahme des erfindungsgemäßen LED-Moduls an einem Buck-Konverter als Beispiel eines erfindungsgemäßen LED-Konverters gemessen werden kann.

Fig. 8

zeigt wie eine Änderung des Stroms durch die Schaltung auf dem erfindungsgemäßen LED-Modul mit dem Strom in einem Buck-Konverter des erfindungsgemäßen LED-Konverters korreliert

Fig. 9

zeigt ein weiteres Beispiel der Schaltung auf dem erfindungsgemäßen LED-Modul

Fig. 10

zeigt ein weiteres Beispiel der Schaltung auf dem erfindungsgemäßen LED-Modul

Fig. 11

zeigt ein weiteres Beispiel der Schaltung auf dem erfindungsgemäßen LED-Modul

Fig. 12

zeigt ein weiteres Beispiel der Schaltung auf dem erfindungsgemäßen LED-Modul.

The present invention will now be described in more detail with reference to the accompanying figures.

Fig. 1

shows schematically the basic principle of the present invention using an LED lamp according to the invention (consisting of an LED module according to the invention and an LED converter according to the invention).

Fig. 2

shows a current-voltage characteristic of an LED path and the readout window according to the invention.

Fig. 3

shows a circuit which enables automatic deactivation of the circuit on the LED module according to the invention.

Fig. 4

shows an example of the circuit on the LED module according to the invention, which represents a current-constant load.

Fig. 5

shows schematically the detection of a constant current load on the LED module according to the invention by the LED converter according to the invention.

Fig. 6

shows a circuit on the LED module according to the invention, which represents a current-variable load and in particular sets a frequency of the change in the power consumption of the LED module according to the invention.

Fig. 7

shows how a change in the power consumption of the LED module according to the invention can be measured on a buck converter as an example of an LED converter according to the invention.

Fig. 8

shows how a change in the current through the circuit on the LED module according to the invention correlates with the current in a buck converter of the LED converter according to the invention

Fig. 9

shows another example of the circuit on the LED module according to the invention

Fig. 10

shows another example of the circuit on the LED module according to the invention

Fig. 11

shows another example of the circuit on the LED module according to the invention

Fig. 12

shows another example of the circuit on the LED module according to the invention.

Figure 1 shows schematically an LED lamp according to the invention, which consists of an LED module 1 according to the invention and an LED converter 10 according to the invention. The LED converter 10 is connected to the LED module 1 via one or more voltage connections 12. The LED converter 10 thus supplies the LED module 1 with a supply voltage. The LED converter 10 can also be designed to operate a plurality of LED modules 1. The supply voltage is preferably a direct voltage, but it can also be a clocked voltage or alternating voltage. The LED converter 10 preferably has a high-frequency clocked converter, for example a buck converter, an isolated flyback converter or a resonant half-bridge converter (preferably isolated, for example an LLC converter). The LED converter 10 can, for example, output a constant output voltage or a constant output current at its voltage connections 12, the voltage at these connections corresponding to the supply voltage of the LED module 1.

The supply voltage is applied via one or more connections 2 of the LED module 1 to at least one LED path 3 connected to it (this also includes a single LED). The LED segment 3 does not have to be part of the LED module 1 according to the invention, but can be a connectable and exchangeable LED segment 3.

The LED module 1 according to the invention therefore only requires connections 2 for at least one LED segment 3. The LED segment 3 can, however, also be permanently installed with the LED module 1. The LED path 3 can have one or more LEDs, which, for example, as in FIG Figure 1 shown are connected in series. LEDs in an LED segment 3 can all light up in the same color, ie emit light of the same wavelength, or light up in different colors. For example, several LEDs, preferably red, green and blue LEDs, can be combined in order to generate mixed radiation, preferably white light.

When it is connected to the connections 2, the LED path 3 is connected in parallel with a circuit 4 with respect to the supply voltage. The circuit 4 is designed, for example, in such a way that it represents a load, preferably an active power load, for the LED converter 10 when the supply voltage applied by the LED converter 10 to the connections 12 is not equal to zero, but is still so low that the LED path 3 connected to connections 2 is not yet conductive. The circuit 4 can therefore also be referred to as a load circuit or a load modulation circuit.

Figure 2 shows an example of a current-voltage characteristic of an LED path 3, in which a current through the LED path in the vertical direction and the voltage at the LED path (ie the supply voltage in Figure 1 ) is applied in the horizontal direction. For a first voltage range (ie a first supply voltage 5a within the readout window), the voltage at the LED path 3 is not equal to zero, but the current through the LED path 3 is also almost zero because the LED path 3 is not conductive . The supply voltage is therefore below the forward voltage. The LED path 3 represents an infinite load for the LED converter 10. The LED module 1 therefore does not consume any power via the LED path 3. In a second voltage range (ie for a second supply voltage 5b outside the readout window) the LED path 3 becomes conductive and it flows a current through the LED path 3, which makes it glow. The supply voltage is therefore above the forward voltage.

The circuit 4 on the LED module 1 is designed, for example, in such a way that it is activated when the first supply voltage 5a is applied and thereby represents a load, preferably an active power load, for the LED converter 10. For the second supply voltage 5b, that is to say when the LED path 3 is lit, the circuit 4 is deactivated and does not represent a load for the LED converter. This is shown in FIG Figure 1 shown schematically by the switch 6, which automatically activates or deactivates the circuit 4 depending on the applied supply voltage. The circuit 4 can represent either a current-constant load or a current-variable load for the LED converter 10. The circuit 4 causes the LED module 1 to consume power, although an LED path 3 is not yet conductive and does not consume any power. A conventional LED module 1 would not consume any power in the readout window. Additionally or alternatively, the circuit 4 on the LED module 1 can also be designed in such a way that it is only activated in a time-limited start phase of the LED module 1.

The power consumption of the LED module 1 in the readout window can be constant or variable in current, depending on the type of circuit 4. The LED converter 10 can detect the power consumption of the LED module 1 or a change in the power consumption of the LED module 1 and, based on the detected power consumption, deduce the operating and / or maintenance parameters of the LED module 1 to be set. The LED converter 10 can use the operating and / or maintenance parameters directly for setting or regulating the LED module 1. The LED converter 10 can also store the operating and / or maintenance parameters in a memory assigned to it and, if necessary, use them later, or display the parameters optically and / or acoustically to a user, or to another device, for example a control unit of a lighting system , send.

The transmission can be done either wirelessly or wired and can be carried out either automatically or only on request from the further device.

To operate an LED module 1 by the LED converter 1 of the present invention, various processes can be carried out in a preferably time-limited start phase of the LED lamp.

First, the LED converter 10 supplies the LED module 1, for example, with a constant supply voltage, preferably a constant DC voltage. For example, the LED converter 10 can be operated with a reduced switch-on ratio compared to normal operation, as a result of which a lower output voltage is achieved. The supply voltage is a first supply voltage 5a, ie it is in the readout window shown in Figure 2 is shown. Since the first supply voltage 5a is not equal to zero, the circuit 4 is activated on the LED module 1 and represents a load for the LED converter 10. The load is preferably an active power load and generates a power consumption of the LED module 1. Now can the LED converter 10, for example, a discharge current of a capacitor via this load (which is only an example that is not the subject of the invention), an absolute current consumption of the circuit 4 (which is only an example that is not the subject of the invention), a Frequency of a change in the power consumption of the LED module 1 (which is only an example which is not the subject of the invention), or a duty cycle according to the present invention or an amplitude (which is only an example which is not the subject of the invention) a Measure change in power consumption. Based on the result of the measurement, the LED converter 10 can infer operating and / or maintenance parameters. For example, the LED converter 10 can determine a target or forward voltage or a target current of the LED module and apply this to the LED module 1. A connected LED path 3 thus becomes conductive and the LED converter 10 operates the LED module 1 in lighting mode. The circuit 4 is now preferably deactivated automatically. The circuit 4 therefore does not consume any power in the lighting operation of the LED path 3 and therefore does not influence the lighting operation of the LED path 3. The LED converter 10 of the LED lamp has thus automatically recognized the LED module 1 and set the appropriate operating parameters .

Alternatively or additionally, the LED converter 10 can also read out the LED module 1 for a limited time, in that the circuit 4 is only active during a start phase on the basis of a predetermined period of time as soon as a supply voltage is applied to the LED module 1. In this case, this supply voltage can also correspond to the nominal output voltage of the LED converter 10 for normal operation. After the supply voltage has been applied, the circuit 4 is activated on the LED module 1 and represents a load for the LED converter 10. The load is preferably a repeatedly changing active power load and generates a power consumption of the LED module 1. In addition, in In this case, the connected LED path 3 will also become conductive, with which the LED converter 10 operates the LED module 1 in lighting mode. Now the LED converter 10 can, for example, a discharge current of a capacitor (which is only an example, which is not the subject of the invention) via this load, an absolute current consumption of the circuit 4 (which is only an example, which is not the subject of the invention) , a frequency of a change in the power consumption of the LED module 1 (which is only an example which is not the subject of the invention), or a duty cycle according to the present invention or an amplitude of a power consumption change (which is merely an example which is not the subject of the Invention is) measure. Based on the result of the measurement, the LED converter 10 can infer operating and / or maintenance parameters. For example, the LED converter 10 can determine a target or forward voltage or a target current of the LED module and apply this to the LED module 1. The circuit 4 is now preferably deactivated automatically after the predetermined time period for the start phase has elapsed. The specification of this time period for the start phase can be established, for example, by a time charging circuit, with a timer capacitor being charged and, after the timer capacitor has been charged, the circuit 4 is deactivated. The circuit 4 therefore does not consume any power in the continuous lighting operation of the LED segment 3 and therefore does not influence the lighting operation of the LED segment 3.

Figure 3 shows a circuit which is at least a part of the circuit 4 in order to automatically deactivate it when the supply voltage is im Area of the second supply voltage 5b is, that is, above the Forward voltage of the LED path 3 is. The circuit 4 can be deactivated by means of the transistors M4 and M3. As the supply voltage, which is provided by the LED converter 10 and is applied to the circuit 4 on the LED module 1, increases, the voltage across the resistor R8 also increases. When this voltage reaches a threshold voltage of transistor M4, it closes and also deactivates transistor M3 by pulling the gate voltage of transistor M3 to ground. The threshold voltage can for example be 1.4 volts (at a voltage of 12.5 volts) of the LED converter 10). In order to reduce losses of the voltage divider R8 and R10, the resistance values should be high, preferably in the range from 20 to 200 kΩ, even more preferably in the range from 40 to 100 kΩ. It is also important that the transistor M3 is designed to withstand the maximum supply voltage that the LED converter 10 can apply and that the voltage across the resistor R8 does not exceed the maximum permitted gate voltage of the transistor M4 when the LED is normally lit. - Distance exceeds 3. Alternatively or optionally, this circuit can be designed, for example by means of an RC element, in such a way that it deactivates itself after a predetermined start time has elapsed (this time corresponding to the start phase) by deactivating the transistor M3 as a function of it, ie opening it. For example, a capacitor can be arranged in parallel with the resistor R8. This capacitor can be designed so that it is charged by the applied supply voltage after the specified start time has elapsed and thus the voltage at the parallel resistor R8 has also risen so far that this voltage has reached a threshold voltage of the transistor M4, so that it closes and the Transistor M3 deactivates by pulling the gate voltage of transistor M3 to ground.

Figure 4 shows an example of a circuit TL432, which is at least part of the circuit 4, which is designed to display a current-constant load for the LED converter 10 in the readout window.

The left side of the Figure 4 shows a circuit diagram of the circuit, the right-hand side shows a corresponding equivalent circuit diagram for the TL431 or TL432 circuit. The constant current is determined by a ratio of the reference voltage of the switching circuit TL431 to the resistance value of the selection resistor R11 (Rcfg). A transistor Q1 is preferably controlled such that the voltage across resistor R11 (Rcfg) is always approximately 2.5 volts. A minimum current of about 1 mA should flow through the TL431 circuit. The in Figure 3 The circuit shown can be used in series with the circuit shown in Figure 4 The circuit shown can be arranged so that the series circuit of the two is arranged in parallel to the LED path on the LED module 1. Preferably, the virtual ground GNDX of the circuit is the Figure 4 connected to the drain of the transistor M3.

Via a constant current load such as in Figure 4 As shown, the LED converter 10 can discharge a capacitor 11, for example, for measuring the constant current. The constant current through the circuit 4 (which corresponds to the discharge current of the capacitor 11) can be determined directly or indirectly based on either the discharge duration and / or the discharge rate. Based on the discharge current, the LED converter can draw conclusions about the circuit 4 used and thus about the connected LED module 1. Furthermore, the LED converter 10 can determine operating and / or maintenance parameters of the LED module, for example using stored tables.

The concept of determining the constant current through the circuit 4 is shown schematically in FIG Figure 5 shown. For example, the LED converter 10 can be designed as a buck converter. The LED converter 10 is provided with the capacitor 11, which can be connected in parallel to the connections 12 for the supply voltage. The voltage at the connections 12 is monitored by the LED converter 10.

When the supply voltage is disconnected from the LED module 1 by opening the switch 13, which is arranged in the LED converter 10 and is preferably clocked at high frequency when the LED converter is in operation, the capacitor 11 discharges via the preferably constant-current load, which is represented by the circuit 4 on the LED module 1. The discharge rate, ie the change in the voltage of the capacitor which is applied to the connections 12, is preferably measured by the LED converter 10 in order to draw conclusions about the operating and / or maintenance parameters of the LED module 1 as described. For example, resistor R11, which is shown in Figure 4 constant current load shown, can be determined when the capacitance of the capacitor 11 is known. This resistance value can then encode the operating and / or maintenance parameter, ie the LED converter 10 can, for example, correlate this resistance value with operating and / or maintenance parameters in stored tables.

Figure 6 shows a circuit TLC555, which is at least part of the circuit 4 and is suitable for generating a load change of the LED module 1 with a certain frequency, ie a change in the power consumption of the LED module 1. On the left of the Figure 6 is a circuit diagram, on the right side a corresponding equivalent circuit diagram for the circuit TLC555 is shown. For example, a capacitor C1 can be charged and discharged between 1/3 and 2/3 of the supply voltage 5a applied by the LED converter 10. As long as the supply voltage 5a applied by the LED converter 10 is constant, a frequency of the load change, a pulse duty factor (pulse duty factor) of the load change or an amplitude of the load change (ie a difference between a load before and a load after the change) can be set. This also requires a change in the power consumption with a corresponding frequency, pulse duty factor (pulse ratio) or an amplitude.

wobei R3, R4 und C1 Widerstands- bzw. Kapazitätswerte der in Fig. 6 gezeigten Komponenten sind.The frequency f of the change is defined as $$\mathrm{f}=1/\left\{\left(\mathrm{R.}3+2\cdot \mathrm{R.}\mathrm{4th}\right)\cdot \mathrm{C.}1\cdot \mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">ln</figure-callout>}\left(2\right)\right\},$$

where R3, R4 and C1 are resistance and capacitance values of the in Fig. 6 components shown are.

und $${\mathrm{T}}_{\mathrm{low}}=\mathrm{R}4\cdot \mathrm{C}1\cdot \ln \left(2\right).$$

The duty cycle (clock ratio) is defined by the ON time (T _high ) and the OFF time (T _low ), with $${\mathrm{T}}_{\mathrm{high}}=\left(\mathrm{R.}3+\mathrm{R.}\mathrm{4th}\right)\cdot \mathrm{C.}1\cdot \mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">ln</figure-callout>}\left(2\right)$$

and $${\mathrm{T}}_{\mathrm{low}}=\mathrm{R.}\mathrm{4th}\cdot \mathrm{C.}1\cdot \mathrm{<figure-callout\; id="2"\; label="ln"\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">ln</figure-callout>}\left(2\right).$$

The pulse duty factor can be changed by changing the pulse duration (switch-on time, ON time, T _high ) or by changing the pause duration (switch-off time, OFF time, T _low ).

The size of the load is determined by the resistor R5 and the converter _voltage V CONV (more precisely the ratio V _CONV / R5).

The circuit 4 can be designed, for example, so that it is only activated during the starting phase of the LED light. This can be achieved, for example, by supplying the circuit TLC555 with the aid of a timing element such as an RC element, for example, this timing element can be designed in such a way that the supply for the circuit TLC555 is only applied for a period of 100 milliseconds, When the capacitor of the RC element is charged via a series resistor (based on the supply voltage of the LED module 1), a predetermined voltage level is reached which leads to the switching off of the supply voltage Vcc for the TLC555 circuit (example not shown). For example, the voltage drop across the RC element can be used to control the base of a switch-off transistor (not shown) which pulls the supply Vcc for the circuit TLC555 to ground as soon as the RC element has been charged. The charging time of the RC element can be designed so that a time of 100 milliseconds, for example, is reached, this time corresponding to the start phase.

A start-up of the TLC555 circuit at the beginning of the start phase can take place by means of a high-impedance feed directly from the supply voltage of the LED module 1, whereby this occurs at the end of the start phase by means of the voltage drop across the RC element via the cut-off transistor in a kind of pull-down configuration Mass is pulled. The circuit 4 can have a controllable switch which switches the resistor R5 on or off as a function of the output signal OUT of the circuit TLC555 and thus causes the load change.

The in Figure 3 The circuit shown can be used in series with the circuit shown in Figure 6 The circuit shown can be arranged so that the series circuit of the two is arranged in parallel to the LED path on the LED module 1. Preferably, the virtual ground GNDX of the circuit is the Figure 6 connected to the drain of the transistor M3. A deactivation of the circuit of the Figure 6 can for example be time-controlled. As with the example of the Figure 3 explained, a capacitor can be arranged in parallel with the resistor R8. In this case, an RC element is also formed. The charging time of the RC element can be designed so that a time of 100 milliseconds, for example, is reached, this time corresponding to the start phase. After the start time specified by the dimensioning of the RC element has elapsed, the voltage at the gate of transistor 4 has reached a threshold voltage of transistor M4, so that it closes and deactivates transistor M3 by connecting the gate voltage of transistor M3 to ground. In this way the circuit of the Figure 6 can only be activated for a specified start phase.

If the circuit 4 generates and outputs a repetitively changing load change (that is to say a modulated load change), two different items of information can also be transmitted, for example. For example, both the frequency and the duty cycle of the load change can be changed.

In this case, a first piece of information (for example the target voltage) could be transmitted in coded form by means of the frequency, while a second piece of information (for example the target current) could be transmitted in a coded manner using the pulse duty factor. Another possibility for the combined transmission of at least two pieces of information would be to change the pulse duration (switch-on time, ON time, T _high ) and the pause duration (switch-off time, OFF time, T _low ) of the load change accordingly.

The change in the power consumption of the LED module 1 can be determined by the LED converter 10, for example by direct current measurement of the current through the circuit 4. Alternatively, the LED converter can take 10 measurements on a buck converter as in Figure 7 perform shown, wherein the buck converter is preferably part of the LED converter 10. So shows for example Figure 8 how the current through the circuit 4 and the current at the Buck converter, which is measured via a shunt, correlates. Figure 8 shows above the current "load current" through circuit 4 and the current "inductor current" through Buck converter plotted against time. The buck converter is only an exemplary example of a high-frequency clocked converter, as an alternative, for example, an isolated flyback converter, boost converter (step-up converter) or a resonant half-bridge converter (preferably isolated, for example an LLC converter) can be used to feed the LED -Module 1 can be used.

The LED converter can be used as in Figure 7 shown have a buck converter. The buck converter can be operated as a constant current source, i.e. regulate to a constant output current. In this case, for example, the output voltage of the buck converter, that is to say the voltage that is output at the output of the LED converter 10 and corresponds to the voltage across the LED module 1, can be recorded and evaluated. Additionally or alternatively, the duration of the switch-on time and the switch-off time of the control of the high-frequency clocked switch of the Buck converter are monitored and evaluated in order to recognize a change in load and thus to read out information from the LED module 1.

The buck converter can also be operated as a constant voltage source, i.e. regulate to a constant output voltage. In this case, a change in the load on the LED module 1 will lead to a change in the peak current occurring through the high-frequency clocked switch during the switch-on phase of the high-frequency clocked switch of the buck converter, and this change can be detected. Additionally or alternatively, the duration of the switch-on time and the duty cycle of the activation of the high-frequency clocked switch of the buck converter can also be monitored and evaluated in order to detect a load change and thus read information from the LED module 1. Alternatively, when operating as a constant voltage source, the level of the output current can also be evaluated in order to detect a change in load.

The buck converter can be operated with a fixed pulse duty factor at a fixed frequency, preferably in continuous conduction mode. In such an operation, the level of the output current and / or the output voltage can be evaluated in order to detect a change in load.

The buck converter of the LED converter 10 can supply the LED module 1 with a constant supply voltage, for example, in a starting phase, preferably a constant DC voltage. In this case, the buck converter is operated as a constant voltage source in the start phase. For example, the LED converter 10 can be operated with a reduced switch-on ratio compared to normal operation, as a result of which a lower output voltage is achieved. The supply voltage can be a first supply voltage 5a, ie it can be in the readout window shown in FIG Figure 2 is shown.

In a starting phase, the buck converter can also supply the LED module 1 with a regulated current, then the buck converter is preferably operated as a constant current source.

Figure 8 shows an enlarged view of this plot below. The greater the load of the circuit 4, the greater a pulse duty factor or a peak current at the measuring resistor (shunt). Depending on a control principle of the LED module 1 by the LED converter 10, a peak current can also be measured at the shunt of the buck converter or a change in the pulse duty factor at the buck converter, which is the subject of the invention. The change in the load of the circuit 4 or the power consumption of the LED module 1 can be detected directly on the shunt on the low potential switch of the buck converter. Either through a periodic change in the pulse duty factor or a periodic change in the peak current, which correlates with a periodic change in the power consumption of the LED module 1.

As already mentioned, the LED converter 10 can, for example, have an isolated converter with a transformer for high-frequency energy transmission (isolated, preferably an isolated flyback converter) for supplying the LED module 1. If the LED converter 10 is designed to be isolated (for example as an isolated flyback converter), that is to say has a transformer, the load change can also be detected by the LED converter 10 on the primary side of the LED converter 10. For example, when using an isolated flyback converter, the current on the primary side of the LED converter 10, which flows through the primary side of the transformer, can be detected. For example, the current through the clock switch, which is arranged in series with the primary winding of the transformer, or the current through the primary winding of the transformer, preferably by means of a shunt connected in series (current measuring resistor), can be detected. For example, on the basis of the peak current at the shunt, the load or also the Load change of the LED module 1 and thus, for example, a change in the duty cycle on the primary side of the LED converter 10 can be measured. For example, the change in the primary-side current can also be recorded over time. For example, the power transmitted by the primary side can be detected on the basis of the measurement of the primary-side current and a measurement or at least knowledge of the voltage feeding the converter. It would be possible, for example, for an active power factor correction circuit such as a step-up converter circuit to be connected upstream of the converter, which provides the input voltage for the high-frequency clocked, isolated converter such as the isolated flyback converter and regulates it to a predetermined value. This predetermined value for the input voltage regulated by the active power factor correction circuit for the high-frequency clocked converter is known due to the specification (for example via a voltage divider) and can thus be taken into account when detecting the power transmitted from the primary side.

As already mentioned, the LED converter can have an isolated flyback converter. The isolated flyback converter can be operated as a constant current source, i.e. regulate to a constant output current. In this case, for example, the output voltage of the isolated flyback converter, that is to say the voltage that is output at the output of the LED converter 10 and corresponds to the voltage across the LED module 1, can be recorded and evaluated. This output voltage can be recorded directly or indirectly, for example by measuring the voltage on a primary-side winding of the transformer of the isolated flyback converter. Additionally or alternatively, the duration of the switch-off time of the activation of the high-frequency clocked switch of the isolated flyback converter can be monitored and evaluated in order to recognize a load change and thus to read out information from the LED module 1.

The isolated flyback converter can also be operated as a constant voltage source, i.e. regulate to a constant output voltage. In this case, a change in the load on the LED module 1 will lead to a change in the output current, and this change can be detected. This change in the output current can lead, for example, to a change in the peak current that occurs through the high-frequency clocked switch during the switch-on phase of the high-frequency clocked switch of the isolated flyback converter. The monitoring of the primary-side current by the high-frequency clocked switch can thus be used to monitor a change in load in order to read out information from the LED module 1.

The isolated flyback converter can also be operated with a fixed pulse duty factor at a fixed frequency. In such an operation, the level of the output current and / or the output voltage can be evaluated in order to detect a change in load. If only the LED path of the LED module is active, then the output voltage will take on the value of the forward voltage of the LED path. If there is a load change through the circuit 4, then the output voltage will drop. This change can be recorded as a load change.

As already mentioned, the LED converter can have an isolated resonant half-bridge converter such as, for example, a so-called LLC converter. The LLC converter can be operated as a constant current source, i.e. regulate to a constant output current. In this case, for example, the output voltage of the isolated flyback converter, that is to say the voltage that is output at the output of the LED converter 10 and corresponds to the voltage across the LED module 1, can be recorded and evaluated. This output voltage can be recorded directly or indirectly, for example by measuring the voltage on a primary-side winding of the transformer of the LLC converter.

If only the LED path of the LED module is active, then the output voltage will take on the value of the forward voltage of the LED path. If there is a load change through the circuit 4, then the output voltage will drop. This change can be recorded as a load change. Additionally or alternatively, the clock frequency of the LLC converter that is set on the basis of the control loop can also be monitored and evaluated in order to recognize a load change and thus to read out information from the LED module 1. If the control loop of the LLC converter is designed in such a way that, when the load changes by the circuit 4, a frequency limit of the control of the half bridge of the LLC converter is reached, this can also be evaluated in order to read out the information.

The isolated resonant half-bridge converter such as LLC converter can also be operated as a constant voltage source by operating it at a fixed frequency, the frequency being selected so that the resulting voltage at the output is below the value of the forward voltage of the LED path. In this case, a change in the load on the LED module 1 will lead to a change in the output current, and this change can be detected. This change in the output current can take place, for example, on the secondary side of the LLC converter and be transmitted to the primary side by means of a coupling element such as a current transformer. The monitoring of the output current can thus be used to monitor a change in load in order to read out information from the LED module 1.

The LED converter 10 is operated, for example, in a start phase in a certain mode, for example in a fixed-frequency mode or also operated as a current source or voltage source, in order to recognize a load change and thus information from the circuit 4 read out, which is transmitted, for example, according to at least one protocol.

The circuit 4 can also have a digital control unit IC1, which is designed to output various types of modulated signals as a preferably modulated load change, for example also a specific pulse sequence as digital coding (sequence of zeros and ones). The LED converter 10 can be designed to query different types of information, that is to say different operating parameters and / or maintenance parameters, from the LED module 1 by changing the supply voltage and also to query one of several LED modules selectively. The supply voltage can be changed, for example, by means of a low-frequency (in the range from a few Hertz to one kilohertz) or high-frequency modulation (in the tens or hundreds of kilohertz or up to the megahertz range).

The digital control unit IC1 of the circuit 4 can be designed as an integrated circuit. For example, the integrated circuit can be designed as an integrated control circuit with only three or four connections.

In an embodiment with three connections, the digital control unit IC1 would have a first connection Vp which is connected to the supply voltage of the LED module 1 ( Fig. 9 ). The digital control unit IC1 can detect the supply voltage of the LED module 1 via this first connection Vp by means of the first analog-digital converter A / D1 connected to this connection Vp. A second connection Vn is connected to the ground of the LED module 1 and enables an internal ground connection within the digital control unit IC1. A third connection Vdd can be connected to a capacitor, the other connection of which is also connected to ground of the LED module 1. The second terminal Vp can be internally connected to the first terminal Vp via a diode and a switch Svdd.

This switch Svdd can be compared by means of a comparator Comp1 as a function of a comparison of the voltage currently present at the connection Vdd with a reference value Ref. Depending on the result of the comparison, the switch Svdd can be switched on by the driver unit VddCtrl when the actual value of the voltage at the terminal Vdd is less than the reference value Ref. A current then flows through the switch Svdd into the capacitor, which is connected to the third terminal Vdd. The voltage present at the third terminal Vdd can be used as an internal voltage supply for the digital control unit IC1. In this case, the connection Vdd serves to stabilize the internal voltage supply of the digital control unit IC1.

According to this example, the digital control unit IC1 can be programmed in advance, for example during manufacture or assembly of the LED module 1. This programming of the digital control unit IC1 can, for example, specify an operating parameter of the LED module 1 such as the target current or the target voltage.

A switching element S6 is integrated into the digital control unit IC1, which functions as the switch 6 in the example of FIG Fig. 1 corresponds and is designed to output at least one modulated signal or different types of modulated signals, preferably as a modulated load change. The voltage at the first terminal Vp is connected internally by closing the integrated switching element S6 to the second terminal Vn directly or indirectly, for example via an integrated resistor R6, and thus pulls the voltage at the terminal Vp to a lower potential. For example, the modulated signal can be a specific pulse sequence and output as digital coding (sequence of zeros and ones).

By means of the switching element S6, the digital control unit IC1 can thus transmit information, for example in a run-up phase (i.e. a time-limited start phase of the LED converter and LED module 1), preferably in accordance with the at least one protocol, which is for example in the LED module 1 and is stored in the LED converter 10. The current through the switching element S6 can be monitored by means of the resistor R6, the switching element S6 being able to be opened if the current through the switching element S6 and thus the resistor R6 becomes too great. The voltage drop across the resistor R6 and thus the current flowing through it can be detected by means of a second analog-digital converter A / D2. The reading out and evaluation of the two analog-digital converters as well as the control of the switching element S6 can be done by a "Config and Com" control block integrated into the digital control unit IC1. All other operations such as signal evaluations and outputs can also be carried out using this control block.

For example, a sensor system for detecting the temperature can also be integrated into the digital control unit IC1, whereby the digital control unit IC1 can transmit an excess temperature or an operating temperature as a maintenance parameter to the LED converter as information in accordance with the at least one protocol. As a maintenance parameter, the digital control unit IC1 can, for example, also have a counter for the operating time and the digital control unit IC1 can be designed to output an aging parameter of the LED module or the LED path or an operating time of the LED module as a maintenance parameter. The digital control unit IC1 can also detect an overvoltage on the LED module 1 and output a corresponding error message as a maintenance parameter. Optionally or alternatively, the LED path of the LED module 1 can be bridged by closing the switching element S6 and thus protected from the overvoltage.

In the Fig. 10 an embodiment of the digital control unit IC1 with four connections is shown. The digital control unit IC1 has a fourth connection Cfg, to which a configuration element such as a resistor Rcfg (selection resistor R11) can be connected. A controllable current source Icfg can be connected internally to this fourth connection Cfg. The voltage drop across the resistor Rcfg, which results from the current fed in by the controllable current source Icfg and the resistance value of the resistor Rcfg, can be controlled by the "Config and Com" control block of the digital control unit IC1 via a third analog-to-digital converter A / D3 can be detected. This detected voltage at the fourth connection Cfg can specify an operating parameter of the LED module 1, such as, for example, the target current or the target voltage. Optionally, for example, a temperature-dependent resistor can also be arranged between the fourth connection Cfg and the third connection Vdd. The temperature-dependent resistor can be designed in such a way that its resistance changes sharply in the event of excess temperature on the LED module 1, as a result of which the voltage at the fourth terminal Cfg also changes. This change can be detected by the digital control unit IC1 and, for example, an excess temperature can be transmitted as a maintenance parameter as information in accordance with the at least one protocol to the LED converter. For example, an NTC can be used as the temperature-dependent resistor, which lowers its resistance when the temperature is too high, as a result of which the voltage at the fourth terminal Cfg increases. The controllable current source Icfg can, for example, only be active when the digital control unit IC1 is started in order to read out the value of the resistor R11, while in continuous operation of the LED module 1 only the voltage resulting from the voltage divider from the temperature-dependent resistor and resistor R11 to detect excess temperature is monitored.

In contrast to the examples of the Fig. 9 and 10 is in this variant the Fig. 11 . the switch not as an integrated switching element S6 but as a external switch 6 analogous to the example of Fig. 1 executed. This switch 6 is controlled by the digital control unit IC1 via a fifth connection Sdrv. A resistor R6 is arranged in series with the switch 6. The current through the resistor R6 can be detected and monitored by the digital control unit IC1 on the basis of the voltage drop across the resistor R6 by means of a sixth terminal Imon.

The example of Fig. 12 shows a further embodiment of the digital control unit IC1. This example, like the example of the Fig. 10 the connections Vp, Vn and Vdd. The fourth connection Cfg is also present, to this in turn a resistor R11 (Riled) is connected as a configuration element. The digital control unit IC1 also has two further connections. A resistor Rovt, which is a temperature-dependent resistor, is connected to a further connection Vovt. An excess temperature can be detected by monitoring the resistance value of this resistance Rovt. For this purpose, a further controllable current source can be arranged in the digital control unit IC1, which outputs a current at the further connection Vovt, which current flows into the resistor Rovt. Depending on the current resistance value, which is monitored on the basis of the detected voltage at this connection Vovt, the digital control unit IC1 can conclude that the LED module 1 is overheating. In an analogous manner, a current can be fed into the temperature-dependent resistor Ritm connected to it via a further controllable current source at the further connection Vitm, and the digital control unit IC1 can use the current resistance value, which is monitored on the basis of the voltage detected at this connection Vitm, to the Close the operating temperature on the LED module 1. Depending on the value of the detected operating temperature, this can be transmitted to the LED converter as information in exactly the same way as an excess temperature as information in accordance with the at least one protocol.

The information about the operating temperature can be evaluated by the LED converter, whereby an intelligent regulation of the current can take place through the LED module 1 without an excess temperature having to be reached.

The switch 6 or the switching element S6 can perform further functions on the LED module 1, which can be controlled by the digital control unit IC1. For example, afterglow protection can be enabled. The digital control unit IC1 can, for example, recognize when the LED module 1 is to be switched off or has already been switched off by switching off the supply voltage. In order to avoid voltages coupled in due to parasitic effects or remaining residual charges, the switch 6 or the switching element S6 can be closed in order to prevent the LED from glowing due to the coupled voltages. Alternatively or additionally, protection of the LED module 1 from overvoltages can also be made possible by at least briefly closing the switch 6 or the switching element S6 in the event of an overvoltage at the supply input of the LED module 1 in order to reduce the overvoltage or to close the LED protect. Protection against overvoltages when the LED module 1 is disconnected from the LED converter when the LED module 1 is in operation can thus also be made possible, as so-called "hot-plug" protection. Such a disconnection can occur unintentionally as a result of a sudden break in contact in the supply line or as a result of a user error due to an intervention, such as, for example, changing the LED module 1 during operation.

The LED converter 10 can bring about a change of the LED module to a communication mode by selectively changing the supply voltage for the LED module 1, and then the LED converter 10 can detect the change in the power consumption of the LED module 1 and according to the decode at least one protocol that is stored, for example, in the LED module 1 and in the LED converter 10.

For example, the LED converter 10 can thus request various information from the LED module 1, it being possible for a specific protocol to be stored for each request. This enables a bidirectional communication path between the LED module and the LED converter without additional lines or pins.

The change in the power consumption of the LED module 1 can be brought about as a function of a value of the first supply voltage 5a according to one of several predetermined protocols and thus a different load change can be brought about according to one of several predetermined protocols.

To detect the change in the power consumption of the LED module 1 by the LED converter 10, three concepts, among other things, can be used. On the one hand, the determination of a current-constant load (which is only an example which is not the subject of the invention), wherein the constant current can be measured, for example, via a discharge rate of a capacitor at the LED converter 10. On the other hand, by determining a frequency of the change in the power consumption of the LED module 1 (which is only an example which is not the subject of the invention), for example by directly detecting the current on the converter side. And finally by indirect detection by means of determining a peak current within the LED converter, which is an embodiment of the present invention, which comprises, for example, an isolated flyback converter or buck converter, which is measured via a shunt. The peak current follows the change in the power consumption of the LED module 1.

In summary, the present invention proposes to transmit information from an LED module 1 to an LED converter 10 which allows conclusions to be drawn about operating and / or maintenance parameters to be set on the LED module 1. The operating parameter to be set can be, for example, the target current or the target voltage.

For this purpose, according to the invention, a circuit 4 (load modulation circuit) is provided on the LED module, which, for example, in a voltage range of a first supply voltage 5a that is not equal to zero and in which an LED path 3 connected to the LED module 1 is non-conductive, a Represents load for the LED converter, and in a voltage range of a second supply voltage 5b, which is not equal to zero and at which a connected LED path 3 is conductive, does not represent a load for the LED converter 10. The circuit 4 can also be activated only temporarily, preferably only during a start phase of the LED_Leuchte. The load can be constant or repeatedly variable (modulated), for example according to a predetermined protocol. For example, a modulated change in load can take place, for example in accordance with a predetermined protocol. The power consumption can be recorded by the LED converter 10, in particular also a change in the power consumption (amplitude, frequency, duty cycle). As a result, the LED converter 10 can determine the operating and / or maintenance parameters. The transmission of this information between the LED module 1 and the LED converter 10 does not require any additional connections (only the connection of the supply voltage). In addition, no interaction with LED module 1 and / or LED converter 10 is necessary. This improves the disadvantages of the known prior art.

Claims (5)

1. LED converter (10) for an LED module (1),

   • the LED module (1) comprising:

   ∘ ports (2) for an LED series (3);

   ∘ ports (12) for the LED converter (10);

   ∘ a circuit (4) designed to constitute a load, preferably an active power load, when a first supply voltage (5a) is applied to the LED module (1) in a starting phase and is designed not to constitute a load when the starting phase has elapsed,
   the circuit (4) being designed during the starting phase to encode at least one operating and/or maintenance parameter of the LED module (1) by a change in a power consumption according to a predetermined protocol,
   the circuit (4) being in addition designed to constitute a variable-current load which causes the change in the power consumption of the LED module (1) according to the predetermined protocol,

   • wherein the LED converter (10) has ports (12) for the LED module (1) and in addition has a high-frequency clocked converter, preferably an isolated flyback converter, and the high-frequency clocked converter has a transformer,
   wherein, by setting the first supply voltage (5a) or a second supply voltage (5b) for the LED module (1), the high-frequency clocked converter is designed to switch selectively between a mode for detecting the power consumption of the LED module (1) when the first supply voltage (5a) is applied and a mode for lighting operation of the LED series (3) when the second supply voltage (5b) is applied; to indirectly detect the power consumption of the LED module (1) on a primary side of the transformer of the high-frequency clocked converter during the starting phase; and to decode the at least one operating and/or maintenance parameter of the LED module (1) on the basis of the indirectly detected power consumption and by means of the predetermined protocol,

   • characterized in that
   for indirect detection, the LED converter is designed to detect a change in the power consumption of the LED module (1) during the starting phase by detecting a change in a duty cycle, the duty cycle corresponding to a timing of the LED converter (10).
2. LED converter (10) according to Claim 1, the at least one operating and/or maintenance parameter being a setpoint current through the LED series (3) connected to the LED module (1), an aging parameter, an operating time, and/or a spectrum of a light emitted by the LED series (3).
3. LED converter (10) according to either of Claims 1 to 2, designed to identify the LED module (1) on the basis of the at least one determined operating and/or maintenance parameter.
4. LED light comprising an LED module (1) according to Claim 1 and an LED converter (10) according to any one of Claims 1 to 3.
5. Method for determining information relating to an LED module (1) according to Claim 1 and at an LED converter (10) according to any one of Claims 1 to 3, wherein the following method steps are carried out by the LED converter (10):

   • indirectly detecting a power consumption of the LED module (1) by the high-frequency clocked converter during a starting phase, wherein the circuit (4) causes a modulated load change on the LED module (1) during the starting phase, wherein for the indirect detection of the power consumption of the LED module (1) a change in a duty cycle is detected, the duty cycle corresponding to a cycle rate of the LED converter (10);

   • determining at least one operating and/or maintenance parameter of the LED module (1) by means of a decoding of the indirectly detected power consumption with the aid of a predetermined protocol.

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