AT17142U1 - Amplitude dimming of light emitting diodes in a very low dimming value range using an analog bypass circuit - Google Patents

Abstract

The present invention provides an operating device (2) for operating a light-emitting diode line (6) with at least one light-emitting diode, the operating device (2) comprising: a) an output (A1, A2) for electrically connecting the light-emitting diode line (6) to the at least a light emitting diode on the operating device (2); b) at least one converter stage (3) for providing an operating current (I2) at the output (A1, A2) of the operating device (2) for the at least one light-emitting diode of the light-emitting diode section (6) that can be connected to the operating device (2); c) a bypass circuit (4) which is connected in parallel to the output (A1, A2) of the operating device (2) and is set up to absorb a current (I3); and d) a control circuit (7) which is set up for amplitude dimming of the at least one light emitting diode of the light emitting diode path (6) connectable to the output (A1, A2) of the operating device (2) by controlling the at least one converter stage (3) and the bypass circuit (4) to set the amplitude of the operating current (I2) according to a dimming value to be achieved. The present invention also relates to a lighting device (1) comprising such an operating device (2) and a light-emitting diode section (6) with at least one light-emitting diode, as well as a method for operating such an operating device (2) for amplitude dimming of a light-emitting diode section (6) with at least one light-emitting diode.

Description

description

AMPLITUDE DIMMING OF LIGHT DIODES IN A VERY LOW DIMMING VALUE RANGE WITH AN ANALOGUE BYPASS CIRCUIT

1. FIELD OF THE INVENTION

The present invention relates to an operating device for operating a light emitting diode line with at least one light emitting diode, which can perform an amplitude dimming of the at least one light emitting diode in a very low dimming value range of, for example, 1% to 0.1% in an advantageous manner. The present invention further relates to a lighting device comprising such an operating device and a light-emitting diode section with at least one light-emitting diode, as well as a method for operating such an operating device for amplitude dimming of a light-emitting diode section with at least one light-emitting diode.

2. BACKGROUND

Operating devices for operating a light source, such as a light-emitting diode line with at least one light-emitting diode, are known from the prior art, which comprise at least one converter stage for providing an operating current for the light source, the light emission of the light source being controlled via the operating current .

It is also known to dimming a light-emitting diode or the light emitted by a light-emitting diode by PWM modulation (PWM dimming) or amplitude modulation (amplitude dimming) of the operating current supplied to the light-emitting diode.

Dimming by means of PWM modulation has the disadvantage that it can produce a flickering or flickering of the emitted light and / or a stroboscopic effect, which can be perceived by the human eye and thus an influence on the human body can have.

In order to circumvent this disadvantage of PWM dimming, amplitude dimming of the light-emitting diode or of the light emitted by the light-emitting diode can be carried out.

However, dimming by means of amplitude modulation has the disadvantage that with standard operating devices for light-emitting diodes, without special additional components for dimming, only dimming values between 10 and 15% can be achieved. Operating devices from the premium segment achieve dimming values of up to 1% without special additional components for dimming.

A “dimming value of 100%” is understood to mean the dimming value at which the light source, such as a light-emitting diode, is operated with the nominal current and thus emits the nominal radiant power (nominal light output). Consequently, with a dimming value of 40%, for example, the light source is only operated with 40% of its nominal current. The lower the dimming value at which a light source is operated, the lower the emitted radiant power, i.e. the smaller the amount of light emitted and consequently the lower the light intensity of the light emitted by the light source. At a dimming value of 0%, a light source does not emit any light, i.e. the light source is switched off or inactive.

[0008] The “nominal current of a light source” is understood to mean the value of the electrical current specified by the manufacturer during normal operation of the light source. Consequently, the nominal current of a light source corresponds to the maximum permissible operating current at which the manufacturer of the light source guarantees safe operation of the light source without damage or destruction of the light source. Therefore, dimming values greater than 100%, i.e. values of the operating current greater than the rated current, can damage or even destroy the light source.

In order to achieve very low dimming values for amplitude dimming, for example between 1% and 0.1%, which are possible according to the DALI standard (“Digital Addressable Lighting Interface Standard”), an operating device must have a highly dynamic control circuit

be used. However, this is disadvantageous because of the high complexity and the high costs of such an operating device.

In the light of this prior art, it is therefore the object of the present invention to provide an operating device for operating light emitting diodes, which is also suitable for amplitude dimming at very low dimming values, for example between 1% and 0.1%, without that an elaborate and

Cost-intensive, highly dynamic control circuit must be provided for this.

[0012] These and other objects, which are mentioned on reading the following description or can be recognized by the person skilled in the art, are achieved by the subject matter of the independent claims. The dependent claims further develop the central concept of the present invention in a particularly advantageous manner.

3. DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, an operating device for operating a light emitting device is

ode section provided with at least one light-emitting diode, wherein the operating device comprises:

a) an output for electrically connecting the light-emitting diode path with the at least one light-emitting diode to the operating device;

b) at least one converter stage for providing an operating current at the output of the operating device for the at least one light-emitting diode of the light-emitting diode path that can be connected to the operating device;

c) a bypass circuit which is connected in parallel to the output of the operating device and is set up to take up a current; and

d) a control circuit which is set up for amplitude dimming of the at least one light-emitting diode of the light-emitting diode path that can be connected to the output of the operating device to adjust the amplitude of the operating current according to a dimming value to be achieved by controlling the at least one converter stage and the bypass circuit.

In other words, an operating device is provided in which part of the current provided by the converter stage can be absorbed by a bypass circuit or can be passed through the bypass circuit to the light-emitting diode path that can be connected to the output of the operating device, the other part of the current provided by the converter stage then corresponding to the operating current for operating the light-emitting diode path. Here, the control circuit for amplitude dimming of the at least one light-emitting diode of the light-emitting diode path can control the amplitude of the operating current supplied to the light-emitting diode path by controlling the converter stage and the bypass circuit. That is, for amplitude dimming, the control circuit can control the amplitude of the operating current by setting or controlling the amplitude of the current provided by the at least one converter stage and the amplitude of the current consumed by the bypass circuit.

Thus, by connecting a bypass circuit in parallel to the output of an operating device for operating a light-emitting path, amplitude dimming in a very low dimming value range, for example between 1% and 0.1%, is made possible without a complex and cost-intensive, highly dynamic process Control circuit is needed.

A “light-emitting diode path with at least one light-emitting diode” is understood to mean a light source which comprises one or more light-emitting diodes. The term “light emitting diode (LED)” includes light emitting diodes with primary excitation, light emitting diodes with secondary excitation, inorganic light emitting diodes, organic light emitting diodes (OLEDs) and all other known types of light emitting diodes.

A converter stage preferably comprises an actively clocked DC / DC converter or DC voltage converter, which is set up to provide an operating current at its output for operating a light-emitting diode line. In other words, a converter stage preferably corresponds to an LED converter which supplies an operating current (LED current) to the light-emitting diode path as a power supply, the light emission of the at least one

Light-emitting diodes of the light-emitting diode path depends on the supplied operating current and consequently the light emission can be controlled by controlling or setting the supplied operating current.

The at least one converter stage can, for example, be an isolated clocked DC / DC converter (clocked DC / DC converter with galvanic separation between input and output), such as a flyback converter Qflyback Converter "), push-pull converter ") Or a resonant converter, or a non-isolated or non-isolated, pulsed DC / DC converter (clocked DC / DC converter without galvanic isolation between input and output), such as a step-down converter (" buck -converter, step-down-converter ”), step-up converter (“ boost-converter, step-up-converter ”) or an inverting converter (“ buck-boost-converter ”/.

The converter stage can additionally or alternatively comprise an AC / DC converter, which is preferably designed as a PFC circuit. A “PFC circuit” is understood to mean a power factor correction circuit. In other words, a PFC circuit corresponds to an electrical circuit that is designed to have a power factor almost | or in accordance with legal requirements. Consequently, the converter stage can correspond to a DC / DC converter and / or an AC / DC converter.

One converter stage can be preceded by further converter stages in the operating device, so that the converter stage is the last stage in a chain of converter stages which provides the operating current or LED current for operating the light-emitting diode line.

Furthermore, the at least one converter stage of the operating device can also be preceded by an AC / DC converter, the AC / DC converter preferably being designed as a PFC circuit. Here, the AC / DC converter can be arranged both in the operating device and externally.

[0022] A “bypass circuit” is understood to mean a circuit which is set up to absorb a current in an activated or active state, the amount or amplitude of the current consumed being adjustable by a control circuit and the bypass circuit can be switched on and off by a control circuit.

[0023] “Amplitude dimming” is understood to mean dimming a light source, such as a light-emitting diode, in which the amplitude of the operating current supplied as a power supply to the light source is changed in order to achieve dimming. The smaller the amplitude of the operating current, the greater the extent or degree of dimming. A light source in a dimmed state, i.e. a dimmed light source, emits less light or light with a lower light intensity compared to a non-dimmed or less strongly dimmed state.

A "dimming value" indicates the extent or degree of dimming of a light source, such as a light-emitting diode, or of the light emitted by the light source. The terms “dimming level”, “dimming level”, “dimming level” etc. are used synonymously in the following. The dimming value is given in percent (%) related to the nominal current of a light source. For example, with a dimming value of 100%, the nominal current is fed to the light source as the operating current. At a dimming value of 40%, an operating current is fed to the light source, the amplitude of which corresponds to 40% of the amplitude of the nominal current. The smaller the dimming value, the smaller the amplitude of the operating current supplied to the light source and consequently the smaller the amount of light or light intensity emitted by the light source.

As already stated above, the “nominal current of a light source” is understood to mean the value of the electrical current specified by the manufacturer during normal operation of the light source. Consequently, the nominal current of a light source corresponds to the maximum permissible operating current at which the manufacturer of the light source guarantees safe operation of the light source without damage or destruction of the light source.

The control circuit is preferably a microcontroller, an ASIC or a hybrid.

the end. Any other control circuit known to those skilled in the art can also be used.

The dimming values are preferably fed to the control circuit as DALI dimming commands. Consequently, the control circuit preferably comprises a DALI interface in order to be able to communicate in accordance with the DALI standard. For example, the control circuit can then receive DALI commands, such as dimming commands, as well as information and output information and / or commands externally.

The amplitude of the current provided by the at least one converter stage at its output preferably corresponds to the sum of the amplitude of the current absorbed by the bypass circuit and the amplitude of the operating current provided at the output of the operating device.

In other words, using the current consumption of the bypass circuit, the operating current supplied to the light-emitting diode path can be set on the basis of the current provided by the at least one converter stage.

Furthermore, the bypass circuit is preferably a current sink circuit which is set up to take up a current with an amplitude that can be set by the control circuit in the switched-on state and not to take up any current in the switched-off state.

Furthermore, the control circuit is preferably set up to switch the bypass circuit on and off and to set the amplitude of the current consumed by the bypass circuit when the bypass circuit is switched on.

Preferably, the bypass circuit comprises at least one transistor and resistor connected in series; and the control circuit is preferably set up to switch the bypass circuit on and off by controlling the transistor.

The control circuit can preferably control or set the current consumption of the bypass circuit by controlling the transistor. The current absorbed by the bypass circuit is preferably dissipated or converted into thermal energy by the resistor.

This is advantageous because a bypass circuit can be implemented using inexpensive electrical components.

Furthermore, the bypass circuit preferably comprises an operational amplifier, a bipolar transistor and a resistance circuit with at least one resistor, wherein the base connection of the bipolar transistor with the output of the operational amplifier, the collector connection of the bipolar transistor with the connection of the higher potential Output of the operating device and the emitter connection is serially connected to a first connection of the resistance circuit. A second connection of the resistance circuit is connected to the connection of the output of the operating device having the lower potential, the node between the emitter connection of the bipolar transistor and the first connection of the resistance circuit is connected to the inverting input of the operational amplifier; and the non-inverting input of the operational amplifier is connected to the control circuit.

This is advantageous because, due to the control properties of the operational amplifier, a stable current consumption is ensured by the bypass circuit, the current consumption, in particular the amount of current consumed, being controlled by the control circuit.

The control circuit for controlling the current consumption of the bypass circuit preferably provides a stable control voltage at the non-inverting input of the operational amplifier.

[0038] “A resistance circuit” is understood to mean an electrical circuit which comprises one or more resistors, the resistors being connected in series and / or in parallel.

Furthermore, the control circuit is preferably set up for a dimming value to be achieved that is greater than or equal to a first predetermined dimming value, the amplitude of the operating current by controlling only the at least one converter stage, preferably regulated according to the dimming value to be achieved, while the Bypass circuit is switched off.

In other words, as long as the dimming value to be achieved (eg 30%) is greater than or equal to a first predetermined dimming value, the control circuit for amplitude dimming preferably only controls the at least one converter stage, the bypass circuit being switched off and not consuming any current . Consequently, in the case of amplitude dimming in this dimming value range (dimming values to be achieved that are greater than or equal to the first predetermined dimming value), the operating current (LED current) provided at the output of the operating device according to the invention for operating the light-emitting diode path preferably corresponds to the current that is supplied by the at least one converter stage its output is provided.

The control circuit therefore controls switching on or off of the bypass circuit, preferably depending on the dimming value to be achieved, the control circuit preferably switching off the bypass circuit for dimming values to be achieved that are greater than or equal to the first predetermined dimming value and for dimming values to be achieved which are smaller than the first predetermined dimming value, the bypass circuit switches on.

The control circuit preferably controls the at least one converter stage in a regulated manner, i.e. with feedback, with the current provided at the output of the at least one converter stage and / or the operating current provided at the output of the operating device being fed to the control circuit as a feedback variable. In this case, a current or voltage corresponding to the dimming value to be achieved preferably corresponds to the reference variable or the setpoint value.

According to a preferred embodiment, the control circuit is preferably set up to operate the at least one converter stage at an operating point that corresponds to the first predetermined dimming value, and the amplitude of the dimming value to be achieved, which is smaller than the first predetermined dimming value Operating current to be set preferably regulated by controlling the bypass circuit according to the dimming value to be achieved.

In other words, for a dimming value to be achieved (eg 0.5% or 0.1%) that is smaller than the first predetermined dimming value, the at least one converter stage is controlled by the control circuit in such a way that the at least one converter stage provides a current corresponding to the first predetermined dimming value. Meanwhile, the control circuit controls the bypass circuit in such a way that the current consumption of the bypass circuit sets an operating current at the output of the operating device that corresponds to the dimming value to be achieved.

In this case, the control circuit controls the at least one converter stage for providing the current corresponding to the first predetermined dimming value, preferably in an uncontrolled manner. In order to set the operating current corresponding to the dimming value to be achieved (which is smaller than the first predetermined dimming value), the control circuit controls the bypass circuit preferably in a regulated manner, that is, with feedback, whereby preferably the current consumed by the bypass circuit and / or that at the output of the operating device provided operating current is supplied as a feedback variable to the control circuit. In this case, a current or voltage corresponding to the dimming value to be achieved preferably corresponds to the reference variable or the setpoint value. The control circuit is preferably also supplied with a measurement signal which reproduces the current provided at the output of the at least one converter stage (which is set to the first predetermined dimming value).

The first predetermined dimming value preferably corresponds to a limit or a threshold value below which stable dimming with only the at least one converter stage is not possible. The first predetermined dimming value preferably corresponds to 3%, particularly preferably

wise 1%.

According to a further preferred embodiment, the control circuit is preferably set up to operate the at least one converter stage at an operating point that corresponds to a second predetermined dimming value and the amplitude for a dimming value to be achieved that is smaller than the first predetermined dimming value of the operating current by controlling the bypass circuit in accordance with the dimming value to be achieved, preferably in a regulated manner. Here, the second predetermined dimming value is smaller than the first predetermined dimming value.

In other words, for a dimming value to be achieved (eg 0.5% or 0.1%) that is smaller than the first predetermined dimming value, the at least one converter stage is controlled by the control circuit in such a way that the at least one converter stage provides a current corresponding to a second predetermined dimming value (which is smaller than the first predetermined dimming value). Meanwhile, the control circuit controls the bypass circuit in such a way that the current consumption of the bypass circuit sets an operating current at the output of the operating device that corresponds to the dimming value to be achieved.

In this case, the control circuit controls the at least one converter stage for providing the current corresponding to the second predetermined dimming value, preferably in an uncontrolled manner. In order to set the operating current to be achieved (which is smaller than the first dimming value and preferably smaller than the second predetermined dimming value), the control circuit controls the bypass circuit preferably in a regulated manner, ie with a feedback, preferably the one recorded by the bypass circuit Current and / or the operating current provided at the output of the operating device is fed as a feedback variable to the control circuit. In this case, a current or voltage corresponding to the dimming value to be achieved preferably corresponds to the reference variable or the setpoint value. The control circuit is preferably also supplied with a measurement signal which reproduces the current provided at the output of the at least one converter stage (which is set to the second predetermined dimming value).

The second predetermined dimming value is preferably selected in such a way that it corresponds to the dimming value to be achieved. In this case, the control circuit then sets the dimming value to be achieved in an uncontrolled manner through the at least one converter stage (the operating point of which is set to the second predetermined dimming value), with the regulation being carried out to the dimming value to be achieved by the bypass circuit.

The control circuit is preferably set up to adapt the operating point of the at least one control circuit to an operating point which corresponds to a smaller dimming value compared to the first predetermined dimming value and / or the second predetermined dimming value when the amplitude of the bypass circuit consumed current exceeds a predetermined upper threshold value for the current consumed by the bypass circuit.

In other words, with an amplitude dimming to a dimming value to be achieved (eg 0.5% or 0.1%) that is smaller than the first predetermined dimming value, it is established that the amplitude of the current absorbed by the bypass circuit exceeds a predetermined upper threshold value (while the control circuit operates the at least one converter stage at an operating point which corresponds to the first predetermined dimming value or the second predetermined dimming value), then the control circuit preferably sets the operating point of the at least one converter stage to an operating point which is a smaller one Dimming value in comparison to the first predetermined dimming value and / or the second predetermined dimming value corresponds.

That is, the control circuit can set the operating point of the at least one converter stage to an operating point of a lower dimming value compared to the first predetermined dimming value and / or the second predetermined dimming value if it is recognized that the control margin of the bypass circuit is too large.

The control circuit preferably sets the operating point of the at least one converter stage in such a way that a predetermined power which is dropped at the bypass circuit is not exceeded or a predetermined upper threshold value for the power dropping at the bypass circuit is not exceeded . In this case, the predetermined power that is allowed to drop at the bypass circuit depends preferably on the components used for the bypass circuit, their thermal coupling and / or the cooling that is present. Furthermore, the predetermined power preferably depends on the LED voltage and thus on the bypass voltage, since the predetermined power depends on both the current and the voltage. The LED voltage preferably corresponds to the voltage with which the light-emitting diode path that can be connected to the operating device is operated or supplied in the connected state, and the bypass voltage preferably corresponds to the voltage that drops or is applied to the bypass circuit.

The predetermined power or the predetermined upper threshold value for the power dropping at the bypass circuit preferably corresponds to 1W, particularly preferably 0.5 W. In other words, 1W or 0.5W is an exemplary limit or an exemplary upper threshold value for the power that may drop at the bypass circuit.

The predetermined upper threshold value for the current consumed by the bypass circuit is selected such that the operation of the operating device or one of its components is not disrupted by the current consumed and / or the operating device or one of its components is not damaged or is destroyed and / or the functionality of the light-emitting diode line is not disturbed (if the light-emitting diode line is connected to the control gear).

The upper threshold value for the current consumed by the bypass circuit is preferably selected such that a predetermined power that may be applied to the bypass circuit is not exceeded. As already stated above, the predetermined power that may drop across the bypass circuit is preferably dependent on the current and voltage as well as on the components used for the bypass circuit, the thermal coupling of these components and / or the existing cooling. In other words, the predetermined power is preferably dependent on the design and / or the components of the operating device used.

For example, the upper threshold value for the current consumed by the bypass circuit preferably corresponds to 5mA when the LED voltage or the bypass voltage is 100V and the upper threshold value for the current consumed by the bypass circuit preferably corresponds to 10mA if the LED voltage or the bypass voltage is 50V. In other words, the upper threshold value for the current consumed by the bypass circuit is preferably selected such that a predetermined power of, for example, 0.5W (100V x 5mA or 50V x 10mA) applied to the bypass circuit is not exceeded will.

As already stated above, the predetermined power preferably corresponds to 1W, particularly preferably 0.5W.

For example, in the case of a converter stage with 1000mA, the upper threshold value for the current consumed by the bypass circuit preferably corresponds to 5mA if the LED voltage or bypass voltage is 100V, and preferably 10mA if the LED voltage or bypass voltage is 50V.

The bypass circuit preferably dissipates or converts the current drawn into thermal energy; and the control circuit is preferably set up to adapt the operating point to an operating point which corresponds to a smaller dimming value compared to the first predetermined dimming value and / or the second predetermined dimming value when the energy dissipation exceeds a predetermined upper threshold value for the energy dissipation.

In other words, an amplitude dimming to one is to be achieved

71717

Dimming value (e.g. 0.5% or 0.1%) that is smaller than the first predetermined dimming value, it is determined that the energy dissipation in the bypass circuit exceeds a predetermined upper threshold value (while the control circuit operates the at least one converter stage at an operating point , which corresponds to the first predetermined dimming value or the second predetermined dimming value), then the control circuit preferably sets the operating point of the at least one converter stage to an operating point which corresponds to a lower dimming value compared to the first predetermined dimming value and / or the second predetermined dimming value.

That is, the control circuit can set the operating point of the at least one converter stage to an operating point of a lower dimming value compared to the first predetermined dimming value and / or the second predetermined dimming value if it is recognized that the control margin of the bypass circuit is too large.

The predetermined upper threshold value for the energy dissipation is selected such that the operation of the operating device or one of its components is not disrupted by the energy dissipation and / or the operating device or one of its components is not damaged and / or the operation is not destroyed the light-emitting diode line is not disturbed (if the light-emitting diode line is connected to the control gear).

The upper threshold value for the energy dissipation is preferably selected in such a way that a predetermined power, which may be applied to the bypass circuit, is not exceeded. The above statements with regard to the upper threshold value for the current consumed by the bypass circuit are also applicable to the predetermined upper threshold value for the energy dissipation. Consequently, the upper threshold value for the energy dissipation is preferably selected such that a predetermined power of preferably 1 W, particularly preferably 0.5 W, is not exceeded. If the amplitude of the current absorbed by the bypass circuit falls below a predetermined lower threshold value for the current absorbed by the bypass circuit and / or the energy dissipation in the bypass circuit falls below a predetermined lower threshold value for the energy dissipation, then the control circuit is preferably used set up to adapt the operating point of the at least one converter stage to an operating point which corresponds to a higher dimming value compared to the dimming value to which the operating point to be adjusted corresponds.

In other words, the control circuit can set the operating point of the at least one converter stage to an operating point of a higher dimming value if it is recognized that the control margin of the bypass circuit is too small.

The lower threshold value for the current consumed preferably corresponds to 1 mA, particularly preferably 0.1 mA.

If the power applied to the bypass circuit falls below a predetermined lower threshold value for the power, then the control circuit is preferably set up to adapt the operating point of the at least one converter stage to an operating point that corresponds to a higher dimming value in comparison to the dimming value to which the operating point to be adjusted corresponds.

The operating device preferably comprises a device for detecting or measuring the current absorbed by the bypass circuit and / or a device for detecting or measuring the energy dissipation in the bypass circuit, these devices then being set up to generate the detection results to be fed to the control circuit.

The first predetermined dimming value preferably corresponds to 3%, particularly preferably 1%.

The second predetermined dimming value preferably corresponds to the dimming value to be achieved, i.e. the dimming value which is preferably to be set in a regulated manner by the bypass circuit (the second dimming value and the dimming value to be achieved being smaller than the first dimming value). The second predetermined dimming value is preferably in the range from 0.1% to 1%

but also correspond to much smaller dimming values, such as 0.03%.

Furthermore, the control circuit for amplitude dimming is preferably set up to control the at least one converter stage and / or the bypass circuit on the basis of the amplitude of the current that is absorbed by the bypass circuit and / or on the basis of the amplitude of the Current that is provided by the at least one converter stage at its output, and / or on the basis of the amplitude of the operating current that is provided at the output of the operating device for the at least one light-emitting diode of the light-emitting diode path that can be connected at the output.

The operating device according to the invention preferably comprises devices for detecting or measuring these currents, which are then set up to feed the detection results to the control circuit.

Furthermore, the operating device according to the invention preferably comprises a current detection circuit for detecting the amplitude of the operating current that is provided at the output of the operating device for the at least one light-emitting diode of the light-emitting diode path that can be connected to the output, and / or the amplitude of the current that is generated by the bypass Circuit is included. In this case, the control circuit is preferably set up to control the bypass circuit in the switched-on state on the basis of the detection result of the current detection circuit.

The control circuit is preferably configured to control the current detection circuit in such a way that the current detection circuit is switched on when the bypass circuit is switched on and the current detection circuit is switched off when the bypass circuit is switched off.

The above-mentioned optional features can be combined in any way according to the present invention in order to produce the device according to the invention.

Furthermore, according to the present invention, a lighting device is provided which comprises an operating device according to the invention, as described above, and a light-emitting diode line with at least one light-emitting diode; wherein the light-emitting diode line is connected to the output of the operating device according to the invention.

Furthermore, according to the present invention, a method for operating an operating device according to the invention, as described above, for the amplitude dimming of a light-emitting diode path with at least one light-emitting diode is provided, in which the control circuit determines the amplitude of the operating current by controlling the at least one converter stage and the bypass circuit according to a dimming value to be achieved.

4. DESCRIPTION OF PREFERRED EMBODIMENTS

A detailed description of the figures is given below. It shows:

FIG. 1 schematically shows a preferred embodiment of an operating device according to the invention;

FIG. 2 schematically shows a further preferred embodiment of an operating device according to the invention; and

FIG. 3 schematically shows a further preferred embodiment of an operating device according to the invention.

Corresponding components have the same reference symbols in the figures.

FIG. 1 schematically shows a preferred embodiment of an operating device according to the invention. The operating device 2 comprises a converter stage 3, a bypass circuit 4, a current detection circuit 5 and a control circuit 7. The operating device 2 and the light-emitting diode section 6 with at least one light-emitting diode together form the lighting device 1, the light-emitting diode section 6 at the two connections A1 and A2 of the output A1, A2 of the operating device 2 is electrically connected.

The converter stage 3 or the output of the converter stage 3 is serially connected to the output A1, A2 of the operating device 2, the bypass circuit 4 being connected in parallel to the converter stage 3 and the output A1 A2 of the operating device 2. Consequently, the current provided by the converter stage 3 corresponds to I; preferably the sum of the current Is consumed by the bypass circuit 4 and the operating current provided at the output A1, A2 of the operating device 2:

1} = I »+13

If the bypass circuit 4 consumes no current, then the operating current I »provided at the output A1, A2 of the operating device 2 corresponds to the current I provided by the converter stage 3 Converter stage 3 provided current I at the output A1, A2 of the operating device 2 and thus past the light-emitting diode section 6, so that the operating current I »for operating the light-emitting diode section 6 is less than the current I; is set.

As already stated above, the converter stage 3 preferably comprises an actively clocked DC / DC converter which is controlled by the control circuit 7 in such a way that the current I} for operating the light-emitting diode path 6 is provided at the output of the converter stage 3. The operating device preferably comprises more than one converter stage, so that one or more converter stages can then be connected upstream of the converter stage 3. Furthermore, the converter stage 3 can also comprise an AC / DC converter or the converter stage 3 can be preceded by an AC / DC converter as a further converter stage, the AC / DC converter preferably being designed as a PFC circuit. Further converter stages, which can be connected upstream of the converter stage 3, can then also be controlled by the control circuit 7.

The bypass circuit 4 is preferably a current sink which, in the switched-on or active state, takes up a current Is set by the control circuit 7 and does not take up any current in the switched-off state. The control circuit 7 is set up to control the bypass circuit, in particular to switch the bypass circuit on and off and to control or set the amplitude of the current I3, ie to control or set the extent of the current consumption of the bypass circuit 4 .

The control circuit 7 can be arranged in the operating device 2 and / or the lighting device 1 or outside the operating device 2 and / or the lighting device 1.

The current detection circuit 5 is arranged according to FIG is to be recorded or measured and fed to the control circuit as a measurement signal. The amount of light emitted by the at least one light-emitting diode of the light-emitting diode path 6 is dependent on the operating current I »or is determined by the operating current I».

A measurement signal is preferably fed to the control circuit 7 by the current detection circuit 5 which determines the operating current I2 and / or the current I; reproduces.

The current detection circuit 5 is preferably switched off by the control circuit 7 when the bypass circuit is switched off in order to minimize or eliminate losses caused by the current detection of the current detection circuit 5 1, for example, to detect the current L provided by the converter stage 3 and / or the current I3 absorbed by the bypass circuit 4.

The control circuit 7 is set up to control the converter stage 3 and the bypass circuit 4 and preferably to control the current detection circuit 5. The control circuit is used to dim the amplitude of the at least one light-emitting diode of the light-emitting diode path 6

set up to receive dimming commands, preferably dimming commands according to the DALI standard, from within the operating device 2 and / or the lighting device 1 (from internal) or from outside the operating device 2 and / or the lighting device 1 (from external). Furthermore, the control circuit is set up to control the converter stage 3 and the bypass circuit 4 for amplitude dimming, preferably in a regulated manner.

The control of the converter stage 3 and the bypass circuit 4 by the control circuit 7 for amplitude dimming of the light-emitting diode path 6, in particular for amplitude dimming in a very low dimming value range of, for example, 1% to 0.1%, is as described above.

FIG. 2 schematically shows a further preferred embodiment of an operating device according to the invention, a preferred embodiment of the bypass circuit 4 and the current detection circuit 5 being shown. The above statements also apply to the preferred embodiment of an operating device according to the invention shown in FIG.

According to FIG. 2, the bypass circuit 4 preferably comprises an operational amplifier OV, a bipolar transistor T1 and a resistor R1. The non-inverting input e1 of the operational amplifier OV is connected to the control circuit 7. The inverting input e2 of the operational amplifier OV is connected to the emitter connection of the bipolar transistor T1 and a first connection of the resistor R1, i.e. to a junction between the emitter connection of the bipolar transistor T1 and the first connection of the resistor R1. The output a1 of the operational amplifier OV is connected to the base connection of the bipolar transistor T1.

The collector connection of the bipolar transistor T1 is connected to the connection A1 of the output A1, A2, of the operating device 2, which has the higher potential of the two connections of the output A1, A2, of the operating device 2. The second connection of the resistor R1 is connected to the second connection A2 of the output A1, A2 of the operating device 2, which has the lower potential of the two connections of the output A1, A2, of the operating device 2.

The control circuit can, by providing a stable control voltage at the non-inverting output e1 of the operational amplifier OV, the current I; control or adjust. The resistor R1 must be dimensioned accordingly. The current Is consumed is preferably dissipated or converted into thermal energy via the resistor R1.

According to the above, it can be seen that other circuits than the circuit shown in FIG. 2 can also be used for the bypass circuit 4, the circuit having to be able to absorb a current I3 under the control of the control circuit 7. In other words, any circuit that represents a controllable current sink can be used for the bypass circuit 4. For example, instead of the bipolar transistor, another transistor, such as a field effect transistor (e.g. MOSFET), can also be used. The operational amplifier OV can also be omitted, an operational amplifier for setting the current consumption of the bypass circuit 4 being recommended for reasons of stability.

According to FIG. 2, the current detection circuit 5 comprises a switch S1 and a resistor R2 (shunt resistor), which are connected in parallel to one another. The switch S1 is preferably a transistor such as a bipolar transistor or a field effect transistor.

The control circuit 7 is preferably set up to switch the switch S1 on or off in order to bridge or not to bridge the shunt resistor R2. If the shunt resistor R2 is not bridged, then the operating current I »can be measured or detected via the voltage drop across the shunt resistor R2. Consequently, this corresponds to an on state of the current detection circuit 5. When the shunt resistor

If R2 was bridged by the switch S1, then the operating current I »does not flow through the shunt resistor R2 and consequently there are no losses at the shunt resistor R2. The bridged state, i.e. when the switch S1 is switched on or closed, corresponds to the switched off state of the current detection circuit 5.

Any other circuit known to the person skilled in the art can preferably be used for the current detection circuit 5, the circuit having to be able to detect or measure a current, in particular the operating current I ».

As already stated above, the control circuit 7 for amplitude dimming is preferably set up to control the at least one converter stage 3 and / or the bypass circuit 4 on the basis of the amplitude of the current Is that is absorbed by the bypass circuit 4, and / or on the basis of the amplitude of the current I, which is provided by the at least one converter stage 3 at its output, and / or on the basis of the amplitude of the operating current I », which is at the output A1, A2, of the operating device 2 for the at least one The light-emitting diode of the light-emitting diode path 6 which can be connected to the output A1, A2 is provided to control.

As shown in Figure 2, the control circuit are preferably supplied by the bypass circuit 4 and the current detection circuit 5 corresponding measurement signals, such as the amplitude value of the current Is from the bypass circuit 4 and the amplitude value of the current I »from the Current detection circuit 5.

Figure 3 shows schematically a further preferred embodiment of an operating device according to the invention, a preferred embodiment of the bypass circuit 4 and the current detection circuit 5 is shown. The above statements also apply to the preferred embodiment of an operating device according to the invention shown in FIG. 3.

The bypass circuit 4 shown in Figure 3 corresponds to the bypass circuit 4 shown in Figure 2, the bypass circuit 4 now includes a capacitor C1 and two further resistors R3 and R4 for stability reasons.

The operating device 2 of Figure 3 also includes a circuit for controlling or switching the switch S1, which comprises a plurality of resistors R5, R6, R7 and R8, two bipolar transistors T2 and T3 and a capacitor C2 Input e3 of this circuit has a constant supply voltage, for example 13V, and applies a control voltage to input e4, via which switch S1 can be switched on and off. The resistors R5 to R8, the bipolar transistors T2 and T3 and the capacitance C2 must be dimensioned accordingly.

Preferably, the control circuit 7 can control the switch S1 of the current detection circuit 5 via another suitable circuit arrangement.

Furthermore, according to FIG. 3, a Zener diode D1 is preferably connected as overvoltage protection in parallel with the current detection circuit 5, in particular with the shunt resistor R2. Any other component suitable for overvoltage protection can also be used.

The voltage or voltage signal which reflects the operating current I »is preferably filtered via a low-pass filter consisting of the resistor R9 and the capacitor C3 before it is fed to the control circuit 7 as a measurement signal.

Claims (10)

Expectations 1. Operating device (2) for operating a light-emitting diode line (6) with at least one light-emitting diode, the operating device (2) comprising: a) an output (A1, A2) for electrically connecting the light-emitting diode path (6) with the at least one light-emitting diode to the operating device (2); b) at least one converter stage (3) for providing an operating current (I2) at the output (A1, A2) of the operating device (2) for the at least one light-emitting diode of the light-emitting diode section (6) that can be connected to the operating device (2); c) a bypass circuit (4) which is connected in parallel to the output (A1, A2) of the operating device (2) and is set up to receive a current (Is); and d) a control circuit (7) which is set up for amplitude dimming of the at least one light emitting diode of the light emitting diode path (6) connectable to the output (A1, A2) of the operating device (2) by controlling the at least one converter stage (3) and the Bypass circuit (4) to set the amplitude of the operating current (I) according to a dimming value to be achieved. 2. Operating device (2) according to claim 1, wherein the amplitude of the current (L) provided at its output by the at least one converter stage (3) is the sum of the amplitude of the current (Is) and absorbed by the bypass circuit (4) corresponds to the amplitude of the operating current (Iz) provided at the output (A1, A2) of the operating device (2). 3. Operating device (2) according to claim 1 or 2, wherein the bypass circuit (4) is a current sink circuit which is configured to receive a current (Is) with an amplitude adjustable by the control circuit (7) when switched on and do not draw any power when switched off. 4. Operating device (2) according to one of the preceding claims, wherein the control circuit (7) is set up to switch the bypass circuit (4) on and off and, when the bypass circuit (4) is switched on, the amplitude of the bypass -Circuit (4) to set the consumed current (ls). 5. Operating device (2) according to one of the preceding claims, wherein the bypass circuit (4) comprises at least one transistor (T1) and resistor (R1) which are connected in series; and wherein the control circuit (7) is set up to switch the bypass circuit (4) on and off by controlling the transistor (T1). 6. Operating device according to one of the preceding claims, - wherein the bypass circuit (4) comprises an operational amplifier (OV), a bipolar transistor (T1) and a resistor circuit with at least one resistor (R1); - The base connection of the bipolar transistor (T1) with the output (a1) of the operational amplifier (OV), the collector connection of the bipolar transistor (T1) with the connection (A1) of the output (A1, A2) of the higher potential Operating device (2) and the emitter connection is serially connected to a first connection of the resistance circuit; - A second connection of the resistance circuit being connected to the connection (A2) of the output (A1, A2) of the operating device (2) having the lower potential; - wherein the node between the emitter connection of the bipolar transistor (T1) and the first connection of the resistance circuit is connected to the inverting input (e2) of the operational amplifier (OV); and - The non-inverting input (e1) of the operational amplifier (OV) is connected to the control circuit (7). 7. Operating device (2) according to one of the preceding claims, - wherein the control circuit (7) is set up for a dimming value to be achieved which is greater than or equal to a first predetermined dimming value, the amplitude of the operating current (I) by controlling only the at least one converter stage (3) according to the dimming value to be achieved, preferably regulated, while the bypass circuit (4) is switched off. 8. Operating device (2) according to claim 7, - wherein the control circuit (7) is set up to operate the at least one converter stage (3) at an operating point for a dimming value to be achieved that is smaller than the first predetermined dimming value corresponds to the first predetermined dimming value, and preferably adjusting the amplitude of the operating current (I2) by controlling the bypass circuit (4) in accordance with the dimming value to be achieved. 9. Lighting device (1) with - an operating device (2) according to one of the preceding claims, - and a light-emitting diode line (6) with at least one light-emitting diode; - The light-emitting diode line (6) being connected to the output (A1, A2) of the operating device (2). 10. A method for operating an operating device (2) according to one of claims 1 to 8 for the amplitude dimming of a light emitting diode path (6) with at least one light emitting diode, wherein the control circuit (7) by controlling the at least one converter stage (3) and the bypass circuit ( 4) adjusts the amplitude of the operating current (I;) according to a dimming value to be achieved. In addition 3 sheets of drawings