DE102017113013A1 - Operating device and method for operating a control gear - Google Patents

Abstract

The invention relates to an operating device (10) having an operating circuit (11) and a lighting arrangement (12). The luminous means arrangement (12) has a plurality of light-emitting strands (12a), (12b) which emit light with different light color, for example warm white light and cold white light. The first output branch (17) with the first light-emitting-material strand (12a) and the second output branch (18) with the second light-emitting string (12b) are connected in parallel with one another and connected to a converter output (16) of a converter circuit (15). The converter circuit (15) provides an output current (IA) at the converter output (16). In series with the output branches (17), (18), a switching device (21) is connected. The switching device (21) is controlled in such a way that at any one time maximum one of the two output branches (17), (18) is electrically conductively connected to the converter output (16), so that not multiple branch currents (I1), (I2) flow simultaneously can. A dimming control device (26) controls the converter circuit (15) to set an amount (A) of the output current (IA) and controls the switching device (21). As a result, the overall brightness of the illuminant arrangement (12) and the light color can be adjusted flicker-free over a wide range.

Description

The invention relates to an operating device and a method for operating a control gear. To the operating device, a lamp arrangement with a plurality of light-emitting strands can be connected. The operating device and the lamp arrangement connected thereto form a lighting system. Each light source string can have one or more light sources, which can be connected in parallel and / or in series. The light-emitting means are preferably semiconductor light-emitting means, in particular light-emitting diodes.

The operating device has a common converter circuit for providing an output current for the lamp arrangement. About a dimming control device, the brightness of the lamp assembly can be adjusted depending on a dimming signal.

An operating device is off, for example DE 10 2015 205 808 A1 known. There are several light sources existing, which are connected in parallel. One of the light-emitting strands is constantly electrically connected to the output of a power source. The other light source can be clocked by switching on and off of a switch based on a pulse width modulated control signal connected to the power source or separated from it. As a result, the output current of the current source is divided between the two output branches in order to keep the light color constant during dimming.

A similar operating device is also in DE 20 2015 103 127 U1 disclosed. Also from EP 2 760 254 and WO 2015/061143 A1 It is known to distribute an output current to different output branches to change the light color.

The end WO 2014/177535 known operating device has two output branches, each with a light source strand. The brightness is specified by a pulse width modulated signal. The switch-on pulse of the pulse-width-modulated signal is split to adjust the light color to the different output branches or light source strands. This can result in relatively long off phases, in which none of the bulbs lights, which can lead to flickering.

In WO 2015/062925 A2 It is proposed to provide for each light source strand of an operating device in each case a separate, controllable converter circuit. As a result, the individual light source strands can indeed be operated independently of each other, but the cost and cost of such a control gear are very high.

EP 2 291 058 B1 describes a method for driving an operating device, wherein a warm white lamp and a cold white lamp are operated via a driver circuit. The driver circuit is driven by two pulse width modulated signals. The two output strands can be operated independently of each other. Again, a high cost of the driver circuit is required to operate the connected lamps independently.

Starting from the state of the art, it can be regarded as an object of the present invention to provide an operating device and a method for operating the operating device, which provides improved control of the brightness and the light color.

This object is achieved by an operating device with the features of claim 1 and a method having the features of claim 15.

To the operating device, a lamp arrangement with a plurality of light-emitting strands can be connected. Each light source string contains one or more light sources. The light sources of a light source string can be arranged in series with one another and / or parallel to one another. Each light source strand is set up to emit a light color different from the other light source strands. In a preferred embodiment, two light-emitting strands are present. The one light-emitting strand can, for example, warm-white light and the other light-emitting strand can emit, for example, cold-white light.

The operating device has a converter circuit, which is preferably designed as a power source. The converter circuit provides an output current at its converter output. The output current is, for example, a direct current. Depending on the specific embodiment of the converter circuit, the direct current current ripple may have. If the amount of the output current is mentioned, this means the time average, if the output current contains current ripple.

Two output branches are connected to the converter output. At each of the output branches, a light source strand of the lighting arrangement can be connected. A switching device is arranged in series between the output branches and the converter output upstream or downstream with respect to the flow direction of the output stream. About the switching device, the output branches can be electrically connected to the converter output or electrically blocked. When manufactured electrically conductive A branch current flows into the output branch in conjunction with the converter output, while with the output branch blocked there is no closed circuit and the flow of a branch current in the output branch is prevented.

The operating device also has a dimming control device. The dimming control device is set up to determine a current setting signal and at least one switching signal as a function of at least one dimming signal. The at least one dimming signal specifies the overall brightness of the lighting arrangement and the light color of the lighting arrangement. Preferably, the dimming control device is provided with two dimming signals for the two parameters. The at least one dimming signal can be set, for example, via an operator interface by an operator. The current setting signal specifies the amount of the output current of the converter circuit and is transmitted to the converter circuit. The current setting signal can be, for example, a pulse-width-modulated signal which activates one or more converter switches for setting the magnitude of the output current.

The at least one switching signal is transmitted to the switching device. It specifies the times at which an output branch is electrically connected to the converter output or electrically blocked. Once the electrical conductive connection to the transducer output has been established, a branch current can flow through the respective output branch. If the electrical connection is blocked or interrupted by the switching device, no branch current flows through the relevant output branch. The at least one switching signal is predetermined such that at any one time at most one of the output branches is electrically conductively connected to the converter output, so that a maximum of one branch current flows through one of the existing output branches.

Over the amount of the output current thus the current amplitude of a clocked via the switching device branch current is predetermined. The mean value of each branch current is given by the ratio between the duty cycle and the turn-off of the respective branch current, ie the periods during which the relevant output branch is electrically connected to the converter output (duty) and the periods during which the relevant output branch is electrically locked (off-time). For example, the mean value of each branch current can be adjusted in a pulse width modulated manner by corresponding switching of the switching device.

Because the current amplitude of the branch current is known at all times and corresponds to the output current amount of the output current, the light color of the lamp arrangement can be set very precisely by the at least one switching signal. The branch current flowing through an output branch does not affect the current amplitude of other branch currents. At any given time, the branch current through at least one output branch is equal to zero.

It is preferred if the dimming control device is set up to determine the current setting signal such that the magnitude of the output current corresponds to at least one minimum current. It is also possible for the converter circuit to be designed in such a way that at least one minimum current is always provided at the converter output, independently of the current setting signal. The total brightness of the lamp arrangement can therefore be adjusted via the output current in a range between the minimum current and a maximum current of the output current.

The operating device is arranged in a preferred embodiment, from a gap-free operation, in which the output current flows without interruption to a latching operation, in which the output current is interrupted during repetitive off phases, switching from the gap-free to the lopsided operation, when the at least one dimming signal requests a total brightness that is less than a minimum brightness.

It is preferred if the dimming control device is set up to determine the at least one switching signal in gap-free operation in such a way that one of the output branches is electrically connected to the converter output at any time when the total brightness requested by the at least one dimming signal corresponds to or is at least equal to a minimum brightness exceeds. If the required total brightness is at least as great as the minimum brightness, the overall brightness of the lighting arrangement can be achieved by an output current flowing without interruption, which corresponds at least to the minimum value. The operating device will be operated without a gap. The output current of the converter circuit flows through one of the output branches at all times. The amount of the uninterrupted flowing output current can be changed to adjust the total brightness between the minimum value and the maximum value.

It is also preferred if the dimming control device is set up to determine the current setting signal in the latching operation such that the magnitude of the output current corresponds to the minimum current and to determine the at least one switching signal such that all output branches are electrically blocked during at least one switch-off phase by the at least one Dimming signal requested total brightness is less than a minimum brightness. In this case, a high dimming level can no longer be achieved solely by reducing the magnitude of the output current since it has already reached its minimum value. A further brightness reduction is achieved by the lopsided operation, in which the output current is interrupted during at least one switch-off phase. During the switch-off phase, all output branches are electrically blocked. During the turn-off phase, the converter circuit may be switched off or in an inactive state, in particular a converter switch is not switched.

During intermittent operation, the output current can be periodically switched on and off, in the manner of a pulse width modulation. For example, for this purpose, the at least one switching signal can be periodic and generate at least one switch-off phase of the output current in each period.

It is preferred if the at least one switching signal is periodic and there are several turn-off phases in each period. As a result, the total switch-off duration of the output current required during a period can be distributed over several switch-off phases. As a result, the flickering of the lamp arrangement is reduced. For example, after each turn-off phase within the same period, another of the existing output branches is electrically connected to the converter output. Thus, during a period, a branch current alternately flows through each of the existing output branches in accordance with the amount of the output current, the turn-off phase between the switching from one branching current to the other branching current being provided.

The dimming control device may also be configured to determine the at least one switching signal in such a way that each of the output branches is alternately electrically connected to the converter output and separated from the converter output by means of the switching device. The branch current flowing through the respective output branch is therefore a clocked current which has a current amplitude which corresponds to the magnitude of the output current. The current amplitudes of the branch currents are preferably the same size. Each branch current may be, for example, a pulse width modulated branch current.

It is also preferred if the dimming control device receives a separate dimming signal for each output branch. The dimming signal indicates the brightness for each output branch or each light source strand. The sum of all dimming signals therefore specifies the overall brightness of the lighting arrangement. The ratio of the dimming signals to each other indicates the light color of the lamp arrangement.

It is preferred if in each case one characteristic, for example at least one equation or at least one characteristic, is present for each dimming signal in the dimming control device. The characteristic assigns each dimming value of the dimming signal a pair of values from the current amplitude or the magnitude of the output current and a duty cycle or a duty cycle for the branch current. For example, the characteristic may include, for each dimming value of the dimming signal, an equation or characteristic for the brightness value of the dimming value describing the relationship between the duty cycle for the branch current and the current amplitude of the branch current. The characteristic indicating the relationship between the current amplitude and the magnitude of the output current and the duty cycle or the duty cycle for the branch current, for example, can be approximately assumed to be hyperbolic.

It is also advantageous if each output branch has a branch capacitor, which is connected in parallel to the respective light source strand in order to reduce current ripple of the at least one light source in the light source strand. In series with each branch capacitor, a branch diode is then preferably connected in order to specify a flow direction of the branch current. The branch diode is arranged in particular in the current flow direction upstream of the branch capacitor and the light source string. This prevents a flow of current from one output branch into an adjacent output branch.

It is also preferred if the switching device in each case has a controllable switch for each of the existing output branches. The dimming control device provides a separate switching signal for each controllable switch. In each case a controllable switch is preferably connected in series with the associated output branch.

An operating device or a lighting system with a dimmable lighting arrangement can therefore be operated as follows:

An output current is provided at the converter circuit or the current source. The dimming control device receives at least one and preferably two dimming signals. By the at least one dimming signal, the overall brightness and the light color of the lamp arrangement is specified. The dimming control device determines a current setting signal and at least one switching signal, preferably in each case one switching signal for each existing output branch. The current setting signal is transmitted to the converter circuit or current source and specifies the amount of the output current. The at least one switching signal is transmitted to the switching device and specifies the times of switching of the switching device. The at least one switching signal therefore specifies at which times a branch current is switched on or off by an output branch. The at least one switching signal is predetermined such that a branch current flows at most through one of the output branches at most times. It is also preferable if exactly one branch current flows through an output branch at any one time. However, there may be turn-off phases, to which all output branches are electrically interrupted, so that no branch current and thus no output current flows. The switch-on phases and the switch-off phases of the output current can be repeated periodically. The total duration of the turn-off phases within a period is preferably less than the total time duration during which the output current flows.

• 1 ein Blockschaltbild eines Ausführungsbeispiels eines Betriebsgeräts,
• 2 eine vereinfachte, schematische Darstellung eines Ausgangsstromes, eines ersten Zweigstromes und eines zweiten Zweigstromes bei einem lückfreien Betrieb des Betriebsgeräts,
• 3 eine vereinfachte, schematische Darstellung des zeitlichen Verlaufs des Ausgangsstromes, eines ersten Zweigstromes und eines zweiten Zweigstromes bei einem lückenden Betrieb des Betriebsgeräts,
• 4 beispielhafte Kurven zur Ermittlung von Betriebsparametern des Betriebsgeräts für den lückfreien Betrieb und
• 5 eine beispielhafte Kurven zur Ermittlung von Betriebsparametern des Betriebsgeräts für einen lückenden Betrieb.

Advantageous embodiments of the invention will become apparent from the dependent claims, the description and the drawings. Hereinafter, preferred embodiments of the invention will be explained in detail with reference to the accompanying drawings. Show it:

• 1 a block diagram of an embodiment of a control gear,
• 2 a simplified, schematic representation of an output current, a first branch current and a second branch current in a gap-free operation of the operating device,
• 3 a simplified, schematic representation of the time course of the output current, a first branch current and a second branch current in a lopsided operation of the operating device,
• 4 exemplary curves for determining operating parameters of the operating device for the gap-free operation and
• 5 an exemplary curves for determining operating parameters of the operating device for a lopsided operation.

1 shows a block diagram of an embodiment of a control gear 10 , To the operating device 10 belongs to an operating circuit 11 and one to the operating circuit 11 connected lighting arrangement twelve , The lighting arrangement twelve has several light sources strands and, for example, a first light source string 12a and a second light source string 12b , The light source strands 12a . 12b emit light with different light colors. In the embodiment, the first light source strand 12a emit white light with a higher color temperature than the second light source 12b , The first light source string 12a For example, cold white light with a color temperature greater than 5000 to 6000 K and the second light source strand 12b emit warm white light with a color temperature less than 3000 to 4000K.

Every light source string 12a . 12b has, for example according to at least one lamp, wherein a plurality of lamps in series and / or can be connected in parallel to each other. The light bulbs may be semiconductor light sources, such as light-emitting diodes.

The operating circuit 11 has a converter circuit 15 on that at a transducer output 16 an output current IA for the lamp arrangement twelve provides. The converter output 16 has a first output port 16a and a second output terminal 16b , Between the two output connections 16a and 16b are several output branches and, for example, a first output branch 17 and a second output branch 18 connected in parallel. The first output branch 17 has the first light source string 12a and the second output branch 18 has the second light source string 12b on.

The two output branches 17 . 18 are essentially identical. Each output branch 17 . 18 has a branch diode 19 , whose anode is connected to the first output terminal 16a connected is. The cathode terminal of the branch diode 19 is with a branch capacitor 20 connected. Parallel to the branch capacitor 20 is the respectively assigned light source string 12a . 12b connected.

Between the output branches 17 . 18 and the second output terminal 16b is a switching device 21 connected in the embodiment for each of the output branches 17 . 18 a separate controllable switch 22 having. Is the switch 22 electrically conductive, can by the associated first output branch 17 or second output branch 18 a respective first branch current I1 or second branch current I2 flow. Is the switch 22 Locking, the flow of a branch current I1 , I2 suppressed. The desk 22 of the first output branch 17 is by a first switching signal S1 and the switch 22 of the second output branch 18 by a second switching signal S2 driven.

The converter circuit 15 is preferably designed as a power source. The output current IA is for example a direct current. Depending on the design of the converter circuit 15 the DC current may have current ripples. Of the output current IA has an amount A , As an amount A of the output current IA is the mean over time to understand. The amount A of the output current IA is by a current setting signal e specified.

The operating circuit 11 also has a dimming control 26 , The dimming control device 26 receives at least one dimming signal and preferably in each case a dimming signal for each existing output branch. For example, the dimming controller becomes 26 therefore a first dimming signal D1 for the first output branch 17 and a second dimming signal D2 for the second output branch 18 transmitted. The dimming signal D1 . D2 each gives the brightness value for the light source strand 12a respectively. 12b the output branch 17 respectively. 18 in front. The overall brightness of the lamp arrangement twelve is therefore due to the two dimming signals D1 . D2 and for example the sum of the dimming signals D1 . D2 specified. The ratio of the brightnesses of the individual illuminant strands 12a . 12b that is due to the relationship between the dimming signals D1 . D2 is predetermined defines the light color of the lamp assembly twelve , The light color of the lamp arrangement twelve can be between the light color of the first light source string 12a and the light color of the second light source string 12b be varied.

The dimming control device 26 is set up, depending on the dimming signals D1 . D2 the current setting signal e and the switching signals S1 . S2 to investigate. In the embodiment illustrated herein, the dimming controller generates 26 also a switch-on signal P , by means of which the converter circuit 15 can be switched on or off.

The converter circuit 15 On the input side, a DC link voltage UZ provided. The DC link voltage UZ can via a DC link capacitor 27 be buffered. The DC link voltage UZ can by another converter circuit, such as a PFC circuit 28 to be provided. The PFC circuit 28 is also set up to perform power factor correction ("PFC" stands for Power Factor Correction). The PFC circuit 28 can be connected to an AC source 29 , For example, be connected to the AC mains.

The operating device 10 or the operating circuit 11 can by means of the dimming control device 26 be operated in a gapless operation or in a lückenden operation. Leak-free operation occurs when the output current IA without interruption through one of the output branches 17 . 18 can flow. Latching operation occurs when all output branches during a switch-off phase 17 . 18 through the relevant switch 22 are electrically locked, so no branch current I1 . I2 and therefore no output current IA can flow.

According to the example, the dimming control device is 26 to set up the operating circuit 11 or the operating device 10 operate in the gap-free operation, if by the dimming signals D1 . D2 predetermined total brightness at least equal to a minimum brightness or greater. Is that through the dimming signals D1 . D2 requested total brightness of the lamp arrangement twelve Less than the minimum brightness, the operating device 10 or the operating circuit 11 operated in a lopsided operation.

Both in the gap-free, as well as in the lopsided operation is in each case at most one of the output branches 17 . 18 electrically conductive. Accordingly, only one branch current flows at any one time, for example the first branch current I1 through the first output branch 17 or the second branch stream I2 through the second output branch 18 , The switching signals S1 . S2 for the switches 22 the switching device 21 are controlled by the dimming controller 26 specified accordingly.

In 2 is exemplary and only schematically the current waveform for the output current IA , the first branch stream I1 and the second branch stream I2 depending on the time specified. Because at any one time only one of the output branches 17 respectively. 18 is electrically conductive, the output current flows IA either as the first branch stream I1 through the first output branch 17 or as a second branch stream I2 through the second output branch 18 ,

Through the dimming control device 26 is determined by the current setting signal e the amount A of the output current IA specified. By choosing the times of switching the controllable switch 22 the switching device 21 , is at a first time t0 the desk 22 of the first output branch 17 in its blocking state and the switch 22 of the second output branch 18 switched to its conducting state. At a second time t1 vice versa is the switch 22 the first output branch 17 conductive and the switch 22 of the second output branch 18 off. This switching repeats periodically. The period of a period is with T designated. A first duty cycle T1 is the time duration during a period T in which the first branch stream I1 flows and a second duty cycle T2 is the length of time during a period T in which the second branch current I2 flows. The sum of the first duty cycle T1 and the second duty cycle T2 corresponds to the cycle time in gap-free operation T ( 2 ).

To adjust the overall brightness and the light color remain two degrees of freedom: one can via the Stromeinstellsignal e the amount A of the output current IA and secondly, the ratio of the first duty cycle T1 and the second duty cycle T2 be changed to adjust the light color. In 4 is for example the determination of the amount for the gap-free operation A for the output current and the first duty cycle T1 and the second duty cycle T2 illustrated.

In the dimming control device 26 is for each dimming signal and, for example, for the first dimming signal D1 and for the second dimming signal D2 given a characteristic, for example at least one equation, for each dimming value of the dimming signals D1 . D2 the operating state of the light source strands 12a . 12b indicates, in particular the respective duty cycle T1 . T2 and the respective current amplitude B1 . B2 , In 4 are an example of a first curve K1 for a given value of the first dimming signal D1 and a second curve K2 for a given value of the second dimming signal D2 illustrated. Every point on the first corner K1 corresponds to the current value for the first dimming signal D1 and therefore a certain predetermined brightness of the first light source strand 12a , Every point on the first corner K1 corresponds to a value pair from a first duty cycle T1 and a first current amplitude B1 for the first branch stream I1 , Likewise, every point corresponds to the second curve K2 the current value for the second dimming signal D2 and therefore the requested brightness of the second light source string 12b , Every point on the second turn K2 corresponds to a value pair from a second duty cycle T2 and a second current amplitude B2 for the second branch stream I2 ,

The curves K1 . K2 are, for example, hyperbola-shaped and mirrored to each other at a parallel to the y-axis (here: axis for the amount of the current). The two curves K1 . K2 have an intersection. This intersection corresponds to the operating state of the operating circuit 11 where the first current amplitude B1 of the first branch stream I1 and the second current amplitude B2 of the second branch stream I2 are the same size and in each case the amount A of the output current IA correspond. The intersection also gives the first duty cycle in gap-free operation T1 and the second duty cycle T2 within the period T at. Will the operating circuit 11 operated at this operating point, the output current IA during a period T during the first duty cycle T1 as the first branch stream I1 through the first output branch 17 and then during the second duty cycle T2 as a second branch stream I2 through the second output branch 18 directed.

As already explained, the gapless operation is exemplary in 2 shown. The first branch stream I1 and the second branch stream I2 have a pulsed or pulsed course and are each pulse width modulated. The current amplitude B1 . B2 is defined as the current value during the relevant duty cycle T1 respectively. T2 flows. Since at no time both output branches 17 . 18 are conducting, are the current amplitudes B1 . B2 for the two branch streams I1 . I2 the same size and according to the amount A of the output current IA ,

Varying the overall brightness of the illuminant assembly twelve by changing the amount A is limited. The amount of the output current IA that the converter circuit 15 is at least as large as the minimum value Imin. Corresponds to the amount A of the output current IA the minimum value Imin, corresponds to the overall brightness of the lamp assembly twelve the minimum brightness in the gap-free operation.

Is due to the dimming signals D1 . D2 a total brightness requested that is less than the minimum brightness, becomes the operating circuit 11 operated in a lopsided operation ( 3 and 5 ). As it is in 3 can be seen, the output current IA no longer flow without interruption. During one or more off phases x1 . tx2 in every period T is the current flow of the output current IA interrupted to the overall brightness of the bulb assembly twelve continue to reduce.

The determination of the parameters for the current setting signal e and the switching signals S1 . S2 are in 5 illustrated. As can be seen, is the intersection of the two curves K1 and K2 in a range below the minimum value Imin for the output current IA , Therefore, as an amount A for the output current IA and therefore as current amplitude B1 . B2 for the branch streams I1 . I2 set the minimum value Imin. This results in the first duty cycle T1 for the first branch stream I1 and the second duty cycle T2 for the second branch stream I2 , It can be seen that the sum of the switch-on duration T1 . T2 is smaller than the period T , The difference of the period T minus the switch-on times T1 . T2 gives the total off time txg , During each period, during a total time, the total turn-off time period flows txg corresponds, no output current IA ,

When the total off time txg is small and, for example, less than a duration threshold, may during a period at a first time t0 after expiration of the first duty cycle T1 the first branch stream I1 be switched off. From this first time t0 can then be the current flow of the output current IA for the total off time txg interrupted and then at a second time t1 the second branch stream I2 during the second duty cycle T2 be turned on. As a result, switching losses can be minimized.

Exceeds the total off time txg However, a time duration threshold, it may cause a flicker of the lamp assembly twelve come. It is then advantageous to use the entire switch-off period txg during a period T split into several switch-off phases. At the in 3 illustrated embodiment, the total off period txg on two off phases x1 and tx2 divided up. During a period, the following switching operations take place: at the first time t0 becomes the first branch current I1 off. Subsequently, the current flow of the output current IA during a first shutdown phase x1 interrupted and at a second time t1 becomes the second branch current I2 switched on. At a third time t2 then becomes the second branch current I2 switched off and the current flow during a second shutdown phase tx2 until a fourth time t3 interrupted, at which the first branch current I1 is turned on. At a fifth time t4 becomes the first branch current I1 switched off and the period is over. The first branch stream I1 is switched off again at the beginning of a subsequent period.

The two off phases x1 . tx2 each separate the first duty cycle T1 and the second duty cycle T2 from each other. At the in 3 illustrated embodiment, the two off phases x1 . tx2 same size. You can also be different in size. By shortening the switch-off phases x1 . tx2 versus the total off time txg , the flickering can be reduced.

As it is based on the 2-5 can be seen, is in all modes of operation at any time in each case only one output branch 17 . 18 electrically conductive with the converter output 16 connected. It can therefore only one of the branch streams at any time I1 or I2 flow. For this reason, the current amplitude corresponds B1 . B2 every branch current I1 . I2 the amount A of the output current IA , As a result, the current amplitude of a branch current is not influenced by the switching on or off of another output branch.

The invention relates to a control gear 10 with an operating circuit 11 and a lighting arrangement twelve , The lighting arrangement twelve has several light sources 12a . 12b that emit light of different light color, for example, warm white light and cool white light. The first output branch 17 with the first light source string 12a and the second output branch 18 with the second light source string 12b are connected in parallel to each other and to a converter output 16 a converter circuit 15 connected. The converter circuit 15 puts at the converter output 16 an output current IA ready. In series to the output branches 17 . 18 is a switching device 21 connected. The switching device 21 is controlled such that at any time maximum one of the two output branches 17 . 18 electrically conductive with the converter output 16 is connected, so not multiple branch streams I1 . I2 can flow at the same time. A dimming control device 26 controls the converter circuit 15 to set an amount A of the output current IA and controls the switching device 21 at. This allows the overall brightness of the lamp arrangement twelve and adjust the light color flicker-free in many areas.

LIST OF REFERENCE NUMBERS

10

control gear

11

operating circuit

12

Mittal light arrangement

12a

first light source string

12b

second light source string

15

converter circuit

16

converter output

16a

first output terminal

16b

second output terminal

17

first output branch

18

second output branch

19

branch diode

20

branch capacitor

21

switching device

22

switch

26

Dimmsteuereinrichtung

27

Link capacitor

28

PFC circuit

29

AC voltage source

A

Amount of the output current

B1

Current amplitude of the first branch current

B2

Current amplitude of the second branch current

D1

first dimming signal

D2

second dimming signal

e

Stromeinstellsignal

I1

first branch stream

I1

second branch stream

IA

output current

K1

first turn

K2

second bend

P

switch-on

S1

first switching signal

S2

second switching signal

t

Time

T

period

t0

first time

t1

second time

t2

third time

t3

fourth time

t4

fifth time

txg

total off time

x1

first switch-off phase

tx2

second switch-off phase

UZ

Intermediate circuit voltage

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015205808 A1 [0003]
• DE 202015103127 U1 [0004]
• EP 2760254 [0004]
• WO 2015/061143 A1 [0004]
• WO 2014/177535 [0005]
• WO 2015/062925 A2 [0006]
• EP 2291058 B1 [0007]

Claims (15)

Operating device (10), which is set up to operate a lighting arrangement (12), with a converter circuit (15) which provides an output current (IA) for the luminous means arrangement (12) at its converter output (16), with at least two output branches (17, 18), which are connected in parallel and connected to the converter output (16), to each output branch (17, 18) a light-emitting strand (12a, 12b) can be connected, wherein the light-emitting strands (12a, 12b ) Emit light with different light colors, with a switching device (21) arranged in series with the output branches (17, 18), which is set up to electrically connect or electrically interrupt the output branches (17, 18) to the transducer output (16), with a dimming control device (26), which is set up, depending on at least one dimming signal (D1, D2), which specifies a total brightness and a light color of the lighting arrangement (12), a current setting signal (E) and at least one switching signal (S1, S2) to be determined, wherein the current setting signal (E) the amount of the output current (IA) and the converter circuit (15) is transmitted, wherein the at least one switching signal (S1, S2), the times of switching the switching device (21) and specifies the switching device (21) is transmitted, wherein the at least one switching signal (S1, S2) is predetermined such that at any time maximum one of the output branches (17, 18) is electrically conductively connected to the converter output (16) that through this output branch ( 17, 18) a branch current (I1, I2) flows. Operating device after Claim 1 , characterized in that the dimming control device (26) is adapted to determine the Stromeinstellsignal (E) such that the amount of the output current (IA) corresponds to at least a minimum current (Imin). Operating device after Claim 2 , Characterized in that to determine at least one switching signal (S1, S2) in such a way that at any time one of the output branches (17, 18) electrically conductively connected to the converter output (16), the Dimmsteuereinrichtung (26) is adapted to such that a branch current (I1, I2) flows when the total brightness requested by the at least one dimming signal (D1, D2) corresponds at least to a minimum brightness. Operating device after Claim 2 or 3 , characterized in that the dimming control device (26) is adapted to determine the Stromeinstellsignal (E) such that the amount of the output current (IA) corresponds to the minimum current (Imin) and the at least one switching signal (S1, S2) to determine such in that during at least one switch-off phase (tx1, tx2) all output branches (17, 18) are electrically blocked when the total brightness requested by the at least one dimming signal (D1, D2) is less than a minimum brightness. Operating device after Claim 4 , characterized in that the at least one switching signal (S1, S2) is periodic and in each period at least one turn-off (tx1, tx2) is present. Operating device after Claim 5 , characterized in that in each period a plurality of turn-off phases (tx1, tx2) are present and after each turn-off (tx1, tx2) within the same period, another of the existing output branches is electrically connected to the converter output (16) when the at least a total brightness demanded by a dimming signal (D1, D2) is less than a minimum brightness and the sum of all the switch-off phases (tx1, tx2) exceeds a time duration threshold value. Operating device according to one of the preceding claims, characterized in that the dimming control device (26) is adapted to determine the at least one switching signal (S1, S2) such that each of the output branches (17, 18) by means of the switching device (21) alternately electrically is conductively connected to the converter output (16) and electrically blocked, so that through the output branches (17, 18) in each case a clocked branch current (I1, I2) flows, wherein the current amplitudes (B1, B2) of the branch currents (I1, I2) respectively are equal to and equal to the amount (A) of the output current (IA). Operating device according to one of the preceding claims, characterized in that the dimming control device (26) for each output branch (17, 18) a separate dimming signal (D1, D2) is provided, the brightness for the at the associated output branch (17, 18) connected light-emitting string (12a, 12b) indicates. Operating device after Claim 7 and 8th , characterized in that in the dimming control device (26) in each case a characteristic for each dimming signal (D1, D2) is present, each value of the dimming signal (D1, D2) a current amplitude (B1, B2) and a duty cycle or a duty cycle (T1 , T2) for the branch current (I1, I2). Operating device according to one of the preceding claims, characterized in that the converter circuit (15) is designed as a current source. Operating device according to one of the preceding claims, characterized in that each output branch (17, 18) has a branch capacitor (20), which is connected in parallel to the respective light-emitting rod (12a, 12b). Operating device after Claim 11 , characterized in that each output branch (17, 18) has a branch diode (19) connected in series with the branch capacitor (20). Operating device according to one of the preceding claims, characterized in that the switching device (21) each have a controllable switch (22) for each output branch (17, 18). Operating device after Claim 13 , characterized in that each switch (22) is connected in series with the respectively associated output branch (17, 18). Method for operating an operating device (10) comprising a converter circuit (15), at least two output branches (17, 18), which are connected in parallel and connected to the converter output (16), wherein each output branch (17, 18) has an illuminant strand (17) 12a, 12b), wherein the light-emitting strands (12a, 12b) emit light with different light colors, a switching device (21) arranged in series with the output branches (17, 18), and a dimming control device (26), comprising the following steps: Providing an output current (IA) at a converter output (16) of the converter circuit (15) for the illuminant arrangement (12), Providing at least one dimming signal (D1, D2) for the dimming control device (26), which specifies a total brightness and a light color of the lighting arrangement (12), - Determining a Stromeinstellsignals (E) and at least one switching signal (S1, S2) depending on the at least one dimming signal (D1, D2), wherein the Stromeinstellsignal (E) the amount of the output current (IA) and the converter circuit (15) is transmitted wherein the at least one switching signal (S1, S2) predetermines the times of switching of the switching device (21) and is transmitted to the switching device (21) and wherein the at least one switching signal (S1, S2) is predetermined such that maximum at any time a branch current (I1, I2) flows through one of the output branches (17, 18).

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