Dimmable LED driver for supplying an LED load with a regulated DC voltage

Abstract

Disclosed is a dimmable LED driver (1) for supplying an LED load (3) with a regulated DC voltage. The LED driver (1) comprises high-side, HS, low-side, LS, and parallel pin, PP, output terminals (11, LED+; 12, LED-; 13, PP); and a pulse-width modulation, PWM, circuit (14) for PWM dimming of its through current. The HS and LS output terminals (11, LED+; 12, LED-) are connectable to the LED load (3); the PWM circuit (14) is connected between the LS output terminal (12, LED-) and an ungrounded LS potential of the dimmable LED driver (1); and the PP output terminal (13, PP) is connected to the ungrounded LS potential of the dimmable LED driver (1) and further connectable to one or more further LED drivers (1, 1').. This enables dimming of parallel-connected constant voltage LED drivers with little wiring effort, no mutual communication or synchronization and no elaborate calibration.

Description

Technical Field

[0001] The present disclosure relates generally to the field of lighting technology, and in particular to a dimmable LED driver for supplying an LED load with a regulated DC voltage, to a driver system comprising the dimmable LED driver, to a lighting system, comprising the driver system, and to a method of operating the driver system.Background Art

[0002] There are various approaches of driving high-power LED loads by means of parallel-connected constant voltage LED drivers, such as "voltage droop control", wherein the output voltage of the respective driver depends on its output current.

[0003] If all LED drivers have such an output characteristic, their output ports can easily be connected in parallel.

[0004] However, the parallel-connected LED drivers cannot be dimmed so easily. All parallel-connected LED drivers had to drive their pulse width modulation (PWM) dimming circuit at exactly the same instant. Such a synchronization requires a elaborate communication between the LED drivers.Summary

[0005] It is an object to overcome the above-mentioned and other drawbacks.

[0006] The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0007] According to a first aspect, a dimmable LED driver is provided for supplying an LED load with a regulated DC voltage. The LED driver comprises high-side, HS, low-side, LS, and parallel pin, PP, output terminals; and a pulse-width modulation, PWM, circuit for PWM dimming of its through current. The HS and LS output terminals are connectable to the LED load; the PWM circuit is connected between the LS output terminal and an ungrounded LS potential of the dimmable LED driver; and the PP output terminal is connected to the ungrounded LS potential of the dimmable LED driver and further connectable to one or more further LED drivers.

[0008] The PWM circuit may comprise a semiconductor switch being connected between the LS output terminal and the ungrounded LS potential of the dimmable LED driver; and a PWM control logic being configured to drive the semiconductor switch using a PWM dimming control signal.

[0009] According to a second aspect, a driver system is provided for supplying an LED load with a regulated DC voltage. The driver system comprises a first LED driver according to the first aspect; and one or more further LED drivers having HS and LS output terminals for their part. The HS output terminals of the first LED driver and the HS output terminals of the further LED drivers are connected; and the PP output terminal of the first LED driver and the LS output terminals of the further LED drivers are connected.

[0010] The further LED drivers may respectively comprise an LED driver being identical with the first LED driver.

[0011] The further LED drivers may respectively comprise an LED driver being different from the first LED driver.

[0012] According to a third aspect, a lighting system is provided, comprising a driver system according to the second aspect; and an LED load connected to the HS and LS output terminals of the first LED driver.

[0013] According to a fourth aspect, a method is provided of operating a driver system according to the second aspect, the method comprising PWM dimming of the through current of the first LED driver.Advantageous Effects

[0014] The present disclosure enables dimming of parallel-connected constant voltage LED drivers.

[0015] This requires only little wiring effort, no mutual communication or synchronization and no elaborate calibration.

[0016] Only a single LED driver has to have the proposed added functionality, and any further LED drivers merely serve as constant voltage power supplies that may be realized inexpensively and straightforwardly.

[0017] LED drivers of different manufacturers and power ratings may be deployed.Brief Description of Drawings

[0018] The above-described aspects and implementations will now be explained with reference to the accompanying drawings, in which the same or similar reference numerals designate the same or similar elements.

[0019] The drawings are to be regarded as being schematic representations, and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to those skilled in the art. FIG. 1illustrates an output section of a dimmable LED driver in accordance with the present disclosure; FIGs. 2 - 3illustrate lighting systems in accordance with the present disclosure; and FIG. 4illustrates a method of operating the driver systems of FIGs. 2 - 3 in accordance with the present disclosure. Detailed Descriptions of Drawings

[0020] In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and which show, by way of illustration, specific aspects of implementations of the present disclosure or specific aspects in which implementations of the present disclosure may be used. It is understood that implementations of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0021] For instance, it is understood that a disclosure in connection with a described method may also hold true for a corresponding apparatus or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary implementations and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0022] FIG. 1 illustrates an output section of a dimmable LED driver 1 in accordance with the present disclosure.

[0023] On the left side of FIG. 1 the depicted output section shows an output / smoothing capacitor of the LED driver 1.

[0024] The LED driver 1 is suitable for supplying an LED load 3 (not shown), such as an LED module, with a regulated DC voltage.

[0025] The LED driver 1 comprises a high-side (HS) output terminal 11, LED+, a low-side (LS) output terminal 12, LED- and a parallel pin (PP) output terminal 13, PP.

[0026] The LED driver 1 further comprises a pulse-width modulation (PWM) circuit 14 for PWM dimming of its through current.

[0027] According to the example of FIG. 1, the PWM circuit 14 may comprise a semiconductor switch 141 such as a MOSFET being connected between the LS output terminal 12, LED- and the ungrounded LS potential of the dimmable LED driver 1; and a PWM control logic 142 being configured to drive the semiconductor switch 141 using a PWM dimming control signal (not shown).

[0028] The HS and LS output terminals 11, LED+; 12, LED- are connectable to the LED load 3.

[0029] The PWM circuit 14 is connected between the LS output terminal 12, LED- and an ungrounded LS potential of the dimmable LED driver 1.

[0030] The PP output terminal 13, PP is also connected to the ungrounded LS potential of the dimmable LED driver 1 and further connectable to one or more further LED drivers 1, 1' as explained in more detail below.

[0031] The additional output terminal 13, PP extends the PWM dimming of the LED driver 1 to the one or more further parallel-connected LED drivers 1, 1 '.

[0032] FIGs. 2-3 illustrate lighting systems 2A, 2B, 3 in accordance with the present disclosure.

[0033] The lighting systems 2A, 2B, 3 respectively comprise a driver system 2A, 2B according to the second aspect (see FIG. 1) being suitable for supplying an LED load 3 with a regulated DC voltage, and the LED load 3 connected to the HS and LS output terminals 11, LED+; 12, LED- of the first LED driver 1 of the driver system 2A, 2B.

[0034] In other words, the first LED driver 1 is directly connected to the LED load 3 via both its HS and LS output terminals 11, LED+; 12, LED-.

[0035] The driver system 2A, 2B respectively comprises the afore-mentioned first LED driver 1 according to the first aspect and one or more further LED drivers 1, 1 ' having HS and LS output terminals 11, LED+; 12, LED- for their part.

[0036] The HS output terminals 11, LED+ of the first LED driver 1 and the HS output terminals 11, LED+ of the further LED drivers 1, 1 ' are connected.

[0037] That is to say, the further parallel-connected LED drivers 1, 1 ' are also directly connected to the LED load 3 via their HS output terminals 11, LED+, and indirectly connected to the LED load 3 via their LS output terminals 12, LED- and via the PP output terminal 13, PP the of the first LED driver 1.

[0038] The PP output terminal 13, PP the of the first LED driver 1 is decoupled from the LED load 3 by its PWM circuit 14.

[0039] A total output current of all LED drivers 1, 1' flows via the PWM circuit 14 of the first LED driver 1, which may thus perform PWM dimming of the output current of the whole driver system 2A, 2B.

[0040] The PP output terminal 13, PP of the first LED driver 1 and the LS output terminals 12, LED- of the further LED drivers 1, 1' are also connected.

[0041] According to the example of FIG. 2, the further LED drivers 1, 1' may respectively comprise an LED driver 1 being identical with the first LED driver 1.

[0042] According to the example of FIG. 3, the further LED drivers 1, 1' may respectively comprise an LED driver 1' being different from the first LED driver 1.

[0043] It is sufficient that only a single (i.e., the first) LED driver 1 of the driver system 2B has the additional output terminal 13, PP. The further parallel-connectable LED drivers 1' serve as constant voltage power sources that may be realized inexpensively, straightforwardly and without any further intelligence.

[0044] FIG. 4 illustrates a method 4 of operating the driver systems 2A, 2B of FIGs. 2 - 3 in accordance with the present disclosure.

[0045] The method 4 comprises PWM dimming 41 of the through current of the first LED driver 1.

[0046] The present disclosure has been described in conjunction with various implementations as examples. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed matter, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word "comprising" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation. A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

Examples

Embodiment Construction

[0020]In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and which show, by way of illustration, specific aspects of implementations of the present disclosure or specific aspects in which implementations of the present disclosure may be used. It is understood that implementations of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0021]For instance, it is understood that a disclosure in connection with a described method may also hold true for a corresponding apparatus or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to ...

Technical Field

[0001] The present disclosure relates generally to the field of lighting technology, and in particular to a dimmable LED driver for supplying an LED load with a regulated DC voltage, to a driver system comprising the dimmable LED driver, to a lighting system, comprising the driver system, and to a method of operating the driver system.Background Art

[0002] There are various approaches of driving high-power LED loads by means of parallel-connected constant voltage LED drivers, such as "voltage droop control", wherein the output voltage of the respective driver depends on its output current.

[0003] If all LED drivers have such an output characteristic, their output ports can easily be connected in parallel.

[0004] However, the parallel-connected LED drivers cannot be dimmed so easily. All parallel-connected LED drivers had to drive their pulse width modulation (PWM) dimming circuit at exactly the same instant. Such a synchronization requires a elaborate communication between the LED drivers.Summary

[0005] It is an object to overcome the above-mentioned and other drawbacks.

[0006] The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0007] According to a first aspect, a dimmable LED driver is provided for supplying an LED load with a regulated DC voltage. The LED driver comprises high-side, HS, low-side, LS, and parallel pin, PP, output terminals; and a pulse-width modulation, PWM, circuit for PWM dimming of its through current. The HS and LS output terminals are connectable to the LED load; the PWM circuit is connected between the LS output terminal and an ungrounded LS potential of the dimmable LED driver; and the PP output terminal is connected to the ungrounded LS potential of the dimmable LED driver and further connectable to one or more further LED drivers.

[0008] The PWM circuit may comprise a semiconductor switch being connected between the LS output terminal and the ungrounded LS potential of the dimmable LED driver; and a PWM control logic being configured to drive the semiconductor switch using a PWM dimming control signal.

[0009] According to a second aspect, a driver system is provided for supplying an LED load with a regulated DC voltage. The driver system comprises a first LED driver according to the first aspect; and one or more further LED drivers having HS and LS output terminals for their part. The HS output terminals of the first LED driver and the HS output terminals of the further LED drivers are connected; and the PP output terminal of the first LED driver and the LS output terminals of the further LED drivers are connected.

[0010] The further LED drivers may respectively comprise an LED driver being identical with the first LED driver.

[0011] The further LED drivers may respectively comprise an LED driver being different from the first LED driver.

[0012] According to a third aspect, a lighting system is provided, comprising a driver system according to the second aspect; and an LED load connected to the HS and LS output terminals of the first LED driver.

[0013] According to a fourth aspect, a method is provided of operating a driver system according to the second aspect, the method comprising PWM dimming of the through current of the first LED driver.Advantageous Effects

[0014] The present disclosure enables dimming of parallel-connected constant voltage LED drivers.

[0015] This requires only little wiring effort, no mutual communication or synchronization and no elaborate calibration.

[0016] Only a single LED driver has to have the proposed added functionality, and any further LED drivers merely serve as constant voltage power supplies that may be realized inexpensively and straightforwardly.

[0017] LED drivers of different manufacturers and power ratings may be deployed.Brief Description of Drawings

[0018] The above-described aspects and implementations will now be explained with reference to the accompanying drawings, in which the same or similar reference numerals designate the same or similar elements.

[0019] The drawings are to be regarded as being schematic representations, and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to those skilled in the art. FIG. 1illustrates an output section of a dimmable LED driver in accordance with the present disclosure; FIGs. 2 - 3illustrate lighting systems in accordance with the present disclosure; and FIG. 4illustrates a method of operating the driver systems of FIGs. 2 - 3 in accordance with the present disclosure. Detailed Descriptions of Drawings

[0020] In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and which show, by way of illustration, specific aspects of implementations of the present disclosure or specific aspects in which implementations of the present disclosure may be used. It is understood that implementations of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0021] For instance, it is understood that a disclosure in connection with a described method may also hold true for a corresponding apparatus or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary implementations and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0022] FIG. 1 illustrates an output section of a dimmable LED driver 1 in accordance with the present disclosure.

[0023] On the left side of FIG. 1 the depicted output section shows an output / smoothing capacitor of the LED driver 1.

[0024] The LED driver 1 is suitable for supplying an LED load 3 (not shown), such as an LED module, with a regulated DC voltage.

[0025] The LED driver 1 comprises a high-side (HS) output terminal 11, LED+, a low-side (LS) output terminal 12, LED- and a parallel pin (PP) output terminal 13, PP.

[0026] The LED driver 1 further comprises a pulse-width modulation (PWM) circuit 14 for PWM dimming of its through current.

[0027] According to the example of FIG. 1, the PWM circuit 14 may comprise a semiconductor switch 141 such as a MOSFET being connected between the LS output terminal 12, LED- and the ungrounded LS potential of the dimmable LED driver 1; and a PWM control logic 142 being configured to drive the semiconductor switch 141 using a PWM dimming control signal (not shown).

[0028] The HS and LS output terminals 11, LED+; 12, LED- are connectable to the LED load 3.

[0029] The PWM circuit 14 is connected between the LS output terminal 12, LED- and an ungrounded LS potential of the dimmable LED driver 1.

[0030] The PP output terminal 13, PP is also connected to the ungrounded LS potential of the dimmable LED driver 1 and further connectable to one or more further LED drivers 1, 1' as explained in more detail below.

[0031] The additional output terminal 13, PP extends the PWM dimming of the LED driver 1 to the one or more further parallel-connected LED drivers 1, 1 '.

[0032] FIGs. 2-3 illustrate lighting systems 2A, 2B, 3 in accordance with the present disclosure.

[0033] The lighting systems 2A, 2B, 3 respectively comprise a driver system 2A, 2B according to the second aspect (see FIG. 1) being suitable for supplying an LED load 3 with a regulated DC voltage, and the LED load 3 connected to the HS and LS output terminals 11, LED+; 12, LED- of the first LED driver 1 of the driver system 2A, 2B.

[0034] In other words, the first LED driver 1 is directly connected to the LED load 3 via both its HS and LS output terminals 11, LED+; 12, LED-.

[0035] The driver system 2A, 2B respectively comprises the afore-mentioned first LED driver 1 according to the first aspect and one or more further LED drivers 1, 1 ' having HS and LS output terminals 11, LED+; 12, LED- for their part.

[0036] The HS output terminals 11, LED+ of the first LED driver 1 and the HS output terminals 11, LED+ of the further LED drivers 1, 1 ' are connected.

[0037] That is to say, the further parallel-connected LED drivers 1, 1 ' are also directly connected to the LED load 3 via their HS output terminals 11, LED+, and indirectly connected to the LED load 3 via their LS output terminals 12, LED- and via the PP output terminal 13, PP the of the first LED driver 1.

[0038] The PP output terminal 13, PP the of the first LED driver 1 is decoupled from the LED load 3 by its PWM circuit 14.

[0039] A total output current of all LED drivers 1, 1' flows via the PWM circuit 14 of the first LED driver 1, which may thus perform PWM dimming of the output current of the whole driver system 2A, 2B.

[0040] The PP output terminal 13, PP of the first LED driver 1 and the LS output terminals 12, LED- of the further LED drivers 1, 1' are also connected.

[0041] According to the example of FIG. 2, the further LED drivers 1, 1' may respectively comprise an LED driver 1 being identical with the first LED driver 1.

[0042] According to the example of FIG. 3, the further LED drivers 1, 1' may respectively comprise an LED driver 1' being different from the first LED driver 1.

[0043] It is sufficient that only a single (i.e., the first) LED driver 1 of the driver system 2B has the additional output terminal 13, PP. The further parallel-connectable LED drivers 1' serve as constant voltage power sources that may be realized inexpensively, straightforwardly and without any further intelligence.

[0044] FIG. 4 illustrates a method 4 of operating the driver systems 2A, 2B of FIGs. 2 - 3 in accordance with the present disclosure.

[0045] The method 4 comprises PWM dimming 41 of the through current of the first LED driver 1.

[0046] The present disclosure has been described in conjunction with various implementations as examples. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed matter, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word "comprising" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation. A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

Examples

Embodiment Construction

[0020]In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and which show, by way of illustration, specific aspects of implementations of the present disclosure or specific aspects in which implementations of the present disclosure may be used. It is understood that implementations of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0021]For instance, it is understood that a disclosure in connection with a described method may also hold true for a corresponding apparatus or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to ...

Claims

1. A dimmable LED driver (1) for supplying an LED load (3) with a regulated DC voltage, the LED driver (1) comprising high-side, HS, low-side, LS, and parallel pin, PP, output terminals (11, LED+; 12, LED-; 13, PP); and a pulse-width modulation, PWM, circuit (14) for PWM dimming of its through current; the HS and LS output terminals (11, LED+; 12, LED-) being connectable to the LED load (3); the PWM circuit (14) being connected between the LS output terminal (12, LED-) and an ungrounded LS potential of the dimmable LED driver (1); and the PP output terminal (13, PP) being connected to the ungrounded LS potential of the dimmable LED driver (1) and further being connectable to one or more further LED drivers (1).

2. The dimmable LED driver (1) of claim 1, the PWM circuit (14) comprising a semiconductor switch (141) being connected between the LS output terminal (12, LED-) and the ungrounded LS potential of the dimmable LED driver (1); and a PWM control logic (142) being configured to drive the semiconductor switch (141) using a PWM dimming control signal.

3. A driver system (2A, 2B) for supplying an LED load (3) with a regulated DC voltage, comprising a first LED driver (1) according to claim 1 or claim 2; and one or more further LED drivers (1, 1') having HS and LS output terminals (11, LED+; 12, LED-) for their part; the HS output terminals (11, LED+) of the first LED driver (1) and the HS output terminals (11, LED+) of the further LED drivers (1, 1') being connected; and the PP output terminal (13, PP) of the first LED driver (1) and the LS output terminals (12, LED-) of the further LED drivers (1, 1') being connected.

4. The driver system (2A) of claim 3, the further LED drivers (1, 1') respectively comprising an LED driver (1) being identical with the first LED driver (1).

5. The driver system (2B) of claim 3, the further LED drivers (1, 1') respectively comprising an LED driver (1') being different from the first LED driver (1).

6. A lighting system (2A, 2B, 3), comprising a driver system (2A, 2B) according to any one of the claims 3 - 5; and an LED load (3) connected to the HS and LS output terminals (11, LED+; 12, LED-) of the first LED driver (1).

7. A method (4) of operating a driver system (2A, 2B) according to according to any one of the claims 3 - 5, the method (4) comprising - PWM dimming (41) of the through current of the first LED driver (1).

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