DE102008029816A1 - Circuit for dimming a lamp and associated method - Google Patents

Abstract

The invention relates to a circuit for dimming a lamp, comprising at least two light units, with a control unit for coupling a brightness and a color temperature depending on an input signal, wherein the at least two light units can be controlled on the basis of the control unit, depending on the input signal. Furthermore, a method for dimming the lamp is specified.

Description

The The invention relates to a circuit for dimming a lamp and a associated method.

Led Lamps for home lighting are increasingly available incandescent replace. A perceived as a pleasant color temperature for the viewer of incandescent lamps can amount to about 2750 K. LEDs reach, but LED lamps offer special advantages at colder color temperatures up to about 8000 K (so-called "sky-white" coloring).

A Dimming of LEDs is easily possible electronically, a change However, the color temperature is with a high electrical control effort connected. This effort reduces customer acceptance and increases Price for the lamp.

Existing Solutions provide a color location of the lamp by means of several single color LEDs on. For example, there are LED combinations in the form of RGB or RGBW (R: red LED, G: green LED, B: blue LED, W: white LED) common. Due to different Properties of each different colored LEDs becomes a complicated, expensive and difficult to set for the customer (three individual controllers) Control needs to be dependent on the color temperature to choose from the brightness of the lamp. additionally conditionally a different aging behavior of the different LEDs a shift in the color location of the lamp.

The The object of the invention is the disadvantages mentioned above to avoid and in particular to specify a lamp whose color temperature with a reduction in performance (eg as part of a Dimming) to warmer color temperatures, similar a light bulb.

These Task is performed according to the characteristics of the independent Claims solved. Further developments of the invention also result from the dependent claims.

• – mit einer Steuereinheit zur Kopplung einer Helligkeit und einer Farbtemperatur abhängig von einem Eingangssignal;
• – wobei abhängig von dem Eingangssignal anhand der Steuereinheit die mindestens zwei Leuchteinheiten ansteuerbar sind.

To achieve the object, a circuit for dimming a lamp comprising at least two light units is specified

• - With a control unit for coupling a brightness and a color temperature depending on an input signal;
• - Wherein, depending on the input signal based on the control unit, the at least two lighting units are controlled.

in this connection the dimming of the lamp means a setting of a lamp parameter, in particular a brightness (lighter or darker) of the lamp. About that In addition, with the dimming an adjustment of the color locus or Color temperature of the lamp done. So with change the brightness of the color temperature can be adjusted. For example It is an advantage that the higher the brightness, the higher the brightness Color temperature (eg 8000 K) and thus increasingly "cold-white" light is set.

Of the The approach presented here allows the brightness and the color temperature in a channel, d. H. the setting of both parameters can be done advantageously by means of the input signal. The implementation on emission characteristics of at least two light units is preferably dependent by means of the control unit of (eg in the form of characteristic curves) stored parameter profiles for brightness and color temperature. It can the parameter curves at least partially -. In terms of color temperature - for each the lighting units individually deposited.

Especially the at least two light units have different color temperatures, so the color temperature of the lamp depends on the brightness is suitably adjustable, in particular with increasing brightness a higher color temperature and with decreasing brightness a lower color temperature is adjustable.

Consequently can be pleasant to the user at lower brightness Color temperature of the lamp ("feel-good light") be set. The operation is intuitive for the user possible based on the input signal. In particular, must be the user of the lamp does not care about it, different Color temperatures depending on the brightness of the lamp in addition adjust.

A Further development is that the lighting unit is an LED or includes an LED module.

there In particular, each LED module can have a large number of LEDs also different colored LEDs can be provided.

Especially be the same or similar LEDs and / or the same or (very) similar phosphors used in the lighting units. This becomes effective a perceptible Aging, d. H. different changes in color temperatures, counteracted.

A Further development is that on the basis of the control unit by means of Input signal based on a dimming characteristic and each one Characteristic curve for color adjustment per light unit which is at least two Lighting units are controlled.

In particular, the control unit comprises ei NEN microcontroller, the stored values, eg. B. on characteristics, and depending on the input signal per light unit outputs a corresponding by one or more characteristics or stored values ascertainable brightness value. As a result of the different actuations of the at least two lighting units relative to one another, it is thus achieved that a desired color temperature can be set as a function of the brightness of the lamp (desired by the user).

For example The dimming characteristic can be dependent on the input signal Provide a first value to use for each Lighting unit a second value based on a specific for the lighting unit Color temperature characteristic is determined. Thus, the first value using several color temperature characteristics to several second values (for each light unit a separate value) and processed this second values are used to control the respective lighting units used.

in this connection It should be noted that the control unit is based on stored values, which are referred to here as characteristic curves, access and an assignment (mapping) based on the stored values can carry out further values. In this respect, the characteristics are as preferably stored and for (further) processing or to understand applicable values for driving the lighting units. Also, the characteristics with functionally stored values be linked, d. H. It can be a rule or function Based on this, it can be used to store an initial value for an input value can be determined. In this case, the pre-storage of a Variety of values or value pairs are eliminated.

A Another development is that the control unit has a color control wherein the color controller depends on a means of of a sensor, the at least two light units controls.

Especially finds in the color slider processing the brightness and the Color temperature instead. For example, by the input signal at least a setpoint is specified and based on the sensor is at least one Actual value provided. The color controller performs a target-actual comparison through and adjusts the lighting units so that the actual value largely corresponds to the setpoint. In this respect, the control can be set to the setpoint continuous or time-discrete (that is, to certain predeterminable Time points iteratively).

Preferably the color controller becomes a target brightness based on the input signal or a desired color temperature impressed. This can be done by the control unit takes place in that the input signal by means of associated with a characteristic curve for color matching a desired color temperature and that the input signal by means of a dimming characteristic of a Target brightness is assigned. The sensor can according to actual values for color temperature and / or brightness.

Especially It is a training that the control unit based on the input signal the brightness and the color temperature are determined.

Also It is a training that the control unit based on the input signal the brightness and the color temperature based on characteristics or stored values.

in this connection It should be noted that the characteristics as stored values in the Control unit, which is preferably designed as a microcontroller with memory is, are stored.

Further It is a training that drivers to control the at least two light units are provided.

in the The scope of additional training is increasing Brightness of the lamp a higher color temperature adjustable.

A next education is that with decreasing Brightness of the lamp a lower color temperature adjustable is.

A Embodiment is that a warm white light unit and a cold white light unit are provided.

For example can one or more lighting units, in particular LEDs or LED modules, which provide a color temperature between warm white and cold white. An advantage is that the emitted light better to a so-called Planck curve can be adjusted. With a passing through the color temperature and / or brightness, the emitted light remains closer the Planck curve and thus looks more natural. From Planck deviating light is usually perceived as having a strong color.

• – bei dem abhängig von einem Eingangssignal eine Helligkeit und eine Farbtemperatur der Lampe ermittelt werden;
• – bei dem abhängig von der ermittelten Helligkeit und Farbtemperatur die mindestens zwei Leuchteinheiten angesteuert werden.

The above object is also achieved by a method for controlling a lamp comprising at least two light units,

• - In which dependent on an input signal, a brightness and a color temperature of the lamp are determined;
• - Wherein depending on the determined brightness and color temperature, the at least two light units are controlled.

A alternative embodiment is that the brightness and determines the color temperature based on at least one characteristic be, in particular depending on a characteristic per lighting unit for an adjustment of the color temperature is provided.

in this connection It should be noted that characteristic stored in any way or cached values and / or functionally determinable values can relate.

A next embodiment is that the input signal on Dimming signal is.

at the dimming signal is preferably a signal with the a user of the lamp can adjust the brightness of the lamp.

Also it is an embodiment that by means of a sensor, a color temperature and / or a brightness of the lamp is / are detected and that depends from the detected color temperature and / or the detected brightness a regulation of at least two lighting units is performed.

Accordingly can be a target-actual comparison between based on the input signal predetermined or determinable values for color temperature and brightness and actual values provided by the sensor for Color temperature and brightness are performed. So can based on the method described here, a continuous or discrete-time Regulation for adjusting the at least two light units accordingly a target specification are performed.

embodiments The invention are illustrated below with reference to the drawings and explained.

It demonstrate:

1 Characteristic curves of a lamp comprising two LEDs relating in particular to color temperatures and brightnesses as a function of a regulator position;

2 Characteristics in a partial logarithmic scaling for a lamp comprising two LEDs, in particular color temperatures and brightnesses depending on a regulator position;

3 a dimming without a color management system;

4 a dimming with a color management system;

5 a dimming taking into account a color temperature setting without a color management system;

6 a dimming taking into account the setting of the color temperature with a color management system.

For example It is assumed that two LEDs (LED1 and LED2) together are installed in a lamp. The LED1 is a Warm white LED with a color temperature (CCT) of 2000 K and LED2 is a cold white LED with a color temperature of 8000 K.

When relative efficiency of warm white LED compared to cold-white LED is assumed in the following 50% (for example due to efficiency disadvantages of the phosphors used).

One Dimmer for home use offers a rule dimension, which is also called the controller position in the following. With the regulator position should a proportional control of the amount of light emitted Lamp are generated.

simultaneously should reduce the color temperature with a reduction in the amount of light become. For example, the color temperature drops from 6500 K at full Light output at 2500 K at less than 20% of the amount of light.

• – Eine Kennlinie 101, die die abgegebene Lichtmenge der warm-weißen LED1 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 104, die die abgegebene Lichtmenge der kalt-weißen LED2 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 103, die die abgegebene Lichtmenge der Lampe umfassend die LED1 und die LED2 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 102 zeigt die Farbtemperatur (CCT) der Lampe in Abhängigkeit von der Reglerstellung.

In 1 the following characteristics are shown by way of example:

• - A characteristic 101 showing the amount of light emitted by the warm-white LED1 as a function of the position of the regulator;
• - a characteristic 104 showing the amount of light emitted by the cold-white LED2 as a function of the position of the regulator;
• - a characteristic 103 showing the output amount of light of the lamp including the LED1 and the LED2 in response to the regulator position;
• - a characteristic 102 shows the color temperature (CCT) of the lamp as a function of the controller position.

The amount of light emitted 103 is approximately linearly correlated with the controller position.

• – Eine Kennlinie 201, die die abgegebene Lichtmenge der warm-weißen LED1 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 204, die die abgegebene Lichtmenge der kalt-weißen LED2 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 202, die die abgegebene Lichtmenge der Lampe umfassend die LED1 und die LED2 in Abhängigkeit von der Reglerstellung zeigt;
• – eine Kennlinie 203 zeigt die Farbtemperatur (CCT) der Lampe in Abhängigkeit von der Reglerstellung.

An alternative characteristic for a brightness control accordingly DIN EN 60929 (logarithmic dependence of the brightness on the controller position) is in 2 shown. 2 includes the following characteristics:

• - A characteristic 201 showing the amount of light emitted by the warm-white LED1 as a function of the position of the regulator;
• - a characteristic 204 showing the amount of light emitted by the cold-white LED2 as a function of the position of the regulator;
• - a characteristic 202 showing the output amount of light of the lamp including the LED1 and the LED2 in response to the regulator position;
• - a characteristic 203 shows the color temperature (CCT) of the lamp as a function of the controller position.

In 2 The power of the LED or the amount of light was scaled logarithmically. For the color temperature, a linear scale is provided.

The Characteristic of the cold white LED2 and the characteristic of the warm white LED1 can be implemented electronically. A compensation different aging of the individual LEDs can be omitted if identical LED chips are used. The different ones used Phosphors are aging stable to a good approximation.

A active monitoring of the color temperature can thus be omitted. The color temperature in the example presented may be in one range from about 6500 K to about 2500 K are set.

Next the two characteristics presented other characteristics are possible. In particular, a relationship between amount of light and color temperature be adjusted in a wide range.

lightbulbs can only be operated up to 3200 K (halogen). Whether by means of the approach presented here, a stronger one or one weaker decrease in color temperature with the amount of light is desired, can be specified individually. A corresponding Adjustment or regulation is possible.

in this connection it is an advantage that at full power both LEDs actually work can be operated at full power and thus one efficient use of the lamp is made possible.

in this connection It should be noted that a plurality of LEDs can be used. For example In this case, two LEDs are called. It also allows LED modules be provided with more than one LED and accordingly several such modules are combined. Especially Several single LEDs can be a cold-white LED module or form a warm white LED module. Furthermore, the lamp comprise at least two LEDs or one or more LED modules.

ever according to the desired control range can be different Characteristic curves for the individual LEDs (LED1 or LED2) in the above Example be given. For low color temperature ranges can be used efficiently such LEDs whose color temperature not far from the actual useful color temperature of the Lamp is removed.

switching examples

3 shows a dimming without color management system (CMS: Color Management System). A dimming signal DIM is provided by a microcontroller 301 received and by means of a stored dimming characteristic 302 (see eg. EN 60929: 2004 E.4.3.7 ) implemented. The dimming characteristic 302 is preferably stored logarithmically or in a parabolic form (y = x ² ).

The microcontroller 301 generates signals for controlling an LED driver 303 and an LED driver 304 , The LED driver 303 controls a warm white LED 305 and the LED driver 304 controls a cold white LED 306 at.

The LED driver 303 and or 304 can be used as a switching regulator, e.g. As a buck, as a step-up converter, as inverters, as sepia, as Cuk, as a flyback converter or as a linear regulator.

The mean output current of the LED driver 303 . 304 is preferably directly proportional to the input signal from the microcontroller 301 provided. An average of the current can be adjusted by a variable current control. Alternatively, it is also possible to switch between different current levels (back and forth). Here, a current level is preferably 0A and another current level is I _max .

The time relationship between the two switched current levels (eg 0A and I _max ) determines the average current through the respective LED. This is a pulse width modulation method for adjusting the brightness of the LEDs 305 . 306 ,

The power supply of the microcontroller 301 and the LED driver 303 . 304 via a power supply 307 ,

4 shows a dimming with a color management system. In addition to the description too 3 here is a microcontroller 401 with a color slider 409 intended.

Further shows 4 a driver 403 that has a red LED 406 drives, a driver 404 that has a green LED 407 drives and a driver 405 that has a blue LED 408 controls. The drivers 403 to 405 as well as the microcontroller 401 be about a power adapter 411 powered.

The microcontroller 401 includes a dimming characteristic 402 , which is controlled by means of a dimming signal DIM. Furthermore, a color temperature CCT can be set externally. The dimming signal DIM is converted by means of the microcontroller into a brightness signal BRI and thus the color controller 409 fed. Furthermore, the color slider 409 charged with the externally adjustable color temperature CCT.

The color slider 409 compensates for LED tolerances, especially when using different LED chip colors. The color slider 409 is with a sensor 410 combined, taking the from the sensor 410 supplied measured values from the color controller 409 be evaluated. The sensor 410 is arranged such that of the LEDs 406 to 408 radiated light is measurable.

The color slider 409 determined by the sensor 410 a current light color and determines and compensates for a deviation from the default value CCT. A deviation from the brightness signal BRI is also determined and compensated.

Such a color control system comprising the color controller 409 as well as the sensor 410 is associated with significant costs. For example, the microcontroller must be more powerful, and the demands on the LED drivers are higher. In addition, it is preferably to be ensured by design measures that as little ambient light as possible falls from the outside onto the sensor and thus incorrect measurements are avoided.

5 shows a possibility for efficient dimming of color temperature without color management system.

5 includes a microcontroller 501 with a dimming characteristic 501 , wherein a dimming signal DIM to the microcontroller 501 created and based on a CCT characteristic 503 into a signal for a white-warm LED 507 and based on a CCT characteristic 504 into a signal for a cold white LED 508 is decomposed. The microcontroller 501 conducts its output signals via a driver 505 to the LED 507 and about a driver 506 to the LED 508 , The drivers 505 . 506 as well as the microcontroller 501 be using a power supply 509 powered.

Thus, the dimming signal DIM by means of the dimming characteristic 502 and by means of the two other characteristics 503 and 504 processed. These two characteristics 503 and 504 determine the amount of light in the warm white LED 507 and the cold-white LED 508 at the total light. As a result, all intermediate colors, which lie in the CIE xy diagram between the color locations of the two LED colors, can be set as a function of the desired brightness of the dimming signal DIM.

Due to the shape of the characteristics, the characteristic, for. B. the color temperature of the dimming signal DIM depending determined and adjusted. It is also possible by suitable choice of the characteristics 503 . 504 Determine if the total light of the two LEDs 507 . 508 as energy-efficient or cost-efficient as possible.

6 shows a dimming with a color management system. In addition to the description too 5 here is a microcontroller 601 with a color slider 604 that has a sensor 605 supplied with a recorded signal (eg, brightness and / or color temperature).

Furthermore, the microcontroller comprises 601 in 6 a characteristic 602 for color temperature adjustment and a dimming characteristic 603 , Based on a dimming signal DIM the microcontroller determines based on the characteristics 602 and 603 a color temperature CCT and a brightness BRI, which are further processed in the color controller to output signals for a red LED 609 , a green LED 610 and a blue LED 611 , The LEDs 609 to 611 be about drivers 606 to 608 driven. Both the drivers 606 to 608 as well as the microcontroller 601 be from a power supply 612 powered.

The color management system includes the color slider 604 and the sensor 605 can directly detect and evaluate a color temperature. On the other hand, based on the characteristic 602 the desired color temperature can be derived from the dimming signal. Accordingly, the color controller 604 Set the actual color temperature so that the target specification corresponds to (almost) the actual value. Such an adjustment can be done iteratively automatically. The same applies to the brightness, whose setpoint value also from the dimming signal DIM based on the dimming characteristic 603 can be determined and based on the color controller 604 automatically taking into account that of the sensor 605 supplied brightness value (actual value) can be set.

101

Curve: Delivered amount of light warm white LED depending the controller position

102

Curve: Color temperature of the lamp depending on the controller position

103

Curve: Delivered amount of light of the lamp depending on the controller position

104

Curve: Delivered amount of light cold white LED depending the controller position

201

Curve: Delivered amount of light warm white LED depending the controller position

202

Curve: Delivered amount of light of the lamp depending on the controller position

203

Curve: Color temperature of the lamp depending on the controller position

204

Curve: Delivered amount of light cold white LED depending the controller position

301

microcontroller

302

Dimming curve

303

LED driver

304

LED driver

305

LED (warm white)

306

LED (Cool white)

307

power adapter

401

microcontroller

402

Dimming curve

403

LED driver

404

LED driver

405

LED driver

406

LED (red)

407

LED (green)

408

LED (blue)

409

color controls

410

sensor

411

power adapter

501

microcontroller

502

Dimming curve

503

CCT characteristic for LED 507

504

CCT characteristic for LED 508

505

LED driver

506

LED driver

507

LED (warm white)

508

LED (Cool white)

509

power adapter

601

microcontroller

602

curve for color temperature adjustment

603

Dimming curve

604

color controls

605

sensor

606

LED driver

607

LED driver

608

LED driver

609

LED (red)

610

LED (green)

611

LED (blue)

612

power adapter

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - DIN EN 60929 [0051]
• - EN 60929: 2004 E.4.3.7 [0060]

Claims (14)

Circuit for dimming a lamp comprising at least two light units ( 507 . 508 ), - with a control unit ( 501 ) for coupling a brightness and a color temperature depending on an input signal (DIM); In which, depending on the input signal (DIM), the at least two light units ( 507 . 508 ) are controllable. Circuit according to Claim 1, in which the lighting unit ( 507 . 508 ) comprises an LED or an LED module. Circuit according to one of the preceding claims, in which by means of the control unit ( 501 ) by means of the input signal on the basis of a dimming characteristic ( 502 ) and on the basis of a color matching characteristic ( 503 . 504 ) per lighting unit the at least two lighting units ( 507 . 508 ) are controllable. Circuit according to one of the preceding claims, in which the control unit ( 601 ) a color controller ( 604 ), wherein the color controller ( 604 ) depending on one by means of a sensor ( 605 ) the at least two light units ( 609 . 610 . 611 ). Circuit according to one of the preceding claims, when the control unit uses the input signal (DIM) the brightness and the color temperature is determined. Circuit according to one of the preceding claims, when the control unit based on the input signal, the brightness and the color temperature based on characteristics or stored Values determined. Circuit according to one of the preceding claims, in which drivers ( 505 . 506 ) for controlling the at least two lighting units ( 507 . 508 ) are provided. Circuit according to one of the preceding claims, in the case of increasing brightness of the lamp a higher Color temperature is adjustable. Circuit according to one of the preceding claims, at the lower the color temperature with decreasing brightness of the lamp is adjustable. Circuit according to one of the preceding claims, in which a warm-white lighting unit ( 507 ) and a cold white light unit ( 508 ) are provided. Method for controlling a lamp comprising at least two light units ( 507 . 508 ), - in which, depending on an input signal (DIM), a brightness and a color temperature of the lamp are determined; In which, depending on the ascertained brightness and color temperature, the at least two lighting units ( 507 . 508 ). The method of claim 11, wherein the brightness and determines the color temperature based on at least one characteristic be, in particular depending on a characteristic per lighting unit for an adjustment of the color temperature is provided. Method according to one of claims 11 or 12, where the input signal is a dimming signal. Method according to one of claims 11 to 13, - in which by means of a sensor ( 605 ) a color temperature and / or a brightness of the lamp is / are detected and - in which, depending on the detected color temperature and / or the detected brightness, a control ( 604 ) of at least two light units is performed.