DE102010031589A1 - Control circuitry of infrared light source for light module e.g. headlight of vehicle, has switching unit that is provided to alternately connect parallel light modules with operation apparatus - Google Patents

Abstract

The control circuitry has an operation apparatus (101) that controls power supply to the light modules (105-107) including white LEDs (103) and infrared LEDs (104) which are provided in series arrangement. The flux voltage of the light modules is controlled such that the flux voltage corresponds with each other and a switching unit (102) is provided to alternately connect the parallel light modules with the operation apparatus. Independent claims are included for the following: (1) method for operating light module; and (2) light source.

Description

The invention relates to a circuit and a method for operating parallel-connected lighting modules.

In vehicles, driver assistance systems are increasingly being used. For example, there are systems that improve visibility in the dark. For this purpose, the environment is illuminated in front of the vehicle with infrared light and from a camera are reflected according to the reflected infrared waves and z. B. the driver shown in a display. This makes it possible, even in complete darkness, people or animals on or near the road, even if they are by the light of a conventional headlight of the vehicle for the driver (not) visible, represent or point to such.

In particular, infrared light sources are integrated into the headlights of the vehicle.

For example, infrared semiconductor light-emitting elements (for example light emitting diodes), also referred to as IR LEDs, are known, as are, for example, B. white LEDs. Such LEDs are current-controlled components. To control the IR LEDs, a high operating voltage range is necessary and requires a complex operating device with a Hochtiefsetzsteller. A headlamp with white LEDs and IR LEDs currently requires two separate power sources to control the different types of LEDs.

It is disadvantageous that this type of control is inefficient and leads to high costs for the headlight or the operating device of the headlight due to the different power sources.

The object of the invention is to avoid the abovementioned disadvantages and in particular to provide an efficient solution for driving white LEDs and IR LEDs of a headlight.

This object is achieved according to the features of the independent claims. Further developments of the invention will become apparent from the dependent claims.

• – bei der die parallel geschalteten Leuchtmodule abwechselnd ansteuerbar sind.

To achieve the object, a circuit is provided for the operation of parallel-connected lighting modules,

• - In which the parallel-connected lighting modules are controlled alternately.

In particular, the lighting modules are lighting modules of a vehicle, for. B. a headlight of a vehicle.

In this case, it is advantageous that an (electronic) operating device can be provided which can be used for a large number of different lighting modules. In addition, several light modules can be used at the same time (operated alternately) without the need for several operating devices or an operating device would have to be dimensioned correspondingly larger.

In particular, the lighting module comprises at least one semiconductor light-emitting element (eg at least one light-emitting diode, LED).

A further development is that the lighting modules connected in parallel can be driven alternately at a frequency which is so high that no flicker is perceptible to the human eye.

For example, a switching or clock frequency of at least 65 Hz can be used for switching.

It should be noted that the individual lighting modules can be activated for the same amount of time or can have different activation times. For example, it is possible for a light module that emits visible light to have a longer activation time than a light module that emits light in a non-visible spectral range (eg, IR light). In principle, it is possible within a cycle to divide the activation or deactivation between the lighting modules into equal temporal components or to provide different temporal components.

• – ein erstes Leuchtmodul eine Reihenschaltung aus Leuchtdioden aufweist,
• – ein zweites Leuchtmodul eine Reihenschaltung aus Leuchtdioden aufweist,
• – wobei eine Flussspannung des ersten Leuchtmoduls im Wesentlichen einer Flussspannung des zweiten Leuchtmoduls entspricht.

Another training is that

• A first lighting module has a series connection of light emitting diodes,
• A second lighting module has a series connection of light emitting diodes,
• - Wherein a forward voltage of the first light-emitting module substantially corresponds to a forward voltage of the second light-emitting module.

Accordingly, the light-emitting diodes are to be selected such that the same flux voltages or substantially equal forward voltages result for the different modules. In particular, the flux voltages should match so that operation with an operating device (which provides only one operating voltage) is possible.

Furthermore, it is an option that further lighting modules are provided parallel to the first and second lighting module.

It should be noted that the lighting modules and parallel circuits of bulbs, z. B. semiconductor light elements, may have. A such parallel connection is preferably considered as a component of the series connection.

Each light-emitting diode preferably has at least one semiconductor light-emitting element.

• – das erste Leuchtmodul weiße Leuchtdioden aufweist,
• – das zweite Leuchtmodul infrarote Leuchtdioden aufweist,
• – wobei das zweite Leuchtmodul ungefähr oder genau doppelt so viele Leuchtdioden wie das erste Leuchtmodul aufweist.

In particular, it is a training that

• The first light-emitting module has white light-emitting diodes,
• The second light module has infrared light emitting diodes,
• - Wherein the second light module has approximately or exactly twice as many LEDs as the first light module.

It is also a development that switching electronics are provided, which connects a driver alternately with the parallel-connected lighting modules.

The driver may be any power supply circuit or operating circuit for the lighting modules. By way of example, such an operating circuit may comprise a high, low or high step converter depending on a supply voltage.

The switching electronics can be set up so that the lighting modules are activated alternately. The lighting modules can be the same length or different lengths of the switching electronics activated.

• – eine bistabile Kippstufe;
• – einen Zähler;
• – ein Schieberegister;
• – einen Mikrokontroller oder Mikroprozessor.

Furthermore, it is a further development that the switching electronics comprise at least one of the following components:

• A bistable flip-flop;
• A counter;
• - a shift register;
• - a microcontroller or microprocessor.

Based on the switching electronics z. B. via electronic switches (eg., Transistors, Mosfets, etc.) for a certain period of time depending on a light module are connected to the driver. For this purpose, the switching electronics may have discrete components and / or integrated circuits. For example, by means of a clock, a shift register can be activated, which in turn activates the connected lighting modules (individually). When one light module is active, preferably all others are inactive.

Furthermore, it is possible that several lighting modules are activated together. For example, eight lighting modules can be alternately connected via the switching electronics to the driver in such a way that always two of the eight lighting modules are activated simultaneously (ie in parallel). In this case, one cycle has four sections, with two of the eight lighting modules being active per section. For example, the composition of the lighting modules per section can also vary, so that a grouping of the lighting modules that are activated together per section can be changed.

It is also a development that the circuit for operating a light source, in particular a light source, for. As a headlight, a vehicle is used.

• – bei dem die parallel geschalteten Leuchtmodule abwechselnd angesteuert werden.

The above-mentioned object is also achieved by means of a method for operating parallel-connected lighting modules,

• - In which the parallel-connected lighting modules are driven alternately.

In particular, the lighting modules connected in parallel are controlled by a single operating device.

The above statements apply accordingly to this method.

The above object is also achieved by a light source comprising the circuit described herein. In particular, the light source may be a light source of a vehicle, e.g. As a headlight act.

Embodiments of the invention are illustrated and explained below with reference to the drawing.

It shows:

1 a schematic block diagram with an (electronic) operating device for supplying a plurality of lighting modules, each lighting module having at least one series connection of a plurality of semiconductor light elements.

For example, it is proposed, for. B. white LEDs and IR LEDs by means of a common operating device to control. Since the forward voltage of a white LED is twice that of an IR LED, n white LEDs and 2n IR LEDs (also referred to as LED strings or LED arrays) are connected in parallel to the operating device and supplied with the same forward voltage. The n white LEDs are a series of n white LEDs; Accordingly, the 2n IR LEDs are a series connection of twice as many (2n) IR LEDs.

Thus, the same drive concept can be used for both LED strings.

Also, a current can alternate in the strand of the n white LEDs and in the strand of the 2n IR LEDs are imprinted. By alternating supply of the different LED strings, only a single electronic operating device (also referred to as a driver or a driver circuit) can be used effectively. This saves costs and installation space. Preferably, the switching frequency for the alternating operation of the LED strands (possibly more than two strands can be operated alternately, even in different Ansteuermustern) above a perceivable flicker frequency, ie above a frequency, which are perceived by the human eye as flicker can.

Another option is that a plurality of strings of light emitting diodes is provided, which have approximately the same forward voltages and are connected in parallel with each other.

1 shows a schematic block diagram with an (electronic) operating device 101 for the supply of several lighting modules 105 to 107 where each light module 105 to 107 has at least one series connection of a plurality of semiconductor light elements. For example, a plurality of LEDs may be connected in series with one another per light module. The LEDs are preferably of the same type, e.g. B. IR LEDs, white LEDs, amber LEDs, etc. Also mixtures of LED types within a series connection are possible. In addition, it is an option that z. B. a part of the lighting modules has only a single LED. The LEDs are, for example, lighting modules with at least one semiconductor element.

In the example according to 1 is the operating device 101 with a switching electronics 102 connected, the z. B. alternately the lighting modules 105 to 107 with the operating device 101 combines. The operating device 101 is still via a ground connection to the ground terminals of the lighting modules 105 to 107 connected. The operating device 101 can an electronic converter, for. B. comprise a full or half bridge circuit, a boost converter, buck converter, a Hochtiefsetzsteller or a cascade circuit. The operating device 101 provides the appropriate flux voltage for the lighting modules 105 to 107 ready.

Another option is that each light module 105 to 107 in each case at least one light-emitting diode z. B. the same color, which is controlled differently bright light per module. Through the alternating activation of the individual lighting modules 105 to 107 (by means of the switching electronics 102 ) can thus be achieved that for the viewer the impression of a total brightness by the mixture of the brightnesses and / or colors of the individual lighting modules 105 to 107 is set. It should be mentioned that z. B. per light module, the brightness and / or color of the at least one light emitting diode by means of a pulse width modulation is adjustable.

The switching electronics 102 is operated at a frequency that alternately activates the lighting modules 105 to 107 allowed, without a flicker from the human eye is perceptible. Preferably, the switching electronics 102 the available time (eg one cycle) evenly on the light modules 105 to 107 divided, ie each of the lighting modules 105 to 107 is essentially alternately activated the same time or turned on.

Preferably, the lighting modules 105 to 107 configured so that in each case the substantially same forward voltage is required for their operation, ie the lighting modules 105 to 107 require only one type of control gear 101 or must the operating device 101 the provided operating voltage for the lighting modules 105 to 107 do not adapt individually.

This can be achieved in that in the light module 105 a number of n white LEDs 103 and in the light module 106 a number of 2n infrared LEDs 104 are connected in series. Thus, essentially twice as many infrared LEDs as white LEDs are present. Generally, depending on the type of LED used in the series connection (and the forward voltage of this LED type), the number of LEDs is adjusted so that the lighting modules 105 to 107 essentially need the same forward voltages. This allows a flexible use of lighting modules in the 1 shown circuit.

It should be noted that the light module 107 is optionally provided. Accordingly, an operation of only two lighting modules 105 and 106 possible, with the switching electronics 102 preferably then alternately between these lighting modules 105 and 106 Switches so fast that the human eye does not perceive flicker.

The light module 107 may have different LEDs of different types (or same type), the z. B. are connected in series and (approximately) the same forward voltage as the lighting modules 105 and 106 exhibit.

The light modules 105 . 106 . 107 can be designed as part of a light source, in particular a headlight of a vehicle. The operating device 101 and / or the switching electronics 102 may be part of the vehicle and / or part of the light source of the vehicle. In particular, the switching electronics 102 also together with the operating device 101 executed or part of the operating device 101 be.

LIST OF REFERENCE NUMBERS

101

(electronic) operating device, driver or current control

102

switch-over

103

white LED

104

Infrared LED (IR LED)

105

light module

106

light module

107

light module

Claims (10)

Circuit for operating parallel-connected lighting modules ( 105 . 106 . 107 ), - in which the parallel-connected lighting modules ( 105 . 106 . 107 ) alternately controllable ( 102 ) are. A circuit according to claim 1, wherein the parallel-connected lighting modules are driven alternately at a frequency which is so high that the human eye no flicker is perceptible. Circuit according to one of the preceding claims, In which a first light-emitting module has a series connection of light-emitting diodes, In which a second light-emitting module has a series connection of light-emitting diodes, - Wherein a forward voltage of the first light-emitting module substantially corresponds to a forward voltage of the second light-emitting module. Circuit according to claim 3, In which the first light module has white light emitting diodes, In which the second light module has infrared light emitting diodes, - Wherein the second light module has approximately or exactly twice as many LEDs as the first light module. Circuit according to one of the preceding claims, wherein a switching electronics is provided, which connects a driver alternately with the parallel-connected lighting modules. A circuit according to claim 5, wherein the switching electronics comprise at least one of the following components: A bistable flip-flop; A counter; - a shift register; - a microcontroller or microprocessor. Circuit according to one of the preceding claims for operating a light source, in particular a light source of a vehicle. Method for operating parallel-connected lighting modules, - In which the parallel-connected lighting modules are driven alternately. Light source comprising the circuit according to one of claims 1 to 7. A light source according to claim 9, wherein the light source is a light source of a vehicle.

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