Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/40—Details of LED load circuits
  • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
  • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/20—Controlling the colour of the light
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/30—Driver circuits
  • H05B45/37—Converter circuits
  • H05B45/3725—Switched mode power supply [SMPS]
  • H05B45/385—Switched mode power supply [SMPS] using flyback topology
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/20—Controlling the colour of the light
  • H05B45/22—Controlling the colour of the light using optical feedback

Definitions

• the present patent application relates to dimming lighting devices, for example LED lighting devices.
• dimmers use the common power line to provide dimming information to the light source by cutting the phase of the mains voltage. These so-called phase cut dimmers can be used to dim existing halogen or incandescent light bulbs. With the rise of LEDs in general lighting, there exists the need to also allow dimming the light emitted by the LEDs. When dimming light, the color point, e.g. the color temperature of an incandescent lighting device, changes in accordance with changing intensity. This change of color temperature needs to be created with an LED as well, to obtain realistic dimming impressions.
• a resonant power LED control circuit for the independent, simultaneous brightness and color or color temperature control of two LEDs.
• a single resonant converter which is formed of a half or full bridge DC/ AC converter.
• a transformer is fed with driving current depending on the intensity information received from the driving power, i.e. the mains power, which is controlled from a dimmer.
• two inductances are connected to the primary side, where the two inductances drive respective LEDs. Depending on the phase of the primary current, the two LEDs driven by the inductances are driven with different driving currents.
• the LEDs This is provided by connecting the LEDs to the respective inductances, such that one LED is driven at a high phase and one LED is driven at a low phase.
• the respective other LED When the phase changes, the respective other LED is activated.
• the LEDs receive respectively different input currents and thus have different bright intensity.
• the LEDs have different primary colors, the combined color point of both LEDs can change with different light intensity of the respective LEDs.
• the proposed solution lacks the possibility to adjust the color point, e.g. the light temperature of the output light from both LEDs according to different needs. Further, the proposed solution requires a transformer having three taps on the secondary side. Also, the driver for driving the primary side of the transformer is complex and not compatible with known dimming solutions for incandescent light bulbs.
• a component comprising an input for receiving input power from a primary power supply, at least one circuit, wherein the circuit is arranged for receiving within the received input power at least light intensity information, wherein the circuit is arranged for driving at least two lighting devices at least according to the light intensity information, and wherein the circuit is arranged for determining the driving ratio between the at least two lighting devices according to the light intensity information.
• a circuit for both obtaining the light intensity information and the driving ratio between the at least two lighting devices increases flexibility for lighting devices.
• the present application improves component integration and reduces manufacturing cost.
• the integration of determining and applying light intensity information and driving ratio to lighting devices reduces the form factor of driving circuits.
• a component comprising an input for receiving input power at a primary side from a primary power supply, a first circuit arranged at the primary side for receiving within the received input power at least light intensity information, and a second circuit at the secondary side for determining at least dimming color point information and for driving a lighting device at least according to the dimming color point information.
• the problem when driving LEDs lies in that the color point does not change with changing light intensity.
• the spectral light information of the light emitted from an LED is always constant.
• incandescent light bulbs change with changing intensity also their color point. This provides for a realistic dimming impression.
• the circuit may be a first circuit arranged at a primary side.
• a second circuit may be arranged for driving the at least two lighting devices and for determining the driving ratio between the at least two lighting devices according to the light intensity information.
• the circuit is capable of receiving the dimming information, in particular in form of phase cut mains voltage.
• This dimming information may, according to embodiments, be transferred to a secondary side together with color point information.
• a particularly arranged circuit may be capable of receiving the light intensity information. From the received light intensity information, the second integrated circuit can determine the corresponding color point.
• the secondary circuit can be arranged for driving a set of LEDs, at least two LEDs, depending on both the light intensity information and the color point information.
• at least one bypass switch may be arranged across at least one of the lighting devices for applying the driving ratios of the at least two lighting devices.
• the bypass switch may be a transistor, i.e.
• the switches may be driven by the circuit obtaining the driving ratio information.
• the first circuit may comprise a switching element, wherein different transfer functions between the switching element and the lighting devices are provided for determining the driving ratios.
• At least one storing element may be coupled to each lighting device according to embodiments.
• the storing element may be at least one of a capacitance, or an inductance.
• the second circuit may determine the driving ratio from a signal input to a dedicated input pin of the second circuit.
• the second integrated circuit may be arranged for calculating the required color point depending on this received information.
• the primary and the secondary sides may be decoupled using a transformer for transforming the input power on the primary side to output power on the secondary side, the transformer electrically decoupling the primary side from the secondary side.
• the second integrated circuit can determine the driving ratio depending on the signal input and a pre-programmed color point curve, according to embodiments.
• the pre-programmed curve can be similar to a black-body curve to mimic the dimming behavior of an incandescent light bulb.
• the preprogrammed curve may be a look-up table for mapping the dimming color point information onto LED driving currents for respective LEDs at output terminals of the second integrated circuit.
• the pre-programmed curve may be stored in an additional memory in the integrated circuit.
• the first integrated circuit may create a stable DC voltage on the secondary side depending on the light intensity information.
• the dimming information entering the component on the primary side needs to be transferred to the second integrated circuit on the secondary side.
• this integrated circuit may already be prepared to handle the special requirements of phase cut dimmers, for example, providing latch currents required to bring the device into conduction mode and providing hold currents required to keep it in conduction.
• the latch current and the hold current provided at input terminals of the first integrated circuit on the primary side may be used as input for the integrated circuit on the secondary side.
• this information may represent the light intensity information.
• This light intensity information may be provided, according to embodiments, to the second integrated circuit on the secondary side via an opto-coupler, an analogue signal, or a pulse-width modulated (PWM) signal.
• PWM pulse-width modulated
• the integrated circuit on the primary side may drive the transformer such that it creates a stable DC supply voltage on the secondary side, input to the integrated circuit.
• This stable driver voltage may allow for driving the LEDs.
• the integrated circuit on the secondary side may calculate both driving current and driving ratio for driving at least two LEDs.
• the first integrated circuit may transmit dimming information for example as phase information to the second integrated circuit, and the second integrated circuit may determine from the dimming information the driving ratio between the at least two lighting devices (e.g. dimming color point information), according to embodiments.
• the dimming information e.g. phase information may be provided by an integrated circuit on the primary side being already capable of determining the latch and hold currents, which already carry the phase information.
• the embodiments, where the first integrated circuit creates a stable DC voltage on the secondary side, and utilizes latch and hold currents may have the advantage, that the dimming range may be broader and the color adjustment may be determined by the integrated circuit on the secondary side.
• the dimming range may be determined by the phase cut dimmer.
• the integrated circuit on the primary side needs to have intelligence to translate the phase information into a usable signal, for example a PWM signal, input to the second integrated circuit. Further, a decoupling capacitor might be required.
• the integrated circuit on the primary side may create a pulsed DC voltage on the secondary side depending on the light intensity information. This may be done by driving the primary side of the transformer, such that the secondary side of the transformer creates a pulsed DC voltage.
• the pulsed DC voltage on the secondary side may have pulses of different width. This pulsed voltage may be regarded as phase cut DC voltage.
• the phase cut of the DC voltage may represent the light intensity information, already received within the mains power on the primary side.
• the first integrated circuit may create a phase cut DC voltage on the secondary side depending on the light intensity information.
• the phase information of the secondary DC voltage may be input to a dedicated pin on the second integrated circuit.
• the second integrated circuit may determine dimming color point information. This may be done by tapping the secondary side of the transformer directly and analyzing the phase information of the pulsed DC voltage on the secondary side.
• the second integrated circuit may determine a dimming color point for driving at least two LEDs.
• the stable DC voltage may also be used for driving the LEDs with respective driving power indicative of the light intensity in accordance with dimming information.
• the first integrated circuit comprises at least one transistor for converting the phase cut input voltage into a light intensity depending drive signal for transformer.
• the first integrated circuit comprises at least one transistor for converting the phase cut input voltage into a light intensity depending drive signal for transformer.
• the color point In order to set the color point using a light emitting diode, it is necessary that at least two different light emitting diodes with different basic colors, e.g. the wave length of the light output by the LED, are driven with according driving currents. By changing the driving currents, and thus the intensity of each of the LEDs, the color point may be adjusted.
• embodiments provide the second integrated circuit driving at least two lighting devices.
• embodiments provide the second integrated driving at least two lighting devices depending on the dimming color point information such that the color point of the combined light of the at least two lighting devices represents a color temperature corresponding to the light intensity.
• an incandescent light changes with changing intensity also its color temperature.
• the combined light of at least two LEDs is may be adjusted such that the light temperature is adjusted accordingly.
• the driving ratio between the at least two lighting devices may be selected such that the color temperature of the combined light of the at least two lighting devices increases with decreasing light intensity.
• Another aspect is an integrated circuit with a component as described above.
• a further aspect is a system with such a component and at least two lighting devices driven by such a component.
• embodiments provide the system with semiconductor lighting devices or organic lighting devices, e.g. LEDs or OLEDs.
• Another aspect is a method comprising receiving input power from a primary power supply, receiving within at least one circuit at least light intensity information from the input power, determining at least driving ratio between the at least two lighting devices and driving a lighting device at least according to the light intensity information with the circuit.
• FIG. 1 Another aspect is a computer program comprising instructions operable to cause a processor to configure a component as previously described to receive input power from a primary power supply, receive within a at least one circuit at least light intensity information from the input power, and determine at least driving ratio between the at least two lighting devices and driving a lighting device at least according to light intensity information with the circuit.
• Fig. 1 an arrangement of a mains voltage with leading and trailing edge phase cutting
• Fig. 2 a first embodiment according to the application
• Fig. 3 a pre-programmed curve for transferring light intensity information into dimming color point information
• Fig. 4 a second embodiment according to the application
• FIG. 5 a third embodiment according to the application
• Fig. 6 a fourth embodiment according to the application
• Fig. 1 illustrates a mains voltage 4 having a sinusoidal curve 2.
• This mains voltage 4 may be used for driving a device, i.e. an incandescent light bulb, using phase cutting.
• devices such as dimmers, which provide for different types of phase cutting.
• R-type dimmers which provide phase cutting at the leading edge of the curve 2, and are only intended for use with standard lightings and mains halogen lamps.
• R, L-type dimmers are also leading edge phase cut dimmers, which are intended for use with standard lightings and halogen lamps.
• R, C-type light dimmers are trailing edge phase cut dimmers, that are intended to be used also for halogen lamps using electronic ballast.
• a usual curve 2 of a mains voltage 4 can be adjusted with a leading edge phase cut.
• the slope 6 of a leading edge phase cut is illustrated.
• each leading edge of a half wave of the curve 2 is put to zero, and the voltage is increased to the actual curve 2 at a certain time.
• the time, at which there is a rise in slope 6 may determine the light intensity.
• a slope 8 of a trailing edge phase cut dimmer As can be seen, the first part of each half period of curve 2 is provided and the slope 8 is forced to zero at a certain time. The longer slope 8 is at zero, the lesser the light intensity.
• Fig. 2 illustrates a driving component 10 with a mains power supply 10a and a dimming component 12. Further illustrated are two LEDs 14a, b, where LED 14a transmits light at a different wave length than LED 14b.
• driving component 10 an AC mains power is adjusted using phase cutting, i.e. using a dimmer.
• the phase cut mains voltage is illustrated within component 10.
• Component 10 provides at its output terminals the phase cut mains voltage to the dimming component 12.
• a dimming component 12 there is provided a first integrated circuit 16, a transformer 18, an opto-coupler 20 (optional) a second integrated circuit 22, a capacitor 24, and a diode 26.
• transistor 16a Within first integrated circuit 16, there is provided a transistor 16a.
• the integrated circuit 22 may comprise a circuit for determining the duty cycle Transformer 18 may be comprised of two inductances electrically decoupled, dividing dimming component 12 into a primary side at which the first integrated circuit 16 is arranged, and a secondary side at which the second integrated circuit 22 is arranged.
• Capacitor 24 may be used for filtering HF components on the secondary side.
• the integrated circuit according to Fig. 2 operates as follows.
• the phase cut AC voltage is provided from component 10 to component 12.
• the phase cut mains voltage carries information about lighting intensity, i.e. provided from a phase cut dimmer. The more the phase of the curve 2 is cut, the less light shall be emitted, e.g. the less the intensity/brightness of the light shall be.
• a latch current and a hold current are determined for transistor 16a.
• transformer 18 is driven with more or less driving power.
• the dimming information e.g. the drive ratio
• the dimming information e.g. the drive ratio
• circuit 23 illustrated in dashed lines comprises functionality which may also be incorporated within the second integrated circuit 22.
• the drive ratio is obtained either on the primary side using opto-coupler, or on the secondary side using circuit 23 as separate component or integrated within integrated circuit 22.
• the secondary side may have phase cut DC voltage and current.
• transformer 18 is driven, such that the secondary side is driven with a stable DC supply voltage.
• Diode 26 and conductance 24 provide for stabilizing the current and voltage within the secondary side.
• second integrated circuit 22 receives the stable DC supply voltage.
• transistor 22a drives the output current for LEDs 14a, 14b.
• transistor 22b, 22c may be driven, such that the currents through LEDs 14a, 14b are turned on and off.
• transistor 22b, 22c By turning on and off the currents within the LEDs 14a, 14b using transistor 22b, 22c, the ratio and light output at which the LEDs 14a, 14b emit light, can be adjusted. This ratio can be used for setting a dimming color point of the light output by both LEDs 14a, 14b.
• Fig. 3 illustrates a pre-programmed curve 30, representing the ratio between the LEDs 14a, 14b depending on the dimming information received via opto- coupler 20.
• the dimming information received the opto-coupler 20 may be face information, for example a face cut angle. Using this face cut angle the light output of LEDs 14a, 14b maybe controlled, such that the overall light output and the color point are adjusted. As can be seen, with increasing face cut angle, the light output of LED 14b decreases faster than the light output of LED 14a. This results in that with a small face cut angle, the ratio between light output by LED 14b and LED 14a is higher to LED 14b. For an increased face cut angle, LED 14a puts out more light than 14b creating a different color point.
• Fig. 4 illustrates a further embodiment.
• the dimming component 12 comprises a first integrated circuit 16, and a second integrated circuit 22.
• the embodiment illustrated in Fig. 4 provides via integrated circuit 16 transformer 18 with a driving power, such that on the secondary side, a phase cut DC voltage is applied.
• This phase cut DC voltage is a representation of the phase cut AC mains voltage.
• the duration of the phases represents the light intensity, which the LEDs 14a, 14b shall emit light.
• the phase cut DC voltage is a representation of the light intensity information received from driving component 10.
• integrated circuit 22 receives information about the phase cut DC voltage within the secondary side circuit. This information is, as previously described, a light intensity information. Receiving this light intensity information on dedicated pin 22e, allows integrated circuit 22 to determine the on/off times of transistor 22b, 22c, in order to drive LEDs 14a, 14b such that they mimic the light color point in accordance with the light intensity state. The phase cut information is thus used within the second integrated circuit to determine the color point at which LEDs 14a, 14b output a combined light.
• Another embodiment is to have signal paths from the primary side to the LED' s 14a and 14b, without the need for integrated circuit at the secondary side.
• Such signal paths may have different transfer functions such that the light output of the LED' s behave in a different way with respect to transferred power, therefore varying the light output ratio.
• Fig. 5 illustrates a further embodiment according to the application. What differs from the embodiment of Fig. 4 is, that on the secondary side, two integrated circuits 22, 22', are provided.
• the transformer 18 is driven, such that light intensity information provides for on both secondary inductances the same output power.
• the phases of the secondary inductances are shifted by 180°. That is, when the diode 26a is conductive, diode 26b is not conductive and vise versa.
• the phase information is provided to each of the circuits 22, 22 ⁇
• the LEDs 14a, 14b are turned on and off for a longer or a shorter period. This allows for adjusting the brightness of the LEDs independent of each other.
• the overall brightness of the LEDs 14a, 14b is, however, adjusted by the phase cut DC voltage on the secondary side.
• Fig. 6 illustrates another embodiment.
• the circuit 23 is arranged at the output of component 10.
• Circuit 23 may obtain both light intensity information as well as the dimming information for driving the lighting devices 14a, b. This information may be provided to circuit 22, within which the drive ratio is obtained and the lighting devices 14 are driven accordingly.
• the proposed component allows for translating the phase information into useful color adjustments for LEDs. This allows simple architecture for providing complains with already known phase cut dimmers. Lighting applications using phase cut dimmers, like residential lighting and commercial lighting may thus be propagated to use LED lighting devices.

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• 2009
  • 2009-08-04 EP EP09786795A patent/EP2322016A1/de not_active Withdrawn
  • 2009-08-04 WO PCT/IB2009/053385 patent/WO2010016002A1/en not_active Ceased

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