DIMMABLE LED LIGHT UNIT AND METHOD OF REPLACING A LIGHT UNIT

• US 20140333223A1
• Filed: 04/11/2014
• Published: 11/13/2014
• Est. Priority Date: 05/07/2013
• Status: Active Grant

• Current Assignee: Goodrich Lighting Systems GmbH (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Goodrich Lighting Systems GmbH (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Trinschek, Robert, Kraemer, Frederik, Geske, Carsten
• Granted Patent: US 10,159,124 B2
• Time in Patent Office: Days
• US Class Current: 315/210
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]

Abstract

A dimmable LED light unit, in particular for a passenger transportation vehicle, such as an aircraft, a road vehicle, a ship or a rail car, is disclosed that comprises a power input adapted to receive electrical power from a power source, at least one LED, and an LED drive and control module coupled between the power input and the at least one LED, wherein the LED drive and control module is adapted to receive an LED control signal indicative of a desired light intensity of the dimmable LED light unit.

Claims

1. Dimmable LED light unit, in particular for a passenger transportation vehicle, such as an aircraft, a road vehicle, a ship or a rail car, the dimmable LED light unit comprising:

a power input adapted to receive electrical power from a power source,

at least one LED, and

an LED drive and control module coupled between the power input and the at least one LED, wherein the LED drive and control module is adapted to receive an LED control signal indicative of a desired light intensity of the dimmable LED light unit,

wherein the LED drive and control module is configured to provide a drive current to the at least one LED resulting in the desired light intensity of the dimmable LED light unit, the drive current having a drive current amplitude and a drive current duty cycle, wherein the LED drive and control module is configured to set the drive current amplitude within an amplitude range and to set the drive current duty cycle within a duty cycle range in response to the LED control signal.

2. Dimmable LED light unit according to claim 1, wherein the LED drive and control module is configured to set the drive current duty cycle to 100% and to variably set the drive current amplitude within the amplitude range, when the desired light intensity is above a first light intensity threshold value (Int_Th,1).

3. Dimmable LED light unit according to claim 2, wherein the first light intensity threshold value (Int_Th,1) is between 15% and 50% of a maximum light intensity, in particular between 20% and 30% of the maximum light intensity, and more in particular at about 25% of the maximum light intensity.

4. Dimmable LED light unit according to claim 2, wherein the LED drive and control module is configured to set the drive current amplitude according to a linear relationship with the desired light intensity, when the desired light intensity is above the first light intensity threshold value (Int_Th,1).

5. Dimmable LED light unit according to claim 1, wherein the LED drive and control module is configured to set the drive current amplitude to a minimum current amplitude value (I_Min) and to variably set the drive current duty cycle within the duty cycle range, when the desired light intensity is below a second light intensity threshold value (Int_Th,2).

6. Dimmable LED light unit according to claim 5, wherein the second light intensity threshold value (Int_Th,2) is between 15% and 50% of the maximum light intensity, in particular between 20% and 30% of the maximum light intensity, and more in particular at about 25% of the maximum light intensity.

7. Dimmable LED light unit according to claim 5, wherein the LED drive and control module is configured to set the drive current duty cycle according to a linear relationship with the desired light intensity, when the desired light intensity is below the second light intensity threshold value (Int_Th,2).

8. Dimmable LED light unit according to claim 5, wherein the first light intensity threshold value (Int_Th,1) is equal to the second light intensity threshold value (Int_Th,2).

9. Dimmable LED light unit according to claim 1, wherein the LED drive and control module comprises:

a controller configured to receive the LED control signal and to provide an amplitude control signal indicative of the drive current amplitude and a duty cycle control signal indicative of the drive current duty cycle, and

an LED driver configured to receive the amplitude control signal and the duty cycle control signal and configured to provide the drive current to the at least one LED (4) as a response to receiving the amplitude control signal and the duty cycle control signal.

10. Dimmable LED light unit according to claim 1, wherein the power input is an AC power input adapted to receive electrical power from an AC power source.

11. Dimmable LED light unit according to claim 10, further comprising a power factor correction circuit coupled between the AC power input and the LED drive and control module, the power factor correction circuit comprising a buffer capacitor.

12. Dimmable LED light unit according to claim 11, wherein the power factor correction circuit is adapted to receive AC power with an AC voltage of between 100 V and 150 V and with an AC current of between 150 mA and 300 mA and wherein the buffer capacitor of the power factor correction circuit is smaller than 75 μ

F, in particular smaller than 50 μ

F.

13. Dimmable LED light unit according to claim 1, wherein the at least one LED is a chain of a plurality of LED'"'"'s.

14. Passenger transport vehicle, such as an aircraft, a road vehicle, a ship or a rail car, having at least one dimmable LED light unit according to claim 1, the at least one dimmable LED light unit being positioned in an interior of the passenger transport vehicle.

15. Method of replacing a used light unit, in particular in a passenger transportation vehicle, such as an aircraft, a road vehicle, a ship or a rail car, with a dimmable LED light unit according to claim 1, the method comprising the steps of:

disconnecting the used light unit from a power source; and

connecting the power input of the dimmable LED light unit according to claim 1 to the power source.