Controller for a lamp

• US 9,961,739 B2
• Filed: 02/07/2017
• Issued: 05/01/2018
• Est. Priority Date: 02/08/2016
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Sedzin, Aliaksei Vladimirovich, Vlemmings, Marc
• Primary Examiner(s): Le, Tung X
• Application Number:
  US15/426,174
• Publication Number:
  US 20170238391A1
• Time in Patent Office: 448 Days
• Field of Search: 315307, 315309, 315312
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/28 using temperature feedback

Abstract

A controller for a lamp, comprising an input terminal for receiving a requested-color-signal representative of a requested-color-value to be provided by the lamp and one or more temperature-values associated with the lamp. The controller includes a full-color-module for providing a full-color-lamp-control-signal for an output terminal; a stabilization-module for providing a stabilized-lamp-control-signal for the output terminal; and a mode controller for comparing the requested-color-value with a threshold value. If the requested-color-value satisfies the threshold value, then the stabilization-module provides the stabilized-lamp-control-signal to the output terminal. If the requested-color-value does not satisfy the threshold value, then the full-color-module provides the full-color-lamp-control-signal to the output terminal. The stabilization-module is configured to: generate stabilized-color-values based on the temperature-values; and provide the stabilized-lamp-control-signal based on the requested-color-value and the stabilized-color-values. The full-color-module is configured to provide the full-color-lamp-control-signal based on the requested-color-value.

Claims

1. A controller for a lamp, comprising

an input terminal configured to receive

a requested-colour-signal representative of a requested-colour-value to be provided by the lamp;

and

one or more temperature-values associated with the lamp;

an output terminal configured to provide a lamp-control-signal to the lamp;

a full-colour-module configured to provide a full-colour-lamp-control-signal for the output terminal;

a stabilization-module configured to provide a stabilized-lamp-control-signal for the output terminal; and

a mode controller configured to compare the requested-colour-value with a threshold value, and

if the requested-colour-value satisfies the threshold value, then instruct the stabilization-module to provide the stabilized-lamp-control-signal to the output terminal;

if the requested-colour-value does not satisfy the threshold value, then instruct the full-colour-module to provide the full-colour-lamp-control-signal to the output terminal;

wherein the stabilization-module is configured to

generate stabilized-colour-values based on the temperature-values; and

provide the stabilized-lamp-control-signal based on the requested-colour-value and the stabilized-colour-values; and

wherein the full-colour-module is configured to

provide the full-colour-lamp-control-signal based on the requested-colour-value.

2. The controller of claim 1, wherein the stabilized-lamp-control-signal represents an equally or less saturated colour than the full-colour-lamp-control-signal.

3. The controller of claim 1, wherein

the stabilization-module is configured to add one or more colour-correction-values to colour-values that define a full-colour-gamut in order to generate the stabilized-colour-values,

the full-colour-lamp-control-signal represents a colour-value in the full-colour-gamut;

and

the stabilized-lamp-control-signal represents a colour-value in a stabilized-colour-gamut, as defined by the stabilized-colour-values.

4. The controller of claim 1, configured to receive information representative of a requestable-colour-gamut for the lamp, and wherein the threshold value corresponds to a boundary of the requestable-colour-gamut.

5. The controller of claim 1, wherein the lamp comprises first, second and third colour LEDs, the stabilized-colour-values comprise RGB values, and wherein the stabilized-lamp-control-signal is representative of a colour-value that is within a colour gamut defined by the stabilized-colour-values.

6. The controller of claim 1, wherein

the stabilized-lamp-control-signal represents a colour within a stabilized-colour-gamut of the lamp having stabilized-chromaticity-limits, and

the full-colour-lamp-control-signal represents a colour within a full-colour-gamut of the lamp having full-colour-chromaticity-limits, and wherein the stabilized-colour-gamut is a subset of the full-colour-gamut.

7. The controller of claim 1, wherein the lamp comprises first, second and third colour LEDs, and wherein the threshold value represents a light output of the lamp provided in accordance with the stabilized-lamp-control-signal for which one of the LEDs has a light output below a LED-threshold-value.

8. The controller of claim 1, wherein the stabilization-module is further configured to

generate the stabilized-colour-values based on the temperature-value, and a difference-value representative of the distance between (i) the requested-colour-value;

and (ii) a boundary of a requestable-colour-gamut.

9. The controller of claim 8, wherein the stabilization-module is configured to set a degree of stabilization that is applied to the requested-colour-value based on the difference-value.

10. The controller of claim 1, wherein the controller is configured to linearly combine the full-colour-lamp-control-signal and the stabilized-lamp-control-signal in order to provide the lamp-control-signal.

11. The controller of claim 10, wherein the coefficients of the linear combination are functions of a difference-value representative of the distance between (i) the requested-colour-value;

and (ii) a boundary of a requestable colour gamut.

12. The controller of claim 1, wherein the full-colour-module is configured to provide the full-colour-lamp-control-signal based on the temperature-values.

13. The controller of claim 1, wherein the threshold value is 1%, 2%, or 5% of a maximum colour value.

14. The controller of claim 1, wherein the lamp comprises a white LED.

15. A method of controlling a lamp, the method comprising

receiving a requested-colour-signal representative of a requested-colour-value to be provided by the lamp;

receiving one or more temperature-values associated with the lamp;

comparing the requested-colour-value with a threshold value;

if the requested-colour-value satisfies the threshold value, then

generating stabilized-colour-values based on the temperature-values; and

providing a stabilized-lamp-control-signal based on the requested-colour-value and the stabilized-colour-values;

if the requested-colour-value does not satisfy the threshold value, then

providing a full-colour-lamp-control-signal based on the requested-colour-value; and

providing a lamp-control-signal to the lamp based on the stabilized-lamp-control-signal or the full-colour-lamp-control-signal.