Methods and circuits for self-calibrating controller

• US 8,581,810 B2
• Filed: 06/24/2008
• Issued: 11/12/2013
• Est. Priority Date: 03/11/2008
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Dhayagude, Tushar, Santo, Hendrik
• Primary Examiner(s): SHERMAN, STEPHEN G
• Application Number:
  US12/145,414
• Publication Number:
  US 20090231247A1
• Time in Patent Office: 1,967 Days
• Field of Search: 345 87-104, 345/204, 345/690, 345 76- 83, 315/169.3
• US Class Current: 345/82
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules

Abstract

The present invention relates to circuits and methods for controlling one or more LEDs or LED drivers. The circuit comprises a programmable decentralized controller coupled to one or more detectors, wherein the one or more detectors are configured to detect one or more measurable parameters of one or more LEDs or LED drivers. The controller is configured to receive information from the one or more detectors related to the one or more measurable parameters. The controller is also configured to adjust one or more controllable parameters until one or more detectors indicate that one or more measurable parameters in one of the LEDs or LED drivers meet a reference condition. The controller is configured to then set one or more of the controllable parameters to operate at a value relative to the value of the controllable parameters at which the reference condition was met.

Claims

1. A circuit comprising:

one or more LED drivers configured for coupling to one or more LEDs and configured to regulate operation of the one or more LEDs, wherein the LED drivers are configured to receive a drive voltage from a power supply;

a programmable decentralized controller coupled to the power supply and one or more detectors, wherein the one or more detectors are configured to detect one or more measurable parameters of the one or more LEDs or LED drivers;

said controller configured to control the power supply to set the drive voltage;

said controller configured to receive information from the one or more detectors related to the one or more measurable parameters;

said controller configured to adjust one or more controllable parameters until one or more detectors indicate that one or more measurable parameters in one of the LEDs or LED drivers meet a reference condition; and

said controller configured to set one or more of the controllable parameters to operate at a value relative to the value of the controllable parameters at which the reference condition was met.

2. The circuit of claim 1, wherein the one or more detectors detect the ambient temperature of at least one of the LEDs or LED drivers.

3. The circuit of claim 1, wherein the one or more detectors detect the current in at least one of the LEDs or LED drivers.

4. The circuit of claim 1, wherein the one or more detectors detect a voltage in at least one of the LEDs or LED drivers.

5. The circuit of claim 1, wherein the one or more detectors detect a luminous intensity of at least one of the LEDs.

6. The circuit of claim 1, wherein the one or more detectors detect a wavelength of the light emitted by at least one of the LEDs.

7. The circuit of claim 1, wherein the controller initiates the adjusting of the controllable parameters relative to the start up of at least one of the one or more LEDs or LED drivers.

8. The circuit of claim 1, wherein the controller initiates the adjusting of the controllable parameters relative to a change in a second measurable parameter in at least one of the one or more LEDs or LED drivers.

9. The circuit of claim 1, wherein the controller initiates the adjusting of the controllable parameters at a fixed or variable time interval.

10. The circuit of claim 1, wherein the controller comprises a DAC and a state machine.

11. A liquid crystal display comprising the circuit of claim 1.

12. The circuit of claim 1, wherein the one or more detectors comprise one or more triode region detectors.

13. The circuit of claim 1, wherein the programmable decentralized controller is not necessary for the operation of the one or more LEDs or LED drivers, and the one or more LEDs or LED drivers can operate independent of the programmable decentralized controller.

14. The circuit of claim 1, wherein the programmable decentralized controller is configured to control the power supply to set the driver voltage at any value relative to the drive voltage at which the reference condition, as detected by the one or more detectors, is met.

15. The circuit of claim 1, further comprises a second programmable decentralized controller coupled to a second set of one or more detectors,

wherein the second set of one or more detectors is configured to detect a second set of one or more measurable parameters of a second set of one or more LEDs or LED drivers,

wherein the power supply is coupled to the second set of one or more LEDs and provides second drive voltage for the second set of one or more LEDs,

wherein the second programmable decentralized controller is configured to control the power supply to set the second drive voltage, and

wherein the programmable decentralized controller and the second programmable decentralized controller are coupled to the power supply through a system for inter-chip communication.

16. A method for controlling one or more LEDs or LED drivers by a programmable decentralized controller, the method comprising:

detecting one or more measurable parameters of the one or more LEDs or LED drivers;

receiving information from the one or more detectors related to the one or more measurable parameters;

adjusting one or more controllable parameters of the one or more LEDs or LED drivers until the measurable parameters in the one or more LEDs or LED drivers meet a reference condition;

setting the controllable parameters to operate at a value relative to the value of the controllable parameters at which the reference condition was met, wherein the setting is performed by a programmable decentralized controller; and

setting a driver voltage for the one or more LEDs by controlling a power supply coupled to the programmable decentralized controller, wherein the power supply provides the driver voltage for the one or more LEDs.

17. The method of claim 16, wherein the reference condition is based on the ambient temperature of at least one of the LEDs or LED drivers.

18. The method of claim 16, wherein the reference condition is based on the current in at least one of the LEDs or LED drivers.

19. The method of claim 16, wherein the reference condition is based on a voltage in at least one of the LEDs or LED drivers.

20. The method of claim 16, wherein the reference condition is based on a luminous intensity of at least one of the LEDs.

21. The method of claim 16, wherein the reference condition is based on a wavelength of the light emitted by at least one of the LEDs.

22. The method of claim 16, wherein the adjusting of the controllable parameters is initiated relative to at least one of the start up of at least one of the LEDs or LED drivers or a change in parameters in at least one of the LEDs or LED drivers.

23. The method of claim 16, wherein the adjusting of the controllable parameters is initiated relative to a fixed or variable time interval.

24. A circuit for controlling one or more LEDs or LED drivers comprising:

a programmable decentralized controller coupled to a power supply and one or more detectors, wherein the power supply provides a drive voltage for the one or more LEDs, and wherein the one or more detectors are configured to detect one or more measurable parameters of the one or more LEDs or LED drivers, wherein the one or more LEDs or LED drivers are configured to operate independent of the programmable decentralized controller;

said controller configured to control the power supply to set the drive voltage;

said controller configured to receive information from the one or more detectors related to the one or more measurable parameters;

said controller configured to adjust one or more controllable parameters until one or more detectors indicate that one or more measurable parameters in one of the LEDs or LED drivers meet a reference condition; and

said controller configured to set one or more of the controllable parameters to operate at a value relative to the value of the controllable parameters at which the reference condition was met.