LED controller

• US 9,820,345 B2
• Filed: 09/20/2016
• Issued: 11/14/2017
• Est. Priority Date: 09/21/2015
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Bthker, Henricus Cornelis Johannes
• Primary Examiner(s): CRAWFORD, JASON
• Application Number:
  US15/270,902
• Publication Number:
  US 20170086270A1
• Time in Patent Office: 420 Days
• CPC Class Codes: B60Q 1/1415 Dimming circuits
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices

Abstract

An LED controller, for connecting to an LED string, comprising: an input terminal configured to receive a light-control-signal representative of a received-profile-identifier; a local memory configured to store a plurality of profile-data, wherein each of the plurality of profile-data defines an association between a plurality of light-values and a plurality of sequence-numbers; a processor configured to: determine one of the plurality of profile-data as selected-profile-data in accordance with the received-profile identifier; and determine a set of LED control signals for the LED string in accordance with light-values of the selected-profile-data for a set of sequence-numbers.

Claims

1. An LED controller, for connecting to an LED string, comprising:

an input terminal configured to receive a light-control-signal representative of a received-profile-identifier;

a local memory configured to store a plurality of profile-data, wherein each of the plurality of profile-data defines an association between a plurality of light-values and a plurality of sequence-numbers;

a processor configured to;

determine one of the plurality of profile-data as selected-profile-data in accordance with the received-profile identifier; and

determine a set of LED control signals for the LED string in accordance with light-values of the selected-profile-data for a set of sequence-numbers.

2. The LED controller of claim 1 wherein the LED controller is provided on an integrated circuit, and wherein the local memory and the processor are provided on the same integrated circuit.

3. The LED controller of claim 1, wherein:

each of the plurality of profile-data comprises coefficient values for a polynomial that defines the light-value as a function of the sequence-number; and

the processor is configured to determine the set of LED control signals in accordance with the polynomial, the coefficient values and the set of sequence numbers.

4. The LED controller of claim 3, wherein the polynomial is up to and including a 3rd order polynomial.

5. The LED controller of claim 3, wherein the processor is configured to:

apply the polynomial to the set of sequence-numbers, using the coefficient values represented by the selected-profile-data, in order to determine a set of associated light-values; and

determine the set of LED control signals in accordance with the determined set of associated light-values.

6. The LED controller of claim 3, wherein:

the set of sequence-numbers comprises a start-sequence-number and one or more subsequent-sequence-numbers, and

the processor is configured to;

apply the polynomial, using the coefficient values represented by the selected-profile-data, to the start-sequence-number in order to determine a start-light-value; and

for each of the plurality of subsequent-sequence-numbers, determine a difference-light-value and add the difference-light-value to a preceding-light-value in order to determine a subsequent-light-value; and

determine the set of LED control signals for the LED string in accordance with the start-light-value and each subsequent-light-value.

7. The LED controller of claim 6, wherein the processor is configured to apply a differentiated version of the polynomial with the coefficient values represented by the selected-profile-data to each subsequent-sequence-number in order to determine the difference-light-value.

8. The LED controller of claim 1, wherein:

each of the plurality of profile-data comprises a plurality of light-values and their associated sequence-numbers.

9. The LED controller of claim 1, wherein the set of sequence-numbers is a subset of the plurality of the sequence-numbers of the selected-profile-data.

10. The LED controller of claim 1, wherein the light-control-signal is also representative of a profile-direction-indicator, and wherein the processor is configured to determine the set of LED control signals for the LED string in accordance with light-values of the selected-profile-data for the set of sequence-numbers in either a forward or reverse direction according to the profile-direction-indicator.

11. The LED controller of claim 1, wherein the light-control-signal is also representative of a shift-value, and wherein the processor is configured to control the speed with which the set of sequence numbers of the selected-profile-data are changed when determining the set of LED control signals in accordance with the shift-value.

12. The LED controller of claim 1, wherein the light-control-signal is also representative of an auto-indicator, and wherein the processor is configured to automatically stitch a plurality of light-change-profiles together in accordance with the auto-indicator.

13. The LED controller of claim 1, further comprising:

two output terminals for each LED in the LED string; and

a switch connected between the two output terminals for each LED, wherein the switch is configured to receive one of the set of LED control signals, such that the switch is opened and closed in accordance with the received LED control signal in order to selectively short circuit an associated LED.

14. The LED controller of claim 1, wherein the set of LED control signals comprises a set of PWM LED control signals, and wherein the processor is configured to set the width of pulses in the set of PWM LED control signals in accordance with the light-values of the selected-profile-data.

15. A method of operating an LED matrix system comprising:

receiving a light-control-signal representative of a received-profile-identifier;

determining one of a plurality of profile-data as selected-profile-data in accordance with the received-profile identifier, wherein each of the plurality of profile-data is stored in local memory and defines an association between a plurality of light-values and a plurality of sequence-numbers; and

determining a set of LED control signals for the LED string in accordance with light-values of the selected-profile-data for a set of sequence-numbers.