LED Driver Circuit and Method

1. A driver circuit for driving at least one LED, the driver circuit comprising: a data input for receiving setpoint data at a first data rate and at a first bit resolution, an LED output for driving the at least one LED with LED driving values at a second data rate and at a second bit resolution, and a processing device arranged for determining from the setpoint data by interpolation at least part of the LED driving values.

2. The driver circuit according to claim 1 , wherein the second data rate is higher than the first data rate, the processing device being arranged to interpolate in time.

3. The driver circuit according to claim 1 , wherein the second bit resolution is higher than the first bit resolution, the processing device being arranged to interpolate in bit resolution.

4. The driver circuit according to claim 1 , wherein the processing device is arranged to, in response to a receiving of a setpoint data, determine a target driving value from the received setpoint data, to determine a slope from the received setpoint data, a previous setpoint data, and an elapsed time between the received setpoint data and the previous setpoint data, and to determine following LED driving values in accordance with the slope and the target driving value.

5. The driver circuit according to claim 4 , wherein the processing device is arranged to determine the target driving value in correspondence with the set point data.

6. The driver circuit according to claim 4 , wherein the processing device is arranged to determine the following LED driving values so as to follow the slope towards the target driving value.

7. The driver circuit according to claim 4 , wherein, the processing device is arranged to further determine if the slope exceeds a predetermined threshold, and if this is the case, to set a next following driving value to the target driving value.

8. The driver circuit according to claim 4 , wherein the processing device is arranged to, when a following setpoint data is received at the data input before the target driving value has been reached, to determine a following target driving value from the following setpoint data, to determine a following slope from the following target driving value, a presently reached LED driving value and an elapsed time between the following setpoint data and the received setpoint data, and to determine following LED driving values in accordance with the following slope towards the following target driving value.

9. The driver circuit according to claim 1 , wherein the processing device is arranged to, in response to the receiving of the setpoint data, predict a target driving value from the received setpoint data and at least one previously received setpoint data, and to determine following LED driving values in accordance with the predicted target driving value.

10. The driver circuit according to claim 9 , wherein the predicting comprises a linear prediction.

11. The driver circuit according to claim 9 , wherein the predicting comprises a finite impulse response filter prediction.

12. The driver circuit according to claim 1 , wherein the processing device is arranged to detect if a direction of a value of a latest received setpoint data changes with respect of a direction of values of previously received successive setpoint data, and if this is the case, to calculate a target value from the latest received setpoint data and to interpolate along a line between an actual led driving value and the target value.

13. The driver circuit according to claim 1 , wherein the processing device is arranged to, in response to the receiving of the setpoint data, predict a first target driving value from the received setpoint data and at least one previously received setpoint data, and to determine following LED driving values in accordance with the predicted first target driving value; wherein the processing device is arranged to detect if a direction of a value of a latest received setpoint data changes with respect of a direction of values of previously received successive setpoint data, and if this is the case, to calculate a second target value from the latest received setpoint data and to interpolate along a line between an actual led driving value and the second target value; and wherein the processing device is arranged to set a third target driving value between the first target driving value and the second target driving value.

14. The driver circuit according to claim 1 , wherein the processing device is arranged to: compare a value of a received setpoint data with a value of a previously received setpoint data, increment an elapsed time measurement counter when the value of the received setpoint data is the same as the value of the previously received setpoint data, repeat the compare and increment until the value of the received setpoint data is different from the value of the previously received setpoint data, store a value of the elapsed time measurement counter in a memory of the processing device, determine an interpolation slope from the received setpoint data and the value of the elapsed time measurement counter as stored in the memory, and interpolate following LED driving values in accordance with the slope.

15. The driver circuit according to claim 14 , wherein the processing device is arranged to increment the elapsed time measurement counter upon each issue of an LED driving value.

16. The driver circuit according to claim 14 , wherein the processing device is arranged to, if the value of the elapsed time measurement counter exceeds a predetermined maximum value, upon receipt of an incremented or decremented setpoint data following successive setpoint data having the same value, store in the memory the predetermined maximum value instead of the value of the elapsed time measurement counter, and interpolate the LED driving value to a value corresponding with the incremented or decremented setpoint data within a time period derived from the predetermined maximum value.

17. The driver circuit according to claim 14 , wherein the processing device is arranged to enable or disable the interpolation upon receipt of a suitable configuration parameter data.

18. The driver circuit according to claim 1 , wherein the processing device is arranged for averaging of received setpoint data, prior to the interpolation of the setpoint data.

19. The driver circuit according to claim 18 , wherein the averaging comprises determining an average of the received setpoint data and one previously received setpoint data.

20. The driver circuit according to claim 1 , wherein the processing device is arranged to compare a difference between the received setpoint data and the previously received setpoint data with a predetermined threshold and in case the difference exceeds the threshold, to interpolate the LED driving value from its present value to a value corresponding with the received setpoint data in a time period substantially equal to the time period between receipt of two successive setpoint data.

21. The driver circuit according to claim 1 , wherein the processing device is arranged to set the second data rate to a video image capture rate or an integer multiple thereof.

22. An LED light fixture comprising the driver circuit in accordance with claim 1 .

23. A method for driving at least one LED, comprising: receiving by a data input of a driver circuit, set point data at a first data rate and at a first bit resolution, driving by means of an LED output of the driver circuit the at least one LED with LED driving values at a second data rate and at a second bit resolution, and wherein at least part of the LED driving values is determined from the set point data by interpolation by a processing device of the driver circuit.