LED lighting system with accurate current control

1. A light emitting diode (LED) lighting system comprising:

a switching power supply for converting a phase modulated signal generated from a dimmer into an output voltage, wherein the dimmer is a phase cut dimmer and operates at a repetitive phase cut rate and generates phase delays in a rectified input voltage wherein the rectified input voltage is rectified from an alternating current input voltage;

an LED controller coupled to the switching power supply; and

light emitting diodes (LEDs) coupled to the LED controller; and

wherein the LED controller controls a current based on the output voltage of the switching power supply and includes components to:

calculate, based on the current and an active time period of an LED current time period, an actual charge amount delivered to the LEDs, wherein the active time period is based on the repetitive phase cut rate; and

utilize the actual charge to modify and provide a desired target charge amount to be delivered during a future active time period of the LED current time period, wherein the future active time period is based on the repetitive phase cut rate.

2. The LED lighting system of claim 1 wherein the desired target charge is based on the phase delays in the rectified input voltage.

3. The LED lighting system of claim 1 wherein the active time period and the future active time period are based on an averaging period that is based on the repetitive phase cut rate.

4. The LED lighting system of claim 1 wherein the active time period is based on a half line cycle of the alternating current input voltage and the future active time period is based on a next half line cycle of the alternating current input voltage.

5. The LED lighting system of claim 1 wherein the LED controller controls dimming of the LEDs.

6. The LED lighting system of claim 5 wherein the LED controller controls dimming of the LED system over a wide dimming frequency range.

7. The LED lighting system of claim 1 wherein the components to utilize the actual charge to modify and provide a desired target charge amount to be delivered during a future active time period of the LED current time period, wherein the future active time period is based on the repetitive phase cut rate further comprises:

components to compare the actual charge amount to a desired charge amount for the active time period and compensate for a difference between the actual charge amount and the desired charge amount during the future active time period.

8. The LED lighting system of claim 7 wherein the LED controller controls dimming of the LEDs.

9. The LED lighting system of claim 8 wherein the LED controller comprises a dimming controller and a current controller wherein the dimming controller drives the current controller.

10. The LED lighting system of claim 9 wherein the dimming controller is driven by the repetitive phase cut rate and the current controller is driven by a switching frequency rate and wherein the repetitive phase cut rate is different than the switching frequency rate.

11. A method for controlling a current in light emitting diodes (LEDs) of an LED lighting system, comprising:

converting, by a switching power supply, a phase modulated signal generated from a dimmer into an output voltage, wherein the dimmer operates at a repetitive phase cut rate and generates phase delays in a rectified input voltage wherein the rectified input voltage is rectified from an alternating current input voltage;

controlling, by the LED controller coupled to the switching power supply and the light emitting diodes, a current based on the output voltage of the switching power supply;

calculating, by the LED controller, based on the current and an active time period of an LED current time period, an actual charge amount delivered to the LEDs, wherein the active time period is based on the repetitive phase cut rate; and

utilizing, by the LED controller, the actual charge to modify and provide a desired target charge amount to be delivered during a future active time period of the LED current time period, wherein the future active time period is based on the repetitive phase cut rate.

12. The method of claim 11 wherein the desired target charge is based on the phase delays in the rectified input voltage.

13. The method of claim 11 wherein the active time period and the future active time period are based on an averaging period that is based on the repetitive phase cut rate.

14. The method of claim 11 wherein the active time period is based on a half line cycle of the alternating current input voltage and the future active time period is based on a next half line cycle of the alternating current input voltage.

15. The method of claim 11 wherein controlling, by the LED controller coupled to the switching power supply and the light emitting diodes, a current further comprises:

controlling, by the LED controller, dimming of the LEDs.

16. The method of claim 15 wherein controlling, by the LED controller, dimming of the LEDs further comprises:

controlling, by the LED controller, dimming of the LEDs over a wide dimming frequency range.

17. The method of claim 11 wherein utilizing, by the LED controller, the actual charge to modify and provide a desired target charge amount to be delivered further comprises:

utilizing the actual charge to modify and provide the desired target charge amount to be delivered during the future active time period of the LED current time period, wherein the future active time period is based on the repetitive phase cut rate further comprises; and

comparing the actual charge amount to a desired charge amount for the active time period and compensate for a difference between the actual charge amount and the desired charge amount during the future active time period.

18. The method of claim 17 wherein controlling, by the LED controller coupled to the switching power supply and the light emitting diodes, a current, further comprises:

controlling, by the LED controller, dimming of the LEDs.

19. The method of claim 18 wherein the LED controller comprises a dimming controller and a current controller and further comprising:

driving, by the dimming controller, the current controller.

20. The method of claim 19 wherein driving, by the dimming controller, the current controller further comprises:

driving the dimming controller at the repetitive phase cut rate; and

driving the current controller at a switching frequency rate that is different than the repetitive phase cut rate.