System and method for a constant current source LED driver
AssigneeSTMicroelectronics S.r.l.
InventorsJianwen Shao, John S. Lo Giudice, Thomas A. Stamm
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Abstract
A system and method for providing a constant current source driver for a light emitting diode string. The converter includes a current sensor that derives feedback signal corresponding to a peak current through the light emitting diode string. The feedback signal is used by a controller to vary a duty cycle of the controller to regulate the average current. The controller is operable to regulate the average current as the number of light emitting diodes is increased and/or decreased.
Claims20
A converter comprising:
- a current sensor configured to derive a feedback signal corresponding to a peak current through a light emitting diode string;
- a switch coupled on a first end to the current sensor;
- and
- a controller coupled on a first port to a second end of the switch and on a second port to the current sensor, wherein the controller is configured to use the feedback signal corresponding to the peak current to regulate the average current.
A light emitting diode system comprising:
- a light emitting diode string;
- and
- power converter, the power converter comprising:
- a current sensor configured to derive a feedback signal corresponding to a peak current through the light emitting diode string;
- a switch coupled on a first end to the current sensor;
- and
- a controller coupled on a first port to a second end of the switch and on a second port to the current sensor, wherein the controller is configured to use the feedback signal corresponding to the peak current to regulate the average current.
For use in a light emitting diode system, a method of providing a constant current source, the method comprising:
- sensing a peak current through a plurality of light emitting diodes;
- deriving a feedback signal corresponding to the peak current;
- regulating the average current based on the feedback signal, wherein regulating further comprises varying a duty cycle of a controller.
Dependencies are inferred from the claim text.