Constant current light emitting diode (LED) driver circuit and method
First Claim
1. A drive circuit operable to supply a drive current to a plurality of light emitting diodes, the drive circuit including a voltage converter circuit having a topology and including at least one inductive element and at least one switching element, the drive circuit operable to sense a current through one of the inductive and switching elements and generate a feedback signal from the sensed current, the feedback signal having a value indicating the drive current being supplied to the light emitting diodes and the drive circuit operable to control the operation of the voltage converter circuit responsive to the feedback signal.
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Accused Products
Abstract
A drive circuit supplies a drive current to a plurality of light emitting diodes. The drive circuit includes a voltage converter circuit having a particular topology and including at least one inductive element and at least one switching element. The drive circuit senses a current through one of the inductive and switching elements and generates a feedback signal from the sensed current. The feedback signal has a value indicating the drive current being supplied to the light emitting diodes and the drive circuit controls the operation of the voltage converter responsive to the feedback signal.
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Citations
27 Claims
- 1. A drive circuit operable to supply a drive current to a plurality of light emitting diodes, the drive circuit including a voltage converter circuit having a topology and including at least one inductive element and at least one switching element, the drive circuit operable to sense a current through one of the inductive and switching elements and generate a feedback signal from the sensed current, the feedback signal having a value indicating the drive current being supplied to the light emitting diodes and the drive circuit operable to control the operation of the voltage converter circuit responsive to the feedback signal.
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12. A drive circuit for supplying a drive current to a plurality of light emitting diodes, the drive circuit comprising:
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a switching and energy storage circuit adapted to receive an input voltage, the switching and energy storage circuit including at least one inductive element and at least one switching element and being operable responsive to a control output signal to provide a first current; an output stage adapted to be coupled to a load, the output stage including at least one capacitive element and being operable to store energy responsive to the first current from the switching and energy storage circuit and operable to supply the drive current to the load; and a control circuit coupled to the switching and energy storage circuit, the control circuit operable to sense a current through one of the inductive and switching elements in the switching and energy storage circuit to obtain an indication of a value of the drive current being supplied to the load, and the control circuit operable responsive to the sensed current to generate pulse width modulated control output signals that are applied to control the operation of the switching and energy storage circuit. - View Dependent Claims (14, 15, 16, 17, 18)
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13. A drive circuit for supplying a drive current to a plurality of light emitting diodes, the drive circuit comprising:
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a switching and energy storage circuit adapted to receive an input voltage, the switching and energy storage circuit including at least one inductive element and at least one switching element and being operable responsive to a control output signal to provide a first current; an output stage adapted to be coupled to a load, the output stage including at least one capacitive element and being operable to store energy responsive to the first current from the switching and energy storage circuit and operable to supply the drive current to the load; a control circuit coupled to the switching and energy storage circuit, the control circuit operable to sense a current through one of the inductive and switching elements in the switching and energy storage circuit and operable responsive to the sensed current to generate pulse width modulated control output signals that are applied to control the operation of the switching and energy storage circuit; and wherein the control circuit is operable to sense the average current through one of the inductive or switching elements in the switching and energy storage circuit.
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19. A method of controlling a drive current being supplied to a plurality of light emitting diodes, the drive current being generated by a voltage converter circuit including switching and inductive elements and the method comprising:
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sensing a current through a selected one of the inductive and switching elements; determining the average current through the selected one of the inductive and switching elements; and controlling the drive current responsive to the determined average current. - View Dependent Claims (20)
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- 21. A drive circuit for supplying a drive current to a plurality of light emitting diodes, the drive circuit including a voltage converter circuit having a topology and including a first inductive element and a first switching element having associated activation and deactivation times, and wherein the drive circuit is operable to sense a current through the first inductive element during the deactivation time of the first switching element and to generate a feedback signal from the sensed current, the feedback signal having a value indicating the drive current being supplied to the light emitting diodes and the drive circuit operable to control the operation of the voltage converter circuit responsive to the feedback signal.
Specification