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US 6,586,890 B2Granted
LED driver circuit with PWM output
AssigneeKoninklijke Philips Electronics N.V.
InventorsYoung-Kee Min, Bernd Clauberg, Bertrand J. E. Hontelé
Life of this patent
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Abstract
The driver circuit for light emitting diodes (LEDs) of the present invention provides power to LEDs using pulse width modulation (PWM). The driver circuit 100 uses current feedback to adjust power to LED arrays 54 and provides a full light and a dim mode.
Claims31
A system for supplying power for an LED array, said system comprising:
- an oscillator generating an oscillating signal, the oscillating signal having a first state and a second state;
- and
- a power supply operatively coupled to the oscillator, the power supply providing output power and being responsive to the oscillating signal;
- wherein said power supply supplies the output power to the LED array when the oscillating signal is in the first state and does not supply the output power to the LED array when the oscillating signal is in the second state.
1 more element
A system for supplying power for an LED array, said system comprising:
- means for sensing current to the LED array, said current sensing means generating a sensed current signal;
- means for generating a reference signal;
- means for comparing the sensed current signal to the reference signal, said comparing means generating a feedback signal;
- means for modulating pulse width responsive to the feedback signal, said pulse width modulating means generating a drive signal;
- and
- means for supplying power responsive to the drive signal, said power supplying means supplying current to the LED array.
3 more elements
A method of supplying power to an LED array, said method comprising:
- sensing current to the LED array and generating a sensed current signal;
- generating a reference signal;
- comparing the sensed current signal to the reference signal;
- generating a feedback signal based on the difference between the sensed current signal and the reference signal;
- generating a pulse width modulated drive signal based on the feedback signal;
- and
- supplying current to the LED array in response to the pulse width modulated drive signal.
4 more elements
A circuit for supplying power to an LED array comprising:
- a power supply 52, the power supply 52 supplying current to the LED array 54 and being responsive to a drive signal;
- a current sensor 60 for sensing current to the LED array 54, the current sensor 60 generating a sensed current signal;
- a reference current source 62 for generating a reference signal;
- a comparator 58 for comparing the sensed current signal to the reference signal, the comparator 58 generating a feedback signal;
- and
- a PWM control IC 56 responsive to the feedback signal, the PWM control IC 56 generating the drive signal.
3 more elements
Dependencies are inferred from the claim text.