WIDE VOLTAGE, HIGH EFFICIENCY LED DRIVER CIRCUIT
First Claim
Patent Images
1. A method of driving at least one light emitting diode, said method comprising the steps of:
- generating an internal reference current;
measuring the current from a DC-DC boost converter powered by a power source, said DC-DC boost converter driving said at least one light emitting diode;
supplying said measured current and said internal reference current to a closed loop control;
using said closed loop control to generate a PWM signal;
controlling the output current of said DC-DC boost converter using said PWM signal; and
driving said at least one light emitting diode with said output current.
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Abstract
An electrical circuit and method for driving light emitting diodes with a constant current via a high efficiency DC-DC converter controlled by a digital controller through pulse width modulation (PWM).
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Citations
20 Claims
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1. A method of driving at least one light emitting diode, said method comprising the steps of:
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generating an internal reference current; measuring the current from a DC-DC boost converter powered by a power source, said DC-DC boost converter driving said at least one light emitting diode; supplying said measured current and said internal reference current to a closed loop control; using said closed loop control to generate a PWM signal; controlling the output current of said DC-DC boost converter using said PWM signal; and driving said at least one light emitting diode with said output current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A LED driver circuit for powering a plurality of light emitting diodes with a power source, said circuit comprising:
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a DC-DC boost converter powered by said power source, said DC-DC boost converter for providing current to said light emitting diodes, said DC-DC boost converter controlled by a microcontroller through pulse width modulation (PWM); a current feedback circuit for measuring the output of said DC-DC boost converter, said current feedback circuit comprising a measurement resistor connected in series with said light emitting diodes, wherein voltage measured across said measurement resistor can be filtered by a filter and amplified by an operational amplifier to create an amplified signal; and said microcontroller, said microcontroller for generating a reference current, said microcontroller comprising a PWM generator for generating a PWM signal based on the difference between said measured current and said reference current, said PWM signal for controlling current output of said DC-DC boost converter. - View Dependent Claims (16, 17, 18, 19)
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20. A LED driver circuit for powering a plurality of series connected light emitting diodes with a plurality of series connected ultracapacitors, said circuit comprising:
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a DC-DC boost converter powered by said power source, said DC-DC boost converter for providing current to said light emitting diodes, said DC-DC boost converter controlled by a microcontroller through pulse width modulation (PWM); a current feedback circuit for measuring the output of said DC-DC boost converter, said current feedback circuit comprising a measurement resistor connected in series with said light emitting diodes, wherein voltage measured across said measurement resistor can be filtered by a filter and amplified by an operational amplifier to create an analog amplified signal; and said microcontroller, said microcontroller for generating a digital reference current, said microcontroller comprising an analog to digital converter for converting said analog amplified signal to a digital measured current, said microcontroller comprising a PWM generator for generating a PWM signal based on the difference between said measured current and said reference current, said PWM signal for controlling current output of said DC-DC boost converter.
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Specification