System and method for driving LED
First Claim
1. A system for providing power to one or more light emitting diodes, the system couplable to an energy source, the system comprising:
- a power converter comprising an inductor and a power switch, the power converter couplable to the one or more light emitting diodes, the power converter having a dual phase cycle comprising an on phase when the power switch is closed and an off phase when the power switch is open;
an output current sensor to sense an output current level;
a peak current sensor to sense a peak current level; and
a regulator coupled to the power converter, to the output current sensor and to the peak current sensor, the regulator to determine an integrated output current level during the off phase, to compare the integrated output current level to a reference signal to provide a control signal indicating a set point, to compare the peak current level to the set point, and to turn off the power switch when the peak current level substantially reaches the set point.
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Accused Products
Abstract
A system drives one or plurality of LEDs regulating their brightness by controlling LEDs average current or voltage. The system includes a switching power converter and an integrated digital regulator with at least one of electrical, thermal and optical feedbacks. The regulator is constructed as a hysteretic peak current mode controller for continuous mode of operation of the power converter. For discontinuous mode of operation of the power converter a pulse averaging sliding mode control is being used. Average LED current is measured by integrating LED pulse current at off time and hysteretically adjusting on time of the power switch. Input battery is protected from discharging at abnormally low impedance of the output.
145 Citations
17 Claims
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1. A system for providing power to one or more light emitting diodes, the system couplable to an energy source, the system comprising:
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a power converter comprising an inductor and a power switch, the power converter couplable to the one or more light emitting diodes, the power converter having a dual phase cycle comprising an on phase when the power switch is closed and an off phase when the power switch is open; an output current sensor to sense an output current level; a peak current sensor to sense a peak current level; and a regulator coupled to the power converter, to the output current sensor and to the peak current sensor, the regulator to determine an integrated output current level during the off phase, to compare the integrated output current level to a reference signal to provide a control signal indicating a set point, to compare the peak current level to the set point, and to turn off the power switch when the peak current level substantially reaches the set point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification