DEVICE AND METHOD FOR DRIVING LED
First Claim
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1. An LED lighting device comprising:
- a rectifier circuit for rectifying an AC source;
an LED array having a plurality of series-connected LEDs;
a floating current source connected in series between the rectifier circuit and the LED array; and
control means for determining the magnitude of an output voltage of the rectifier circuit and, depending on the determination result, controlling the on/off of a driving current to each LED of the LED array.
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Abstract
An LED lighting device of AC power-driven type having a comparatively simple constitution and a high power efficiency. The device compares a signal voltage (rectified voltage) obtained by rectifying an AC source with a predetermined reference voltage and controls ON/OFF of a driving current to each LED of an LED array in response to a comparison result. In this constitution, a large voltage of AC source enables lighting of more number of LEDs, while a small voltage thereof enables lighting of less number of LEDs, thus enhancing power efficiency of the LED lighting device.
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Citations
13 Claims
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1. An LED lighting device comprising:
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a rectifier circuit for rectifying an AC source;
an LED array having a plurality of series-connected LEDs;
a floating current source connected in series between the rectifier circuit and the LED array; and
control means for determining the magnitude of an output voltage of the rectifier circuit and, depending on the determination result, controlling the on/off of a driving current to each LED of the LED array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification