Light emitting diode circuits for general lighting

摘要

Improved circuits minimize, or eliminate, energy losses in the supply of energy to control LEDs. Diodes and a capacitor reduce or eliminate LED blinking, and create smooth and continuous, infinitely variable dimming. The components are added to supply power to each LED during the half of the AC cycle where it would normally be turned off. A first added diode allows an added capacitor to charge during the half cycle that the original diode is turned on, but does not allow the other half cycle to discharge the added capacitor. When the added capacitor is charged enough to turn on the original diode, it stays on throughout the AC cycle. The same relationship exists between the second added diode, the added capacitor and the second original diode. Zener diodes protect the LEDs from voltage surges/spikes by shunting current around LEDs when the voltage exceeds the Zener diode's breakdown voltage.

主权项

1. Electrical apparatus for controlling back-to-back light-emitting diodes (LEDs) powered by an alternating current (AC) line voltage, the apparatus comprising:
a pair of electrically controlled switches connected in parallel with one another, and with the switches in parallel being connected in series with the LEDs; a voltage divider outputting a signal representative of the AC line voltage; an electrical component having a value providing a signal that determines the brightness of the LEDs through a range of brightness levels up to a maximum brightness level; a control circuit in electrical communication with the voltage divider, the electrically controlled switches, and the electrical component, the control circuit being operative to independently control the electrically controlled switches to adjust the brightness level of the LEDs as a function of the signals received from the voltage divider and the electrical component; and wherein the value of the electrical component is intentionally selected to produce an LED brightness level below the maximum brightness level, such that the light produced by the LEDs is substantially constant over a wide range of AC line voltages.