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Light adjustment circuit for alternating-current light emitting diodes (AC-LED's)

  • US 8,111,009 B2
  • Filed: 11/30/2009
  • Issued: 02/07/2012
  • Est. Priority Date: 09/07/2009
  • Status: Active Grant
First Claim
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1. A light adjustment circuit for alternating-current light emitting diodes (AC-LED'"'"'s), the light adjustment circuit being connected to an AC power supply and a plurality of AC-LED'"'"'s, the light adjustment circuit comprising:

  • a light adjustment unit, modulating AC power from the AC power supply while providing the plurality of AC-LED'"'"'s with the modulated AC power; and

    a pulse width modulation (PWM) control circuit, modulating an external voltage signal in correspondence to variation in input AC power to enable each of the AC-LED'"'"'s to achieve a predetermined brightness;

    wherein the AC-LED'"'"'s are turned off by modulating the external voltage signal to prevent the AC-LED'"'"'s from being burnt out when the input AC power is too high.

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