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Apparatus for controlling an electrochromic device

  • US 5,978,126 A
  • Filed: 09/21/1998
  • Issued: 11/02/1999
  • Est. Priority Date: 09/21/1998
  • Status: Expired due to Fees
First Claim
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1. Apparatus for controlling a charge state of an electrochromic device, comprising:

  • a first current source, coupled to a capacitor, for selectively charging said capacitor in accordance with a first current produced therefrom;

    a second current source, coupled to an electrochromic device, for selectively charging said electrochromic device in accordance with a second current produced therefrom;

    a comparator, coupled to said capacitor, for comparing a voltage level of said capacitor to a reference voltage level and responsively producing an output signal indicative of said comparison;

    a first switch, coupled to said capacitor and said comparator, for decoupling said first current from said capacitor in response to said output signal indicating that said capacitor voltage level exceeds said reference voltage level;

    a second switch, coupled to said electrochromic device, for decoupling said second current from said electrochromic device in response to said output signal indicating that said capacitor voltage level exceeds said reference voltage level.

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