Apparatus for controlling an electrochromic device
First Claim
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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Abstract
An apparatus for controlling a charge state of an electrochromic devices according to the invention, where the electrochromic devices receives a charging current, comprises: a reference impedance, coupled to receive a reference current proportional to the charging current, the reference impedance having a known impedance relationship with the electrochromic device; a comparator, coupled to the reference impedance, for comparing a voltage level of the reference impedance to a threshold voltage level and producing an output signal indicative of the comparison; and control logic, coupled to the comparator, for simultaneously adapting the reference current and the charging current in response to the output signal of the comparator. In one embodiment of the invention, the apparatus is included within a pair of eyeglasses.
140 Citations
18 Claims
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1. Apparatus for controlling a charge state of an electrochromic device, comprising:
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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. - View Dependent Claims (2, 3, 4)
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5. Apparatus for controlling a charge state of an electrochromic devices, said electrochromic device receiving a charging current, said apparatus comprising:
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a reference impedance, coupled to receive a reference current proportional to said charging current, said reference impedance having a known impedance relationship with said electrochromic device; a comparator, coupled to said reference impedance, for comparing a voltage level of said reference impedance to a threshold voltage level and producing an output signal indicative of said comparison; and control logic, coupled to said comparator, for simultaneously adapting said reference current and said charging current in response to said output signal of said comparator. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. In a pair of sunglasses having a lens portion optically cooperating with an electrochromic material, apparatus for controlling a charge state of said electrochromic material, said electrochromic material receiving a charging current, said apparatus comprising:
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a reference impedance, coupled to receive a reference current proportional to said charging current, said reference impedance having a known impedance relationship with said electrochromic material; a comparator, coupled to said reference impedance, for comparing a voltage level of said reference impedance to a threshold voltage level and producing an output signal indicative of said comparison; and control logic, coupled to said comparator, for simultaneously adapting said reference current and said charging current in response to said output signal of said comparator. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification