Method and apparatus for controlling an electrochromic device
First Claim
1. In a system for controlling a charge state of an electrochromic device by selectively imparting, via control logic, one of a positive charge and a negative charge to said electrochromic device in response to changes in a value representative of a desired charge state, apparatus for correcting said desired charge state representative value comprising:
- an analog to digital converter, coupled to measure said charge state of said electrochromic device without significantly altering said charge state, for producing a value representative of an actual charge state of said electrochromic device;
a code converter, coupled to said analog to digital converter, for converting said actual charge state representative value into a corrected charge state representative value;
a timer, coupled to said control logic, for providing a control signal indicative of said electrochromic device achieving a substantially quiescent charge state; and
a value changer, responsive to said quiescent state indicative control signal and said corrected charge state representative value, for replacing said desired charge state representative value with said corrected charge state representative value.
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Abstract
A method and concomitant apparatus for use in an electrochromic control system in which components causing the charging and discharging of an electrochromic device are subject to drift errors and other errors. In the case of such errors, the actual programming level and the desired programming level as indicated by, e.g., a count value, may diverge. The invention periodically determines the actual programming level of the electrochromic device and responsively adjusts a parameter representative of the desired programming level.
139 Citations
14 Claims
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1. In a system for controlling a charge state of an electrochromic device by selectively imparting, via control logic, one of a positive charge and a negative charge to said electrochromic device in response to changes in a value representative of a desired charge state, apparatus for correcting said desired charge state representative value comprising:
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an analog to digital converter, coupled to measure said charge state of said electrochromic device without significantly altering said charge state, for producing a value representative of an actual charge state of said electrochromic device; a code converter, coupled to said analog to digital converter, for converting said actual charge state representative value into a corrected charge state representative value; a timer, coupled to said control logic, for providing a control signal indicative of said electrochromic device achieving a substantially quiescent charge state; and a value changer, responsive to said quiescent state indicative control signal and said corrected charge state representative value, for replacing said desired charge state representative value with said corrected charge state representative value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 12)
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8. Apparatus controlling a charge level of an electrochromic device, comprising:
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a charge source, for imparting a charge to said electrochromic device; a memory, for storing a value indicative of a desired charge level; a controller, coupled to said memory and said charge source, for adapting said imparted charge in response to said desired charge level; and a voltage measurement unit, coupled to said electrochromic device, for measuring a voltage level of said electrochromic device and producing therefrom a voltage level indicative signal;
whereinsaid controller, in response to said voltage level indicative signal, calculates an actual charge level of said electrochromic device; and if said actual charge level is different than said desired charge level stored in said memory, said controller causes said desired charge level stored in said memory to be replaced by a value indicative of said actual charge level. - View Dependent Claims (9, 10, 11)
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13. In a system for controlling a charge state of an electrochromic device by selectively imparting, via control logic, one of a positive charge and a negative charge to said electrochromic device in response to changes in a value representative of a desired charge state, a method for correcting said desired charge state representative value comprising the steps of:
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measuring, during a substantially quiescent state, the voltage across the electrochromic device; relating, to said desired charge state representative value, the measured voltage level across the electrochromic device; and replacing said desired charge state representative value with a value representative of the actual charge state of the electrochromic device. - View Dependent Claims (14)
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Specification