Method and apparatus for controlling an electrochromic device
OwnerPhillip C. Yu, David L. Backfisch +1inventors
InventorsPhillip C. Yu, David L. Backfisch, Charles R. Coleman
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Abstract
A method and apparatus for controlling a charge/discharge voltage applied to an EC device to ensure that an appropriate voltage drop across the EC device is maintained during charge and/or discharge modes of operation. The appropriate voltage drop is determined with respect to a temperature measurement proximate the EC device. The charge level of the device is monitored using a coulomb counter circuit having a topology designed to minimize interference in the operation of the EC device.
Claims38
Apparatus for controlling a charge state of an electrochromic (EC) device, comprising:
- a controllable voltage source, for providing a charging voltage to said EC device;
- a temperature sensor, for providing an indicium of a temperature proximate said EC device;
- and
- a controller, for determining, in response to said temperature indicium, an appropriate voltage to be applied to said EC device by said controllable voltage source, said determined voltage defining a rate of charge.
The apparatus of claim.4, further comprising:
- a counter, said counter being incremented in response to pulses provided during a charge mode and decremented in response to pulses provided during a discharge mode, said count being indicative of a present charge level of said EC device.
Apparatus for controlling a charge state of an electrochromic (EC) device, said electrochromic device receiving a charging current said apparatus comprising:
- 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 window comparator, coupled to said reference impedance, for comparing a voltage level of said reference impedance to upper and lower threshold levels and producing an output signal indicative of said comparison;
- and
- a controller, coupled to said window comparator, for determining a charge level of said EC device using said window comparator output signal.
In eyewear having a lens portion optically cooperating with an electrochromic material, apparatus for controlling a charge state of said electrochromic material, comprising:
- a controllable current source, for providing a current to said electrochromic device;
- a charge counter, for counting charge quanta imparted to said electrochromic device;
- a temperature sensor, for providing an indicium of a temperature proximate said electrochromic device;
- and
- a controller, for determining, in response to said temperature indicium,, an appropriate voltage to be produced by said controllable current source;
- said controller causing said current source to stop producing said current when said charge quanta imparted to said electrochromic device reaches a desired level.
Apparatus for controlling a charge state of an electrochromic device, comprising:
- a controllable voltage source, for providing a charging voltage to said electrochromic device;
- a charge counter, for counting charge quanta imparted to said electrochromic device;
- a temperature sensor, for providing an indicium of a temperature proximate said electrochromic device;
- and
- a controller, for determining, in response to said temperature indicium, an appropriate voltage to be applied to EC device by said controllable current source;
- said controller causing said current source to stop producing said current when said charge quanta imparted to said electrochromic device reaches a desired level.
A method for maintaining charge delivered to an electrochromic device at a predetermined level as the temperature proximate said device varies, wherein said charge is induced by an applied voltage, said method comprising the steps of:
- (a) sensing the temperature proximate said device;
- and
- (b) adjusting said applied voltage in accordance with the temperature sensed in step (a) so as to maintain said charge at said predetermined level.
A method for maintaining charge delivered to an electrochromic device at a predetermined level as the temperature proximate said device varies, wherein said charge is induced by an applied current, said method comprising the steps of:
- (a) sensing the temperature proximate said device;
- and
- (b) adjusting said applied current in accordance with the temperature sensed in step (a) so as to maintain said charge at said predetermined level.
A method for adapting the charge level of an electro-optic device, comprising the steps of:
- (a) sensing the temperature proximate said device;
- and
- (b) simultaneously adjusting a rate of charge and a maximum charging voltage in accordance with the sensed temperature to achieve a desired charge level in said electro-optic device.
A method, comprising the step of:
- simultaneously controlling, according to a temperature proximate an electrochromic (EC) device, a total charge applied to the EC device and a rate at which the charge is applied to the EC device.
Dependencies are inferred from the claim text.