U.S. patent application number 10/813155 was filed with the patent office on 2005-10-13 for controlling system with fixed frequency driver for controlling an electrochromic element and method for the same.
This patent application is currently assigned to EXON SCIENCE INC.. Invention is credited to Chen, Kuei-Hung, Hsiao, Shun-Hsiang, Huang, Tai-Hsiung, Su, Wen-Wei.
Application Number | 20050225830 10/813155 |
Document ID | / |
Family ID | 35057302 |
Filed Date | 2005-10-13 |
United States Patent
Application |
20050225830 |
Kind Code |
A1 |
Huang, Tai-Hsiung ; et
al. |
October 13, 2005 |
CONTROLLING SYSTEM WITH FIXED FREQUENCY DRIVER FOR CONTROLLING AN
ELECTROCHROMIC ELEMENT AND METHOD FOR THE SAME
Abstract
A controlling system and method for controlling an
electrochromic element, utilizes a simplified architecture,
including at least a microcontroller, a A/D converter and a
charging circuit, to reduce complexity of the whole system for
reaching both of a respond time and cost savings for the
electrochromic element. And the controlling system and method only
utilizes a fixed frequency to drive the electrochromic element for
reaching a better reliability than a variable duty cycle driver
used in prior art.
Inventors: |
Huang, Tai-Hsiung; (Taoyuan,
CN) ; Hsiao, Shun-Hsiang; (Taoyuan, CN) ; Su,
Wen-Wei; (Taoyuan, CN) ; Chen, Kuei-Hung;
(Taoyuan, CN) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
EXON SCIENCE INC.
|
Family ID: |
35057302 |
Appl. No.: |
10/813155 |
Filed: |
March 31, 2004 |
Current U.S.
Class: |
359/265 |
Current CPC
Class: |
G02F 1/163 20130101 |
Class at
Publication: |
359/265 |
International
Class: |
G02F 001/153; G02F
001/15 |
Claims
1. A controlling system for controlling a reflectance of an
electrochromic element, including: an analog-to-digital converter
reading an averaged voltage before the averaged voltage is applied
on the electrochromic element, and then transforming said averaged
voltage; a microcontroller provided with at least a look up table
and a PWM unit for providing a PWM function, receiving a input
averaging voltage transformed from the analog-to-digital converter
and then determining whether an output voltage with a fixed
frequency in PWM signal form is relatively generated, by way of
looking up several corresponding output voltages pre-stored in the
look up table for the voltage of input signal and only judging
whether the input averaged voltage is less than the pre-stored
output voltage; and a charging circuit capable of being disabled by
the microcontroller to release overloading voltages in the
electrochromic element when the input averaged voltage is in
contrast of being less than the pre-stored output voltage.
2. The controlling system as described in claim 1 wherein the look
up table is pre-set in a programmable memory located in the
microcontroller.
3. The controlling system as described in claim 1 further including
an amplifier for amplifying an output voltage with fixed frequency
generated from PWM unit of the microcontroller.
4. The controlling system as described in claim 2 further including
an amplifier for amplifying an output voltage with fixed frequency
generated from PWM unit of the microcontroller.
5. The controlling system as described in claim 4 wherein the
output voltage is set low by microcontroller when the input
averaged voltage is in contrast of being less than the pre-stored
output voltage.
6. The controlling system as described in claim 1 wherein the
electrochromic element is an electrochromic mirror with variable
reflection rate.
7. A controlling method for controlling a reflectance of an
electrochromic element, including the steps of: a A/D converter
reading an averaged voltage before the averaging voltage applied in
the electrochromic element for transforming the averaged voltages;
looking up a corresponding output target voltage in the look up
table that pre-stored several required output target voltages
corresponding to a PWM averaged voltage from the A/D converter; and
only determining whether the input averaged voltage is less than
the output target voltage to generate the PWM output voltage with a
fixed frequency in PWM signal form by way of a PWM unit.
8. The controlling method as described in claim 5 further including
the step of: setting the output voltage low when the input averaged
voltage is in contrast of being less than the pre-stored output
voltage.
9. The controlling method as described in claim 6 further including
the step of: releasing overloading voltages in the electrochromic
element by way of disabling a charging circuit when the input
averaged voltage is in contrast of being less than the pre-stored
output voltage.
10. A controlling circuit for controlling an electronic device,
comprising: an input signal providing an averaged voltage before
the averaged voltage is applied on the electronic device; a
microcontroller provided with at least a look up table and a PWM
unit for providing a PWM function, receiving the input averaging
voltage and then determining whether an output voltage with a fixed
frequency in PWM signal form is relatively generated, by way of
looking up several corresponding output voltages pre-stored in the
look up table for each input averaging voltage and only judging
whether the input averaged voltage is less than the pre-stored
output voltage; and a driving circuit capable of being disabled by
the microcontroller to release overloading voltages in the
electronic device when the input averaged voltage is in contrast of
being less than the pre-stored output voltage.
11. The controlling circuit as described in claim 10 wherein the
input signal is an analog signal and processed by an
analog-to-digital converter then transformed into a digital
signal.
12. The controlling circuit as described in claim 11 wherein the
electronic device is an electrochromic mirror used in automobile
applications.
13. The controlling circuit as described in claim 12 wherein the
electrochromic mirror is a liquid phase, self-erasing
electrochromic mirror.
14. The controlling circuit as described in claim 13 wherein the
driving circuit is a charging circuit capable of being disabled by
the microcontroller to release overloading voltages in the liquid
phase, self-erasing electrochromic mirror.
15. The controlling circuit as described in claim 10 wherein the
look up table is pre-set in a programmable memory located in the
microcontroller.
16. The controlling circuit as described in claim 10 further
including an amplifier for amplifying an output voltage with fixed
frequency generated from PWM unit of the microcontroller.
17. The controlling system as described in claim 15 further
including an amplifier for amplifying an output voltage with fixed
frequency generated from PWM unit of the microcontroller.
18. The controlling system as described in claim 17 wherein the
output voltage is set low by microcontroller when the input
averaged voltage is in contrast of being less than the pre-stored
output voltage.
19. The controlling system as described in claim 5 wherein the
electrochromic element is an electrochromic mirror with variable
reflection rate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a controlling system and
method for controlling an electrochromic element, and more
particularly in to a controlling system and method using a fixed
frequency for driving a reflectance of an electrochromic
element.
[0003] 2. Description of the Prior Art
[0004] As known, various electrochromic elements, i.e.
electrochromic mirror and window systems applied in automotive
applications, are being widely used. Relatively, several apparatus
for controlling the reflectance of said electrochromic elements are
progressively developed. For example, U.S. Pat. No. 6,084,700 as
illustrated in FIGS. 1 and 2, discloses that an electrical circuit
utilizes active loading or voltage feedback of electrochromic
element to control a reflectance of an electrochromic element. The
electrical circuit provided a programmable microcontroller is
capable of generating a variable duty cycle driver to adjust the
current voltage of electrochromic elements. In illustration of FIG.
1, the microcontroller gets an element voltage with a PWM (pulse
width modulated signal) input voltage during measurement and
therefore looks up a corresponding output voltage target pre-stored
in a lookup table of the microcontroller. Furthermore, the
microcontroller compares the output voltage target with said
element voltage to increase/decrease the PWM input duty cycle as
forming the variable output duty cycle. The flowchart for software
PWM installed in the microcontroller is illustrated in FIG. 2.
However, there are several problems in use of the variable output
duty cycle for electrochromic element. It is over complexity in
design and therefore possibly makes unreliable.
SUMMARY
[0005] It is an object of the present invention to provide a
controlling system and method for controlling an electrochromic
element.
[0006] It is a further object of the present invention to provide a
controlling system and method for controlling an electrochromic
element, which utilizes a simplified architecture to reduce
complexity of the whole system for reaching both of a respond time
and cost savings for electrochromic element.
[0007] It is a further object of the present invention to provide a
controlling system and method for controlling an electrochromic
element, which only utilizes a fixed frequency to drive the
electrochromic element for reaching a better reliability than said
variable duty cycle driver used in prior art.
[0008] Briefly summarized, the present invention relates to a
controlling system for controlling a reflectance of an
electrochromic element. The controlling system includes an
analog-to-digital (A/D) converter, a microcontroller, a charging
circuit and a amplifier. Meanwhile, the A/D converter is capable of
reading out an averaged voltage before the averaged voltage is
applied on the electrochromic element, and then transforming said
averaged voltage. And, the microcontroller is provided with at
least a programmable memory for storing a look up table and a PWM
unit for providing a PWM function. The microcontroller is used to
receive a input averaging voltage transformed from the A/D
converter and then determines whether an output voltage with a
fixed frequency in PWM signal form is relatively generated, by way
of looking up several corresponding output voltages pre-stored in
the look up table for each input averaging voltage, and only judges
whether the input averaged voltage is less than the pre-stored
output voltage. When the input averaged voltage is in contrast of
being less than the pre-stored output voltage, the output voltage
is set low and therefore the charging circuit is disabled by the
microcontroller to release overloading voltages in the
electrochromic element for controlling the reflectance. The
amplifier is used for amplifying an output voltage with fixed
frequency generated from the PWM unit of the microcontroller.
[0009] Each of the circuits in accordance with the present
invention is adapted to be used to control the reflectance of an
electrochromic element as a function of the voltage across the
element. Such electrochromic elements are described in detail as in
U.S. Pat. No. 4,917,477. Such electrochromic elements are adapted
to be controlled typically between 0 to 3 volts to control the
reflectance. As described herein, the electrochromic elements may
be liquid phase, self-erasing electrochromic mirrors used in
automobile applications.
[0010] Furthermore, the present invention relates to a controlling
method for controlling a reflectance of an electrochromic element.
The controlling method includes the following steps:
[0011] a A/D converter reading out an averaged voltage before the
averaging voltage applied in the electrochromic element for
transforming the averaged voltages;
[0012] looking up a corresponding output target voltage in the look
up table that pre-stored several required output target voltages
corresponding to each input averaged voltage from the A/D
converter;
[0013] only determining whether the input averaged voltage is less
than the output target voltage to generate the PWM output voltage
with a fixed frequency in PWM signal form by way of the PWM unit;
and
[0014] setting the output voltage low and releasing overloading
voltages in the electrochromic element by way of disabling a
charging circuit when the input averaged voltage is in contrast of
being less than the pre-stored output voltage.
[0015] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0016] These and other objects of the present invention will be
readily understood with reference to the following specification
and attached drawing, wherein:
[0017] FIG. 1 is a flow chart for an input routine of a prior art
that utilizes voltage feedback.
[0018] FIG. 2 is a flow chart for software PWM of the prior art
that utilizes voltage feedback.
[0019] FIG. 3 is a schematic diagram of an electronic circuit
according to one preferred embodiment of the present invention for
providing a PWM output signal with use of fixed frequency to
controlling an electrochromic element.
[0020] FIG. 4 is a flow chart for an input process in accordance
with the preferred embodiment of the invention, which disables a
charging circuit for reducing overloading voltage of the
electrochromic element.
[0021] FIG. 5 is a graphical illustration of the PWM output signal
with use of fixed frequency according to the preferred embodiment
of the present invention.
DETAILED DESCRIPTION
[0022] Differently from the prior art as mentioned above, the
present invention relates to an controlling system for an
electrochromic element driven by a pulse width modulated (PWM)
signal which incorporates averaging of the modulated signal before
the modulated signal is applied to the electrochromic element
(hereinafter detailed).
[0023] Referring first to illustration in FIG. 3, the controlling
system according to a preferred embodiment of the present
invention, has a simplified architecture and therein includes a
microcontroller 10, an amplifier 20, an analog-to-digital (A/D)
converter 35, and a charging circuit 40.
[0024] Meanwhile, said microcontroller 10 is further provided with
at least a programmable memory like ROM for pre-setting a look up
table thereon, and a PWM unit for providing PWM function. The
amplifier 20 is electrically coupled with a limited current circuit
25 for amplifying a PWM output signal with fixed frequency
generated from PWM unit of the microcontroller 10. The A/D
converter 35 can read out an averaged voltage before the averaging
voltage applied in a loading 30 as the electrochromic element and
then provides the microcontroller 10 with said input averaged
voltage. The charging circuit 40 consisting of a numbers of
resistors and capacitors is electrically coupled with the
microcontroller 10 and applied to release the overloading voltages
in the loading 30 when charging circuit 40 is disabled by way of
determination of the microcontroller 10 to make an active
switch.
[0025] Referring further to illustration in FIG. 4, a flow chart
for a method for rapidly controlling a reflectance of an
electrochromic element. Initially, in step S50 the A/D converter 40
can read the averaged voltage before the averaging voltage applied
in a loading 30 as the electrochromic element, for transforming the
averaged voltages and ensuring the current voltage of the
circuit.
[0026] In the step S55, a corresponding output target voltage is
looked up in the look up table that pre-stored several required
output target voltages corresponding to each input averaged voltage
including said averaged voltage.
[0027] In the step S60, it is further determined whether the input
averaged voltage is less than the output target voltage. If so, an
output voltage with a fixed square frequency in PWM signal form, as
described in step S62, is generated by the PWM unit of the
microcontroller 10. As shown in FIG. 5, the graphical illustration
of the PWM output signal with use of fixed frequency, of which each
duty cycle takes the time of 100 us.
[0028] In contrast, the PWM output signal is set "low" as described
in step S65 so that the charging circuit is disabled by the
microcontroller 10 to release overloading voltages in the loading
30 as described in steps S70 & S75. In this way, the averaged
voltage is able be controlled by the Fix frequency as required.
[0029] It is noted that each action of said steps S60, S62, S65,
and S70 optimally can be implemented by at least a program
pre-stored in the programmable ROM of the microcontroller 10.
Therefore, various parameters i.e. the corresponding voltages can
be pre-adjusted or pre-modified on demand via the program. In
comparison with the prior art shown in FIGS. 1 & 2, the present
invention has better response time saving due to simplified
architecture design in both of hardware and software.
[0030] In conclusion, the controlling system and method for
controlling an electrochromic element, according to the present
invention, can reduce complexity of the whole system due to only
need of generation of fixed frequency, rather than a variable duty
cycle as the prior art, thereby reaching both of a respond time and
cost savings of the electrochromic element. Simultaneously, the
simplified architecture design can further facilitate a better
reliability than said variable voltage driver for the
electrochromic element.
[0031] Those skilled in the art will readily observe that numerous
modifications and alterations of the device may be made while
retaining the teachings of the invention. Accordingly, the above
disclosure should be construed as limited only by the metes and
bounds of the appended claims.
* * * * *