# US 10,768,503 B1 · Two rail design and safety circuit for electrochromic windows > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,503 B1 - Document ID: US10768503B1 - Status: Granted - Kind: B1 - Application number: 16/504,102 - Filed: 2019-07-05 - Granted: 2020-09-08 - Earliest claimed: 2016-11-23 - Assignees: Kinestral Technologies, Inc. - Applicants: Kinestral Technologies, Inc. - Inventors: Paul Nagel; Wally Barnum; Doug Brainard - Web page: https://patentgrep.com/patent/US10768503B1 ## CPC - G02F 1/163: Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor - G09G 3/38: using electrochromic devices - H02J 4/00: Circuit arrangements for mains or distribution networks not specified as AC or DC; Circuit arrangements for mains or distribution networks combining AC and DC sections or sub-networks (arrangements using intermediate DC-AC-DC conversion H02J1/002; arrangements using high-voltage DC [HVDC] links H02J3/36) - G09G 2330/02: Details of power systems and of start or stop of display operation - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A dual rail driver for an electrochromic device is provided. The dual rail driver includes a power supply having a first power supply rail and a second power supply rail and an H bridge connected to the first power supply rail and the second power supply rail and configurable to couple to an electrochromic device. The dual rail driver includes a controller coupled to the H bridge through a failsafe module and configurable to control switches of the H bridge to charge and discharge the electrochromic device from the first power supply rail and the second power supply rail. The failsafe module is configurable to override one or more signals from the controller that controls the switches of the H bridge through the failsafe module, responsive to detecting anomaly of the electrochromic device. ## Claims ### Claim 1 A driver for an electrochromic device, comprising: a power supply; a plurality of switches, coupled to the power supply and configurable to couple to an electrochromic device having a first terminal and a second terminal; and circuitry configurable to direct the plurality of switches to connect and disconnect a positive voltage of the power supply to the first terminal of the electrochromic device, and connect and disconnect a negative voltage of the power supply to the first terminal of the electrochromic device. ### Claim 2 (depends on 1) The driver for an electrochromic device of claim 1, wherein the one or more switches comprises an H bridge. ### Claim 3 (depends on 1) The driver for an electrochromic device of claim 1, wherein the one or more switches comprises: a first switch connected to the positive voltage of the power supply; a second switch connected to the negative voltage of the power supply; and the first switch and the second switch connected to the first terminal of the electrochromic device. ### Claim 4 (depends on 1) The driver for an electrochromic device of claim 1, wherein the power supply comprises a dual rail power supply. ### Claim 5 (depends on 1) The driver for an electrochromic device of claim 1, wherein the power supply comprises: a first switching regulator having the positive voltage of the power supply; and a second switching regulator having the negative voltage of the power supply. ### Claim 6 (depends on 1) The driver for an electrochromic device of claim 1, wherein the circuitry comprises a microcontroller coupled to a failsafe circuit that is connected to the one or more switches. ### Claim 7 (depends on 1) The driver for an electrochromic device of claim 1, wherein the circuitry comprises a failsafe circuit that is to direct the one or more switches to disconnect the positive voltage and the negative voltage of the power supply from the first terminal of the electrochromic device. ### Claim 8 A driver for an electrochromic device, comprising: a power supply that is to drive a positive voltage and a negative voltage; a plurality of switches coupled to the power supply and configurable to couple to a first terminal of an electrochromic device; and circuitry coupled to the plurality of switches, to direct the plurality of switches to connect the positive voltage of the power supply to the first terminal of the electrochromic device, disconnect the positive voltage from the first terminal of the electrochromic device, connect the negative voltage of the power supply to the first terminal of the electrochromic device, and disconnect the negative voltage from the first terminal of the electrochromic device. ### Claim 9 (depends on 8) The driver for an electrochromic device of claim 8, wherein the plurality of switches comprises an H bridge having a first switch and a third switch connected to the power supply, and a second switch and a fourth switch connected to the first terminal of the electrochromic device. ### Claim 10 (depends on 8) The driver for an electrochromic device of claim 8, wherein the plurality of switches comprises: a first switch having a first terminal connected to the positive voltage of the power supply; a second switch having a first terminal connected to the negative voltage of the power supply; and a second terminal of each of the first switch and the second switch connected to each other and to the first terminal of the electrochromic device. ### Claim 11 (depends on 8) The driver for an electrochromic device of claim 8, wherein the power supply comprises a dual rail switching regulator. ### Claim 12 (depends on 8) The driver for an electrochromic device of claim 8, wherein the power supply comprises: a first switching regulator, to produce a first voltage rail having the positive voltage; a second switching regulator, to produce a second voltage rail having the negative voltage; and a power manager to control the first switching regulator and the second switching regulator, and to select AC (alternating current) power or DC (direct current) power for the first switching regulator and the second switching regulator. ### Claim 13 (depends on 8) The driver for an electrochromic device of claim 8, wherein the circuitry comprises: a microcontroller to control the plurality of switches; and a failsafe circuit, having no processor, to override the microcontroller and direct the plurality of switches to disconnect the positive voltage and the negative voltage from the first terminal of the electrochromic device in case of a failure. ### Claim 14 (depends on 8) The driver for an electrochromic device of claim 8, a microcontroller to control the plurality of switches; and a failsafe circuit, having no processor, to override the microcontroller and direct the plurality of switches to disconnect the first terminal of the electrochromic device from the power supply and to connect the first terminal of the electrochromic device to a second terminal of the electrochromic device, in case of a failure. ### Claim 15 A method for tinting and bleaching an electrochromic device, performed by a driver, the method comprising: directing a plurality of switches to connect a positive voltage of a power supply to a first terminal of an electrochromic device; directing the plurality of switches to disconnect the positive voltage of the power supply from the first terminal of the electrochromic device; directing the plurality of switches to connect a negative voltage of the power supply to the first terminal of the electrochromic device; and directing the plurality of switches to disconnect the negative voltage of the power supply from the first terminal of the electrochromic device. ### Claim 16 (depends on 15) The method of claim 15, wherein: the directing the plurality of switches to connect the positive voltage of the power supply to the first's terminal of an electrochromic device comprises closing a first switch; the directing the plurality of switches to disconnect the positive voltage of the power supply from the first terminal of the electrochromic device comprises opening the first switch; the directing the plurality of switches to connect the negative voltage of the power supply to the first terminal of the electrochromic device comprises closing a second switch; and the directing the plurality of switches to disconnect the negative voltage of the power supply from the first terminal of the electrochromic device comprises opening the second switch. ### Claim 17 (depends on 15) The method of claim 15, wherein the directing the plurality of switches to disconnect the positive voltage of the power supply from the first terminal of the electrochromic device and the directing the plurality of switches to disconnect the negative voltage of the power supply from the first terminal of the electrochromic device are in response to reaching a tinting level and results in the first terminal of the electrochromic device being allowed to float. ### Claim 18 (depends on 15) The method of claim 15, further comprising: driving a constant voltage for one of the positive voltage or the negative voltage of the power supply, and then driving a variable voltage or current for the one of the positive voltage or the negative voltage of the power supply. ### Claim 19 (depends on 15) The method of claim 15, wherein the directing the plurality of switches to disconnect the positive voltage of the power supply from the first terminal of the electrochromic device and the directing the plurality of switches to disconnect the negative voltage of the power supply from the first terminal of the electrochromic device are performed by a failsafe circuit in response to detection of a failure. ### Claim 20 (depends on 15) The method of claim 15, further comprising: directing the plurality of switches to connect the first terminal of the electrochromic device to a second terminal of the electrochromic device, in response to detection of a failure.