Field grading protection design surrounding galvanic or capacitive isolators

Abstract

A microisolator has been described that exhibits an enhanced isolation breakdown voltage. The microisolator may include an electrically floating ring surrounding one of the isolator elements of the microisolator. The isolator element may be a capacitor plate or a coil. The electrically floating ring surrounding one of the isolator elements may reduce the electric field at the outer edge of the isolator element, thereby enhancing the isolation breakdown voltage.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. Patent Application No. 16 / 887,719, filed May 29, 2020, entitled "ELECTRIC FIELD GRADING PROTECTION DESIGN SURROUNDING A GALVANIC OR CAPACITIVE ISOLATOR," filed under Attorney Docket No. G0766.70303US00, which application is incorporated herein by reference in its entirety.

[0002] This application relates to isolators that provide galvanic isolation between circuits. [Background technology]

[0003] An isolator provides electrical isolation between circuits that communicate with each other. In some situations, the circuits that communicate with each other may operate at different voltages, for example, one at a relatively high voltage and the other at a relatively low voltage. In some situations, the circuits may or may not operate at different voltages from each other, but are referenced to different ground potentials. Isolators can be used to electrically isolate circuits in either of these situations. Summary of the Invention [Means for solving the problem]

[0004] According to one aspect of the present application, a microisolator exhibiting an enhanced isolation breakdown voltage is described. The microisolator may include an electrically floating ring surrounding one of the isolator elements of the microisolator. The isolator element may be a capacitor plate or a coil. The electrically floating ring surrounding one of the isolator elements can reduce the electric field at the outer edge of the isolator element, thereby increasing the isolation breakdown voltage.

[0005] According to some embodiments, a microisolator having an enhanced isolation breakdown voltage is provided, comprising: a first isolator element in a first plane; a second isolator element in a second plane; a first dielectric material comprising a polymer disposed between the first isolator element and the second isolator element; and an electrically floating ring disposed in the first plane and surrounding the first isolator element.

[0006] According to some embodiments, a microisolator having an enhanced isolation breakdown voltage comprises a first isolator element and a second isolator element disposed in respective planes, a dielectric material including a polymer disposed between the first isolator element and the second isolator element, and an electrically floating ring surrounding the first isolator element in the plane.

[0007] According to some embodiments, an isolator system includes a first device configured to operate in a first voltage domain, a second device configured to operate in a second voltage domain, and an isolator coupled between the first and second devices and including an electrically floating ring surrounding a first isolator element of a pair of vertically separated isolator elements. [Brief explanation of the drawings]

[0008] Various aspects and embodiments of the present application may be described with reference to the following drawings. It should be understood that the drawings are not necessarily drawn to scale. Items that appear in more than one figure are designated by the same reference numeral in all figures in which they appear.

[0009] [Figure 1A] FIG. 1 illustrates a cross-sectional view of a microisolator having two isolator elements with a floating conductive ring around one, according to a non-limiting embodiment of the present application. [Figure 1B]1B is a top view of the microisolator of FIG. 1A taken along line 1B-1B of FIG. 1A. [Figure 2] 1 illustrates an alternative microisolator according to a non-limiting embodiment. [Figure 3] FIG. 10 illustrates a cross-sectional view of an alternative microisolator comprising multiple floating conductive rings, in accordance with a non-limiting embodiment of the present application. [Figure 4] 10 shows a cross-sectional view of an alternative microisolator in which the floating conductive ring is not encapsulated by the same nonlinear dielectric material that encapsulates the isolator element 104a, according to an alternative embodiment. [Figure 5] FIG. 10 illustrates a cross-sectional view of an alternative microisolator in which the nonlinear dielectric material bridging the gap between the isolator element and the floating conductive coil is a different material than that encapsulating the isolator element, in accordance with a non-limiting embodiment of the present application. [Figure 6] 10 illustrates a cross-sectional view of an alternative microisolator in which a floating conductive ring surrounding an isolator element has a different height than the isolator element, according to a non-limiting embodiment of the present application. [Figure 7] FIG. 1 illustrates a top view of a microisolator having a serpentine isolator element surrounded by multiple floating conductive rings, according to a non-limiting embodiment of the present application. [Figure 8] FIG. 1 illustrates a top view of a microisolator having a segmented floating conductive ring surrounding an isolator element, according to a non-limiting embodiment of the present application. [Figure 9] FIG. 1 illustrates a cross-sectional view of a microisolator having a floating conductive ring surrounding both the top and bottom isolator elements, in accordance with a non-limiting embodiment of the present application. [Figure 10] FIG. 1 is a block diagram illustrating an example of a system including an isolator of the type described herein. DETAILED DESCRIPTION OF THE INVENTION

[0010] According to one aspect of the present application, an isolator element is disposed within an electrically floating conductive ring having a nonlinear dielectric material therebetween. In some embodiments, the isolator element is a coil, and in other embodiments, it is a capacitor plate. In some embodiments, the isolator element and the electrically floating conductive ring are both encapsulated by a dielectric material, and in some embodiments, the dielectric material may be the same nonlinear dielectric material between the isolator element and the electrically floating conductive ring. In some embodiments, the isolator element is encapsulated by a nonlinear dielectric material, but the electrically floating conductive ring is not. In some embodiments, the isolator element is encapsulated by a dielectric material that is different from the nonlinear dielectric material between the isolator element and the electrically floating conductive ring. According to some embodiments, multiple electrically floating conductive rings may surround the isolator element. These may be the same height as the isolator element or different heights. In some embodiments, an isolator including two isolator elements includes one or more electrically floating conductive rings around each of the isolator elements.

[0011] The above-mentioned aspects and embodiments, as well as additional aspects and embodiments, are further described below. These aspects and / or embodiments may be used individually, all together, or in any combination of two or more, as the application is not limited in this respect.

[0012] 1A shows a cross-sectional view of a microisolator 100 having two isolator elements with a floating conductive ring around one of them. The microisolator 100 comprises a substrate 102, a first isolator element 104a, a second isolator element 104b, a floating conductive ring 106, a dielectric layer 108, a nonlinear dielectric 110, and a dielectric layer 112.

[0013] In this non-limiting example, the first isolator element 104a and the second isolator element 104b are coils. Thus, the microisolator 100 can function as an inductive microisolator and can be a transformer. The first isolator element 104a and the second isolator element 104b can be made of a metal, such as gold, aluminum, or copper. In some embodiments, the first isolator element 104a and the second isolator element 104b are made of different materials. For example, the isolator element 104a can be made of gold and the isolator element 104b can be made of aluminum. In some embodiments, they can be made of the same material, such as made of the same metal.

[0014] The floating conductive ring 106 may be made of metal. In some embodiments, the floating conductive ring 106 may be made of the same metal as the first isolator element 104a. For example, they may be patterned from the same metal layer, although not all embodiments are limited in this regard. The first isolator element 104a and the floating ring 106 may be made of gold. The first isolator element 104a and the floating conductive ring 106 have a height H. In this non-limiting embodiment, they have the same height, although alternatives are possible, using examples further described below. As can be seen in FIG. 1B, electrical contact can be made to the first isolator element 104a at its ends.

[0015] FIG. 1B is a top view of the microisolator 100 taken along line 1B-1B in FIG. 1A. As shown, the floating conductive ring 106 surrounds the first isolator element 104a. The floating conductive ring is concentric with the outside of the first isolator element 104a. Electrical contact to the first isolator element 104a is made through pad 114 and end 116 (which may be a separate pad). The first isolator element 104a may pass above or below the floating conductive ring 106 near end 116 to avoid electrical contact. In an alternative embodiment, the floating conductive ring 106 may include a break or gap near end 116 through which the first isolator element 104a passes. In some embodiments, the first isolator element 104a may be configured to receive high voltages, such as greater than 200 volts, greater than 500 volts, greater than 1000 volts, 500V to 3.5 kV, or any range or value within those ranges.

[0016] The first isolator element 104a and the floating conductive ring 106 can have any suitable shape. In the non-limiting example of FIG. 1B, they are circular. However, alternative shapes are possible, as various aspects described herein are not limited to any particular shape for the isolator element or the floating conductive ring.

[0017] 1A , the dielectric layer 108 can be any suitable dielectric for isolating the first isolator element 104a from the second isolator element 104b. In some embodiments, the dielectric layer 108 comprises a polymer. For example, it can be a polyimide. In some embodiments, the dielectric layer can include multiple layers. For example, the dielectric layer 108 can include two or more layers of polyimide, or one layer of polyimide and one layer of a second type of dielectric.

[0018] The first isolator element 104a and the floating conductive ring 106 are separated in a plane by a gap g. The gap g may have any suitable distance. The floating conductive ring 106 serves to reduce electric field buildup at the outer edges of the first isolator element 104a and may perform a grading function to smooth the voltage between the first isolator element 104a and surrounding structures. As a result, the breakdown voltage of the microisolator 100 is increased compared to if the floating conductive ring 106 were omitted. The value of g may be selected to provide a desired level of electric field reduction. If g is too large, the floating conductive ring 106 may not significantly reduce the electric field at the outermost edges of the first isolator element 104a. If g is too small, electrical breakdown may occur between the first isolator element 104a and the floating conductive ring 106. In some embodiments, g may be in the range of 0.5 microns to 10 microns, including any value within that range. Other values ​​are also possible.

[0019] The gap g is filled with a nonlinear dielectric 110. The nonlinear dielectric 110 may be a relatively conductive isolator to assist the field grading function of the floating conductive ring 106. In some embodiments, the nonlinear dielectric 110 is a stoichiometric silicon nitride (SiN 1.33 ) or non-stoichiometric silicon nitride (SiN x, x is not equal to 1.33). Alternatives include silicon oxide (SiONx), doped amorphous silicon (a-Si:H), doped amorphous carbon (aC:H), silicon carbide (SiC), and zinc oxide (ZnO). When doped materials are used, any suitable doping may be used to provide a level of conductivity that results in the desired level of field grading. In some embodiments, the nonlinear dielectric 100 may be a high-k ferroelectric material such as barium titanate (BaTiO3), strontium titanate (SrTiO3), titanium dioxide (TiO2), hafnium dioxide (HfO2), zirconium dioxide (ZrO2), or alumina (Al2O3), which may exhibit similar field grading behavior. It should be noted that including a floating conductive ring in an isolator without having a nonlinear dielectric between the first isolator element and the floating conductive ring can reduce the breakdown voltage of the isolator, rather than diminishing the isolator. Thus, the combination of a floating conductive ring with a conductive nonlinear dielectric material between the isolator element and the floating conductive ring can provide a desired increase in breakdown voltage.

[0020] The dielectric layer 112 may be a passivation layer. In some embodiments, the dielectric layer 112 is a polyimide. In some embodiments, the dielectric layer 112 is an oxide. Alternative materials are possible for the dielectric layer 112.

[0021] Non-limiting examples of implementations of the microisolator 100 are provided below. The substrate 102 may be formed of silicon or a dielectric material (such as glass). The first isolator element 104a may be formed of gold. The second isolator element 104b may be formed of aluminum. The floating conductive ring 106 may be formed of gold. The alternate isolator elements 104a and 104b and the floating conductive ring 106 may be formed of copper. The dielectric layer 108 may be formed of polyimide and may be 50 microns to 200 microns thick. The nonlinear dielectric 110 may be formed of silicon nitride. The dielectric layer 112 may be formed of oxide. The height H may be 10 microns, and the gap g may be 1 micron. In other embodiments, other materials and dimensions may be used. Also, while some embodiments of the microisolators described herein include one or more elements formed from the specific materials described above, it should be understood that one or more elements may be formed from different materials.

[0022] 1A and 1B, it can be seen that in some embodiments, a microisolator having an enhanced isolation breakdown voltage is provided. The microisolator may include a first isolator element in a first plane, a second isolator element in a second plane, a first dielectric material comprising a polymer such as polyimide disposed between the first and second isolator elements, and an electrically floating conductive ring disposed in the first plane and surrounding the first isolator element. The first and second isolator elements may be separated in a vertical dimension (top-to-bottom in FIG. 1A ), and the first isolator element and the floating conductive ring may be separated in a second dimension (left-to-right in FIG. 1A ).

[0023] FIG. 2 illustrates an alternative microisolator according to a non-limiting embodiment. Microisolator 200 differs from microisolator 100 in that it is a capacitive microisolator, with capacitor plates as the isolator elements. Specifically, microisolator 200 includes substrate 102, first isolator element 204a, second isolator element 204b, floating conductive ring 206, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112. Substrate 102, dielectric layer 108, nonlinear dielectric 110, dielectric layer 112, gap g, and height H were previously described in connection with FIG. 1A and therefore will not be described again in detail here.

[0024] The first isolator element 204a and the second isolator element 204b are capacitor plates. They may be formed of any suitable material, such as those previously described in connection with the first isolator element 104a and the second isolator element 104b, respectively. The isolator elements 204a and 204b may have any suitable shape. In some embodiments, they are circular, in other embodiments, rectangular or square, and in still other embodiments, they may have different shapes. The floating conductive ring 206 may surround the first isolator element 204a. In some embodiments, the floating conductive ring 206 has the same shape as the first isolator element 204a, e.g., a circle, a square, or another suitable shape. The floating conductive ring 206 may be made of any of the materials previously described in connection with the floating conductive ring 106.

[0025] 3 shows a cross-sectional view of an alternative microisolator comprising multiple floating conductive rings according to a non-limiting embodiment of the present application. Microisolator 300 comprises substrate 102, first isolator element 104a, second isolator element 104b, floating conductive rings 306a, 306b...306n, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112. Substrate 102, first isolator element 104a, second isolator element 104b, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112 have been previously described herein in connection with FIGS. 1A and 1B and therefore will not be described again in detail here.

[0026] The floating conductive rings 306a, 306b...306n may be any suitable floating conductive rings. Each of them may be substantially similar in material and size to the floating conductive ring 106 described above in connection with Figures 1A and 1B. The floating conductive rings 306a, 306b...306n have different radii (in the xy plane), with floating conductive ring 306a having a shorter radius than floating conductive ring 306b, which in turn has a shorter radius than floating conductive ring 306n. The floating conductive rings 306a...306b may be positioned concentrically with respect to one another.

[0027] Any suitable number n of floating conductive rings may be provided. In the embodiment of Figure 3, there may be between 2 and 10 floating conductive rings. However, other numbers are possible.

[0028] In some embodiments, the floating conductive rings 306a...306n may be identical in terms of material, spacing, height, and width. However, in those embodiments in which multiple floating conductive rings are provided, one or more of these variables may vary between the floating conductive rings. For example, in some embodiments, two or more floating conductive rings 306a...306n may have different heights (in the z-direction of the figure). For example, some of the floating conductive rings may have the aforementioned height H, while others may have a lower height, as described further below in connection with FIG. 6. Any suitable gap may be provided between the floating conductive rings, as shown. Gap g1 is between the outermost edge of the first isolator element 104a and floating conductive ring 306a. Gap g2 is between floating conductive ring 306a and floating conductive ring 306b. In some embodiments, the gap is larger from the first isolator element 104a. That is, the gap sizing can be increased by moving away from the first isolator element 104a. Increasing the gap size can increase the resistance between the floating conductive rings, which can facilitate field grading. The floating conductive rings can have a width w. In some embodiments, they have a uniform width. In other embodiments, the width can vary between the floating conductive rings 306a...306n.

[0029] FIG. 4 illustrates a cross-sectional view of an alternative microisolator according to an alternative embodiment, in which the floating conductive ring is not encapsulated by the same nonlinear dielectric material that encapsulates the isolator element 104a. The microisolator 400 includes many of the same components previously described in connection with FIGS. 1A and 1B. However, in contrast to the microisolator 100 of FIG. 1, the microisolator 400 is configured such that the nonlinear dielectric 110 does not encapsulate the floating conductive ring 106. Such a configuration may be used for any suitable purpose. In some embodiments, fabrication of the microisolator may be simplified by forming the floating conductive ring 106 without being encapsulated by the nonlinear dielectric 110. Other benefits may also be realized.

[0030] 5 illustrates a cross-sectional view of an alternative microisolator in which the nonlinear dielectric material bridging the gap between the isolator element and the floating conductive ring is a different material than that encapsulating the isolator element, according to a non-limiting embodiment of the present application. Microisolator 500 comprises substrate 102, first isolator element 104a, second isolator element 104b, floating conductive ring 106, dielectric layer 108, nonlinear dielectric 110, dielectric layer 112, and nonlinear dielectric 502. Substrate 102, first isolator element 104a, second isolator element 104b, floating conductive ring 106, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112 have been previously described herein in connection with FIGS. 1A and 1B and therefore will not be described again in detail here.

[0031] In the microisolator 500, the nonlinear dielectric 110 does not completely fill the space between the first isolator element 104a and the floating conductive ring 106. The nonlinear dielectric 110 encapsulates the first isolator element 104a and the floating conductive ring 106 in this non-limiting example; however, a second nonlinear dielectric 502 is included between the first isolator element 104a and the floating conductive ring 106. The nonlinear dielectric 502 can be any suitable nonlinear dielectric. In some embodiments, the nonlinear dielectric 110 and the nonlinear dielectric 502 can exhibit similar characteristics. In some embodiments, the nonlinear dielectric 110 and the nonlinear dielectric 502 can exhibit different nonlinear characteristics. For example, one can be more strongly nonlinear than the other in response to an electric field. One can be more conductive than the other.

[0032] 6 shows a cross-sectional view of an alternative microisolator in which a floating conductive ring surrounding an isolator element has a different height than the isolator elements. Microisolator 600 includes substrate 102, first isolator element 104a, second isolator element 104b, floating conductive ring 606, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112. Substrate 102, first isolator element 104a, second isolator element 104b, dielectric layer 108, nonlinear dielectric 110, and dielectric layer 112 have been previously described herein in connection with FIGS. 1A and 1B and therefore will not be described again in detail here.

[0033] The floating conductive ring 606 differs from the floating conductive ring 106 of FIG. 1A in that its height is different from the height of the first isolator element 104a. The floating conductive ring 606 has a height Hr that is different from the height H of the first isolator element 104a. The height Hr may be selected to simplify processing. Filling the gap between the first isolator element 104a and the floating conductive ring may be difficult in practice depending on the height H of the first isolator element 104a. Setting the height Hr less than H may make it easier to fill the gap with the nonlinear dielectric 110. The height Hr may be less than 90% of the height H, for example, 10% to 90% of the height H, 25% to 75% of the height H, less than 10% of the height H, or less than 1% of the height H, including any value within these ranges. As a non-limiting example, H may be 10 microns and Hr may be less than 1 micron, e.g., on the order of 10 nanometers. In some alternative embodiments, Hr may be greater than H.

[0034] FIG. 7 illustrates a top view of a microisolator having a serpentine isolator element surrounded by multiple floating conductive rings according to a non-limiting embodiment of the present application. The illustrated serpentine isolator element 702 may be formed from any of the materials previously described herein in connection with the first isolator element 104a and the second isolator element 104b. The floating conductive rings 704 are oval or racetrack shaped and may be formed from any of the materials previously described herein in connection with the floating conductive rings 106. The number of floating conductive rings 704 is not limiting. In this non-limiting example, ten floating conductive rings 704 are included. Each floating conductive ring 704 surrounds a serpentine isolator element 702. The floating conductive rings 704 are positioned concentrically with respect to one another.

[0035] FIG. 8 shows a top view of a microisolator having a segmented floating conductive ring surrounding an isolator element in accordance with a non-limiting embodiment of the present application. The illustrated microisolator comprises an isolator element 104a and a segmented floating conductive ring 802. The isolator element 104a was previously described in connection with FIGS. 1A and 1B and will not be described in detail again here. The segmented floating conductive ring 802 surrounds the isolator element 104a. The segmented floating conductive ring 802 comprises multiple segments 804 separated by gaps gr. The number of segments 804 and the distance of the gaps gr can be selected to provide a desired level of field grading.

[0036] While Figure 8 shows an example of a segmented floating conductive ring, a further alternative is a ring formed by a plurality of metal inclusions. That is, in some embodiments, a ring of dielectric material having metal inclusions may be used as the floating conductive ring. The amount and size of the metal inclusions may be selected to provide a desired level of field grading.

[0037] 9 shows a cross-sectional view of a microisolator having a floating conductive ring surrounding both the top and bottom isolator elements, according to a non-limiting embodiment of the present application. The microisolator 900 comprises a substrate 102, a first isolator element 104a, a second isolator element 104b, a floating conductive ring 106, a dielectric layer 108, a nonlinear dielectric 110, a dielectric layer 112, and a floating conductive ring 902. The substrate 102, the first isolator element 104a, the second isolator element 104b, the floating conductive ring 106, the dielectric layer 108, the nonlinear dielectric 110, and the dielectric layer 112 have been previously described herein in connection with FIGS. 1A and 1B and therefore will not be described again in detail here.

[0038] A floating conductive ring 902 surrounds the isolator element 104b. The floating conductive ring 902 may be substantially the same as the floating conductive ring 106. However, in some embodiments, the floating conductive ring 902 may be formed from the same material as the isolator element 104b. Thus, in some embodiments, the floating conductive rings 106 and 902 are made of different materials.

[0039] 9 shows that the microisolator 900 can include electrical access to the second isolator element 104b via a pad 904 and an electrical interconnect structure 906. In this way, the center of the second isolator element 104b can be electrically contacted even though the pad 904 is in the same plane as the second isolator element 104b.

[0040] Microisolator 900 also includes an enclosure 908. Enclosure 908 can be a resin or any other suitable material.

[0041] While FIG. 1A shows a microisolator with a floating conductive ring surrounding the top isolator element and FIG. 9 shows an embodiment with floating conductive rings surrounding both the top and bottom isolator elements, alternative embodiments of the microisolator include a floating conductive ring surrounding only the bottom isolator element. In general, it may be desirable to have a floating conductive ring surrounding an isolator element that accepts high voltages. In some embodiments, it may be the top isolator element, and in some embodiments, it may be the bottom isolator element. Thus, a floating conductive ring of the type described herein may be disposed around either the top or bottom isolator element, or both. In some embodiments, the microisolator includes two or more isolator elements with a floating conductive ring surrounding one or more of them.

[0042] Isolators of the type described herein can be deployed in a variety of settings to galvanically isolate one portion of an electrical circuit from another. One such setting is in industrial applications. In some embodiments, the isolator may isolate a motor driver from other portions of an electrical system. The motor driver, in some embodiments, may operate at voltages of 600 V or more (e.g., up to 3.5 kV or more) and may include an inverter for converting a DC signal to an AC signal. In some embodiments, the motor driver may include one or more insulated gate bipolar transistors (IGBTs) and may drive an electric motor according to a three-phase configuration.

[0043] Another such setting is in a solar power system. In some embodiments, an isolator may be installed in the solar power system to isolate the solar panels and / or inverter from the rest of the system. In some embodiments, the isolator may be installed between the solar panels and the inverter.

[0044] Another such setting is in electric vehicles. In some embodiments, isolators of the type described herein may be used to isolate any suitable portion of an electric vehicle, such as a battery or motor driver, from other portions of the vehicle.

[0045] 10 is a block diagram illustrating an example of a system including an isolator of the type described herein. System 1000 may include an isolator 1002, a low-voltage device 1004, and a high-voltage device 1006. In some embodiments, low-voltage device 1004 may include a device operating below 500V. In some embodiments, high-voltage device 1006 may include a device operating above 500V.

[0046] The isolator 1002 may be implemented using a microisolator 100, 200, 300, 400, 500, 600, or 900 and may be placed between a low-voltage device and a high-voltage device. By isolating the two devices from each other, a user may be able to physically contact the low-voltage device without receiving an electric shock or injury. The low-voltage device 1004 may include a user interface unit, such as a computer or other type of terminal, and / or a communication interface, such as a cable, antenna, or electronic transceiver. The high-voltage device 1006 may include a motor driver, an inverter, a battery, a solar panel, or any other suitable device operating at 500V or above. In embodiments in which the high-voltage device 1006 includes a motor driver, the high-voltage device 1006 may be connected to an electric motor 1008.

[0047] It should be understood from the description of FIG. 10 and the types of microisolators described herein that some embodiments of the present application provide an isolator system comprising: a first device configured to operate in a first voltage domain; a second device configured to operate in a second voltage domain; and an isolator coupled between the first and second devices and comprising an electrically floating ring surrounding a first isolator element of a pair of vertically separated isolator elements.

[0048] The electrically floating ring may be a first electrically floating ring, and the isolated system may further include a second electrically floating ring surrounding a second isolator element of a pair of vertically separated isolator elements. In some embodiments, when multiple floating conductive rings are provided, one or both are split rings. In some embodiments, the electrically floating conductive ring may be shorter than the isolator element it surrounds. In any such embodiment, the nonlinear dielectric material may encapsulate the isolator element surrounded by the floating conductive ring.

[0049] Aspects of the present application may provide one or more benefits, some of which have been described above. Described herein are some non-limiting examples of such benefits. It should be understood that not all aspects and embodiments necessarily provide all of the benefits described herein. Furthermore, it should be understood that aspects of the present application may provide benefits in addition to those described herein.

[0050] Aspects of the present application provide an isolator that can withstand voltages in excess of 300 V (e.g., 1 kV, 1.5 kV, 2 kV, 2.5 kV, 3 kV, and 3.5 kV) while limiting the probability of electrical breakdown. As a result of this reduced probability of electrical breakdown, the life of the isolator can be extended.

[0051] The terms "approximately" and "about" may be used to mean, in some embodiments, within ±20% of a target value, in some embodiments, within ±10% of a target value, in some embodiments, within ±5% of a target value, and even in some embodiments, within ±2% of a target value. The terms "approximately" and "about" may include the target value.

Claims

1. 1. A microisolator having an enhanced isolation breakdown voltage, comprising: a first isolator element in a first plane; a second isolator element in the second plane; and a first dielectric material disposed between the first isolator element and the second isolator element, the first dielectric material comprising a polymer; a first electrically floating ring disposed in the first plane and surrounding the first isolator element; a second electrically floating ring surrounding the first electrically floating ring; a third electrically floating ring surrounding the second electrically floating ring; a second gap between the first electrically floating ring and the second electrically floating ring that is larger than a first gap between the first isolator element and the first electrically floating ring, and a third gap between the second electrically floating ring and the third electrically floating ring that is larger than the second gap.

2. 10. The microisolator of claim 1, wherein the first isolator element and the second isolator element are separated in a vertical dimension, and the first isolator element and the first electrically floating ring are separated in a second dimension.

3. 10. The microisolator of claim 1, further comprising a second dielectric material separating the first isolator element from the first electrically floating ring.

4. The microisolator of claim 3 , wherein the second dielectric material encapsulates the first isolator element.

5. 10. The microisolator of claim 1, wherein the first isolator element has a first height and the first electrically floating ring has a second height that is less than the first height.

6. 10. The microisolator of claim 1, wherein the first electrically floating ring is a segmented ring.

7. 10. The microisolator of claim 1, wherein the first isolator element is configured to couple to a higher voltage than the second isolator element.

8. 1. A microisolator having an enhanced isolation breakdown voltage, comprising: a first isolator element and a second isolator element disposed in respective planes; a dielectric material including a polymer disposed between the first isolator element and the second isolator element; a first electrically floating ring having a plane and surrounding the first isolator element; a second electrically floating ring surrounding the first electrically floating ring; a third electrically floating ring surrounding the second electrically floating ring; a second gap between the first electrically floating ring and the second electrically floating ring that is larger than a first gap between the first isolator element and the first electrically floating ring, and a third gap between the second electrically floating ring and the third electrically floating ring that is larger than the second gap.

9. 9. The microisolator of claim 8, wherein the dielectric material is a first dielectric material, and the microisolator further comprises a second dielectric material separating the first isolator element from the first electrically floating ring.

10. 10. The microisolator of claim 9, wherein the second dielectric material encapsulates the first isolator element but not the first electrically floating ring.

11. 9. The microisolator of claim 8, wherein the first electrically floating ring is shorter than the first isolator element.

12. The microisolator of claim 8 , wherein the first electrically floating ring comprises one or more gaps.

13. 9. The microisolator of claim 8, wherein the first isolator element is configured to couple to a higher voltage than the second isolator element.

14. An isolated system comprising: a first device configured to operate in a first voltage domain; a second device configured to operate in a second voltage domain; a first electrically floating ring coupled between the first device and the second device and surrounding a first isolator element of a pair of vertically separated isolator elements; a second electrically floating ring surrounding the first electrically floating ring; a third electrically floating ring surrounding the second electrically floating ring; an isolator, wherein a second gap between the first electrically floating ring and the second electrically floating ring is larger than a first gap between the first isolator element and the first electrically floating ring, and a third gap between the second electrically floating ring and the third electrically floating ring is larger than the second gap.

15. An isolated system as described in claim 14, further comprising an additional electrically floating ring surrounding a second isolator element of the pair of vertically separated isolator elements.

16. 15. The isolated system of claim 14, wherein the first electrically floating ring is a segmented ring.

17. 15. The isolated system of claim 14, wherein the first electrically floating ring is shorter than the first isolator element.

18. 15. The isolated system of claim 14, further comprising a nonlinear dielectric material encapsulating the first isolator element.

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