ELECTRICAL DEVICE COMPRISING AN AC VOLTAGE DIVIDER AND CAPACITORS ARRANGED IN INTEGRATED COMPONENTS

Abstract

An electrical device is provided with an AC voltage divider that includes a board, a plurality of dividing stages each associated with a dividing ratio, an input terminal arranged on the board for receiving an input voltage, and an output terminal arranged on the board for outputting a divided voltage. Moreover, each dividing stage comprises a plurality of capacitors, and for each dividing stage, the plurality of capacitors of the respective dividing stage is arranged in a same integrated component assembled on the board and electrically connected between the input terminal and the output terminal.

Claims

1. An electrical device with an AC voltage divider comprising: a board; a plurality of dividing stages each associated with a dividing ratio; an input terminal arranged on the board for receiving an input voltage; and an output terminal arranged on the board for outputting a divided voltage, wherein each dividing stage comprises a plurality of capacitors, and for each dividing stage, the plurality of capacitors of the respective dividing stage is arranged in a same integrated component assembled on the board and electrically connected between the input terminal and the output terminal, and wherein the electrical device comprises a plurality of distinct integrated components assembled on the board and connected between the input terminal and the output terminal.

2. The device of claim 1, wherein each integrated component comprises the plurality of capacitors of a single dividing stage.

3. The device of claim 1, wherein an integrated component comprises the plurality of capacitors of at least two dividing stages.

4. The device of claim 1, wherein each dividing stage comprises only two capacitors.

5. The device of claim 3, wherein each integrated component comprises an intermediary output port connected to the two capacitors.

6. The device of claim 1, wherein the capacitors are 3D capacitors.

7. The device of claim 1, wherein capacitors arranged in a same integrated component are supported by a same semiconductor substrate.

8. The device of claim 7, wherein the same semiconductor substrate comprises a semiconductor region forming an electrode of each of said capacitors supported by the semiconductor substrate.

9. The device of claim 1, wherein each integrated component is assembled as a chip-on-board module on the board.

10. The device of claim 1, wherein at least one of the integrated component comprises: a substrate, a first bottom conductive region and a second bottom conductive region separated from the first bottom conductive region, with the separated conductive regions disposed above the substrate, a dielectric layer disposed above the separated conductive regions and the substrate, the dielectric layer having at least one opening above the first bottom conductive region, a first top conductive region arranged above the dielectric layer and the first bottom conductive region so as to form a first capacitor, a second top conductive region arranged above the dielectric layer and the second bottom conductive region so as to form a second capacitor, wherein the second top conductive region extends to the opening of the dielectric layer so as to form an electrical connection between the second top conductive region and the first bottom conductive region, and so as to connect the first capacitor and the second capacitor.

11. A method of manufacturing an electrical device comprising an AC voltage divider, the method comprising: providing a board having an input terminal for receiving an input voltage and an output terminal for outputting a divided voltage; forming a plurality of dividing stages each associated with a dividing ratio, wherein each dividing stage comprises a plurality of capacitors, and for each dividing stage, the plurality of capacitors of the respective dividing stage is arranged in a same integrated component, wherein there is a plurality of distinct integrated components; and assembling each integrated component on the board, so as to electrically connect each integrated component between the input terminal and the output terminal.

12. The method of claim 11, comprising using a chip-on-board process to assemble each integrated component on the board.

13. The method of claim 11, comprising, for each integrated component, forming the capacitors of this integrated component using at least one parallel manufacturing process.

14. The method of claim 11, further comprising the forming the plurality of capacitors of a same dividing stage in an integrated component by: providing a substrate, forming, above the substrate, a first bottom conductive region and a second bottom conductive region, forming a dielectric layer above the two separated conductive regions and the substrate, the dielectric layer having at least one opening (OP) above the first bottom conductive region, forming a first top conductive region above the dielectric layer and the first bottom conductive region so as to form a first capacitor, forming a second top conductive region above the dielectric layer and the second bottom conductive region so as to form a second capacitor, wherein the second top conductive region extends to the opening of the dielectric layer so as to form an electrical connection between the second top conductive region and the first bottom conductive region, and so as to connect the first capacitor and the second capacitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further features and advantages of the present invention will become apparent from the following description of certain embodiments thereof, given by way of illustration only, not limitation, with reference to the accompanying drawings in which:

[0048] FIG. 1 is a circuit diagram of an electrical device according to an exemplary embodiment,

[0049] FIG. 2 is a cross section of an integrated component according to an exemplary embodiment,

[0050] FIGS. 3A and 3B illustrate forming an integrated component according to another exemplary embodiment,

[0051] FIG. 4 is a top view of an electrical device according to an exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0052] An electrical device is described herein that comprises an AC voltage divider which uses integrated components equipped with dividing stages.

[0053] In an exemplary aspect, this device can be adapted for high-voltage applications (as will be described hereinafter in reference to FIG. 1), but also for low-voltage applications, as the capacitors are arranged in integrated devices and can benefit from the advantages of silicon technology, for example.

[0054] FIG. 1 is a circuit diagram of a device 100 including a voltage divider. The board and the integrated components that form this voltage divider will be visible on the exemplary representations of FIGS. 2, 3A, 3B and 4.

[0055] As shown, the device of FIG. 1 comprises an input terminal 101 able to receive a voltage of 1500V (high-voltage application), and an output terminal 102 which, through the voltage divider's operation, is configured to output a voltage of 5V.

[0056] To achieve this, a first dividing stage is connected to the input terminal 101. This first dividing stage comprises a capacitor 103A, connected to the input terminal and to an intermediary output terminal 104 (the output terminal of the first dividing stage), and a capacitor 103B, connected to the intermediary output terminal 104 and to the ground GND. Capacitor 103A has a capacitance of 1 pF while capacitor 103B has a capacitance of 5.7 pF. Both capacitors 103A and 103B are manufactured in parallel, on a same integrated component (i.e. above a same semiconductor substrate), as they belong to a same dividing stage. Their dividing ratio is equal to (1+5.7/1)=6.7, which leads to a voltage of about 224V outputted by this first dividing stage.

[0057] A second dividing stage is connected to the intermediary output terminal 104. This second dividing stage comprises a capacitor 105A, connected to the intermediary output terminal 104 and to an intermediary output terminal 106 (the output terminal of the second dividing stage), and a capacitor 105B, connected to the intermediary output terminal 106 and to the ground GND. Capacitor 105A has a capacitance of 1 pF while capacitor 105B has a capacitance of 5.7 pF. Both capacitors 105A and 105B are formed in parallel, on a same integrated component (preferably an integrated component distinct from the one of the first dividing stage), as they belong to a same dividing stage. Their dividing ratio is equal to (1+5.7/1)=6.7, which leads to a voltage of about 33V outputted by this second dividing stage.

[0058] A third dividing stage is connected to the intermediary output terminal 106. This third dividing stage comprises a capacitor 107A, connected to the intermediary output terminal 106 and to the output terminal 102, and a capacitor 107B, connected to the output terminal 102 and to the ground GND. Capacitor 107A has a capacitance of 1 pF while capacitor 107B has a capacitance of 5.7 pF. Both capacitors 107A and 107B are formed in parallel, on a same integrated component (preferably an integrated component distinct from the one of the first dividing stage and from the one of the second dividing stage), as they belong to a same dividing stage. Their dividing ratio is equal to (1+5.7/1)=6.7, which leads to a voltage of about 5V outputted by this third dividing stage.

[0059] It should be noted that in the circuit of FIG. 1, a deviation of a parameter of which will affect the capacitance (with respect to a nominal capacitance value) of a capacitor of a dividing stage will also affect the capacitance (also with respect to a nominal capacitance value) of the other capacitor of this same stage, because there is a matching of their parameters as they have been manufactured in parallel. Hence, the dividing ratio may be unaffected by a deviation of both capacitances.

[0060] FIG. 2 is a cross section of an integrated component 200 that comprises two capacitors 201 and 202, for example to implement the first, the second, or the third dividing stage of the circuit of FIG. 1.

[0061] Both capacitors 201 and 202 are formed above a same semiconductor substrate 203 (typically but not necessarily silicon).

[0062] The semiconductor substrate 203 is used to connect the two electrodes of the capacitors. For example, it can be doped so as to be conductive in its entirety or locally doped so as to form an electrical connection between the capacitors 201 and 202.

[0063] The first capacitor will have its remaining elements, in addition to its bottom electrode formed in the substrate 203, above the substrate. Here, a dielectric region DI1 is formed above the substrate and an upper electrode 204 is formed on the dielectric region DI1. The upper electrode 204 is a connecting pad which allows a wire to be bonded. It also forms the intermediary input of the dividing stage.

[0064] The second also has its remaining elements, in addition to its bottom electrode formed in the substrate 203, above the substrate. Here, a dielectric region DI2 is formed above the substrate and an upper electrode 205 is formed on the dielectric region DI1. The upper electrode 204 is a connecting pad which allows a wire to be bonded, for example for a connection to the ground.

[0065] An electrical contact 206 is formed on the substrate, in the form of a connecting pad. This electrical contact 206 forms the intermediary output terminal of the dividing stage of this integrated component.

[0066] It should be noted that for the sake of simplicity, the capacitors are represented as 2D capacitors. However, in order to increase the capacitance of the capacitors, it is possible to use 3D capacitors. By way of example, 3D structures can be formed in the semiconductor substrate 203 to form pillars, trenches, or holes, that are then filled with a stack of dielectric and electrode.

[0067] FIG. 3A is a cross section of a structure which will form subsequently and as formed on FIG. 3B an integrated component. This structure comprises a substrate 210 which can be a semiconductor substrate, or even an insulating substrate.

[0068] Above the substrate 210, a first bottom conductive region 211A and a second bottom conductive region 211B separated from the first bottom conductive region are formed by depositing a conductive layer and patterning this layer to obtain the two regions.

[0069] Then, a dielectric layer 212 is formed, here in a conformal manner. An opening OP is formed in this layer above the first bottom conductive region.

[0070] As shown on FIG. 3B, a first top conductive region 213A is formed above the dielectric layer 212 and above the first bottom conductive region so as to form a first capacitor 214A.

[0071] Also, a second top conductive region 213B is formed above the dielectric layer 212 and above the second bottom conductive region so as to form second first capacitor 214B.

[0072] The second top conductive region extends to the opening OP of the dielectric layer so as to form an electrical connection CT between the second top conductive region and the first bottom conductive region, and so as to connect the first capacitor and the second capacitor.

[0073] This structure allows obtaining more flexibility on the type of substrate.

[0074] Also, additional electrodes can be formed, and the substrate can be connected to any one of the electrodes.

[0075] FIG. 4 is a top view of an electrical device 300 comprising a board BRD and a plurality of dividing stages each consisting in a distinct integrated component.

[0076] More precisely, three dividing stages/integrated components 200A, 200B, and 200C are assembled on the board, using a chip-on-board technique, and wire bonding.

[0077] The integrated components 200A, 200B, and 200C are identical and have a structure which is similar to the component described in reference to FIG. 2.

[0078] Here, the board BRD comprises an input terminal 301 for receiving an input voltage, and a wire WBI is bonded between this input terminal and the intermediary input terminal 204A of component 200A. Another wire WBAB is bonded between the intermediary output terminal 206A and the intermediary input terminal 204B to connect the dividing stages 200A and 200B. In order to connect the dividing stages 200B and 200C, a wire WBBC is bonded between the intermediary output terminal 206B and the intermediary input terminal 204A. Finally, the intermediary output terminal 206C is connected to the output terminal 302 of the board.

[0079] Wires are also used to connect the dividing stages to a ground terminal 303 arranged on the board.

[0080] In the illustrated example, if each dividing stage is associated with a dividing ratio Q=(X+Y)/X (where X is the capacitance of the capacitor connected to the input and Y the capacitance of the capacitor connected to the ground), the output voltage for a given input AC voltage U is U/Q.sup.3.

[0081] The above described voltage dividers use capacitors that have capacitance values that can be disregarded when designing a voltage divider as long as the dividing ratio is known. This dividing ratio is particularly stable, as all the capacitors of a stage are formed in a same integrated component (and will therefore be affected similarly by an elevation of temperature, for example—it should be noted that this is also an advantage over MLCC components where the temperature derating is component dependent).

[0082] The present voltage divider benefits from the advantages of using a semiconductor substrate to manufacture capacitors.

[0083] Also, the capacitance used can be small, as only the ratio is relevant.

[0084] In addition, it is noted that although the present invention has been described above with reference to certain exemplary embodiments, it will be understood that the invention is not limited by the particularities of the specific embodiments. Numerous variations, modifications and developments may be made in the above-described embodiments as would be appreciated to one skilled in the art.