Sensor device

Abstract

A sensor device (1) for measuring a quantity (P) has a casing body in which an electronic circuit is arranged, that comprises first circuitry (29), configured for detecting the quantity (P) and providing accordingly a first signal representative of a value of the quantity (P). The electronic circuit comprises a temperature sensor (TH, TS) configured to detect a temperature of a circuit support (51), and generate accordingly a second signal. The electronic circuit comprises a control circuit (104) configured to enable electrical power supply to at least one circuit component (IC) if the second signal provided by the temperature sensor (TH, TS) is representative of a temperature higher than a first determined temperature.

Description

[0001] "Sensor Device"

[0002] * * *

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the invention

[0005] The present invention relates to electronic devices in general, and was developed with particular reference to sensor devices, such as pressure and / or strain and / or temperature sensor devices, capable of operating under severe temperature conditions, for example temperatures below -40°C. The invention has a preferred application in the field of pressure sensor devices for high-pressure application (e.g., up to 900 bar), in particular sensors for detecting the pressure of a gaseous medium, such as hydrogen, for example in relation to vehicle engines.

[0006] Prior art

[0007] Pressure sensor devices for fluid media are widely known. Such devices typically include a pressure-sensitive element housed in a casing body having an inlet passage for a fluid.

[0008] The sensing element has an elastically deformable detection membrane, which faces one end of said passage, to be accessible by the fluid. On one side of the membrane not exposed to the fluid, a detection circuit is typically associated, which generally includes capacitive, resistive, or pi ezoresi stive elements (typically arranged in a Wheatstone bridge configuration) suitable for detecting the deflection of the membrane, where such deflection is representative of the value of the fluid pressure. Inside the device casing a so-called PCBA (Printed Circuit Board Assembly) is often provided, i.e., an electrically insulating support, such as a PCB (Printed Circuit Board), carrying electrical and / or electronic components of a related control circuit, which is connected to the electrical terminals of the sensing element. In some known solutions (see, e.g., WO 2008 / 078184A2), the sensing element has a PCBA support element associated therewith.

[0009] In certain applications, wherein the sensor device is intended to detect very high pressures, the device casing includes an inlet body, defining said passage for the fluid, which is made of metal material, e.g., steel. The inlet body serves as a hydraulic connection element and for this reason typically has a lower cylindrical portion with external threading. The inlet body is provided with a blind hole, whose bottom is near an upper part of the body itself, so as to define a membrane portion, to the outer side of which the circuit for detecting the corresponding deflection is associated, representing the pressure of the fluid present in said blind hole. As a matter of fact, therefore, in many solutions, the inlet body also forms at the same time the membrane, or at least part of the sensing element of the device.

[0010] To the metal inlet body is then associated, at the top, a connector body, which carries the electrical terminals for connecting the sensor device to an external system, e.g., to a vehicle engine control unit. The connector body defines a cavity that, together with the metal inlet body, forms a housing chamber where the PCBA is disposed, which is electrically connected, on one side, to the deflection detection circuit, and on the other side, to said electrical terminals.

[0011] Some of these sensor devices designed to operate at very high pressures are used in conjunction with fluids that can reach low temperatures. In these applications, the inlet body of the device, being made of metal material - and thus a good thermal conductor - negatively affects the operation of certain active electronic components of the PCBA (such as an integrated circuit), potentially causing detection errors or even irreversible failures of the components.

[0012] Electronic components capable of operating under low-temperature conditions, typically down to -40°C, are known, meeting the usage requirements typical of the automotive sector, i.e., they are suitable for functioning under the climatic conditions expected for this sector. Electronic components for military or avionic applications are also known, capable of ensuring proper operation at temperatures lower than those typical of the automotive sector, e.g., down to -55°C: however, the product range of such electronic components is limited and specialized, not to mention their very high costs, still considered prohibitive for other applications, such as automotive use. It is therefore difficult to source electronic components suitable for large-scale applications in sensor devices intended to operate at temperatures below -40°C.

[0013] The Applicant has realized that widely available electronic components which can be typically found in commerce at acceptable costs may lead to malfunctioning issues under certain operational conditions encountered in the use of a sensor device. In the specific case of sensor devices applied in certain vehicles, particularly hydrogen-fueled vehicles, it has been observed that under certain conditions, the expansion of the gas can cause significant cooling in some parts of the onboard fuel system, reaching temperatures even below -60°C, particularly in tanks and / or duct sections where sensors, such as a pressure sensor, are typically located.

[0014] For example, it has been observed that when a hydrogen tank is nearly empty, and thus the internal pressure is relatively low (e.g., < 50 or 100 bar), and the vehicle continues to be used, a rapid tank depletion may occur, with a sudden pressure drop and consequent gas temperature decrease. This phenomenon is exacerbated when it coincides with low ambient temperatures, e.g., under climatic conditions of low temperature (such as -30°C or -40°C), in which case cooling down to -60°C / -70°C may occur in the tank and / or some vehicle supply ducts.

[0015] Similar issues arise with other types of sensor devices, such as temperature sensors and strain or stress sensors.

[0016] Summary of the invention

[0017] In view of the above, the present invention aims to propose new solutions capable of addressing the aforementioned issues, particularly through a sensor device, such as a pressure sensor, a strain sensor, or a temperature sensor, of simple and economical construction, with high detection sensitivity and long-term reliability.

[0018] This and other purposes, which will become clearer hereafter, are achieved according to the present invention by a sensor device having the features indicated in the claims.

[0019] The claims form an integral part of the technical teaching provided herein in relation to the invention.

[0020] Brief description of the drawings

[0021] Further aims, features, and advantages of the present invention will become clear from the detailed description that follows, made with reference to the accompanying schematic drawings, provided purely by way of non-limiting example, in which:

[0022] - Figures 1 and 2 are schematic views, respectively in perspective and side elevation, of a sensor device according to possible embodiments;

[0023] - Figure 3 is a schematic perspective view of a part of a first body of a sensor device of the type shown in Figures 1-2;

[0024] - Figure 4 is an enlarged detail of Figure 3;

[0025] - Figure 5 is a schematic cross-section of the body part of Figure 3;

[0026] - Figures 6 and 7 are schematic perspective views, from different angles, of another part of a first body of a sensor device of the type shown in Figures 1-2;

[0027] - Figure 8 is a schematic cross-section of the body part of Figures 6-7;

[0028] - Figure 9 is a schematic cross-section of a first body of a sensor device of the type shown in Figures 1-2, formed by joining the body parts of Figures 5 and 8;

[0029] - Figure 10 is a schematic cross-section of a first body of a sensor device according to alternative embodiments to that of Figure 9;

[0030] - Figures 11 and 12 are schematic perspective views, from different angles, of a second body of a sensor device of the type shown in Figures 1-2;

[0031] - Figure 13 is a schematic perspective view of some components of a second body of a sensor device of the type shown in Figures 11-12;

[0032] - Figures 14 and 15 are schematic perspective views, from different angles, of a circuit arrangement of a sensor device according to possible embodiments;

[0033] - Figures 16 and 17 are schematic exploded views, from different angles, of a sensor device of the type shown in Figures 1-2;

[0034] - Figure 18 is a schematic cross-sectional representation of an assembly stage of a sensor device of the type shown in Figures 1-2;

[0035] - Figures 19-22 are schematic perspective representations of corresponding assembly stages of a sensor device of the type shown in Figures 1-2;

[0036] - Figure 23 is a schematic cross-sectional representation of a further assembly stage of a sensor device of the type shown in Figures 1-2;

[0037] - Figure 24 is a schematic cross-section along line XXIV-XXIV of Figure 2;

[0038] - Figures 25 and 26 are schematic sectioned perspective views, from different angles, of a sensor device of the type shown in Figures 1-2;

[0039] - Figure 27a represents a first possible principle diagram of a sensor device according to possible variant embodiments;

[0040] - Figure 27b graphically illustrates the operating principle of the diagram in Figure 27a;

[0041] - Figures 28, 29, 30 and 31 illustrate possible control and / or protection circuit diagrams of a sensor device according to possible embodiments;

[0042] - Figures 32 and 33 illustrate preferential control and / or protection circuit diagrams of a sensor device according to possible embodiments;

[0043] - Figures 34 and 35 represent a second and third principle diagram, respectively, of a sensor device according to possible embodiments;

[0044] - Figures 36 and 37 are schematic views, respectively in perspective and side elevation, of a first body of a sensor device according to further embodiments;

[0045] - Figure 38 is a schematic cross-section along line XXXVIII -XXXVIII of Figure 37;

[0046] - Figures 39 and 40 are schematic perspective views, from different angles, of a second body of a sensor device according to further embodiments;

[0047] - Figures 41, 42 and 43 are schematic perspective views of corresponding components of a sensor device employing a first and second body of the type shown in Figures 36-38 and 39-40;

[0048] - Figures 44, 45 and 46 are schematic perspective views of corresponding assembly stages of a sensor device employing a first body of the type shown in Figures 36-38 and components of the type shown in Figures 41-42;

[0049] - Figures 47 and 48 are schematic views, respectively in perspective and side elevation, of corresponding assembly stages of a sensor device employing a second body of the type shown in Figures 39-40 and a component of the type shown in Figure 43;

[0050] - Figures 49 and 50 are schematic cross-sectional representations of corresponding assembly stages of a sensor device using bodies and components of the type shown in Figures 36-43;

[0051] - Figure 51 is a schematic perspective view of a component of a sensor device according to further possible embodiments;

[0052] - Figures 52 and 53 are schematic views, respectively in perspective and side elevation, of a first body of a sensor device equipped with a component of the type shown in Figure 51;

[0053] - Figure 54 is a schematic cross-sectional view along line LIV-LIV of Figure 53;

[0054] - Figures 55 and 56 are schematic perspective views of some assembly stages of components of a sensor device equipped with a component of the type shown in Figure 51;

[0055] - Figures 57 and 58 are schematic perspective views of corresponding components of a sensor device according to further possible embodiments;

[0056] - Figures 59 and 60 are schematic views, respectively in perspective and side elevation, of a first body of a sensor device equipped with a component of the type shown in Figure 57;

[0057] - Figure 61 is a schematic cross-sectional view along line LXI-LXI of Figure 60; - Figures 62, 63 and 64 are schematic perspective views of some assembly stages of a sensor device equipped with components of the type shown in Figures 57 and 58;

[0058] - Figure 65 is a schematic cross-section of a sensor device equipped with components of the type shown in Figures 57-58; and

[0059] - Figure 66 is a schematic cross-section of a first body of a sensor device according to further possible embodiments.

[0060] Description of preferred embodiments of the invention

[0061] The reference to "an embodiment" within this description indicates that a particular configuration, structure, or feature described in relation to the embodiment is included in at least one embodiment. Therefore, phrases such as "in one embodiment" and similar, possibly present in different parts of this description, do not necessarily refer to the same embodiment. Furthermore, particular configurations, structures or features or electronic components or circuit portions described or illustrated may be combined in any suitable manner in one or more embodiments, even different from those depicted. Some configurations, structures or features or electronic components or circuit portions described or illustrated in reference to "an embodiment" may be at least partially present or absent in other embodiments. The references used here are for convenience only and thus do not define the scope of protection or the extent of the embodiments. The spatial references (such as "upper", "lower", "high", "low", "vertically", etc.) used here are for convenience only and refer to the examples as shown in the figures.

[0062] The reference numbers used in different figures are intended to indicate similar or technically equivalent parts, elements or components, even if referred to different embodiments.

[0063] Referring initially to Figures 1 and 2, 1 indicates as a whole a sensor device according to possible embodiments. In the exemplified case, the device 1 is a pressure sensor, intended for detecting pressures of a fluid, even high pressures, such as pressures up to 900 bar, and capable of operating at very low temperatures, in particular below -40°C, for example down to -70°C. In the following, it is assumed for example that the device 1 is used for detecting the pressure of a gaseous fuel, specifically hydrogen gas for powering a vehicle engine.

[0064] The device 1 has a casing body that defines a housing space, in which an electronic circuit is arranged. In various embodiments the device 1 has a casing that comprises at least a first body 2, preferably made of metal material, such as stainless steel, and a second body 3, preferably made of moldable plastic material. The two bodies 2 and 3 are coupled together, with possible interposition of sealing means, such as an annular gasket or a resin-sealing. Given that in the illustrated example the device 1 is a pressure sensor device, the first body 2 will hereinafter also be referred to as inlet body 2, and the second body 3 also referred to as connector body: this is because, in the example shown, the body 2 is provided with a passage for the fluid whose pressure is to be measured, and the body 3 is provided with means for electrical connection to the outside.

[0065] In various embodiments the inlet body 2 is itself formed in multiple parts, for example two body parts indicated with 2' and 2": this is however not an essential feature.

[0066] Referring also to Figures 3-5, the body part 2' of the inlet body 2 may have substantially the shape of a solid of revolution (except for two flattened portions identified later), with a lower portion 2a' configured for fastening and / or hydraulic connection, and an upper portion 2b' that forms part of a pressure-sensitive element.

[0067] In the specific case shown, the lower portion 2a' includes a generally cylindrical part 20, preferably provided with an external thread and a lower end 21 of a substantially truncated-conical shape, suitable for sealingly couple with a corresponding truncated-conical seat of the user apparatus.

[0068] In the exemplified case, above the cylindrical part 20, the upper portion 2b' of the body part 2' has a flange part 22, which protrudes radially outward. From the flange part 22 there rises centrally a body portion that is shaped to define a top part 23. In the example the flange part 22 has a central disk-shaped protrusion 24, from which there rises an axial or substantially columnar portion 25, which may be provided with an intermediate radially protruding flange 26, and which defines at the upper end the aforementioned top part 23. The columnar portion 25 may have a narrowing 27, for example made via an annular groove, between the top part 23 and the intermediate flange 26. The intermediate flange 26 and the narrowing 27 may be provided to reduce mechanical stresses that could be transmitted to the top part 23, belonging to the sensing element of the device 1.

[0069] The body part 2' of the inlet body 2 has an axial passage, indicated with 28 in Figure 5, preferably in a central position. In the example shown, the passage 28 consists of a blind hole of the body part 2', here formed as a single metallic piece through mechanical machining. The passage 28 opens at the lower end 21 of the cylindrical portion 20, and its bottom is located near the upper surface of the top part 23: in this way, in said top part 23, a thin-walled portion is defined, which forms a detection membrane 23a of the device 1. The passage 28 provides an inlet passageway or port for the fluid whose pressure is to be measured, here hydrogen in gaseous form. As visible in Figures 3-5, at least a portion of a circuit 29 for detecting the deflection of said membrane 23a is arranged at the membrane.

[0070] The top part 23 and the intermediate flange 26 may have respective peripheral flattened portions 23b and 26b, on a same side of the body part 2'. These possible flattened portions may be provided, for example, to polarize the body part 2' during the assembly process of the circuit 29, and / or during coupling with the body part 2", and / or during the assembly of a PCBA described later, and / or during an electrical connection phase, particularly wire bonding.

[0071] The circuit 29 is preferably formed on the upper surface of the top part 23, to form, together with its membrane 23a, a pressure-sensitive element.

[0072] For example, the circuit 29 may be obtained at least partially through screen printing with thick film technology of a resistive or piezoresistive material. Alternatively, the circuit 29 may be obtained at least partially through MSG (micro strain gauge or microfused strain gauge) technology, preferably by making one or two elements (strain gauge) comprising pairs of resistors in a half-bridge configuration, which can be made of silicon on a support (or on two respective supports) of glass, subsequently fixed - for example via glass frit bonding - to the top part 23, in correspondence with the membrane 23 a.

[0073] The circuit may include, for example, a plurality of electrical detection elements connected to each other, arranged in a bridge configuration (particularly a Wheatstone bridge) or in a half-bridge configuration. Said detection elements are preferably resistors, i.e., passive components. In various embodiments, the circuit 29 includes a temperature sensor, whose signal can be used to compensate for the pressure measurement or to detect the fluid temperature.

[0074] A possible further part 2" of the inlet body 2 is visible in different views in Figures 6-8. The body part 2" is also preferably made of metal material and is preferably configured for coupling with the connector body 3, as explained below.

[0075] The body part 2" has an axially hollow centrally portion 30, or provided with a through hole 30a, preferably having circular cross-section. Preferably, the external diameter of the central portion 30 substantially matches the external diameter of the flange part 22 of the body part 2'. Also preferably, the internal diameter of the hole 30a is slightly larger than the external diameter of the diskshaped portion 24 of the body part 2'.

[0076] Near the base of the portion 30, a flange portion 31 extends radially outward, whose external surface preferably defines a plurality of flat faces, in particular to facilitate the fastening in position of the device; for this purpose, in the example shown, the external surface of the flange portion 31 substantially defines a hexagonal head.

[0077] In various embodiments, from the flange portion 31 there rises an annular coupling wall 32, having a diameter (or other cross-sectional dimension) larger than the hollow central portion 30 and substantially coaxial thereto: in this way, between the outside of the hollow portion 30 and the inside of the wall 32, an annular cavity 33 is defined. Preferably, the wall 32 extends in height beyond the hollow central portion 30.

[0078] The body parts 2' and 2" are preferably designed to be coupled and / or joined together, in particular through welding. Specifically, as visible in Figure 9, the body part 2" is inserted onto the upper portion 2b of the body part 2', so that the lower surface of the portion 30 of part 2" abuts against the upper surface of the flange part 22 of part 2', and the disk-shaped portion 24 of part 2' is inserted into the axial hole 30a of part 2". The two parts 2' and 2" are preferably welded together at the interface surface.

[0079] In various embodiments, and as noted in Figure 9, in the coupled condition between parts 2' and 2", the upper surface of the portion 30 of part 2" is at a greater height than the upper surface of the top part 23 of part 2'.

[0080] Note that, as mentioned earlier, the inlet body 2 could be formed as a single piece, as shown in Figure 10, i.e., with such a single body 2 machined to integrate the various elements previously described in relation to body parts 2' and 2". The configuration with body part 2" welded to body part 2' is advantageous in terms of production flexibility, for example, to allow the use of the same body part 2' while varying the shape of body part 2", e.g., in its external profile. This configuration also has the advantage of having the weld between the two body parts 2' and 2" not in contact with the hydrogen. The construction n two-part 2' and 2" can also facilitate the production of circuit 29.

[0081] Referring to Figures 11 and 12, in various embodiments, the connector body 3 preferably has a lower part 3a and an upper part 3b axially extending, having a tubular shape, i.e., generally hollow. In the illustrated example, the lower part 3a and the upper part 3b have peripheral walls 3a' and 3b' with substantially circular and quadrangular cross-sections, respectively, but this is not an essential feature. In general, at least the cross-section of the lower part 3a, i.e., its wall 3a', is substantially congruent or complementary with that of the annular cavity 33 of the inlet body 2 and / or the body part 2".

[0082] The connector body 3 may be formed as a single piece of plastic material, which is preferably overmolded onto a plurality of electrical terminals described later, for the external connection of the device 1, where such terminals have a respective portion extending axially inside the upper part 3b, thereby forming an electrical connector.

[0083] The two hollow parts 3 a and 3b of the connector body 3 are separated by an intermediate transverse wall of the body 2, indicated with 35 in Figures 11-12, in which a seat 36 is preferably defined for an element at least partially permeable to gas or air, such as a pressure compensation element, particularly in the form of a membrane (also known as a DAE membrane), of a per se known type. The seat 36 is defined in correspondence with a through hole 37 of the wall 35.

[0084] As already indicated, the inlet body 2 and the connector body 3 are coupled to each other, and so that between the two bodies in question a housing chamber — indicated with C in Figures 23-24 — is defined, in which part of the body 2 extends and where a PCBA is located, i.e., a circuit support, such as a PCB, on which electronic components of a control circuit, in particular a protection circuit, of the device 1 are assembled, as explained later.

[0085] If the chamber C were hermetically sealed, the air contained within it, upon cooling, could create a vacuum sufficient to cause moisture to be drawn inside the same chamber, with the risk of jeopardizing the operation of certain components of the PCBA or the corresponding electrical contacts. To balance these pressure variations caused by temperature fluctuations, the aforementioned compensation element is preferably provided, in particular in the form of a membrane permeable to air and impermeable to moisture. The presence of the hole 37, which crosses the wall 35 opening into the hollow part 3a of the connector body 3 (see, e.g., Figure 50), and the fact that the compensation element allows air passage, also has the function not to hinder the deflection of the membrane 23 a of the inlet body 2 (which would occur if the chamber C were hermetically sealed).

[0086] Still referring to Figures 11-12, in various embodiments, from the intermediate wall 35 there protrude, toward the inside of the cavity — indicated with D — of the lower part 3a, one or more formations 38 in which axial seats 38a are defined, for housing respective elastic electrical contact elements, in particular in the form of spiral springs.

[0087] In various embodiments, between the intermediate wall 35 and the peripheral wall 3a' of the lower portion 3a, positioning seats 39 are defined for elastic or resilient constraint elements for a PCBA, as described below. For example, three seats 39 may be provided, spaced 120° apart along the inner circumference of the peripheral wall 3a' of the lower portion 3a. Along this circumference, an additional seat — indicated with 39' in Figure 22 — may also be defined for a ground electrical contact, as described below.

[0088] Figure 13 shows in isolation some of the components previously mentioned in relation to the connector body 3, specifically the aforementioned electrical terminals, indicated with 40, the aforementioned elastic electrical contact elements, indicated with 41, the aforementioned compensation element, indicated with 42, the aforementioned elastic constraint elements, indicated with 43, and the aforementioned ground electrical contact, indicated with 44.

[0089] As previously mentioned, in various embodiments, the connector body 3 is overmolded onto corresponding electrical terminals, indicated with 40 in Figure 13, preferably but not necessarily three terminals. In various embodiments, the terminals 40 have a respective first portion 40a extending axially inside the upper portion 3b of the same body 3, thereby forming an electrical connector. In various preferential embodiments, the terminals 40 have an intermediate bend or are at least partially shaped substantially in an L-configuration, to define respective second portions, indicated with 40b, which are substantially orthogonal to said first portions 40a (or the second portions 40b extend according to a plane substantially orthogonal to an axis of the first portions 40a).

[0090] The connector body 3 is preferably overmolded onto the terminals 40 such that said second portions 40b are at least partially embedded in the intermediate wall 35 of the connector body, but with a corresponding surface area directly exposed at the bottom of the seats 38a for the contact elements, indicated with 41 in Figure 13. In this way, electrical continuity can be ensured between the terminals 40 and the elastic electrical contact elements 41, preferably in the form of helical springs made of electrically conductive material. The springs 41 preferably have coils with diameters decreasing toward the two axial ends, for example to facilitate assembly and / or reduce the contact area on corresponding pads of a PCB, thereby minimizing the size of such pads. The symmetry of the spring ends may also eliminate the need to orient the springs during assembly.

[0091] Also in Figure 13, a possible implementation of the aforementioned compensation element 42 is schematically shown, in the form of a DAE membrane, here circular in profile and intended for mounting in correspondence with the respective seat 36 in Figures 11-12.

[0092] Still in Figure 13, with 43 are indicated the aforementioned elastic constraint elements, having a body preferably made of elastomeric material. In various embodiments, the body of each constraint element 43 has a base or coupling portion 43a and a head portion 43b defining an inclined surface. The base portion 43a is intended to be coupled to the corresponding seats 39 in Figures 11-12, so that said inclined surface of the head portion faces substantially toward the central part of the cavity D (Figures 11-12) of the lower portion 3a of the connector body 3. Finally, in Figure 13, with 44 is indicated the aforementioned ground contact, which, as will be seen, is intended to partially protrude outward from the cavity D and may be configured substantially as a leaf spring.

[0093] Figures 14 and 15 show a possible implementation of the aforementioned PCBA, indicated as a whole with 50; in these figures, the representation of some parts has been omitted for clarity reasons, such as protective materials or layers preferably present on the faces of the PCBA, for example outer layers of the insulating material of a multilayer PCB and / or a "solder resist" layer and / or a "conformal coating" layer.

[0094] The PCBA 50 comprises a circuit support or PCB, indicated with 51, made of electrically insulating material - for example, a ceramic material (such as alumina), LTCC (Low Temperature Cofired Ceramic), or a composite material (such as fiberglass or FR4) - on which a plurality of components of a protection and / or control circuit of the device 1 are mounted, among which active electronic components (e.g., an integrated circuit, operational circuit, MOSFETs, etc.) and passive components (e.g., resistors, capacitors, diodes, etc.).

[0095] In the example, with 52 are indicated some of said components, and with IC is indicated an integrated circuit, particularly an ASIC, which are arranged on a first major face of the PCB 51, here conventionally defined as the upper face.

[0096] On this upper face there are also defined conductive tracks for connecting the various circuit components, some of these tracks being indicated with 53. Preferably, some of the tracks 53 are provided at their respective ends with contact pads 53a, on which respective ends of the contact springs 41 are intended to rest elastically. A track 53 may be provided with a respective pad 53b for the ground contact 44.

[0097] In preferential embodiments of the invention, the PCB 51 is provided with a through-opening 51a, preferably in a substantially central position relative to its major faces, through which elements for the electrical connection of the circuit 29 for detecting the deflection of the membrane 23 a (Figures 3-5) can pass. The circuit 29 is electrically connected to respective conductive tracks 53 on the PCB 51 of the PCBA 50: in various embodiments, this electrical connection is preferably made via wires, such as wire bonding, using suitable connection wires indicated with W in Figures 14-15, according to a per se known technique. Various alternative connection types are possible, such as thin-wire or thick-wire wire bonding, or soldering, or connections via intermediate terminals or others.

[0098] In general terms, the electronic circuit of the sensor device 1 therefore comprises:

[0099] - first circuitry, comprising the circuit 29, configured for the detection of the quantity of interest and accordingly provide a first signal representative of a value of the quantity, and

[0100] - second circuitry, configured to receive from the first circuitry the aforesaid first signal, and generate an output signal of the sensor device, wherein the second circuitry is in signal communication with the first circuitry and is arranged at least in part on the circuit support 51 located in the housing space C defined by the casing body 2, 3.

[0101] As visible in Figure 15, on the second major face of the support 51, here conventionally defined as the lower face, at least one electrical heater H is located, in particular a serpentine heater. The heater H may be formed, for example, with resistive material deposited directly on the PCB 51. In various embodiments, the ends of the heater are located at metallized holes 54 that preferably pass through the PCB 51, possibly connected via other intermediate tracks in the case of a multilayer PCB, for connection to respective tracks 53 used for the electrical supply of the heater H.

[0102] Possible examples of the circuit implemented in the PCBA of the device according to the invention will be described later, with the understanding that - in the proposed application - at least one active circuit component of the PCBA, such as the integrated circuit IC, is designed to operate correctly, i.e., not be damaged, provided it is not electrically powered when the surrounding temperature is below a determined value, for example a first determined temperature equal to -40°.

[0103] In various embodiments, the PCBA is mounted in the casing 2-3 of the device 1 in a position vertically spaced from the membrane 23 a of the metal body 2: preferably, the distance is such that the signal provided by the circuit 29 is not perturbed by a heating of the PCBA 50 operated by the electrical heater H.

[0104] In various embodiments, the distance between the PCBA and the circuit 29 is predefined such that the heating of the PCBA operated by the electrical heater H does not heat or otherwise cause a significant heating of capacitive, or resistive, or piezoresistive elements intended to detect the deflection of the membrane 23a, i.e., does not cause significant variations in the resistance or capacitance values of elements intended to detect a pressure value.

[0105] In various embodiments, there is provided a heating of a PCBA distinct and spaced apart from the circuit 29 associated with the top portion 23 of the body 2', preferably made of metal: in this way a faster and more uniform heating of the PCBA is allowed, as the heating temperature of the heater H is not dissipated by the body 2'; at the same time, the dissipation of temperature through the body 2' helps in preventing or reducing the heating of the circuit 29 associated therewith, even if a minimal portion of heat potentially radiated by the heater H could reach the circuit 29.

[0106] The PCBA can be supported at the aforesaid distance by respective support and / or positioning elements defined in the connector body 3 of fixed thereto, using relatively extended conductors to electrically connect the same PCBA to the circuit 29.

[0107] However, in various preferential embodiments, and as previously mentioned, the inlet body 2 can be configured to support and position the PCBA within a respective housing chamber, in a position vertically spaced apart from the top portion 23 of the same inlet body 2. In various embodiments, the PCBA is nonetheless constrained relative to the bodies 2 and / or 3, as explained below.

[0108] Figures 16 and 17 illustrate, with exploded views from different angles, the components of a device 1 according to the embodiments described so far.

[0109] For the assembly of the device 1, the circuit 29 for detecting the deflection of the membrane 23a is formed or associated on the top portion 23 of the inlet body (or its body part 2'), as visible, for example, in the lower part of Figure 16.

[0110] In various preferential embodiments, the circuit 29 may include elements obtained at least partially with MSG technology (micro strain gauge or microfused strain gauge. Such an application proves suitable, for example, for certain preferential circuit configurations, wherein one or two elements (strain gauge) comprise pairs of resistors in a half-bridge configuration, which can be made of silicon on a support (or on two respective supports) of glass, subsequently fixed - for example via glass frit bonding - to the top portion 23, at the membrane 23a.

[0111] This application proves preferable, for example, in the circuit configuration of Figures 32 and 33, where the two sensitive elements (i.e., the resistor pairs Rp in Figures 32 and 33 in a half-bridge configuration) can be made of silicon on a support (or on two respective supports) of glass, subsequently fixed via glass frit bonding at the membrane 23a.

[0112] This is followed by the coupling and / or welding of the parts 2' and 2" of the inlet body 2, as visible in Figure 9. As mentioned with reference to Figure 10, however, the inlet body 2 could be formed as a single piece.

[0113] The previously prepared PCBA 50 is then placed on the upper surface of the hollow central portion 30 of the inlet body 2. In various preferential embodiments, the lower face of the PCB 51 is fixed or glued onto said upper surface of the hollow central portion 30.

[0114] In various preferential embodiments, an electrically and / or thermally insulating material is interposed between the lower face of the PCB 51 and the upper surface of the aforesaid hollow central portion 30, for example a protective layer (such as an outer layer of the insulating material of a multilayer PCB and / or a solder resist layer and / or a conformal coating layer), which covers at least part of the PCBA 50; alternatively, an annular electrically and / or thermally insulating element and / or an electrically and / or thermally insulating adhesive may be provided (see, for example, the layer indicated with IL in Figure 26).

[0115] In preferential embodiments, the diameter (or other cross-sectional dimension) of the PCB 51 is substantially similar to the diameter (or other cross- sectional dimension) of the hollow central portion 30, as seen, for example, in Figure 18.

[0116] The positioning is such that the passage 51a of the PCB 51 (Figures 14-15) is substantially above or aligned with the detection circuit 29 associated with the upper surface of the top portion 23 of the inlet body 2. Thanks to this arrangement, the electrical connection between conductive traces of the PCBA 50 and the circuit 29 can thus be made (see, for example, Figure 18). As mentioned, the connection is preferably made via wire bonding, for example with thin wire, using the bonding wires W.

[0117] The result of the assembly steps described above is visible in Figure 18, where it can be seen how the PCBA 50 is positioned in the volume laterally delimited by the annular coupling wall 32 of the inlet body 2. Figure 18 in particular shows how, in the assembled condition, the PCBA 50 is mounted in a position vertically spaced apart from the membrane 23a of the metal body 2, i.e., above it and without direct contact with it.

[0118] As mentioned, the connector body 3 is preferably made of plastic material, for example overmolded onto the terminals 40 of Figure 13. The molding is performed so that the portions 40a of the terminals 40 extend axially into the portion 3b of the connector body 3, while the portions 40b are substantially embedded in the intermediate wall 35 of the connector body 3. As indicated, an area of the portions 40b of the terminals is exposed at the bottom of the seats 38a defined in the formations 38 of Figures 11-12, for the positioning of the electrical contact springs 41 (Figure 13).

[0119] Figure 19 schematically shows the phase of gluing or fixing of the aforementioned compensation membrane 42 at the corresponding seat 36 defined in the intermediate wall 35 of the connector body 3.

[0120] Figure 20, on the other hand, schematically shows the phase of coupling the elastic constraint elements 43, i.e., the base portions 43a thereof (Figure 13), at the respective seats 39, with the inclined surfaces of the elements 43 facing toward the central part of the chamber D.

[0121] Figure 21 schematically shows the phase of insertion of the electrical contact springs 41 into the corresponding seats 38a of the formations 38 at the intermediate wall 35 of the connector body 3; as mentioned, a corresponding surface area of the portion 40b of each terminal 40 (Figure 13) is directly exposed at the bottom of said seats 38a, so that the contact springs 41 are electrically in contact with the terminals themselves.

[0122] Figure 22 schematically shows the phase of positioning the ground electrical contact 44. As previously mentioned, between the intermediate wall 35 and the peripheral wall 3a' of the connector body 3, a positioning seat 39' is defined for the element 44, where this seat is in correspondence with a through opening in the same peripheral wall 3a'. The ground electrical contact 44, substantially in the form of a leaf spring, is positioned so that a portion thereof passes through a passage - indicated with 3a" in Figure 21 - of the wall 3a', partially protruding outward from the device 1, or in any case accessible, for ground connection.

[0123] At this point, the inlet body 2 and the connector body 3 are coupled together. As shown in Figure 23, the coupling is performed by inserting the peripheral wall 3a' of the connector body into the seat 33 of the inlet body 2, i.e., the seat defined between the hollow central portion 30 and the annular wall 32 of the same inlet body (or its body part 2" - see Figure 9). Following this phase, the part of the ground electrical contact 44 protruding from its passage 3a" (Figure 21) comes into contact with the inner surface of the annular wall 32 of the inlet body, providing a ground reference.

[0124] Subsequently, the upper part of the annular wall 32 of the inlet body 2 is mechanically crimped, i.e., deformed, onto the connector body 3, as shown in Figure 24. Preferably, the profile of the intermediate wall 35 of the connector body 3 is shaped to define an inclined external surface, particularly a truncated-conical surface, indicated with 3c in Figures 16, 23, and 24: the annular wall 32 is crimped in a position corresponding to said truncated-conical surface 3c. However, the profile of the intermediate wall 35 of the plastic connector body 3 could have another shape, for example with an edge, subsequently deformed during the crimping of the body 2, for example to obtain an inclined or curved external surface 3 c. Said crimping of the body 2 and possible deformation of the connector body 3 could be configured to create a seal between the bodies 2 and 3.

[0125] The assembly is preferably completed with the application of a sealing material, such as a resin, in correspondence with the deformed portion of the annular wall 32. The application of such a sealing material could however be performed before the deformation of the end portion of the wall 32, for example within the annular seat 33 of the inlet body 2. The sealing material also has the effect of preventing possible entry of external moisture through the passage 3a" (Figure 21) for the ground contact 44.

[0126] Following the coupling between the inlet body 2 and the connector body 3, the contact springs 41 - at the ends opposite with respect to the corresponding seats 38a - are pressed into contact with the corresponding pads 53a provided on the PCBA 50, as visible in Figure 25. As visible in the same figure, the proximal portion of the ground contact 44 is also elastically pressed against the corresponding pad 53b. As can be inferred from Figures 24 and 25, the constraint elements 43 are elastically pressed, at the corresponding inclined surface, against the outer edge of the upper face of the PCB 51, contributing to keeping the PCBA 50 in position.

[0127] Figure 26 also schematically shows the coupled condition between bodies 2 and 3, from a different angle, highlighting the PCB 51 resting on the free end of the hollow central portion 30 of the inlet body 2, preferably with the interposition of an annular electrically and / or thermally insulating element, such as the annular element indicated with IL. As mentioned earlier, in addition to or as an alternative to the element IL, the application of at least one layer of electrically insulating material on the PCB may be provided, preferably a material that is also thermally insulating. The lower face of the PCB 51, and thus the heater H, is positioned at a distance from the top part 23 of the same inlet body 2.

[0128] In accordance with an important aspect of the invention, and as previously mentioned, the PCBA 50 is indeed provided with at least one electric heater H, to reduce or eliminate the negative effect on the respective electronic components that could be caused by the potential low temperature in the area of the PCBA 50, for example determined by a low temperature of the inlet body 2.

[0129] The heater H is preferably a resistive heater and can be, for example, screen- printed or deposited on the lower face of the PCB 51, i.e., on the side opposite to that where the control electronics are located: such a configuration allows primarily heating the PCBA 50, so as not to distort the measurement performed by the circuit 29 associated with the detection membrane. The heater H could, however, be obtained in other ways: for example, the heater H could be a flexible heater glued to the PCB 51, or an additional element mounted on the PCB, e.g., using SMD technology.

[0130] Figure 27a shows a first possible principle diagram of a sensor device according to the invention. In this example, the connector body 3 of the device 1 includes three terminals 40 of the type already indicated, i.e., it implements a three- way connector, with a single electrical supply line for both pressure detection, via the circuit 29, and the heater H.

[0131] In this figure, the terminals 40 labeled VCC +, GND -, and VOUT are intended respectively for powering the device 1 (positive supply voltage VCC +), ground connection (negative electrical supply voltage GND), and the output signal of the device, representative of the pressure measurement (voltage signal VOUT, referenced to said negative voltage or ground GND).

[0132] The block H represents the aforementioned electric heater, for example comprising a resistor or resistive material, possibly a PTC thermistor or positive temperature coefficient resistor, while the block 100 schematically represents an active circuit component of the PCBA, here assumed to be the integrated circuit IC, in particular of the ASIC type, whose operation can only be guaranteed up to a certain determined minimum temperature (e.g., -40°C), or a component susceptible to damage if electrically supplied at temperatures below said determined minimum temperature.

[0133] The block 101 represents a first control device, such as a switch, placed on the power supply of the heater H, for example connected in series with the block H with respect to the power terminals VCC + and GND -, in particular between the block H and the terminal VCC + (alternatively, it could be between the block H and GND -). In other possible embodiments, however, the heater could be inserted between VCC + and the block or switch 101.

[0134] The block 102 represents a second control device, in particular a protection device, such as a switch or the output of an integrated circuit (preferably an operational circuit or a microcontroller), placed on the power supply of the block 100. The protection device 102, e.g., an electronic switch, can be placed in series with the block 100 with respect to the power terminals VCC + and GND -, in particular between the block 100 and the terminal VCC +.

[0135] The devices 101 and / or 102 can be of any type suitable for enabling or disabling the electrical power supply to a device according to the invention, or to a circuit element thereof, such as the heater H or the integrated circuit IC. If the devices 101 and / or 102 include switching means, these can be of any type suitable for interrupting and restoring a connection to the electrical power supply of a device according to the invention or a circuit element thereof, for example an electronic switch, such as a MOSFET, or an electromechanical switch, such as a relay.

[0136] In general terms, the electronic circuit equipping the sensor device 1 comprises temperature sensing means, configured to detect at least one of the temperature of the PCBA and the temperature existing in the housing space C, and to provide at least one corresponding second signal representative of the at least one detected temperature.

[0137] For this purpose, the block 104 represents a detection and protection circuit, in particular the detection of at least one temperature and consequent control of at least part of the circuit present on the PCBA, such as the detection of a temperature at which the device 1 operates, and particularly the temperature of the PCBA, or the internal area (chamber C) of the device 1 where the PCBA is located: this temperature does not necessarily correspond to the temperature of the environment outside the device 1.

[0138] Hereinafter, this temperature of interest will be referred to for simplicity as "PCBA temperature" taking for granted that that this definition is intended to also encompass the temperature of the internal area of the device 1 where the PCBA 50 is positioned. The block 104, which may comprise, for example, a temperature sensor, such as a resistor or NTC thermistor, is configured to control the aforementioned control devices 101 and 102, for example configured to generate a signal for opening or closing respective switching means.

[0139] As can be seen, the exemplary diagram of Figure 27a is such that the temperature detection circuit 104 is always powered when the device 1 is supplied by a corresponding external system (such as an ECU control unit) via the terminals GND - and VCC +, regardless of the open or closed condition of the switches 101 and 102.

[0140] Figure 27b graphically illustrates a possible operating mode of the circuit diagram of Figure 27a. In this Figure 27b, where the abscissa represents time and the ordinate represents temperature, the following symbols are used:

[0141] Tnom indicates a steady-state operating temperature of the electronics of the sensor device 1;

[0142] Tuon indicates a determined temperature threshold corresponding to the turnon temperature of the heater H; for exemplary purposes, assume that this temperature is not below -40°C;

[0143] Tuoff indicates the predetermined turn-off temperature of the heater H;

[0144] TASICOII indicates the minimum temperature (or first determined temperature) at which the correct operation of the electronic components, or at least the component of block 100, assumed here to be the integrated circuit IC, can be guaranteed; for the following example, the minimum temperature guaranteed for the correct operation of the remaining circuit components of the PCBA (or second determined temperature) could be -55°C: however, the minimum temperature guaranteed for the correct operation of all components could itself be -40°C;

[0145] TASiCoff indicates the minimum temperature at which the correct operation of at least the component of block 100 cannot be guaranteed;

[0146] Tpcba indicates the temperature on the PCBA;

[0147] Text indicates the temperature surrounding the PCBA;

[0148] Tmin indicates a temperature lower than Tuon, assumed here for purely exemplary purposes to be between -60°C and -70°C.

[0149] According to the non-limiting embodiment graphically depicted in Figure 27b, a preferential objective of the heater H is to ensure that the temperature Tpcba does not fall below a determined temperature threshold Tuon, excluding, of course, limited effects of thermal inertia.

[0150] According to an important aspect, the circuit equipping the device 1 is provided with a protection, in particular a protection designed to intervene in case the temperature Tpcba falls below the value of TASiCoff, (for example, in case of possible malfunctions, if the heater H fails). According to this aspect, said protection comprises the protection circuit 104, which is configured to control the device 102, in order to disable power to the block 100, protecting thereby one or more components of interest, and thus preventing it use or their use at temperatures below those guaranteed by their technical specifications.

[0151] In various embodiments, the value of TASiCoff is predefined or set slightly above the exemplified value of -40°C, to avoid risking reaching the critical temperature for the operation of the component or components of block 100, even considering the tolerances of the various components mounted on the PCBA. Preferably, however, in the correct operation of the sensor device 1, the aforesaid protection should not activate (since the PCBA should never reach temperatures below -40°C, as clarified below).

[0152] The presence of the device 102 is therefore useful to avoid the risk of damage to at least one component of block 100 (in the example, the integrated circuit IC), ensuring its non-operation when the temperature Ppcba falls below the value of TASiCoff.

[0153] Upon detecting the temperature TASICOII by the detection and protection circuit 104, the circuit itself controls the device 102 to re-enable power supply to the block 100, after it had been shut down for safety (the value of TASICOII will therefore be predefined or set to a value close to, but slightly above, TASiCoff).

[0154] As previously assumed, the minimum temperature (or second determined temperature) which ensures the correct operation of the sensor's circuit components other than block 100 may be -55°C: this means that, to ensure the operation of the heater H and blocks 101, 102, and 104, the temperature Tpcba can be at a minimum of -55°C (though, in this non-limiting example, this temperature should never occur during the correct operation of the sensor device).

[0155] During the transient with decreasing temperature Text, the operational sequence is as follows:

[0156] - from Tnom to Tnon: power supply to the heater H is disabled via the device 101, and the sensor device 1 operates normally;

[0157] - when the protection circuit 104 detects that the temperature Text (and thus the temperature Tpcba) has fallen below the determined threshold temperature Tuon, the same circuit controls the device 101 to enable power supply to the heater H (point ONH in Figure 27b): thus, while the temperature Text continues to decrease, the temperature Tpcba begins to rise with a slight delay due to thermal inertia;

[0158] - the temperature Text continues to decrease until Tmin, while the temperature Tpcba rises until Tnoff, at which point power supply to the heater H is disabled via the device 101 (point OFFH in Figure 27b); preferably, Tuoff will be predefined or set above the determined threshold temperature Tuon, so as to allow the PCBA to heat sufficiently before interrupting power supply to the heater H: during this phase, the temperature Tpcba will oscillate cyclically between Tuoff and Tuon, since the temperature Text is lower than Tuon and the heater H is powered only within this range;

[0159] - when the temperature Text begins to rise again, the temperature Tpcba continues to be maintained within the range between Tuon and Tnoff, until the temperature Text is sufficiently high to no longer require powering the heater H: at this point, the temperatures Text and Tpcba will continue to rise similarly.

[0160] Figure 28 shows a possible practical implementation of a principle schematic of the type shown in Figure 27a. In this Figure 28, reference 51 schematically represents the PCB on which the control electronics of the device are implemented, here comprising the controller indicated as IC, particularly an ASIC- type integrated circuit.

[0161] Reference 23 schematically represents a part of the inlet body 2, comprising the membrane 23a on which the pressure P of the fluid subject to detection acts, here hydrogen gas. Reference 29 indicates a detection circuit, such as the circuit for detection of the membrane deflection, here including four resistors Rp in a Wheatstone bridge configuration, connected to respective pins of the controller IC.

[0162] As mentioned, the circuit 29 may include a temperature sensor, e.g., for compensation of a pressure measurement: in the illustrated example, this temperature sensor comprises a PTC resistor indicated as Tp, connected in a halfbridge configuration with another resistor RT provided on the PCB 51.

[0163] VCC +, GND -, and VOUT schematically represent the aforementioned terminals for power supply, ground connection, and output of signals representative of the detected pressure, respectively.

[0164] Between power supply and ground, a resistive component implementing the aforementioned heater H is connected; 101 indicates the related enabling switch, here represented by a MOSFET with its control terminal (gate) connected to the output of an operational circuit configured as a voltage comparator CH, preferably in the form of an integrated circuit.

[0165] Reference 104 globally indicates the aforementioned protection circuit, also configured for detecting the PCBA temperature, which preferably includes at least a voltage divider, hereinafter also simply referred to as "divider," comprising at least two resistors. In preferential embodiments, the protection circuit 104 includes at least: a reference divider, here consisting of the resistors Pl and P2 connected in series between power supply and ground, between which a reference voltage is present and / or detectable; a first measurement divider, here consisting of the resistors TH and RH connected in series between power supply and ground, between which a first measurement voltage is present and / or detectable; and a second measurement divider, here consisting of the resistors TS and RS connected in series between power supply and ground, between which a second measurement voltage is present and / or detectable.

[0166] The switch to enable or disable power supply to the controller IC (block 102 of Figure 27a) is here represented by an operational circuit configured as a comparator, indicated as CS, preferably in the form of an integrated circuit CS.

[0167] As mentioned, in the example, the resistors Pl and P2 form a reference divider and may have equal resistive values, e.g., 10 kQ, particularly to obtain a reference voltage equal to half the VCC+ voltage applied across the divider, hereinafter also referred to as the threshold or reference voltage VCC / 2.

[0168] In the example, the aforementioned first measurement divider is composed of a fixed resistor RH and a negative temperature coefficient (NTC) resistor or thermistor, indicated as TH, which has a variable resistance. For example, the resistor RH may have a resistive value of 40 k , and the resistor TH may have a resistive value of approximately 40 kQ at the temperature of -10°C. The dividers P1-P2 and RH-TH are connected to respective inputs of the comparator CH.

[0169] In the example, the reference voltage of the reference divider is connected to the non-inverting input "+" of the comparator operational circuit CH, while the measurement voltage of the first measurement divider is connected to the inverting input of the comparator operational circuit CH.

[0170] The operation can be divided into two cases: a) TH<RH: when the resistive value of TH is less than RH, the voltage value at the input "+" of the comparator CH is lower than the threshold or reference voltage VCC / 2 set by the reference divider P1-P2: in this case, the output of the comparator CH will be forced or switched to a low or negative voltage, such as the said GND - or 0 V voltage, and the MOSFET 101 will not be able to conduct sufficient current to power the heater H; b) TH>RH: when the resistive value of TH is greater than RH, the voltage value at the input "+" of the comparator CH is higher than the threshold VCC / 2 set by the reference divider P1-P2: in this case, the output of the comparator CH will be forced or switched to a positive voltage, such as the VCC + voltage (e.g., 5 V), and the MOSFET 101 will be able to conduct sufficient current to power the heater H.

[0171] The aforementioned second measurement divider is also composed of a fixed resistor RS and a negative temperature coefficient (NTC) resistor or thermistor, indicated as TS, having a variable resistance. For example, the resistor RS may have a resistive value of 100 kQ, and the resistor TS may have a resistive value of approximately 100 k at a temperature of -30°C, which can be considered a safety or protection temperature. The dividers P1-P2 and RS-TS are connected to respective inputs of the comparator CS.

[0172] Here too, the operation can be divided into two cases: a) TS<RS: when the resistive value of TS is less than RS, the voltage value at the input of the comparator CS is lower than the threshold VCC / 2 set by the reference divider P1-P2: in this case, the output of the comparator CS will be forced or switched to a positive voltage, such as the VCC+ voltage (e.g., 5V), and the comparator itself will be capable of supplying sufficient current to power the controller IC; b) TS>RS: when the resistive value of TS is greater than RS, the voltage value at the input of the comparator CS is higher than the threshold VCC / 2 set by the reference divider P1-P2: in this case, the comparator output will be forced or switched to a low or negative voltage, such as the said GND or 0V voltage, and the comparator will not enable power supply to the controller IC. As can be seen, in the exemplified case, the following scenarios may occur: - when the PCBA temperature is higher than -10°C, power supply to the controller IC is enabled, while power supply to the heater H is not enabled;

[0173] - when the PCBA temperature is between -30°C and -10°C, power supply is enabled both to the controller IC and to the heater H;

[0174] - when the PCBA temperature is below -30°C, power supply to the heater H is enabled, while power supply to the controller IC is not enabled.

[0175] Regarding the last point, and assuming that the first determined temperature at which the proper operation of the controller IC is guaranteed is -40°C, it will be appreciated that - according to the invention - it is in any case possible to set, as needed, a protection temperature (-30°C in the example) higher than the first determined temperature.

[0176] It will be noted that the electronics implemented on the PCBA 50 include:

[0177] - a first circuit for enabling electrical power supply to the heater H, comprising a first temperature sensor TH; in the example, this first circuit comprises the reference divider P1-P2, the measurement divider TH-RH, and the comparator CH, which controls the switch 101 represented by the MOSFET;

[0178] - a second circuit for enabling electrical power to the controller IC, comprising a second temperature sensor TS; in the example, this second circuit comprises the reference divider P1-P2, the measurement divider TS-RS, and the comparator CS, with the latter acting as a switch for controlling power supply to the controller IC.

[0179] As can be seen, the protection circuit 104 is configured to enable electrical power supply to the controller IC if the signal provided by the temperature sensing means is representative of a temperature not lower than a first determined temperature, for which the proper operation of the integrated circuit IC can be guaranteed, or not lower than a protection temperature, higher than the first determined temperature.

[0180] For control purposes, in the example, the circuit 104 is capable of operating at temperatures even below -40°C.

[0181] In Figure 28, the circles marked with "c" are intended to represent respective pads present on the PCB 51 and on the part 23 of the inlet body 2 comprising the membrane 23a, between which the respective wires or electrical connections W, preferably wire bonding wires, are fixed to connect the detection circuit 29 to the PCBA 50. Figure 29 shows possible alternative embodiments of the circuit of Figure 28, which can also be implemented separately, namely:

[0182] - the use of comparators with hysteresis, i.e., operational circuits in which the reference voltage value at input is slightly varied at each switching of the output to create a hysteresis aimed at preventing continuous switching of the comparator itself, where, for example, each operational or comparator CH and CS has a dedicated input to which one end of a respective resistor RI is directly connected, while the other end of resistor RI is connected to the negative potential or ground GND;

[0183] - the use of a block configured for the protection on the power supply, which comprises, for example, two Zener diodes Z1 and Z2 connected in opposition (or anti-series) between the power supply terminals VCC+ and GND-;

[0184] - the use of a block configured to stabilize the power supply voltage of the controller IC toward the input +, comprising, for example, a capacitor Cl connected between the output of the comparator CS and the ground terminal GND-;

[0185] - the use of a protection block 111 at the output VOUT of the controller IC, which preferably includes a capacitor C2 connected between the signal output OUT of the controller IC and the ground terminal GND-, and two Zener diodes Z3 and Z4 connected in opposition (or anti-series) between the output terminal VOUT and the ground terminal GND-, for stabilizing the output signal voltage; additionally or alternatively, the block 111 may include a protection resistor RI connected between the signal output OUT of the controller IC and the output terminal VOUT, for example, to limit current to the controller IC in case of a short circuit involving the output VOUT;

[0186] - the use of at least one capacitor C3 connected across the half-bridge RT- Tp and / or across the pressure measurement bridge Rp, in particular to stabilize the corresponding signal.

[0187] Figure 30 shows further possible alternative embodiments of the circuit of Figure 28, which can also be implemented separately, namely:

[0188] - the relocation, on the portion 23 of the inlet body 2, of the resistor RT paired with the resistor Tp in a half-bridge configuration;

[0189] - the use of different comparators with hysteresis, where in this case the resistors RI are connected between input and output, so as to feed back to the reference input of the corresponding comparator CH or CS part of the respective output voltage, in order to create a hysteresis aimed at preventing continuous switching of the comparator itself.

[0190] Regarding this last embodiment, two separate reference dividers may be provided, for example, to prevent that the variations due to the switching of one comparator from cause variations also in the threshold of the other comparator. In the case shown in Figure 30, there are therefore provided a first reference voltage divider P1-P2 for the comparator CH, and a second reference voltage divider P3- P4 for the comparator CS.

[0191] As a possible variant embodiment, the circuit diagram of Figure 30 includes a switch 102, represented by a MOSFET, for the control of the power supply to the controller IC, interposed between the power supply VCC+ and the positive power input (+) of the controller IC.

[0192] In this example, the circuit for enabling power supply for the heater H (in the example, the reference divider Pl -P2, the measurement divider TH-RH, and the comparator with hysteresis CH, which controls the switch 101 represented by the MOSFET) operates similarly to what was described above with reference to Figure 28; the operation of the circuit for enabling power supply for the controller IC (in the example, the reference divider P3-P4, the measurement divider TS-RS, and the hysteresis comparator CS) is also substantially similar to what was described, but with the difference that, in this case: a) TS<RS: when the resistive value of TS is less than RS, the voltage value at the input of the comparator CS is lower than the threshold VCC / 2 set by the reference divider P3-P4: in this case, the output of the comparator CS will be forced or switched to a positive value, such as the power supply voltage VCC+ (e.g., 5V), and the switch represented by MOSFET 102 will be capable of supplying the controller IC; b) TS>RS: when the resistive value of TS is greater than RS, the voltage value at the input of the comparator CS is higher than the threshold VCC / 2 set by the reference divider P3-P4: in this case, the output of the comparator CS will be forced to a low voltage value, such as GND, e.g., 0V, and the switch represented by MOSFET 102 will not be capable of conducting sufficient current to supply the integrated circuit IC.

[0193] As a further possible variant embodiment, in the circuit diagram of Figure 31, the protection circuit 104 comprising the operational circuits CH and CS is replaced by a microcontroller (or an ASIC, or another suitable control chip), provided with an analog input IN ADC configured to detect the temperatures corresponding to the various voltages determined by the variation of the sensor represented by the divider TZ-RH, to compare these voltages with stored reference values, and to process the data and accordingly control the outputs 0UT 1 and 0UT 2 to enable or disable the controller IC and the heater H, following logics or modes substantially similar to those previously exemplified.

[0194] Figure 32 shows a preferential embodiment of the invention, wherein the circuit is conceptually similar to that of Figure 29, but wherein the detection circuit 29 includes two sensing elements in a half-bridge configuration (i.e., each formed by two resistors Rp), connected to the PCBA via six wire-bonding wires W, i.e., three wires per half-bridge. Some of the wires W are electrically interconnected via corresponding conductive tracks provided on the PCB 51, so as to implement the bridge configuration required for detection, in particular a Wheatstone bridge. As mentioned, such a configuration is preferable in the case of a circuit 29 of the type known as micro strain gauge or microfused strain gauge (MSG), with two sensing elements (each formed by a respective pair of resistors Rp) in a half-bridge configuration, as visible for example in Figure 4 (in Figure 4, the two sensing elements are substantially longitudinally aligned, but this is not an essential feature).

[0195] In the case of Figure 32, the temperature sensor Tp of Figures 28-31 is not present, as it is not strictly necessary. However, as visible in Figure 33, with a basic scheme analogous to that of Figure 32, the PTC resistor Tp connected in a halfbridge configuration with the resistor RT may be present.

[0196] Figure 34 shows a second possible principle diagram of a sensor device according to the invention. In this example, the connector body 2 of the device 1 includes four terminals 40 of the type already indicated, i.e., it implements a fourway connector. In this case, two distinct power supply lines are provided: one power supply line for the heater H, which can be controlled externally, for example kept always on, and one power supply line for the control electronics implemented in the PCBA 50.

[0197] In this figure, the terminals 40 labeled V2 + and VS + are intended for the supply with positive voltage to the heater 42 and the detection circuit 29 with the corresponding control electronic components implemented in the PCBA 50 (block 100), respectively. The terminal 40 labeled GND - is intended for ground or negative power supply connection, while the terminal 40 labeled VOUT is intended for the output signal of the device, representative of the pressure and / or temperature measurement, as in the case of the diagram in Figure 27. Blocks H and 100 are analogous to those already indicated in relation to Figure 27. The control devices or switches 101 and 102 and the protection circuit 104 of Figure 27 are not required here.

[0198] In this solution, when the device 1 is powered via the external system to which it is connected, such as an ECU control unit, the power supply to the heater H is always guaranteed via the line connected to the terminal 40 labeled V2 +.

[0199] The at least one component of block 100 (the integrated circuit IC, in the example) is powered by the external system only subsequently, i.e., after a predetermined time has elapsed since the start of power supply to the heater H, with this time being sufficient to ensure compliance with the operating temperatures of the electronics itself.

[0200] The value of said predetermined time can be predefined based on experimental tests, for example for sensors with analogous structure and materials, or predefined based on simulations and / or calculations, and may be a stored value, for example in the memory of an electronic control unit (ECU). The predetermined time could result from real-time processing and / or calculations, which may take into account both stored information and real-time detectable information, such as the external ambient temperature. Following power supply to the block 100, the external system can receive the pressure and / or temperature signal from the terminal 40 labeled VOUT.

[0201] The same scheme of Figure 34 can also be managed with a different logic, i.e., by powering and not powering the heater H. Also in this case, when the device 1 is powered via the external system, power supply to the heater H is guaranteed via the line connected to the terminal 40 labeled V2 +, while the block 100 is powered by the external system only subsequently, i.e., after a predetermined time has elapsed since the start of power supply to the heater H, with this predetermined time being considered sufficient to ensure compliance with the operating temperatures of the electronics itself.

[0202] Following power supply to the control electronics of device 1 (excluding block 100), the heater H is nevertheless powered, to ensure in all conditions that block 100 reaches a temperature above -40°C before it can be powered, and to provide information regarding the temperature of the PCBA (and thus of block 100 itself). With block 100 powered, the external system receives from the terminal 40 labeled VOUT both the pressure signal and the temperature signal, for example thanks to a temperature sensor integrated in the component of block 100.

[0203] The external system therefore manages the appropriate switching on / off of the heater H, so as to ensure a correct operating temperature for the control electronics implemented in the PCBA 50.

[0204] Figure 35 shows a third possible principle diagram of a sensor device according to the invention. In this example as well, the connector body 2 of the device 1 includes four terminals 40 analogous to those already indicated in relation to Figure 37, so as to have two power supply lines for the heater H and for the control electronics implemented in the PCBA 50.

[0205] Compared to the case of Figure 34, blocks 101 and 104 analogous to those described with reference to Figure 27 are additionally provided here. The device or switch 101 is therefore placed on the power supply line of block 100, connected to the terminal 40 labeled V2 +, where on the same line, upstream of the device or switch 101, the protection circuit 104 is also connected, configured to measure the temperature of the PCBA or its vicinity, and generate a signal to open or close the device or switch 101.

[0206] In this solution, when the device 1 is powered via the external system to which it is connected, power supply to the terminal 40 labeled V2 + is guaranteed, but not to the heater H, as the switch 101 is normally open.

[0207] The at least one component of block 100 is powered by the external system only subsequently, i.e., after a predetermined time counted from the power supply to the heater H, where this predetermined time is considered sufficient to ensure compliance with the operating temperatures of the control electronics.

[0208] In this case, the heater H is powered only when the temperature detected by the temperature measurement circuit 104 controls the closing of the switch 101. In this way, the heater H is powered when the ambient temperature is lower than a predetermined minimum temperature, below which compliance with the operating temperatures of block 100, and thus correct pressure detection, could not be guaranteed.

[0209] Figures 36-38 show an inlet body 2 implemented according to possible alternative embodiments, for example formed as a single piece of metallic material: given that the body 2 in question has parts or portions analogous or technically equivalent to those already described above (labeled with analogous reference numbers), the following will mainly highlight the differences compared to the embodiments of Figures 1-26. In the case shown, the body 2 has a flange portion 22 whose external surface preferably defines a plurality of flat faces, and from which an annular coupling wall 32 rises, whose upper end portion (particularly the portion where the line of reference 32 ends in Figure 36) preferably has a reduced thickness, to facilitate deformation thereof, as clarified below.

[0210] In the upper portion 2b of the inlet body, an annular cavity 33 is defined here, delimited externally by the wall 32, and internally by an axial or columnar portion 25 of the body 2. Also in this case, the upper portion 2b may have a narrowing 27, so as to define the top portion 23, which is part of a pressure-sensitive element. In correspondence with the corresponding membrane 23a, at least a part of a circuit 29 for detecting the deflection of said membrane is arranged, for example implemented similarly to those already described above.

[0211] Referring to Figures 39-40, the connector body 3 intended for coupling with the inlet body of Figures 36-38 is also preferably formed as a single piece of plastic material, overmolded onto a plurality of electrical terminals 40. In this case, the peripheral wall 3a' of the lower portion 3a of the body 3 is shaped, at its lower edge region, so as to define a seat, indicated with 60 in Figure 39, for positioning an annular sealing element (indicated with 61 in Figures 43 and 48), described below, intended to cooperate with the inlet body 2, in particular inside the corresponding annular cavity 33.

[0212] Also in this case, at the intermediate wall 35 of the connector body 3, a seat 36 is provided for a pressure compensation element 42, of the type already described, this seat being defined at a through hole, not visible in Figure 40 but indicated with 37 in Figures 49-50.

[0213] Referring again to Figure 40, from the intermediate wall 35 there protrudes, toward the inside of the cavity D of the upper portion 31, a formation 38 in which axial seats 38a are defined, for housing respective elastic contact elements 41, in particular in the form of spiral springs of the type already described (Figure 13).

[0214] Also in the embodiment considered here, the PCBA is intended to be mounted in the casing 2-3 of the device 1 in a position vertically spaced from the membrane 23a of the metal body 2, for the reasons already explained above. In general, and in various embodiments, the PCBA can be supported at said distance by respective support and / or positioning elements defined in the connector body 3 or fixed thereto, using relatively extended conductors to electrically connect the same PCBA to the circuit 29. However, in various preferential embodiments, the device 1 comprises an element for supporting and positioning the PCBA inside the corresponding housing chamber, in a position vertically spaced from the top portion 23 of the inlet body 2. In various embodiments, the support and positioning element is preferably fixed or otherwise constrained to the inlet body 2. In various embodiments, said PCBA is preferably fixed or otherwise constrained to said support and positioning element.

[0215] A possible implementation of such a support and positioning element is shown in Figure 41.

[0216] In this example, the support and positioning element - indicated as a whole with 70 - has an electrically conductive lower part 70a, preferably metallic, and an upper part 70b made of electrically insulating material, and preferably with low thermal conductivity, for example a moldable plastic.

[0217] The upper part 70b is overmolded onto the metal lower part 70a, which essentially has a plurality of protrusions or legs 71, each of which has at least a respective lower portion extending in a substantially axial or vertical direction. In the example, six legs 71 are provided, but the number may vary, preferably not less than three. The lower part 70a of the element 70 can be formed by a plurality of legs 71 distinct from each other but joined by the same upper part 70b overmolded at the upper end of such legs, or, preferably, the metal lower part 70a has the shape of a framework defining the various legs 71 as a single piece (see, for reference, the shape of the element 70' shown in Figure 51): in such a case, the upper part 70b of the support and positioning element 70 is overmolded onto the upper end of this framework. The legs 71 are preferably shaped and arranged so that their lower ends can be inserted into the annular cavity 33 of the inlet body 2, to rest on the bottom of the latter.

[0218] The electrically insulating upper part 70b defines a support surface 72 for a PCBA. From the surface 72 preferably there rise a series of peripheral positioning elements or protrusions 73, which create lateral constraints between which the PCBA itself can be positioned. Preferably, one of said positioning protrusions is an angular protrusion, i.e., with a substantially L-shaped profile in a plan view. More generally, the protrusions 73 are shaped and arranged to define a seat whose profile is substantially congruent or complementary to that of the PCBA. The upper part 70b of the element 70 may have a central through opening 74, to prevent - following the assembly of the device 1 and during its normal operation - the detection membrane 23a from interfering with the same upper part 70b, although this is not an essential feature.

[0219] Figure 42 shows in a purely schematic form a possible implementation of said PCBA 50 usable in combination with the support and positioning element 70, while maintaining the characteristics already described above, including the presence of a heater H. In the example, the peripheral profile of the respective PCB 51 is substantially polygonal, but naturally this profile may vary as needed, and thus also the shape and arrangement of the peripheral positioning protrusions 73 of the support and positioning element 70. The PCB 51 may be provided with one or more through holes or seats S, preferably but not necessarily in peripheral positions, in particular to receive corresponding positioning and / or fastening elements belonging to the support and positioning element 40, as also described below.

[0220] Figure 43, on the other hand, schematically represents the aforementioned annular sealing element 61, in particular in the form of a ring made of elastomeric material, for example an o-ring type gasket.

[0221] Figure 44 schematically represents a first assembly phase of the device 1, in which the support and positioning element 70 is mounted on the inlet body 2. As can be seen, the element 70 is arranged such that the lower ends of its legs 71 rest on the bottom of the annular cavity 33. Preferably, the legs 71 are at least partially elastically deformable so as to be able to press - if necessary - also against the peripheral surface of the top portion 23 of the same body 2 and / or the portion 25 of the body 2 that delimits the inner circumference of the same cavity 33. In various preferential embodiments, at least some of the legs 71, or a lower end portion thereof, are welded to the bottom of the annular cavity 33 and / or to the peripheral surface of the aforesaid portion 25 of the body 2. The length of the legs 71 is such that the upper part 70b of the support and positioning element 70 is located above the top portion 23 of the inlet body 2, possibly at a distance therefrom.

[0222] Figure 45 schematically represents a second assembly phase of the device 1, in which the previously obtained PCBA 50 is placed on the surface 72 (Figure 44) of the upper part 70b of the element 70, in particular between the peripheral positioning elements 73. The PCB 51 of the PCBA 50 can be fixed to the element 70, for example glued onto the aforesaid support surface 72. In addition or as an alternative to fixing in position by gluing, pins may rise from the cited support surface 72 onto which the holes S (Figure 42) of the PCB 51 are fitted, and the upper portion of such pins is subsequently flattened or deformed, particularly hot- deformed, to fix the PCB in position. After mounting onto the element 70, the PCBA 50 is in a position vertically spaced from the top portion of the inlet body 2.

[0223] Figure 46 schematically represents a third assembly phase of the device 1, in which the circuit for detection of the deflection of the membrane is electrically connected to respective conductive tracks present on the PCB 51 of the PCBA 50. The electrical connection can be made, for example, via thick wires wire bonding via wires W, as already described.

[0224] Figure 47 schematically shows the phase of gluing the compensation membrane 42 at the corresponding seat 37, and positioning the contact springs 41 in the corresponding seats 38a. As in previously described embodiments, the connector body 3 is overmolded onto the terminals 40 (see, for example, Figure 13), so that the portions 40b of the terminals have a respective surface area directly exposed at the bottom of the seats 38a for the contact springs 41.

[0225] The subsequent Figure 48 schematically shows the phase of coupling the aforementioned annular sealing element 61 at the corresponding seat (60, Figure 39) defined at the lower edge region of the annular wall 3a' of the part 3a of the connector body 3.

[0226] Figure 49 schematically shows the subsequent phase of coupling between the connector body 2, with the respective associated elements (element 70 and PCBA 50), and the connector body 3, with the respective associated elements (terminals 40, springs 41, compensation element 42, and sealing element 61). The two bodies 2 and 3 are coupled so that the lower edge of the connector body 3 (i.e., its wall 3a'), carrying the sealing element 61, is inserted into the annular cavity 33 of the inlet body 2. Following this positioning, the ends of the springs 41 are in contact with the portion 40b of the terminals 40, on one side, and with respective pads connected to respective conductive tracks of the PCBA 50, at the other side. The PCBA 50 is positioned inside the cavity C formed between the bodies 2 and 3.

[0227] Figure 49 schematically shows the subsequent phase of relative fixing between the two bodies 2 and 3, in which the upper part of the annular wall 32 of the inlet body 2 is mechanically crimped, or deformed, onto the connector body 3. Also in this case, preferably, the peripheral wall 3a' of the lower part 3a of the body 3 is appropriately shaped to define an external surface 3c of the type previously described, preferably inclined or truncated-conical (Figure 48), at which the annular wall 32 is crimped.

[0228] Figure 51 shows a support and positioning element 70', according to possible alternative embodiments. In this solution, the element 70' is entirely made of electrically conductive material, particularly a metal material, so as to define in a single piece both the lower part 70a and the upper part 70b. The body of element 70' can be conveniently formed through punching and bending operations starting from a metal strip or sheet. In this solution as well, the lower part 70a features a plurality of legs 71, and the upper part 70b defines a support surface 72 for the PCBA 50. The lower end portions of the legs may optionally include a bend to define a support foot. The upper part 40b may feature a central through opening 74 also in this case.

[0229] The body of element 70" defines, in a peripheral position with respect to the surface 72, a plurality of upright tabs 73', which delimit therebetween a positioning seat for a PCBA 50 of the type already described above.

[0230] Figures 52-54 schematically show the support and positioning element 70' mounted on the inlet body 2, of construction similar to that previously described in relation to Figures 36-38. Here too, the element 70' is arranged so that the lower ends of its legs 71, or their respective feet if provided, rest on the bottom of the annular cavity 33, with the legs themselves being at least partially elastically deformable to press against - if necessary - the peripheral surface of the top portion 23 of the same body 2 and / or its portion 25. Here as well, at least some of the legs 71, or a lower end portion thereof, are welded to the bottom of the annular cavity 33 and / or to the peripheral surface of the aforesaid portion 25. The length of the legs 71 is such that the upper portion 70b of the support and positioning element 70' is located above the top portion 23 of the inlet body 2, possibly at a distance therefrom.

[0231] Figure 55 schematically shows the assembly phase in which the previously prepared PCBA 50 is placed on the upper portion 70b of the element 70', in particular within the seat defined between the peripheral tabs 73’. The PCB 51 of the PCBA 50 can be glued to the support surface 72 (Figure 51) of the upper portion 70b of the element 70’. In any case, in addition to or as an alternative to the fixing via gluing, the tabs 73' can be crimped, i.e., bent, onto the upper face of the PCBA 50, or its PCB 51. Here too, after mounting on element 40', the PCBA 50 is positioned at a vertically position spaced from the top portion of the inlet body 2. This is followed by the electrical connection phase of the circuit for detection of the membrane deflection to respective conductive tracks present on the PCB 51 of the PCBA 50, as shown in Figure 56. Here as well, the electrical connection is preferably made via wire bonding using thick wires, with suitable connection wires w.

[0232] The sensor device 1 is then completed with operations similar to those previously described with reference to Figures 47-50.

[0233] Figure 57 shows a support and positioning element 70", according to further possible alternative embodiments. In this solution, the element 70" is entirely made of electrically insulating material, in particular a plastic material, and is intended to rest directly on the top portion 23 of a corresponding inlet body 2 of the type already described, for example with reference to Figures 36-38. The element 70" therefore does not have legs intended to rest on the bottom of the annular cavity of body 2.

[0234] The body of the element 70", for example having an at least partially circular external profile, can be conveniently formed by molding plastic material. This body is formed so as to define a support surface 72 for the PCBA, from which there rise a plurality of protruding parts 73", whose surfaces facing toward the central part of the body itself define an internal housing seat 75 for the PCBA. In various preferential embodiments, positioning pins 76 rise from the support surface 72 of the element 70", for example in diametrically opposite positions, intended to couple with corresponding holes in the PCBA's PCB. The element 70" also preferably features a central through opening 74.

[0235] In various preferential embodiments, the body of the element 70" comprises a plurality of peripheral axial seats, for example in the form of blind or through holes, for positioning respective elastic elements, for example formed of resilient synthetic material, used to elastically constrain the element 70" in position, as described below. In the example shown in Figure 57, these axial seats are indicated with 77.

[0236] Figure 58 is instead exemplified one of said elastic constraint elements, indicated as a whole with 80. The constraint element 80 has a body formed, for example, of elastomeric material, defining an enlarged head 81 and a narrowed stem 82, i.e., having cross-sectional dimensions smaller than the head 8. In the example, both the head 81 and the stem 82 have a substantially circular cross-section. The diameter of the stem 82 is such that it can be received within a respective axial seat 77 of the support and positioning element 70" of Figure 57, also taking advantage of the elasticity thereof.

[0237] Figures 59-61 show an inlet body 2 of the type already described, on whose top portion the element 70" is resting.

[0238] Figure 62 shows a subsequent assembly phase, in which the previously prepared PCBA 50 is placed within the seat 75 defined between the protruding parts 73". In this phase, the holes S of PCB 51 (see also Figure 42) are fitted onto the pins 76, so that the PCBA 50 rests on surface 72 (Figures 57 and 61) of element 70". The PCB 51 can be glued to surface 72. In any case, in addition to or as an alternative to gluing, the upper portion of pins 76 is subsequently flattened or deformed, particularly by heat, to fix the PCB in position. Here too, after mounting on element 70", the PCBA 50 is positioned at a height spaced from the top portion 23 of the inlet body 2.

[0239] This is followed by the electrical connection phase of the detection circuit of the membrane deflection to respective conductive tracks on the PCB 51 of the PCBA 50. Here as well, as visible in Figure 63, the electrical connection is preferably made via wire bonding using thick wires, such as the connection wires W.

[0240] Figure 64 shows a subsequent phase, in which the stem 81 of a corresponding elastic constraint element 80 of Figure 58 is inserted into each axial seat 77 of the element 70" (Figure 57). The seats 77 and the stems 72 may have lengths such that only the heads 81 of the elements 80 are exposed relative to the protruding parts 73", but this is not an essential feature.

[0241] The device 1 is then completed with operations similar to those previously described with reference to Figures 47-50. In this case, the height of the elastic elements 80 is such that the upper surface of their respective heads 81 is elastically pressed against the lower surface of the intermediate wall 35 of the connector body 3, as shown in Figure 65. In this way, as can be understood, the support and positioning element 70" is elastically maintained in position on the top portion 23 of the inlet body 2, between the elements 80 and the upper surface of the same top portion.

[0242] The control methods and possible circuit arrangements usable in combination with the embodiments of Figures 36-65 may be similar or at least partly analogous to those described in relation to the embodiments of Figures 1-35.

[0243] In the embodiments previously described with reference to Figures 36-65, the inlet body 2 is configured as a single piece, but this is not an essential feature. In various embodiments, in fact, the body 2 of Figures 36-65 can also be configured to include at least two parts made solidary with each other, for example formed of the same metal material and welded together. An example of this type is schematically shown in Figure 66, where the body 2 is formed by the sealed joining of a lower piece 2i and an upper piece 22.

[0244] In the example, the lower piece 22 integrally defines the elements previously identified with 20, 21, 22, 25, and 32, while the piece 22 integrally defines the element previously indicated with 23, i.e., the top portion of the body 2 defining the membrane 23a to which the circuit 29 for detecting the deformation of the same membrane is associated. In embodiments of this type, the axial passage for the fluid whose pressure is to be detected will substantially comprise a through hole 28a of the piece 2i and a blind hole 28b of the piece 22. Moreover, in the case of a flat and relatively thin piece 22 directly defining the membrane 23a, such piece does not necessarily require said blind hole. Referring to the example, the two pieces 2i and 22, particularly made of metal material, are welded together so that the holes 28a and 28b are axially aligned and substantially coaxial.

[0245] In solutions of this type, the upper piece 22 effectively forms a sensing element of the device, which can be obtained separately from the lower piece 22. Such solutions are advantageous because the circuit 29 can be formed on a piece, i.e., the piece 22, of reduced dimensions, thus more easily handled during the production of the aforesaid circuit. In this way, the circuit itself can also be defined with greater accuracy.

[0246] Naturally, the shape of the piece 22 may differ from the exemplified one, while maintaining its functionalities. The same applies to the general configuration of the inlet body 2 and the connector body 3, compared to the cases previously described and illustrated, while maintaining their functionalities.

[0247] In the preceding description, a pressure sensor device has been exemplified, but as already indicated, the issues underlying the invention may be encountered in other sensor devices, such as sensors designed to operate under conditions similar to those previously described and / or sensors whose onboard electronics may malfunction at low temperatures, particularly temperatures below -40°C, for example strain or deformation sensors and temperature sensors.

[0248] For instance, the preceding description is suitable for illustrating the invention also in relation to a temperature sensor device, given that - as previously explained - the exemplified device 1 includes at least one temperature sensor. This description is also suitable for illustrating the invention in relation to a strain or deformation sensor device, given that such devices employ - as elements for sensing strain or deformation - strain gauges or resistors or piezoresi stive elements connected in a bridge or half-bridge configuration, which, as previously explained, can also be used in a device 1 as exemplified.

[0249] Furthermore, the invention relates to any sensor device that includes the use of at least some electronic components not designed to operate under certain low- temperature conditions to which the sensor may be subjected, for example electronic components designed to operate only at temperatures equal to or above - 40°C.

[0250] The description makes clear the characteristics of the present invention, as well as its advantages. It is clear that numerous variations are possible for a person skilled in the art to the device described as an example, without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1. A sensor device (1) for measuring a quantity (P), having a casing body (2, 3) which defines a housing space (C) in which an electronic circuit (29, 50) is arranged, wherein the electronic circuit (29; 50) comprises:- first circuitry (29; Tp), configured for detection of the quantity (P) and consequently provide a first signal representative of a value of the quantity (P), and- second circuitry (50), configured to receive from the first circuitry (29; Tp) the first signal and to generate an output signal of the sensor device (1), the second circuitry (50) being connected in signal communication with the first circuitry (29) and being arranged at least in part on a circuit support (51) arranged in the housing space (C), wherein the second circuitry (50) comprises at least one first circuit component (IC), capable of operating at temperatures not lower than a first determined temperature, wherein the electronic circuit (29; 50) comprises second circuit components, which include temperature sensor means (TH, TS; TZ) configured to detect at least one of a temperature of the circuit support (51) and a temperature existing in the housing space (C), and to provide to the second circuitry (50) at least one corresponding second signal representative of the at least one of the temperature of the circuit support (51) and the temperature existing in the housing space (C), wherein the second circuit components of the second circuitry (50) comprise a protection circuit (104) configured to enable electrical supply to the at least one first circuit component (IC) if the at least one second signal provided by the temperature sensor means (TH, TS; TZ) is representative of a temperature higher than the first determined temperature.

2. The sensor device (1) as claimed in claim 1, wherein:- the at least one first circuit component (IC) is a component guaranteed to operate only up to a minimum temperature corresponding to the first determined temperature and / or susceptible to damage if electrically supplied at temperatures below the first predetermined temperature; and / or- the second circuit components comprise components capable of operatingat temperatures below the first determined temperature, but not below a second determined temperature that is lower than the first determined temperature; and / or- the protection circuit (104) is configured to prevent or interrupt electrical supply to the at least one first circuit component (IC) if the at least one second signal provided by the temperature sensor means (TH, TS; TZ) is representative of a temperature not higher than the first predetermined temperature or representative of a temperature not higher than a safety temperature that is higher than the first determined temperature.

3. The sensor device (1) as claimed in claim 1, wherein the electronic circuit (29, 50) comprises an electric heater (H) controllable by the second circuitry (50) to heat the circuit support (51).

4. The sensor device (1) as claimed in claim 3, wherein the protection circuit (104) is configured to prevent or enable electrical supply to the electric heater (H) depending on whether the at least one second signal provided by the temperature sensor means (TH, TS; TZ) is representative of a temperature higher or lower, respectively, than a predetermined activation threshold.

5. The sensor device (1) as claimed in claim 1, wherein the protection circuit (104) comprises a first enabling circuit (TS, RS, Pl, P2, CS; TS, RS, Pl, P2, CS, RI; TS, RS, P3, P4, CS, RI; TZ, IC1) configured to prevent or enable electrical supply to the at least one first circuit component (IC) as a function of the at least one second signal.

6. The sensor device (1) as claimed in claim 4, wherein the protection circuit (104) comprises a second enabling circuit (TH, RH, Pl, P2, CH; TH, RH, Pl, P2, CH, RI; TZ, IC1) configured to prevent or enable electrical supply to the electric heater (H) as a function of the at least one second signal.

7. The sensor device (1) as claimed in claim 5, wherein the first enabling circuit comprises first temperature sensing means (TS-RS; TZ) and first comparator means (CS; IC1) configured to compare a voltage provided by the first temperature sensing means (TS-RS; TZ) with a respective reference voltage.

8. The sensor device (1) as claimed in claim 6, wherein the second enabling circuit comprises second temperature sensing means (TH-RH; TS) and second comparator means (CH; IC1) configured to compare a voltage provided by the second temperature sensing means (TH-RH; TZ) with a respective reference voltage.

9. The sensor device (1) as claimed in claim 5 or claim 6, wherein the first enabling circuit, respectively the second enabling circuit, comprises control circuit means (CS; CH; 102; IC1; 101) switchable as a function of a value, such as a voltage, provided by the temperature sensor means (TH, TS; TZ).

10. The sensor device (1) as claimed in claim 3 or claim 4, wherein the circuit support (51) is mounted in the casing body (2, 3) in a position spaced apart from the first circuitry (29; Tp), preferably to prevent the first signal from being perturbed by heating induced by the electric heater (H).

11. The sensor device (1) as claimed in any one of claims 1-10, wherein the first circuitry (29; Tp) is connected to the second circuitry (50) via wires, preferably of a wire bonding type.

12. The sensor device (1) as claimed in any one of claims 1-11, the sensor device (1) being a pressure sensor device and the quantity (P) being the pressure of a fluid, wherein:- the casing body (2, 3) comprises a first body (2) having an inlet portion (2a) and a detection portion (2b), in the first body (2) there being defined an inlet passage (28) for the fluid that is open at one end of the inlet portion (2a) and has a bottom at the detection portion (2b), in a position generally opposite the first end of the inlet portion (2a), the detection portion (2b) defining a membrane (23a) at the bottom of the inlet passage (28), such that a pressure of the fluid in the inlet passage (28) is susceptible to causing a deflection of the membrane (23a),- the first circuitry (29; Tp) is configured to detect the deflection of the membrane (23a) and the first signal is a signal representative of a pressure value determined by the deflection of the membrane (23a),- the first circuitry (29; Tp) is arranged on the first body (2) at the membrane (23 a),wherein preferably the circuit support (51) is mounted in the casing body (2, 3) in a position spaced apart from the membrane (23a) and / or the first circuitry (29; Tp).

13. The sensor device (1) as claimed in any one of claims 1-12, wherein the first body (2) is a body made of metal material comprising at least a first body part (2') and a second body part (2") fixed to each other.

14. The sensor device (1) as claimed in claim 13, wherein:- the first body part (2') comprises the membrane (23a) and a first portion (28b) of the inlet passage (28), and the second body part (2") comprises a second portion (28a) of the inlet passage (28), or- the first body part (2') comprises the inlet portion (2a) and the detection portion (2b), and the second body part (2") comprises at least one of: a coupling seat (33) for a peripheral wall (3b1) of the second body (3), a peripheral wall (32) mechanically deformed onto a corresponding portion (3c) of the second body (3), an hollow axial central portion (30) defining a surface for supporting the circuit support (51) in a position vertically spaced apart from the membrane (23a).

15. The sensor device (1) as claimed in any one of claims 13-14, comprising a support and positioning element (70; 70’; 70”) mounted on the first body (2) and configured to support the circuit support (51) in a position spaced apart from the membrane (23a).

16. The sensor device (1) as claimed in any one of claims 1-15, wherein the circuit support (51) has a central passage through which electrical connecting elements (W) extend for connection of the first circuitry (29; Tp) to the second circuitry (50).

17. The sensor device (1) as claimed in any one of claims 1-15, wherein the first circuitry (29; Tp) comprises two pairs of resistive or piezoresistive elements (Rp) connected in a half-bridge configuration, the first circuitry (29; Tp) beingpreferably of a microfused strain gauge type.

18. A pressure sensor device (1), for measuring the pressure of a fluid (P), having:- a casing body (2, 3) comprising a first body (2) having an inlet portion (2a) and a detection portion (2b), in the first body (2) there being defined an inlet passage (28) for the fluid (P) that is open at a first end of the inlet portion (2a) and has a bottom at the detection portion (2b), in a position generally opposite the first end of the inlet portion (2a), the detection portion (2b) defining a membrane (23a) at the bottom of the inlet passage (28), such that a pressure of the fluid (P) in the inlet passage (28) is susceptible to causing a deflection of the membrane (23a),- an electronic circuit (29; 50) comprising first circuitry (29), configured to detect the deflection of the membrane (23 a) and consequently provide a first signal representative of a pressure value determined by the deflection of the membrane (23 a), and second circuitry (50), configured to receive from the first circuitry (29) the first signal and to generate an output signal of the sensor device (1), the first circuitry (29) being arranged on the first body (2) at the membrane (23a) and the second circuitry (50) being connected in signal communication with the first circuitry (29) and arranged at least in part on a circuit support (51), the circuit support (51) being preferably mounted in the casing body (2, 3) in a position spaced apart from the membrane (23 a), wherein the second circuitry (50) includes temperature sensor means (TH, TS; TZ), an electric heater (H), and at least one circuit component (IC) that is suitable to operate at temperatures not lower than a first determined temperature, and wherein the electric heater (H) is set on the circuit support (51) and is controllable by the second circuitry to heat the circuit support (51) and the at least one circuit component (IC) when a temperature detected by the temperature sensor means (TH, TS; TZ) is lower than a determined temperature threshold that is not lower than the first determined temperature.

19. A pressure sensor device (1), for measuring the pressure of a fluid (P), comprising:- a casing body (2, 3) having a housing space (C) and an inlet passage (28) for the fluid (P) that is closed at one end by a membrane (23a),- an electronic circuit (29; 50) arranged in the housing space (C) configured to detect deflection of the membrane (23a) and subsequently provide a signal representative of a pressure value determined by the deflection of the membrane (23 a), the pressure sensor device (1) having at least one of- an electric heater (H) on a circuit support (51) which carries at least a respective part of the electronic circuit (29, 50),- a protection circuit (104) configured to control electric supply to at least one of an electric heater (H) and a circuit component (IC) of the electronic circuit (29, 50),- temperature sensor means (TH, TS; TZ; Tp) on a circuit support (51),- at least a first body (2) and a second body (3) coupled together to form at least part of the casing body (2, 3).

20. A method for measuring a quantity (P) by means of a sensor device (1) in which an electronic circuit (29, 50) is arranged, comprising:- first circuitry (29; Tp), configured for detecting the quantity (P) and consequently providing a first signal representative of a value of the quantity (P), and- second circuitry (50), configured to receive from the first circuitry (29; Tp) the first signal and to generate an output signal of the sensor device (1), the second circuitry (50) including at least one circuit component (IC) capable of operating at temperatures not lower than a first determined temperature, the second circuitry (50) being arranged at least in part on a circuit support (51) positioned in a corresponding housing space (C) of the sensor device (1), the method comprising the steps of i) detecting at least one of a temperature of the circuit support (51) and a temperature existing in the housing space (C), ii) providing to the second circuitry (50) a second signal representative of the at least one of the temperature of the circuit support (51) and the temperature existing in the housing space (C), iii) preventing or enabling electrical supply to the at least one circuit component (IC) depending on whether the at least one second signal provided by temperature sensor means (TH, TS; TZ) is representative of a temperature lower or higher, respectively, than the first determined temperature or a protectiontemperature that is not lower than the first determined temperature.

21. A detection arrangement comprising a sensor device (1) for measuring a quantity (P), and an external system for controlling electrical supply to the sensor device (1), wherein the sensor device has a casing body (2, 3) in which a housing space (C) is defined, wherein an electronic circuit (29, 50) is arranged, wherein the electronic circuit (29; 50) comprises:- first circuitry (29; Tp), configured for detecting the quantity (P) and consequently providing a first signal representative of a value of the quantity (P), and- second circuitry (50), configured to receive from the first circuitry (29; Tp) the first signal and to generate a corresponding output signal of the sensor device (1), the second circuitry (50) being connected in signal communication with the first circuitry (29; Tp) and being arranged at least in part on a circuit support (51) arranged in the housing space (C),- an electric heater (H), wherein the second circuitry (50) comprises at least one first circuit component (IC) capable of operating at temperatures not lower than a first determined temperature threshold, wherein the external system is configured to provide electrical supply to the electric heater (H) via a first supply line (V2 +, GND -), and wherein the external system is further configured to enable electrical supply to the at least one first circuit component (IC) via a second supply line (VS +, GND -), after a determined time has elapsed since enabling the electrical supply to the electric heater (H).

22. A sensor device (1) for measuring a quantity (P), having a casing body (2, 3) defining a housing space (C) in which an electronic circuit (29, 50) is arranged, wherein the electronic circuit (29; 50) comprises:- first circuitry (29; Tp), configured for detecting the quantity (P) and consequently providing a first signal representative of a value of the quantity (P), and- second circuitry (50), configured to at least receive from the first circuitry (29; Tp) the first signal and to generate an output signal of the sensor device (1), the second circuitry (50) being connected in signal communication with the first circuitry (29) and being arranged at least in part on a circuit support (51) arranged in the housing space (C), the device further comprising at least one of- a first circuit component (IC), capable of operating at temperatures not lower than a first determined temperature;- second circuit components capable of operating at temperatures lower than a first determined temperature;- second components which include temperature sensor means (TH, TS; TZ);- second components configured to detect and provide to the second circuitry (50) at least one of a temperature of the circuit support (51) and a temperature existing in the housing space (C);- second circuit components comprising a protection circuit (104) configured to enable or disable electrical supply to at least one of a first circuit component (IC) and a heater (H);- a support and positioning element (30, 70, 70’, 70”) for an electronic circuit or PCBA (50);- a heater (H), preferably associated with a support (51) for an electronic circuit or PCBA (50);- an enabling circuit (TS, RS, Pl, P2, CS; TS, RS, Pl, P2, CS, RI; TS, RS, P3, P4, CS, RI; TZ, IC1) configured to prevent or enable electrical supply to at least one first circuit component (IC) based on information representative of a temperature;- an enabling circuit (TH, RH, Pl, P2, CH; TH, RH, Pl, P2, CH, RI; TZ, IC1) configured to prevent or enable electrical supply to an electric heater (H) based on information representative of a temperature.

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