Assembly including a power module, a temperature sensor and a printed circuit board

Abstract

The present invention relates to an assembly (100, 200) comprising a power module (10), a temperature sensor (20, 50), and a printed circuit board (40). The power module (10) comprises a housing (11) incorporating at least one electronic chip (14). The housing (11) comprises a lower face (12) facing the printed circuit board (40) and an upper face (13). The printed circuit board (40) comprises an upper face (41) on which the power module (10) is arranged and a lower face (42). The temperature sensor (20, 50) is arranged adjacent to the power module (10) between the lower face (12) of the power module (10) and the lower face (42) of the printed circuit board (40). The invention also relates to an on-board charger device or an inverter for a motor vehicle comprising such an assembly. Figure for the abbreviation: Figure 1

Description

Title of the invention: Assembly comprising a power module, a temperature sensor and a printed circuit board

[0001] The present invention relates to the field of electronic systems comprising at least one power module connected to a printed circuit board.

[0002] More specifically, the invention is of particular interest in the field of on-board chargers and inverters for electric vehicles.

[0003] On-board chargers and inverters include various electronic components, including power modules. These power modules are generally made in the form of a package, particularly in epoxy, which integrates several components, including switching components made of semiconductor materials (Si, SiC, GAN) which are more generally referred to as electronic chips.

[0004] Electric vehicles require ever-increasing charging power to reduce charging times. This increase in charging power is accompanied by a growing production of heat during the operation of on-board chargers, and these power modules are among the electronic components that generate the most heat.

[0005] In order to construct the control laws of the on-board chargers, the temperature of the electronic chips is a crucial piece of data to know instantly.

[0006] Thanks to this temperature data, the on-board charger can activate a regulation strategy to protect the electronic chip before it reaches a critical temperature that could damage it.

[0007] There are power modules that integrate a temperature sensor directly inside the housing, in particular a negative temperature coefficient thermistor. This temperature sensor is generally located far from the electronic chip, which means that the measurement is not sufficiently accurate.

[0008] Furthermore, some power modules do not incorporate such temperature sensors. These power modules have the advantage of being relatively inexpensive compared to power modules incorporating a temperature sensor, but they do not allow for temperature measurement near the electronic chips.

[0009] It is therefore necessary to propose an effective means of measuring the temperature of the electronic chips of power modules not integrating a temperature sensor inside the housing.

[0010] Thus, the invention proposes an assembly comprising a power module, a temperature sensor and a printed circuit board, the power module The device comprises a housing incorporating at least one electronic chip; the housing includes a lower face facing the printed circuit board and an upper face; the printed circuit board includes an upper face on which the power module is arranged and a lower face. According to the invention, the temperature sensor is arranged opposite the power module, between the lower face of the power module and the lower face of the printed circuit board.

[0011] This arrangement allows for direct measurement of the electronic chip temperature without impacting the volume of the power module. It also makes this arrangement compatible with the trend towards size reduction in the field of vehicle on-board chargers.

[0012] The term "at the right of" means that the temperature sensor is located under the power module in a space defined by a projection of the contour of the housing onto the printed circuit board.

[0013] According to the invention, at least two electrical connection pins extend from the power module housing. These electrical connection pins are in contact with conductive tracks arranged on the printed circuit board. These electrical connection pins are also electrically connected to the electronic chip(s) located in the power module housing. The housing is preferably made of epoxy.

[0014] According to a first embodiment of the invention, the temperature sensor comprises a housing having a lower face facing the printed circuit board and an upper face facing the power module. At least two electrical connection pins extend from the temperature sensor housing. These electrical connection pins are in contact with conductive tracks arranged on the printed circuit board. These electrical connection pins are also electrically connected to at least one temperature-sensitive element located in the temperature sensor housing.

[0015] According to one feature of the invention, a cavity is formed on the underside of the power module. Advantageously, the temperature sensor is partially housed within this cavity. Thanks to this arrangement, the underside of the power module and the underside of the temperature sensor are substantially in the same plane, making the assembly more compact.

[0016] According to the invention, the cavity is obtained by removing material from the underside of the power module, for example by machining or laser ablation. Alternatively, the cavity can be obtained directly during the molding of the power module housing. The cavity is open towards the printed circuit board. Advantageously, the cavity has a substantially complementary to the external shape of the temperature sensor housing. The bottom of the cavity defines the lower face of the power module.

[0017] According to an additional feature of the invention, a thermal interface material is disposed between the power module and the temperature sensor to ensure thermal contact between the power module and the temperature sensor. This material is disposed in a space left free between the power module and the temperature sensor.

[0018] According to a second embodiment of the invention, the temperature sensor is integrated into the printed circuit board between the upper surface on which the power module is located and the lower surface. Compared to the first embodiment, this second embodiment has the advantage of not requiring a cavity to be cut into the power module housing. Therefore, there is no dimensional impact on the power module for the integration of a temperature measurement.

[0019] According to the invention, the electronic board is multilayered and incorporates a plurality of intermediate conductive tracks arranged between the upper and lower surfaces of the electronic board. Advantageously, the temperature sensor is in electrical contact with one of the conductive tracks of the electronic board, in particular one of the intermediate conductive tracks. In this case, a thermal connection with the upper surface of the electronic board must be provided, for example, via metallized blind contacts.

[0020] According to the invention, a thermal interface material is disposed between the power module and the top surface of the electronic board, ensuring thermal contact between the power module and the top surface of the electronic board. Temperature measurement is thus accurate because the thermal behavior of the thermal interface material and the power module housing material is well known. This material is located in a gap between the power module and the top surface of the electronic board.

[0021] According to the invention, the assembly further comprises a heat sinking element, and the upper surface of the power module is in contact with the heat sinking element. The upper surface of the power module thus provides cooling for the assembly. This architecture is known as "top-side cooling." The upper surface of the power module is in contact with the heat sinking element either directly or indirectly via a thermal interface material.

[0022] The invention also relates to an on-board charger device or inverter for a motor vehicle, in particular electric or hybrid, comprising an assembly according to at least one of the aforementioned characteristics.

[0023] Other features and advantages of the invention will become apparent from the following reading of two detailed embodiments, with reference to the attached figures:

[0024] [Fig.1] represents a view of an assembly according to the invention and according to a first embodiment;

[0025] [Fig.2] represents a view of an assembly according to the invention and according to a second embodiment.

[0026] It should be noted that the figures disclose the invention in sufficient detail for its implementation, and that the figures help to further define the invention if necessary. However, the invention should not be limited to the embodiments disclosed in the description.

[0027] Figure 1 shows an assembly 100 according to a first embodiment. This assembly 100 comprises a power module 10, a temperature sensor 20 and a printed circuit board 40.

[0028] The power module 10 allows a plurality of electronic chips 14 to be compiled in a small space. More specifically, the power module 10 comprises a housing 11 within which electronic chips 14 are arranged side by side.

[0029] The power module 10 has a rectangular shape, defined by the rectangular shape of the housing 11. In other words, the power module comprises two opposing edges, each with a greater elongation dimension than the other two edges. Of course, the housing of the power module can have other geometric shapes, for example, a square shape.

[0030] The housing 11 comprises a lower face 12 facing the printed circuit board 40 and an upper face 13 opposite the lower face 12. The upper face 13 is preferably in contact with a heat-dissipating element (not shown) in order to cool the assembly 100.

[0031] The printed circuit board 40 comprises an upper face 41 on which the power module 10 is arranged and a lower face 42 opposite the upper face 4L

[0032] The electronic chips 14 are connected to electrical connection pins 15, 16 which extend outside the power module 10, in particular to allow the electrical connection of the electronic chips 14, housed inside the housing 11, to an electrical network via the printed circuit board 40. The electrical connection pins 15, 16 are in contact with conductive tracks arranged on the printed circuit board 40. The electrical connection pins 15, 16 protrude from the housing 11 on one or both edges having the largest elongation dimension.

[0033] The temperature sensor 20 is arranged to the right of the power module 10 between the lower face 12 of the power module 10 and the lower face 42 of the printed circuit board 40.

[0034] The temperature sensor 20 includes a housing 21 having a lower face 22 facing the printed circuit board 40 and an upper face 23 facing the power module 10. Electrical connection pins 24, 25 are extended from the housing 21 of the temperature sensor 20. These electrical connection pins 24, 25 are in contact with conductive tracks arranged on the upper face 41 of the printed circuit board 40.

[0035] A cavity 17 is provided at the lower face 12 of the power module 10. The temperature sensor 20 is partially provided in this cavity 17.

[0036] The cavity 17 is obtained by removing material from the lower face 12 of the power module 10, in particular by laser ablation.

[0037] A thermal interface material 30 is disposed between the power module 10 and the temperature sensor 20.

[0038] Figure 2 shows an assembly 200 according to a second embodiment. Unlike the first embodiment, this assembly 200 includes a temperature sensor 50 which is integrated into the printed circuit board 40 between the upper face 41 on which the power module 10 is arranged and the lower face 42.

[0039] To this end, the electronic board 40 is multilayered, incorporating a plurality of intermediate conductive tracks 43 arranged between the upper face 41 and the lower face 42 of the electronic board 40. The temperature sensor 50 is preferably in contact with one of the intermediate conductive tracks. A thermal connection with the upper face of the electronic board 40, for example via metallized blinds, may be provided.

[0040] A thermal interface material 30 is disposed between the power module 10 and the upper face 41 of the electronic board 40.

[0041] Although the invention has been described in connection with two particular embodiments, it is quite evident that it is by no means limited to them and that it includes all the technical equivalents of the means described.

[0042] In the claims, the reference symbols in parentheses should not be interpreted as a limitation of the claim.

Claims

Demands

1. Assembly (100, 200) comprising a power module (10), a temperature sensor (20, 50) and a printed circuit board (40), the power module (10) comprising a housing (11) integrating at least one electronic chip (14), the housing (11) comprising a lower face (12) facing the printed circuit board (40) and a upper face (13), the printed circuit board (40) comprising an upper face (41) on which the power module (10) is arranged and a lower face (42), characterized in that the temperature sensor (20, 50) is arranged opposite the power module (10) between the lower face (12) of the power module (10) and the lower face (42) of the printed circuit board (40).

2. Assembly (100, 200) according to claim 1, characterized in that at least two electrical connection pins (15, 16) are from the housing (11) of the power module (10), these electrical connection pins (15, 16) being in contact with conductive tracks arranged on the printed circuit board (40).

3. Assembly (100) according to claim 1 or 2, characterized in that the temperature sensor (20) comprises a housing (21) having a lower face (22) facing towards the printed circuit board (40) and an upper face (23) facing towards the power module (10), at least two electrical connection pins (24, 25) are from the housing (21) of the temperature sensor (20), these electrical connection pins (24, 25) being in contact with conductive tracks arranged on the printed circuit board (40).

4. Assembly (100) according to any one of the preceding claims, characterized in that a cavity (17) is provided at the lower face (12) of the power module (10), said temperature sensor (20) is provided partly in this cavity (17).

5. Assembly (100) according to claim 4, characterized in that the cavity (17) is obtained by removing material from the lower face (12) of the power module (10).

6. Assembly (100) according to claim 4 or 5, characterized in that a thermal interface material (30) is disposed between the power module (10) and the temperature sensor (20).

7. Assembly (200) according to claim 1 or 2, characterized in that the temperature sensor (50) is integrated into the printed circuit board (40) between the upper face (41) on which the power module (10) is placed and the lower face (42).

8. Assembly (200) according to claim 7, characterized in that the electronic card (40) is multilayer integrating a plurality of intermediate conductive tracks (43) arranged between the upper face (41) and the lower face (42) of the electronic card (40).

9. Assembly (100, 200) according to claim 7 or 8, characterized in that a thermal interface material (30) is disposed between the power module (10) and the upper face (41) of the electronic board (40).

10. Assembly (100, 200) according to any one of the preceding claims, characterized in that it further comprises a heat-dissipating element, the upper face (13) of the power module (10) being in contact with the heat-dissipating element.

11. On-board charger device or inverter for motor vehicle comprising an assembly (100, 200) according to at least one of the preceding claims.

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