Patent Application
20250133658
This application claims priority to DE application Serial No. 102023128796.6 filed Oct. 19, 2023, the disclosure of which is hereby incorporated in its entirety by reference herein.
The present disclosure relates to a circuit board system.
Modular circuit board systems with electrically interconnected circuit boards are becoming more and more popular as the modularity of such arrangements allows swiftly adapting existing technologies. An exemplary circuit board system is described in US 2014/0063748 A1.
In many conventional circuit board systems, the connections between individual circuit boards are implemented as plug-in connections. However, plug-in technology is expensive as such a technology requires plugs and sockets. Aside from that, plug and socket technology occupies a lot of space on the circuit boards. If, on the other hand, soldered connections are used instead of plug-in technology, the operating temperature of the system is limited in range and/or cycles. At increased temperatures and temperature cycles, the failure probability is significantly higher than for systems that use plug-in technology. At the same time, there is a need to maintain or reduce the dimensions of circuit board systems.
Hence there is a need for an improved circuit board system.
In the following, each of the described systems, devices, apparatuses, examples, and
The present disclosure relates to a circuit board system with two or more electrically connected circuit boards, wherein one or more cavities are formed in one or more of the circuit boards. The cavities are arranged to accommodate electronic components arranged on one of the circuit boards. The cavities enable arranging electronic components on opposite surfaces of the circuit boards and to decouple the cooling of components on the opposite surfaces. The circuit boards may be electrically connected to one another by a land grid array (LGA) or a ball grid array (BGA).
According to a first aspect of the present disclosure, there is provided a circuit board system including: a main board having a top side and a bottom side, wherein the main board has at least one cavity on its top side; a printed circuit board, PCB having a top side and a bottom side; and at least one first electronic component arranged on the top side of the PCB, and at least one second electronic component arranged on the bottom side of the PCB, wherein the PCB is arranged on the top side of main board, and wherein the at least one second electronic component on the bottom side of the PCB extends into the cavity on the top side of the main board.
This arrangement enables implementing an LGA-module, for example, as a dual-side assembly. Such LGA-module may have a System on Chip (SoC) and one or more Power Management ICs (PMICs) on one side of the PCB, and memory modules (memory ICs) arranged next to the SoC on the opposite side of the PCB. Passive electronic components may be placed underneath the SoC on the same side of the PCB as the memory modules. These components (memory modules, passive components) may be received in openings in a main board that is electrically coupled to the PCB through an LGA. The dimensions and positions of the openings are variable and may be made dependent on the component size.
In contrast to conventional LGA-modules implemented as single-side assemblies with a common heat-sink for the SoC, PMICs, memory and power controller, the dual side assembly according to embodiments of the present disclosure enables, among other things, decoupling a heat sink for the SoC and/or PMICs, on the one hand, and a heat sink for other components such as memory, on the other hand. In other words, the SoC and/or PMICs and the memory may each be coupled to its own heat sink. Such decoupling of the heat sink is a significant improvement in terms of dealing with the increasing power consumption of the latest SoC generations.
The dual-side assembly according to embodiments of the present disclosure enables the use of low temperature grade memory. Also, the removal/omission of components saves space on the SoC side of the PCB, thereby enabling improved layout-designs. In addition, the assembly can be implemented as an LGA-type module without requiring (expensive) connectors. Further, due to the spatial isolation between the main heat sources, namely the SoC on one side and memory on the other side, the heat sink design(s) can be simplified.
In an embodiment, the at least one cavity extends through the main board from the top side to the bottom side thereof. In other words, the at least one cavity is implemented as a through-opening in the main board. Accordingly, an electrical component on the bottom side of the PCB can extend through and beyond the bottom surface of the main board.
In an embodiment, the circuit board system includes a plurality of said second electronic components arranged on the bottom side of the PCB; and a plurality of cavities on the top side of the main board, wherein the cavities are arranged to match the locations of and receive the second electronic components at the bottom of the PCB. Accordingly, the main board can be tailored to accommodate electronic components at the bottom side of the PCB while retaining a sufficiently large surface for an LGA- or BGA-type electrical connection between the PCB and the main board.
In an embodiment, the circuit board system includes a plurality of said second electronic components arranged on the bottom side of the PCB, wherein one or more but not all of the second electronic components extend into one or more corresponding ones of said at least one cavity. In other words, cavities may be provided for accommodating selected ones of the electronic components arranged at the bottom side of the PCB. For example, some of the electronic components may have larger vertical dimensions (i.e., project further from the PCB's bottom surface) than others. Cavities may be provided for those larger components, while there may already be sufficient space between the PCB and the main board for accommodating the other (smaller) components.
In an embodiment, the PCB is connected to the main board through an LGA. An LGA-type connection may be employed to reduce the overall vertical dimensions of the circuit board system.
In an alternative embodiment, the PCB is connected to the main board through a BGA. In a BGA-type connection, there may be more space between the PCB and the main board. This space may be sufficient to accommodate some of the components at the bottom side of the PCB without requiring corresponding cavities in the main board.
In an embodiment, the at least one first electronic component is attached to a heat sink at the top side of the PCB. Thus, the at least one first electronic component, e.g., an SoC, has its own heat sink isolated from a heat sink that may be provided for electronic components (e.g., memory) provided at the bottom side of the PCB.
In an embodiment, the at least one second electronic component is attached to a heat sink, heat spreader, chassis cover or metal-sheet cover at the bottom side of the PCB. Accordingly, electronic components arranged at the bottom side of the PCB may (also) have their own heat sink, or heat dissipation may be provided for by other mechanisms, for example, through connection to a chassis cover or metal-sheet cover of a device in which the circuit board system is mounted. Thus, it is possible to use existing elements for heat dissipation. Such elements may have a lower heat dissipation than dedicated heat sinks, but this may be sufficient, as the electronic components at the bottom side of the PCB produce less heat and are thermally uncoupled from the electronic components (e.g., an SoC) at the top side of the PCB that may produce more heat.
In an embodiment, the at least one second electronic component is attached to the heat sink, heat spreader, chassis cover or metal-sheet cover through a thermally conductive mold compound or resin. Accordingly, the at least one second electronic component may be thermally coupled to elements which are not directly adjacent (in contact) with them.
In an embodiment, the at least one first electronic component includes an SoC. The at least one first electronic component may also include one or more PMICs. The at least one second electronic component may include one or more DRAMs and/or one or more multilayer ceramic chip capacitors, MLCCs.
The at least one second electronic component may include one or more passive electronic components arranged on the bottom side of the PCB opposite to an SoC arranged on the top side of the PCB. Passive electronic components such as MLCCs do not generate additional heat and/or are sufficiently resistant to heat that may emanate from the SoC and are thus well suited for an arrangement underneath the SoC. This arrangement makes efficient use of the available PCB space.
In an embodiment, the PCB includes a plurality of said cavities in the main board and one or more bridges between said cavities. The bridges between the cavities improve the rigidity of the main board. Also, the bridges may be used to arrange pins, pads or balls thereon for connecting the PCB to the main board. This arrangement makes efficient use of the available space for electrical connections between the main board and the PCB.
Example embodiments of the disclosure will be described, by way of example only, with reference to the accompanying drawings in which:
There now follows, by way of example only, a description of exemplary embodiments of the present disclosure. These examples are described in reference to the figures identified above, which are included to provide further detail and clarity. It should be understood that the examples described herein are not limiting, and that other examples falling within the scope of the claims are envisaged.
Between the cavities 41, 42 and 43, the main board 40 includes bridges 44. Accordingly, in this embodiment, instead of a single, large cavity (cavity 11 of
It is noted that any number of cavities 51 can be provided within the main board 10 to accommodate any type of active or passive electronic components arranged at the bottom side of the PCB 21.
Again, it is noted that the present disclosure is not limited to the illustrated, exemplary number and combination of electronic components and cavities.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 128 796.6 | Oct 2023 | DE | national |
