High-Tg Multi-Layer PCB Thermal Bridge for Gearbox Control
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Solution Overview
Problem
Existing printed circuit boards fail to adequately address high temperature, chemical, and mechanical stress requirements in vehicle applications, particularly in transmission control systems, where operating temperatures range from -40°C to 160°C and beyond, and are not suitable for high current carrying capacities.
Innovation Solution
A multi-layer printed circuit board design with glass transition temperatures greater than or equal to 170°C, featuring thermally conductive layers and vias that form a thermally conductive bridge from the top to the bottom layer, utilizing glass fiber reinforced plastic with ceramic particles, and copper thermally conductive layers and vias for enhanced heat dissipation and current carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional printed circuit boards with glass transition temperatures below 170°C are used, then manufacturing and assembly are easier, but the boards cannot withstand high operating temperatures in transmission controls
Solution Approach 1:
The patent changes the fundamental parameter of glass transition temperature by selecting base materials with Tg ≥ 170°C, fundamentally altering the thermal performance envelope of the PCB to match transmission control requirements
Solution Approach 2:
The patent employs composite base materials combining glass fiber reinforcement with high-Tg resin systems, creating a material structure that simultaneously achieves high temperature resistance and mechanical strength
2Loss of energy
If standard PCB structures without extensive thermal pathways are used, then device complexity is reduced, but heat dissipation capability is insufficient for high-power semiconductor components
Solution Approach 1:
The patent transitions from two-dimensional surface heat dissipation to three-dimensional thermal pathways by implementing vertical thermal vias that conduct heat through multiple PCB layers to large copper planes and heat sinks
Solution Approach 2:
The patent segments the thermal management system into distinct functional zones: device mounting areas with integrated thermal vias, intermediate heat distribution planes, and peripheral heat sink connection areas, allowing optimized thermal pathways for each function
3Reliability
If PCBs designed for moderate temperature ranges (-40°C to 85°C) are used, then component selection and assembly are simpler, but the boards fail to meet transmission control operating temperature requirements of -40°C to 160°C and beyond
Solution Approach 1:
The patent systematically changes multiple parameters simultaneously: base material Tg ≥ 170°C, copper layer thickness ≥ 35 μm, via diameter ≥ 100 μm, and thermal via density, creating a coordinated design that achieves high-temperature reliability
4Power
If thin copper layers and small via diameters are used to reduce material usage and cost, then manufacturing cost decreases, but current carrying capacity and thermal conduction capability are insufficient for high-power applications
Solution Approach 1:
The patent compensates for increased copper quantity per layer by reducing the number of layers required, using thick copper (≥35 μm) to achieve high current capacity in fewer layers, thereby reducing total copper volume while maintaining power handling capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively dissipates heat and supports high current carrying capacities, ensuring reliable operation under extreme temperatures and mechanical loads, while protecting components from environmental influences.
Implementation Method 1
the vias and the thermally conductive layers of the circuit board layers form a thermally conductive bridge from an uppermost circuit board layer to a lowermost circuit board layer
Implementation Method 2
a plurality of printed circuit board layers arranged one above the other, wherein the circuit board layers are each formed from a base material whose glass transition temperature is greater than or equal to 170° C.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Disclosed is a control unit for vehicle applications having at least one circuit board. The invention relates to a circuit board (4), comprising a plurality of circuit board layers arranged one over the other. According to the invention, the circuit board layers are each made of a base material, the glass transition temperature of which is greater than or equal to 170 °C, and the circuit board layers each have at least one thermally conducting layer (19 to 24) applied to the electrically insulating base material, wherein several vias (16, 17, 18) extending in a z direction (z) perpendicular to the circuit board layers are provided, which vias connect the thermally conducting layers (19 to 24) of different circuit board layers in such a way that the vias (16, 17, 18) and the thermally conducting layers (19 to 24) of the circuit board layers form a thermal conduction bridge from a topmost circuit board layer to a bottommost circuit board layer. The invention further relates to a control unit (1) for vehicle applications and to a use of the control unit (1).