Vertical Power Loop Structure for Low Inductance
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Solution Overview
Problem
Conventional power module structures exhibit high power loop inductance and thermal resistance, leading to voltage overshoot and inefficiency during high-speed switching, particularly in medium voltage devices, due to the layered structure and conductive baseplates.
Innovation Solution
A low inductance power module with a vertical power loop structure and insulated baseplates is introduced, featuring a substrate bottom conduction layer for electrical conduction, integrated decoupling capacitors, and a thermal dissipation structure between the substrate and cooling layer, utilizing lamination technology and high in-plane thermal spreading materials to reduce inductance and enhance thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional layered substrate structure with conductive baseplates is used, then mechanical support and electrical conduction are provided, but power loop inductance increases
Solution Approach 1:
The patent transitions from a conventional planar layered structure to a vertical three-dimensional structure where current flows vertically through the substrate thickness rather than horizontally across the surface. This vertical current path significantly reduces the loop area and thus the inductance, while the substrate still provides mechanical support through its structural integrity.
Solution Approach 2:
The substrate is segmented into distinct functional layers: a top conduction layer for electrical connections, a bottom conduction layer for current collection, and an insulating layer in between. This segmentation allows the current paths to be optimized vertically while maintaining mechanical support through the layered structure.
2Reliability
If a conventional layered structure from semiconductor dies to heatsink is used, then mechanical support and electrical connections are established, but thermal resistance increases
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the top and bottom conduction layers. This insulating layer has high thermal conductivity to facilitate heat transfer while providing electrical insulation. The thermal interface material between the substrate and heatsink is also optimized to reduce thermal resistance at the interface.
3Reliability
If higher voltage rating devices are used to handle voltage overshoot, then voltage margins are sufficient, but cost and conduction losses increase
Solution Approach 1:
The patent applies preliminary anti-action by reducing the power loop inductance before voltage overshoot occurs. By optimizing the current paths vertically through the substrate and minimizing the loop area, the inductance is reduced in advance, preventing voltage overshoot and oscillation before they can cause damage or require higher voltage rating devices.
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 vertical power loop structure significantly reduces power loop inductance and internal electrical fields, improving thermal dissipation and efficiency while minimizing parasitic capacitance and voltage overshoot, allowing for thinner, less expensive substrate materials and enhanced high-power density operation.
Implementation Method 1
The vertical power loop structure may utilize a substrate bottom conduction layer for electrical conduction
Implementation Method 2
The thermal dissipation structure may include a plurality of insulated baseplates... a material with a high in-plane thermal spreading capability between the substrate bottom conduction layer and the thermal dissipation structure
Implementation Method 3
the baseplate is pressed to a metal heatsink through thermal interface material for cooling
Data Source
AI summary
A low inductance power module with low power loop inductance and high-power density is provided. The power module may include a vertical power loop structure, a cooling layer, and a thermal dissipation structure. The vertical power loop structure may utilize a substrate bottom conduction layer for electrical conduction. The thermal dissipation structure may be disposed between the substrate bottom conduction layer and the cooling layer. The vertical power loop structure may include integrated decoupling capacitors. Alternatively, the structure may include no integrated decoupling capacitors. The vertical power loop structure may include one or more half-bridge structures connected in parallel, each with its own integrated decoupling capacitors. The vertical power loop structure reduces power loop inductance in the power module, and the thermal dissipation structure provides electrical insulation, mechanical support, and thermal conduction.