Power Electronics Package Layout With Kelvin Source Routing
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Solution Overview
Problem
Conventional power semiconductor packages experience reduced switching quality, slower speeds, and potential destruction due to coupling between power and signal loops, which is exacerbated by layout complexities and transconductance mismatches in paralleled die configurations.
Innovation Solution
A discrete power package design with a power substrate, power semiconductor die, and a Kelvin connection contact, where the Kelvin connection pad is coupled to each die via a conductive trace on the substrate, simplifying layout and reducing connection lengths, thereby maintaining independent power and signal loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the second power switching contact and Kelvin connection contact are coupled together before connecting to power semiconductor die, then the layout is simplified, but coupling between power switching loop and signal loop occurs causing feedback
Solution Approach 1:
The patent segments the connection paths by providing separate connection points for the second power switching contact and the Kelvin connection contact to the power semiconductor die. Instead of coupling these contacts together before connection, the invention creates independent connection paths: the second power switching contact connects to the second power switching pad, while the Kelvin connection contact connects to the Kelvin connection pad, thereby eliminating the harmful coupling between power and signal loops.
2Reliability
If metal connection length between second power switching contact and power semiconductor die is reduced, then stray inductance is minimized, but layout flexibility is reduced
Solution Approach 1:
The patent utilizes the substrate plane to route the Kelvin connection contact directly to the Kelvin connection pad of the power semiconductor die, rather than forcing a linear connection through the second power switching contact. This dimensional approach allows independent optimization of both connection paths, minimizing the length of the Kelvin connection path to reduce stray inductance while maintaining layout flexibility through appropriate trace routing on the substrate.
3Power
If power semiconductor die are paralleled to increase current capacity, then power handling capability is improved, but transconductance mismatches and loop coupling increase
Solution Approach 1:
The patent applies segmentation by providing separate Kelvin connection pads and connection paths for each power semiconductor die in the paralleled configuration. This ensures that each die has its own independent Kelvin connection to the signal loop, preventing coupling between the power switching loops of different dies and eliminating the need for balancing currents, thereby maintaining reliable switching performance even when multiple dies are paralleled to increase current capacity.
Data Source
AI summary
A package for power electronics includes a power substrate, a number of power semiconductor die, and a Kelvin connection contact. Each one of the power semiconductor die are on the power substrate and include a first power switching pad, a second power switching pad, a control pad, a semiconductor structure, and a Kelvin connection pad. The semiconductor structure is between the first power switching pad, the second power switching pad, and the control pad, and is configured such that a resistance of a power switching path between the first power switching pad and the second power switching pad is based on a control signal provided at the control pad. The Kelvin connection pad is coupled to the power switching path. The Kelvin connection contact is coupled to the Kelvin connection pad of each one of the power semiconductor die via a Kelvin conductive trace on the power substrate.