Dual-Kelvin Power Module Layout for Ringing and Gate Noise
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Solution Overview
Problem
SiC power modules in automotive traction inverters face EMC test failures due to switching ringing and gate oscillation issues caused by the coupling of snubber and gate drive loops, leading to reduced reliability.
Innovation Solution
A power module design utilizing two dedicated Kelvin pins for gate drive and snubber circuits, decoupling the power and gate drive loops to suppress ringing and reduce noise, enhancing module reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If snubber circuit is directly connected to source and drain signal pins of switch, then voltage spike and ringing are suppressed, but power loop noise is coupled into gate driver loop causing gate oscillation
Solution Approach 1:
The patent divides the previously shared source pin connection into two separate Kelvin pins: one dedicated to the gate driver loop and another to the snubber circuit. This segmentation isolates the gate drive signal path from the noisy snubber circuit, preventing power loop noise from coupling into the gate driver while maintaining effective voltage spike and ringing suppression.
2Productivity
If multiple dies are connected in parallel to fulfill increasing demand for greater output current, then output current capability is improved, but parasitic coupling between power loop and gate drive loop increases
Solution Approach 1:
The patent introduces dedicated Kelvin pins as intermediary connection points between the multiple parallel dies and the external circuitry. These specialized pins provide low-inductance, isolated connection paths that mediate between the high-current power switches and the control circuits, reducing parasitic coupling effects while maintaining high output current capability.
Data Source
AI summary
A power module includes first and second electrode terminals adapted to electrically connect to a power source, a first switch element, a second switch element, a first Kelvin source pin, and a second Kelvin source pin. The first switch element is electrically connected to the first electrode terminal. The second switch element is electrically connected between the first switch element and the second electrode terminal and includes a drain and a source electrically connected to the first switch element and the second electrode terminal respectively. The first Kelvin source pin is electrically connected to the source of the second switch element and is adapted to receive a gate drive signal for driving the second switch element. The second Kelvin source pin is electrically connected to the source of the second switch element and is configured to be electrically connected to a snubber circuit.