Semiconductor Switching Device Third Emitter Terminal Noise Suppression
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Solution Overview
Problem
Conventional semiconductor switching devices face challenges in accurately detecting main current due to significant inductive noise interference, caused by the large closed loop of wiring between the main emitter and second emitter terminals, which affects the reliability of current detection.
Innovation Solution
The semiconductor switching device incorporates a third emitter terminal positioned close to the second emitter terminal, allowing the current detector to connect to both, thereby reducing the loop size and minimizing inductive noise impact, while also including a diode connected in parallel to the semiconductor switching element to manage voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the current detector is electrically connected to the main emitter terminal and the second emitter terminal, then the main current can be detected, but the closed loop of wiring becomes large causing strong inductive noise interference
Solution Approach 1:
The patent divides the emitter terminal function into multiple separate terminals: a main emitter terminal for current conduction and second/third emitter terminals for current detection. This segmentation allows the detection circuit to use a small closed loop (between second and third terminals) while the main terminal handles the bulk current, resolving the contradiction between detection accuracy and inductive noise interference.
2Object-affected harmful factors
If the main emitter terminal and the second emitter terminal are positioned close to each other, then the wiring loop size is reduced suppressing inductive noise, but the voltage drop between them cannot be used for current detection
Solution Approach 1:
The patent creates separate functional terminals: the main emitter terminal handles current conduction while the second and third emitter terminals (positioned close together) handle detection. The third terminal detects voltage drop between itself and the second terminal, enabling accurate current measurement with minimal inductive noise due to the small loop area.
3Ease of manufacture
If a floating inductance component and floating resistive component are present in the package, then the semiconductor switching element can be connected to terminals, but voltage drop is generated affecting current detection accuracy
Solution Approach 1:
The patent introduces the third emitter terminal as an intermediary measurement point that detects voltage drop locally between the second and third terminals. This local measurement approach eliminates the influence of floating inductance and resistive components in the package, as these components affect only the main current path and not the local voltage between closely-spaced second and third terminals.
Data Source
AI summary
A semiconductor switching device includes a package, and a semiconductor switching element provided in the package and having a collector electrode and an emitter electrode. A main collector terminal and a main emitter terminal reflect voltage drop generated during application of current by a floating component in the package. A second collector terminal and a second emitter terminal detect a voltage between the collector electrode and the emitter electrode without reflecting the voltage drop. A third emitter terminal is arranged close to the second emitter terminal, and detects the voltage drop generated between the main emitter terminal and the second emitter terminal.