Semiconductor Device Inductance Configuration for Current Detection
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Solution Overview
Problem
The accuracy of short circuit current detection in large-capacity IPM semiconductor devices is compromised due to the gate voltage difference and current ratio variations between the main and sense sections of IGBTs, caused by differing inductances in the emitter and sense sections.
Innovation Solution
The semiconductor device design includes a transistor with a main terminal and a sense terminal, where the wiring inductance from the main terminal to the main output electrode is greater than from the sense terminal to the sense output electrode, thereby reducing the gate voltage difference and improving current ratio accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the emitter current detection scheme is used with large-capacity IPM, then the allowable power of the external shunt resistor needs to be increased, but the current sense current detection scheme is used instead which has accuracy deterioration problem
Solution Approach 1:
The patent applies local quality by creating different inductance characteristics in different parts of the circuit. Specifically, the main terminal section is designed with larger wiring inductance (through longer or more wire bonds) compared to the sense terminal section, which has smaller wiring inductance. This local differentiation compensates for the inherent inductance difference caused by the detection scheme, thereby maintaining current balance and detection accuracy in large-capacity IPM applications.
2Reliability
If the resistor for short circuit current detection is connected to the sense terminal, then the gate voltage difference between main section and sense section is produced, but the accuracy of short circuit current detection deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the harmful inductance difference before it affects the current balance. The wiring inductance in the main terminal section is intentionally made larger than in the sense terminal section, creating a counteracting effect that offsets the inductance difference introduced by connecting the detection resistor to the sense terminal. This preliminary compensation prevents gate voltage difference and maintains accurate current detection.
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
This design enhances the accuracy of short circuit current detection by minimizing the gate voltage difference and current ratio variations between the main and sense sections of the IGBT, leading to more reliable short circuit current detection.
Implementation Method 1
a wiring inductance from the main terminal to the main output electrode is larger than a wiring inductance from the sense terminal to the sense output electrode
Data Source
AI summary
A semiconductor device includes: a transistor including a main terminal and a sense terminal; a main output electrode connected to the main terminal via a first wire; a sense output electrode connected to the sense terminal via a second wire; and a package sealing the transistor, the first and second wires, part of the main output electrode and part of the sense output electrode, wherein a wiring inductance from the main terminal to the main output electrode is larger than a wiring inductance from the sense terminal to the sense output electrode.