Diode-Integrated IGBT Current Detection With Switched Pathway
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Solution Overview
Problem
Existing semiconductor devices with diode-integrated IGBT elements face difficulties in accurately detecting small currents due to noise interference and incorrect detection of diode operation, particularly in the small-current region, as they rely on potential differences across sense resistors which are prone to noise from switching signals.
Innovation Solution
The semiconductor device incorporates a diode-integrated IGBT element with a sense element and a switch element, where the switch element controls a second current pathway independently of the diode sense element, allowing for accurate detection of current flow through the diode element by varying the electric current state of the second pathway, thereby enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sense resistor is used to detect current flow through the diode element, then current detection is enabled, but noise interference increases and detection accuracy deteriorates in small current regions
Solution Approach 1:
The invention divides the detection system into two separate pathways: a first current pathway for normal operation and a second current pathway for detection. The switch element segments the connection between these pathways, allowing the detection circuit to operate independently from the main power circuit, thereby isolating the detection signal from noise generated by switching operations.
Solution Approach 2:
The switch element acts as an intermediary between the first current pathway (diode sense element) and the second current pathway (detection circuit). By controlling the connection state of this intermediary component, the system can selectively enable detection while maintaining isolation from noise sources, thus improving measurement precision without exposing the detection circuit to harmful noise factors.
2Reliability
If the diode sense element directly connects to the detection circuit, then detection simplicity is maintained, but detection reliability deteriorates due to incorrect detection in small current regions
Solution Approach 1:
The invention segments the detection system into distinct functional blocks: the diode sense element in the first current pathway and the detection circuit in the second current pathway, connected through a switch element. This segmentation improves detection reliability by preventing incorrect detection in small current regions, while the modular structure keeps the overall device complexity manageable.
Solution Approach 2:
The switch element is configured to preliminarily establish the connection between the first and second current pathways only when detection is required. This preliminary action ensures that the detection circuit is properly connected before measurement begins, improving reliability by preventing incorrect detection states while avoiding unnecessary complexity through conditional connection.
Data Source
AI summary
A semiconductor device includes: a diode-integrated IGBT element in a same semiconductor substrate having a diode element and an IGBT element driven by a drive signal towards a gate; a sense element having a diode sense element with a current proportional to a current through the diode element and an IGBT sense element with a current proportional to a current through the IGBT element; a switch element connected to a first current pathway through the diode sense element and to a second current pathway different from the first current pathway. The switch element is turned off to control the second current pathway to be discontinuous with the first current pathway when no current flows through the diode sense element, and is turned on to control the second current pathway to be continuous with the first current pathway and apply a current when a current flows through the diode sense element.