Semiconductor Substrate with Segmented Source Electrodes for Current Detection
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Solution Overview
Problem
Existing technologies face challenges in detecting operating current and diode current in miniaturized MOSFETs like trench-gate type MOSFETs, which hinders efficient loss reduction and noise minimization in switching circuits.
Innovation Solution
A semiconductor substrate design with distinct current sensing regions allows for the detection of MOSFET and diode currents, featuring separate electrodes for current detection, enabling optimization of dead time to minimize recovery and conduction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the source electrode is in contact with both p-type body region and n+-type source region in a generally used MOSFET, then the MOSFET structure is simple and easy to manufacture, but it is difficult to independently detect operating current of the MOSFET and current flowing in the body diode
Solution Approach 1:
The source electrode is divided into two separate electrodes: a first source electrode contacting the n+-type source region for detecting MOSFET operating current, and a second source electrode contacting the p-type body region for detecting body diode current. This segmentation allows independent detection of the two current types while maintaining the functional integrity of the MOSFET structure.
Solution Approach 2:
An insulating film is introduced as an intermediary between the first source electrode and the n+-type source region, and between the second source electrode and the p-type body region. This insulating film enables electrical isolation and independent current detection paths while maintaining the structural simplicity and manufacturability of the MOSFET.
2Loss of energy
If switching timing is crossed too much to reduce recovery loss, then recovery loss is reduced, but large through current flows
Solution Approach 1:
The patent employs current detection feedback by measuring the operating current of the MOSFET and the current flowing in the body diode through the separated source electrodes. This feedback mechanism enables dynamic adjustment of the dead time to optimize the switching timing, reducing recovery loss while preventing excessive through current by continuously monitoring actual current conditions.
Solution Approach 2:
The dead time is made dynamic rather than fixed, allowing adjustment based on detected current conditions. The switching timing can be optimized in real-time by varying the dead time according to the detected MOSFET operating current and body diode current, enabling reduction of recovery loss while preventing large through current under different operating conditions.
Data Source
AI summary
A semiconductor substrate capable of detecting operating current of a MOSFET and diode current in a miniaturized MOSFET such as a trench-gate type MOSFET is provided. A semiconductor substrate includes a main current region and a current sensing region in which current smaller than main current flowing in the main current region flows. The main current region has a source electrode disposed on a main surface, the source electrode being in contact with a p-type semiconductor region (body) and an n+-type semiconductor region (source), and the current sensing region has a MOSFET current detecting electrode and a diode current detecting electrode on a main surface, the MOSFET current detecting electrode being in contact with the p-type semiconductor region (body) and the n+-type semiconductor region (source), the diode current detecting electrode being in contact with the p-type semiconductor region (body).