Semiconductor Element Segmentation for Switching Loss Reduction

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Solution Overview

Problem

Conventional semiconductor devices face a trade-off between turn-on loss and turn-off loss, making it difficult to reduce the total switching loss effectively.

Innovation Solution

The semiconductor device incorporates multiple element portions with separate gates, where signal transmission means control the simultaneous turn-on and staggered turn-off of these portions to minimize switching losses, allowing for reduced turn-on and turn-off losses by optimizing the element area and operation timing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a single semiconductor element is used with conventional gating, then the device structure is simple, but the switching loss cannot be reduced due to the trade-off between turn-on loss and turn-off loss

Engineering Contradiction:

Improveswitching lossVSAvoidelement structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The semiconductor element is divided into multiple element portions (first element portion and second element portion), each with its own gate (first gate and second gate). This segmentation allows independent control of each portion, enabling reduced switching loss by optimizing turn-on and turn-off sequences for each segment while maintaining overall device functionality.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If multiple element portions with separate gates are used, then turn-on and turn-off losses can be reduced, but the device complexity increases

Engineering Contradiction:

Improveturn-on loss and turn-off lossVSAvoidgate control structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The control system dynamically adjusts the timing of gate signals to different element portions based on the switching state. During turn-on, all element portions are activated simultaneously for fast response. During turn-off, element portions are deactivated sequentially (first element portion then second element portion) to minimize overlapping conduction and reduce switching losses, adapting the control strategy to operational requirements.

Inventive Principle:

Principle #15Dynamics

3Temperature

If element portions are turned off simultaneously, then the control structure is simple, but high current density and heat generation occur

Engineering Contradiction:

Improveheat generationVSAvoidsignal control timing

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The first element portion is turned off before the second element portion during the turn-off sequence. This preliminary action allows the current to be gradually redistributed, preventing sudden high current density spikes that would occur with simultaneous turn-off. The staged deactivation reduces peak power dissipation and heat generation in any single element portion.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8994147B2Semiconductor device and semiconductor element

Publication Date: 2015.03.31 MITSUBISHI ELECTRIC CORP

AI summary

A semiconductor device includes a semiconductor element including a first element portion having a first gate and a second element portion having a second gate, wherein the turning on and off of the first and second element portions are controlled by a signal from the first and second gates respectively. The semiconductor device further includes signal transmission means connected to the first gate and the second gate and transmitting a signal to the first gate and the second gate so that when the semiconductor element is to be turned on, the first element portion and the second element portion are simultaneously turned on, and so that when the semiconductor element is to be turned off, the second element portion is turned off a delay time after the first element portion is turned off.