Switch Element Gate Control Using Variable Pre-Control Voltage

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Solution Overview

Problem

Existing circuit arrangements for switching semiconductor elements, such as transistors, suffer from high switching losses and heat generation, leading to reduced performance and shorter device maintenance cycles due to the use of fixed control voltages during switching states.

Innovation Solution

A circuit arrangement with a control circuit that applies a variable pre-control voltage dependent on the switching state of the semiconductor element, allowing for optimized adaptation of control voltages between conductive and blocking states to minimize switching losses, by adjusting the pre-control voltage values during switching phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed control voltages are applied to the gate terminal of switching elements, then the switching element can be reliably turned on and off, but switching losses increase and heat generation occurs during intermediate states

Engineering Contradiction:
Improveswitching element control reliabilityVSAvoidswitching losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by transitioning from fixed control voltages to variable pre-control voltages that adapt based on the switching state. The control circuit dynamically adjusts the pre-control voltage applied to the gate terminal, switching between a first pre-control voltage (e.g., 0 V) when the switching element is off and a second pre-control voltage (e.g., +15 V) when it is on, thereby optimizing performance and reducing losses during transitions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements preliminary action by applying a pre-control voltage to the gate terminal before the actual switching operation. This pre-control voltage prepares the switching element for the upcoming state change, ensuring it is ready to transition smoothly between on and off states, which reduces switching losses and minimizes time spent in harmful intermediate states.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If fixed control voltages are used during switching states, then the circuit operation is simple, but switching losses occur and performance is reduced due to heat generation

Engineering Contradiction:
Improvecontrol circuit complexityVSAvoidcircuit performance
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The control circuit employs dynamics by using variable pre-control voltages instead of fixed voltages. The circuit adapts the gate terminal voltage based on the desired switching state, improving performance by reducing switching losses and heat generation while maintaining manageable complexity through a straightforward voltage switching mechanism.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by varying the pre-control voltage parameter applied to the gate terminal. By switching between different voltage levels (e.g., 0 V and +15 V for unipolar supply, or -8 V and +15 V for bipolar supply), the circuit optimizes switching performance and reduces losses without significantly increasing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If fixed control voltages are applied to switching elements, then the control method is simple, but switching losses increase and device lifespan is reduced

Engineering Contradiction:
Improvecontrol method simplicityVSAvoiddevice lifespan
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary action by applying a pre-control voltage to the gate terminal before the actual switching operation. This pre-control voltage prepares the switching element for the upcoming state change, ensuring it is ready to transition smoothly between on and off states, which reduces switching losses and minimizes time spent in harmful intermediate states.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies dynamics by transitioning from fixed control voltages to variable pre-control voltages that adapt based on the switching state. The control circuit dynamically adjusts the pre-control voltage applied to the gate terminal, switching between a first pre-control voltage (e.g., 0 V) when the switching element is off and a second pre-control voltage (e.g., +15 V) when it is on, thereby optimizing performance and reducing losses during transitions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3997790B1Circuit arrangement for switching switch elements
Publication Date: 2025.01.15 ROBERT BOSCH GMBH
  • EP3997790B1 patent drawingFigure 1
  • EP3997790B1 patent drawingFigure 2~2d
  • EP3997790B1 patent drawingFigure 3~3d

AI summary

The invention relates to a circuit arrangement (100), comprising a control circuit (104) and a switch element (101) for switching between a first and a second switching state of the switch element (101). The control circuit (104) is designed to provide a variable pre-control voltage dependent on the switching state of the switch element. The pre-control voltage is a voltage that is switched as the control voltage at the switch element (101) during one of the two switching states. The control circuit (104) is also designed to vary the pre-control voltage during each of the switching states.