Power Element Drive Circuit Eliminating Gate Resistor

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing drive circuits for power elements like IGBTs face inefficiencies due to high switching losses and the need for expensive IGBTs with high short-circuit withstand capability, especially when operation voltage thresholds change with temperature, and they often require complex configurations to mitigate these issues.

Innovation Solution

A drive circuit configuration that eliminates the gate resistor by using a series circuit with a semiconductor switching element and a Zener diode or constant voltage supply with a positive temperature characteristic, allowing stable positive biasing of the power element regardless of temperature changes, thus reducing the required short-circuit withstand capability and simplifying the circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a gate resistor is used in the drive circuit to control the power element, then the circuit can be operated, but switching losses increase and power conversion efficiency decreases

Engineering Contradiction:

Improveswitching lossesVSAvoidcircuit configuration

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The invention extracts and removes the gate resistor from the drive circuit. By eliminating this resistive element, the circuit achieves lower switching losses and improved power conversion efficiency while maintaining functionality through an alternative drive mechanism using semiconductor switching elements

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention substitutes the traditional resistive gate control mechanism with an active semiconductor switching element-based drive system. This replacement enables dynamic control of the power element while reducing energy losses associated with resistive elements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If IGBTs with high short-circuit withstand capability are used to handle temperature-dependent voltage threshold changes, then reliability improves, but device cost increases

Engineering Contradiction:

Improveshort-circuit withstand capabilityVSAvoiddevice cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the drive approach by using semiconductor switching elements that can dynamically adjust drive conditions. This allows standard IGBTs to operate reliably across temperature ranges without requiring expensive high-endurance devices, as the switching elements provide adaptive control

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses less expensive semiconductor switching elements in the drive circuit rather than relying on expensive IGBTs with enhanced short-circuit capability. The switching elements provide the necessary protection and control, allowing standard IGBTs to be used cost-effectively

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If the drive circuit is simplified by removing the gate resistor, then manufacturing cost decreases, but maintaining stable positive biasing across temperature variations becomes challenging

Engineering Contradiction:

Improvemanufacturing costVSAvoidpositive biasing stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The invention introduces semiconductor switching elements as intermediary components between the control signal and the power element gate. These switching elements actively maintain stable positive biasing conditions while allowing circuit simplification and cost reduction

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The semiconductor switching elements in the drive circuit provide dynamic feedback control to maintain stable biasing conditions. This feedback mechanism ensures reliable operation across temperature variations while enabling a simpler, more cost-effective circuit design

Inventive Principle:

Principle #23Feedback

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 configuration reduces switching losses, eliminates the need for excessive gate voltage, and simplifies the circuit design, making it more cost-effective and compact while maintaining stable operation of the power element across varying temperature conditions.

Implementation Method 1

a series circuit with a semiconductor switching element and a Zener diode or constant voltage supply with a positive temperature characteristic

Methodology Applied

Scientific EffectZener breakdown: Avalanche Breakdown

Data Source

PatentUS10243549B2Drive circuit for power element

Publication Date: 2019.03.26 FUJI ELECTRIC CO LTD

AI summary

There is provided a drive circuit for turning on/off a power element which controls a main current flow between a first main electrode and a second main electrode in response to a drive signal applied to a control electrode. The drive circuit includes a a first semiconductor switching element and a second semiconductor switching element which are connected in series with a semiconductor element and provided between the power supply terminal and the ground terminal, third semiconductor switching element and a fourth semiconductor switching element which are connected in series, and a control circuit which controls turn-on/off of the power element by turning on/off the first to fourth semiconductor switching elements. The semiconductor element has a positive temperature characteristic.