Gate Driver Preventing Reverse Conduction in Power Switches

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Solution Overview

Problem

Power electronic devices, such as inverters used in traction vehicles and industrial applications, face reliability and efficiency issues due to improper switching modes, leading to potential short circuits and increased conduction losses in reverse conduction modes.

Innovation Solution

A drive circuit system that determines the conduction mode of switch modules using sense circuits and maintains forward conducting mode even if reverse conduction is indicated, preventing spurious triggering and optimizing gate voltage levels to reduce losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drive circuit enables forward conducting mode based on sense circuit indications, then the switch module can operate in reverse conduction mode, but this leads to spurious triggering and short circuits

Engineering Contradiction:

Improveswitch module operation reliabilityVSAvoidspurious triggering and short circuits

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional approach by having the drive circuit ignore reverse conduction mode indications from the sense circuit once forward conducting mode is established, rather than responding to each sense circuit signal. This inversion prevents spurious triggering while maintaining reliable operation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary action by establishing forward conducting mode before reverse conduction mode indications can cause problems. The drive circuit proactively maintains forward conducting mode once initiated, preventing the harmful effects of reverse conduction before they can occur.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the drive circuit continuously monitors sense circuit signals, then conduction mode can be accurately detected, but this increases device complexity and response time

Engineering Contradiction:

Improveconduction mode detection accuracyVSAvoiddrive circuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses preliminary action by detecting conduction mode once at the beginning and establishing the appropriate operating state before reverse conduction mode indications can cause problems. This preliminary detection eliminates the need for continuous monitoring, reducing complexity while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The drive circuit serves itself by maintaining the established forward conducting mode without requiring continuous external sensing or control signals. Once forward conducting mode is established, the system self-maintains this state without needing to continuously process sense circuit signals.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9948290B2Reverse conduction mode self turn-off gate driver

Publication Date: 2018.04.17 TRANSPORTATION IP HOLDINGS LLC

AI summary

An apparatus includes a switch module, a sense circuit coupled to the switch module and configured to indicate an operating conduction mode of the switch module, and a drive circuit operatively coupled to the switch module to enable and disable forward conducting mode of the switch module. Once the switch module is in forward conducting mode, the drive circuit is configured to maintain enablement of the forward conducting mode even if the sense circuit indicates reverse conduction mode.