Self-Powered Gate Drive Circuit for IGBT Parasitic Turn-On

Solution Overview

Problem

Conventional gate drive circuits for power transistors, particularly IGBTs, require a dual power supply, which increases complexity and cost, and are susceptible to parasitic turn-on due to high dV/dt transients during switching, potentially damaging the gate drive circuit.

Innovation Solution

A self-powered gate drive circuit that operates using a single power supply, drawing current and voltage from the IGBT collector to pre-charge and power itself, employing capacitors and resistors to manage voltage and current to prevent parasitic turn-on, and using a passive pull-down circuit to maintain a low dVCE/dt during start-up.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dual power supply is used to drive the gate driver, then the gate driver can reliably switch the IGBT on and off, but the circuit complexity and cost increase

Engineering Contradiction:

Improvegate driver switching reliabilityVSAvoidpower supply complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the dual power supply requirement into a single power supply configuration. The gate driver circuit is designed to operate with only one power supply by utilizing the IGBT collector voltage as the power source, eliminating the need for separate positive and negative power supplies while maintaining reliable switching functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gate driver circuit uses the IGBT collector voltage to power itself during operation. The circuit automatically charges its internal capacitors from the collector voltage during the IGBT off-state, enabling self-powered operation without external dual power supplies

Inventive Principle:

Principle #25Self-service

2Reliability

If a dual power supply is used to drive the gate driver, then the gate driver can reliably switch the IGBT on and off, but the cost increases

Engineering Contradiction:

Improvegate driver switching reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the dual power supply requirement into a single power supply configuration. The gate driver circuit is designed to operate with only one power supply by utilizing the IGBT collector voltage as the power source, eliminating the need for separate positive and negative power supplies while maintaining reliable switching functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gate driver circuit uses the IGBT collector voltage to power itself during operation. The circuit automatically charges its internal capacitors from the collector voltage during the IGBT off-state, enabling self-powered operation without external dual power supplies

Inventive Principle:

Principle #25Self-service

3Productivity

If the gate driver operates during IGBT switching, then it can control the power transistor, but it becomes susceptible to parasitic turn-on due to high dV/dt transients

Engineering Contradiction:

Improvepower transistor switching controlVSAvoidparasitic turn-on susceptibility

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces capacitors as intermediary elements between the power supply and the gate driver circuit. These capacitors act as filters that block high-frequency dV/dt transients while allowing the gate driver to function normally, thereby preventing parasitic turn-on caused by voltage spikes during IGBT switching

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The circuit employs a passive pull-down circuit and clamping diodes that preemptively counteract the harmful effects of dV/dt transients before they can cause parasitic turn-on. The pull-down circuit maintains the gate voltage at a safe level during transient conditions

Inventive Principle:

Principle #9Preliminary anti-action

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

The self-powered gate drive circuit reduces complexity and cost by eliminating the need for a dual power supply and effectively prevents parasitic turn-on, ensuring reliable operation of the IGBT module.

Implementation Method 1

A self-powered gate drive circuit includes a first capacitor electrically coupled to a collector-to-emitter voltage transient of a power transistor, a rectifier circuit electrically coupled to the first capacitor, and a supply capacitor electrically coupled to the rectifier circuit

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9548732B2Self-powered gate drive circuit apparatus and method

Publication Date: 2017.01.17 NXP USA INC

AI summary

A self-powered gate drive circuit comprising a first capacitor electrically coupled to a power semiconductor collector node of the circuit; a first switch arranged between the first capacitor and a second capacitor, the first switch electrically coupling the first and second capacitors when switched on; the second capacitor; a first diode, the first diode anode electrically coupled to the first capacitor and the first diode cathode electrically coupled to the first switch; a second diode, the second diode cathode electrically coupled to the first capacitor and the second diode anode electrically coupled with a ground node of the circuit; and a second switch, wherein the second switch electrically couples the second capacitor with a power semiconductor gate node when switched on.