Highly Integrated Gate Drivers for Si and GaN Power Transistors

✍ Scribed by Achim Seidel, Bernhard Wicht

• Publisher: Springer
• Year: 2021
• Tongue: English
• Leaves: 137
• Category: Library

✦ Synopsis

This book explores integrated gate drivers with emphasis on new gallium nitride (GaN) power transistors, which offer fast switching along with minimum switching losses. It serves as a comprehensive, all-in-one source for gate driver IC design, written in handbook style with systematic guidelines. The authors cover the full range from fundamentals to implementation details including topics like power stages, various kinds of gate drivers (resonant, non-resonant, current-source, voltage-source), gate drive schemes, driver supply, gate loop, gate driver power efficiency and comparison silicon versus GaN transistors. Solutions are presented on the system and circuit level for highly integrated gate drivers. Coverage includes miniaturization by higher integration of subfunctions onto the IC (buffer capacitors), as well as more efficient switching by a multi-level approach, which also improves robustness in case of extremely fast switching transitions. The discussion also includes a concept for robust operation in the highly relevant case that the gate driver is placed in distance to the power transistor. All results are widely applicable to achieve highly compact, energy efficient, and cost-effective power electronics solutions.​

✦ Table of Contents

Preface
Contents
Acronyms
List of Abbreviations
List of Symbols
1 Introduction
1.1 Motivation
1.2 Scope and Outline of This Book
References
2 Fundamentals
2.1 Gate Drivers and Power Stages
2.1.1 Driver Configurations and Building Blocks
2.1.2 Gate Driver Output Stage
2.1.3 Basic Gate Driver Operation
2.1.4 Gate Loop Parasitics
2.1.5 Buffer Capacitor CDRV
2.1.6 Gate Driver Types
2.1.7 Efficiency of Resonant and Non-resonant Gate Drivers
2.1.8 Power-Transistor Switching Losses
2.2 Power Transistors and Applications
2.2.1 Silicon Transistors
2.2.2 GaN Transistor
2.2.3 GaN Versus Silicon Transistors
2.2.3.1 Losses
2.2.3.2 Safe-Operating Area (SOA)
2.2.3.3 Gate Control
2.2.3.4 Applications
2.3 Gate Drive Schemes
2.3.1 Unipolar and Bipolar Gate Drive Scheme
2.3.2 Multi-level Gate Drive Schemes and Active Gate Control
2.4 Gate Driver Supply and Signal Transmission
2.4.1 Isolated and Non-isolated Gate Driver Supplies
2.4.2 Bootstrap Driver Supply
2.4.3 Signal Transmission
2.4.4 Combined Driver Supply and Signal Transmission
2.4.5 Coupling Currents Between Low-Side and High-Side
Appendix A: Exemplary Gate Loop Inductance Values
Appendix B: Losses Caused by Coss
References
3 Gate Drivers Based on High-Voltage Charge Storing (HVCS)
3.1 The Concept of HVCS
3.2 Circuit Options of a Gate Driver Output Stage Based on HVCS
3.3 Driver Implementation
3.3.1 Charge Pump Concept
3.3.2 Series Regulator
3.3.3 Level Shifters
3.3.3.1 Level Up Shifter
3.3.3.2 Level Down Shifter
3.3.4 Gate Driver Circuit
3.4 Further Applications of the Proposed Bootstrap Circuit
3.5 Bootstrap Capacitor Sizing
3.5.1 Sizing Equations
3.5.2 Sizing Equations for Stacked Bootstrap Capacitors
3.5.3 Sizing Example
3.5.4 Comparison with Conventional Bootstrap Circuit
3.6 Experimental Results
3.7 Comparison with Prior Art
Appendix: Level Shifter Circuit
References
4 Gate Drivers Based on High-Voltage Energy Storing (HVES)
4.1 The Concept of HVES
4.1.1 Gate Charge Delivery
4.1.2 Gate Drive Speed
4.1.3 Efficiency Considerations of Buffer Implementation Methods
4.1.4 Bootstrap Capacitor Voltage Clamping
4.1.5 Design Scenarios with HVES
4.1.6 Bipolar Gate Drive Operation
4.2 Gate Driver Implementation
4.2.1 Gate Driver Architectures
4.2.2 Gate Driver Implementation for a Non-isolated and an Isolated Supply
4.2.3 Operation as High-Side Gate Driver
4.2.4 GaN GIT Support
4.2.5 Driver Sub-circuits
4.2.5.1 VHV Control
4.2.5.2 ``MHVx Control'' and Active Rectifier
4.2.5.3 Level Shifter
4.3 Experimental Results
4.4 State-of-the-Art Comparison and Limitations
4.4.1 Limitations of Gate Drivers Based on HVES
4.4.2 HVES Versus HVCS and Conventional Gate Drivers
4.4.3 Comparison with Prior Art
References
5 Gate Drivers for Large Gate Loops Based on HVES
5.1 Introduction
5.2 Concept
5.3 Implementation
5.4 Experimental Results and Comparison to Prior Art
References
6 Outlook and Future Work
6.1 Gate Drivers Based on High-Voltage Charge Storing (HVCS)
6.2 Gate Drivers Based on High-Voltage Energy Storing (HVES)
6.3 Gate Drivers for Large Gate Loops
6.4 Boost Converter High-Side Driver Supply
References
7 Conclusion
References
Index