SiC Power Device｜Application
SiC MOSFETs: Methods for Suppressing Gate-Source Voltage Surges ー Summary ー
2023.11.08
This concludes the series “SiC MOSFETs: Methods for Suppressing Gate-Source Voltage Surges”. Past articles have explained surges that occur in gate-source voltages, surge suppression circuits, positive voltage surge countermeasures, negative voltage surge countermeasures, and guidelines relating to PCB layout for surge suppression circuits.
Gate signals for SiC MOSFETs in a bridge configuration cause unanticipated voltage surges in gate-source voltages of the MOSFETs, with their mutually interrelated operation. As methods for suppressing such surges, apart from adding a suppression circuit, the PCB pattern layout is also important. The suppression methods described in this series should be useful when searching for the optimal measures to adopt for given circumstances.
As a final summary, the key points and links to each of the articles are listed below.
▶About Surges in Gate-Source Voltages
Key Points of This Article
・In recent years, SiC MOSFETs have been used increasingly frequently in power supply and power line switching applications, but they are so fast that the effects of the self inductance of the package of the MOSFET and that of peripheral circuit wiring cannot be ignored.
・For this reason, unexpected surges sometimes occur in the gate-source voltage in particular, and these must be addressed.
Key Points of This Article
・Positive surges in the gate-source voltage (VGS) occur on both switching and non-switching sides, but positive surges on the non-switching side (HS) during LS turn-on are particularly problematic.
・In essence, measures to suppress surges are necessary, including other surges, and so surge suppression circuits must be added.
▶Positive Voltage Surge Countermeasures
Key Points of This Article
・Countermeasures to deal with positive surges in the gate-source voltage can prevent false HS turn-on while the LS is on.
・This is done by adding special circuits, shown in the example circuits.
・Surge suppression using a mirror clamp is difficult when the gate driver IC has no relevant control functions.
・In place of a mirror clamp, the method of adding a false turn-on suppression capacitor can be used.
▶Negative Voltage Surge Countermeasures
Key Points of This Article
・Countermeasures to deal with negative surges in the gate-source voltage can prevent false HS turn-on while the LS is on.
・This is done by adding special circuits, shown in the example circuits.
・Surge suppression using a mirror clamp is difficult when the gate driver IC has no relevant control functions.
・As a replacement for a mirror clamp, in consideration of positive surges, a clamping Schottky barrier diode and a false turn-on suppressing capacitor can be used together for optimization.
▶Guidelines Relating to PCB Layout for Surge Suppression Circuits
Key Points of This Article
・In designing the PCB layout for a surge suppression circuit, consideration must be paid to switching large currents at high speed.
・Parasitic capacitances, inductances, and resistances should be minimized.
・Return line loops should be minimized to deal with EMI.
【Download Documents】 Basics of SiC Power Devices
This handbook explains the physical properties and advantages of SiC, the differences in characteristics and usage of SiC Schottky barrier diodes and SiC MOSFETs with a comparison to Si devices, and includes a description of full SiC modules with various advantages.
SiC Power Device
Basic
- What are SiC Schottky barrier diodes? ? Introduction
- What are SiC-MOSFETs? – SiC-MOSFET Features
- What are Full-SiC Power Modules?
- Summary
- Introduction
- What is silicon carbide?
Application
-
Introduction
- SiC MOSFET Bridge Configuration
- SiC MOSFET Gate Driving Circuit and Turn-On/Turn-Off Operation
- Currents and Voltages Occurring Due to Switching in Bridge Circuits
- Behavior of the Gate-Source Voltage During Low-side Switch Turn-on
- Behavior of the Gate-Source Voltage During Low-side Switch Turn-off
- Summary
- SiC MOSFETs: Method for Determining Losses from Switching Waveforms
-
SiC MOSFETs： Snubber Circuit Designs ーIntroductionー
- Non-Discharge RCD Snubber Circuit Design
- Surges Occurring between Drain and Source
- Types and Selection of Snubber Circuits
- C Snubber Circuit Design
- RC Snubber Circuit Design
- Discharge RCD Snubber Circuit Design
- Non-Discharge RCD Snubber Circuit Design
- Differences in Surge Occurrence Depending on Package
- SiC MOSFETs： Snubber Circuit Designs ーSummaryー
- Points to Note When Measuring SiC MOSFET Gate-Source Voltages: General Measurement Methods
-
Conventional MOSFET Driving Method
- Packages Provided with Driver Source Terminals
- Differences Made by and Benefits of a Driver Source Pin
- Benefits of a Driver Source Terminal: Comparisons Using Double Pulse Tests
- Behavior of Gate-Source Voltages when in a Bridge Configuration: Behavior at Turn-on
- Behavior of Gate-Source Voltages when in a Bridge Configuration: Behavior at Turn-off
- Points to be Noted Relating to Board Wiring Layout Key Points of This Article
- Verification of Loss Reduction Using Latest-Generation SiC MOSFETs
- About Surges in Gate-Source Voltages
Product Information
- SiC Schottky Barrier Diodes
- SiC MOSFET
- SiC Power Modules
- SiC Schottky barrier diode Bare Die
- SiC MOSFET Bare Die
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