SiC Power Device｜Basic
Tips for Practical Use: The Effects of Specialized Gate Drivers and Snubber Modules
2018.11.22
Points of this article
・Surges and ringing can be dramatically suppressed by using a specialized gate driver and a snubber module.
・Where losses are concerned, there is an increase in Eon and a decrease in Eoff. When comparing overall losses (Eon+Eoff), losses are reduced.
In this article, as important points in utilizing full-SiC modules, in addition to the snubber capacitors that were discussed in the previous article we explain improvements to switching characteristics when a specialized gate driver is used.
Driving Specifications and Basic Configuration of Full-SiC Modules
The characteristics resulting when using snubber capacitors and specialized gate drivers are compared for the following conditions and circuit configuration. The circuit configuration is provided with the electrolytic capacitors and film capacitors described in the previous article. When a specialized gate driver is not used, as a false gate turn-on countermeasure, a capacitance CGS of microfarad order is added, and -5 V is applied to VGS as a negative bias (for the case of a full-SiC module equipped with second-generation SiC MOSFETs).
Specialized Gate Driver Board for Full-SiC Module Evaluation and Ceramic Snubber Capacitor Module
These are a specialized gate driver and snubber capacitor for addition to the above basic configuration. They are made available for use in evaluating full-SiC modules.
This is actual equipment with these components installed.
Effect of Specialized Gate Driver and Snubber Module
To begin with, waveforms are compared when the equipment is turned on, both before and after installing the specialized gate driver and the snubber capacitors.
In order from the top, the ID, VD, and VG waveforms are shown, with red and orange representing the waveforms for cases in which the specialized gate driver and the snubber module are installed, and the blue and green representing waveforms when they are not installed. It is clearly seen that surges and ringing are suppressed.
Next, the turn-off waveforms are shown.
Surges and ringing are likewise greatly reduced.
Where losses are concerned, Eon is increased from 4.3 mJ to 5.3 mJ, while Eoff is reduced from 5.3 mJ to 3.8 mJ. This is because with decreasing inductance, which exerts a large influence, Eon increases while Eoff decreases. On comparing the overall loss (Eon+Eoff), we see that loss is reduced by 0.4 mJ.
In conclusion, we can say that in order to fully utilize the performance of a full-SiC module, it is a good idea to add a snubber and use a gate driver with a specialized design. Up till now, taking as our theme important points in utilizing full-SiC modules, we have considered gate drivers and explained the effect of snubbers, and, in this article, the use of specialized gate drivers. In order to perform extremely high-speed switching of high voltages and large currents, the use of such complementary components, as well as adjustments based on evaluations, are important points. Particularly during initial evaluations, using an evaluation board and other tools can greatly smooth development.
【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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