A Lower Forward Voltage Drop Does Not Always Bring Benefits
Schottky barrier diode (SBD) is a unipolar device, which means electron (majority carrier) is the only carrier that conducts current during the normal operation of the Schottky diode. SiC, because of its wide bandgap, exhibits a higher Schottky barrier compared to Si and consequently a higher cut-in voltage (the forward-biased voltage where the diode starts conducting). However, the higher Schottky barrier and dielectric strength of SiC also enable the voltage rating of the SiC Schottky diode to easily reach 3300V. In the meantime, the voltage rating of the Si Schottky diode rarely exceeds 200V. Today, SiC Schottky diodes have replaced Si PiN diode (which is a bipolar device with a much higher reverse recovery charge and longer reverse recovery time) in many applications as switching diodes.
The forward voltage (VF) is one of the parameters people care about most in the datasheet of the SiC Schottky diode because it is directly related to the conduction loss. However, a paper published by Stanford scientists suggested that the junction capacitive charge (Qc) is another parameter as important as VF. The authors compared commercial SiC Schottky diodes and showed that the diode with a higher VF and a lower Qc can outperform the diode with a lower VF but a higher Qc, depending on the operation conditions. The reason is that the diode also dissipates energy during each cycle of charging and discharging its junction capacitance.
That says VF*Qc is a better measure (figure-of-merit) that should be used to evaluate the performance of the SiC Schottky diode. Generally, if the rms current is relatively low and/or the switching frequency is relatively high, choosing low Qc rather than low VF will give you a better chance to improve the efficiency.
- +1 Like
- Add to Favorites
Recommend
- SLKOR Launched BAT54C Schottky Barrier Diode with an Integrated Guard Ring for Stress Protection
- SiC Schottky Compared to Normal Schottky Diode
- Nomenclature for the Schottky Diode MBR Family
- SHINDENGEN Additional Line-up of TO-252 Package: Low Vf Schottky Barrier Diodes and Ultra-fast Recovery Diodes
- The Difference Between a Schottky Diode and a Fast Recovery Diode
- New Littelfuse 1700V SiC Schottky Barrier Diodes Dramatically Reduced Switching Losses Compared to Si Bipolar Diodes
- The Difference Between Schottky Diode (SBD) and Common Diode
- New 650V and 1200V SiC Schottky Barrier Diodes for Power Conversion Systems | PANJIT
This document is provided by Sekorm Platform for VIP exclusive service. The copyright is owned by Sekorm. Without authorization, any medias, websites or individual are not allowed to reprint. When authorizing the reprint, the link of www.sekorm.com must be indicated.
Integrated Circuits
Discrete Components
Connectors & Structural Components
Assembly UnitModules & Accessories
Power Supplies & Power Modules
Electronic Materials
Instrumentation & Test Kit
Electrical Tools & Materials
Mechatronics
Processing & Customization
