Surge Voltage Absorption by a Silicon Carbide Avalanche-Diode with P-N structure

A SiC avalanche-diode with P-N structure has been developed to utilize it as a surge voltage absorber in power converter circuit. To evaluate the static characteristics, correlation between clamping voltage and avalanche current has been measured. The temperature dependence of the clamping voltage was also measured. The effectiveness in suppressing surge voltage by SiC avalanche-diode has been demonstrated in step-down DC/DC converter. By comparative studies with the RC and RCD snubbers, sufficient performance has been accomplished with avalanche-diode. Moreover, by measuring power efficiency, it is confirmed that the avalanche-diode effectively suppress the surge voltage without introducing additional power dissipation.