Short pulse, peak current ratings of diodes

Peak current ratings for diodes are usually given as a surge current rating for a specified pulse. These surge current ratings can be as high as several 10´s of kA for the larger devices. It has been found that these devices are capable of conducting much higher peak currents for short pulse durations (hundreds of microseconds). These short-pulse, peak current ratings are important for the design of power supplies that deliver high currents for short durations (as in distributed energy stores). Theoretical and experimental results obtained for diodes operated at high peak currents for short pulse durations are described. What the peak current rating depends on for short pulses is explained. A model for determining what the peak current rating should be for short pulses is given. A description of the experimental setup and the test procedures used for obtaining V-I data is provided. Results are given for a 100 μs long pulse at peak currents up to 200 kA for a single device. Test results indicate that the current capability of high-power diodes is not current limited but is rather a function of the junction temperature