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| Pulsing PSU |
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| David Hess:
--- Quote from: ricko_uk on November 28, 2019, 03:05:47 pm ---What are the best types of caps for pulse applications and fast discharge (apart from the classic low ESR electrolitics)? --- End quote --- Given your voltage and capacitance requirements, film capacitors are the most suitable. Almost any type will do however the larger metal film rather than metalized film have a lower ESR. Special high ripple current ones which use spade or screw terminals are available. Many lower value leaded parts in parallel will reduce ESR and ESL but a careful layout is necessary for good current sharing. --- Quote ---Any suggestions, pointers or even better partial or full schematics would be very much appreciated :) :) --- End quote --- In the past I would have tried using an SCR for the discharge switch however an IGBT is probably be a better choice now. The initial discharge profile is very much like turn off into an inductive load which high power thyristors and transistors of all types are often characterized for so finding a suitable part from datasheets should be easy. For best performance, pay attention to construction with heavy conductors to minimize resistance and inductance. Keep loop areas at a minimum. I have built things like this which were more like plumbing projects. If the peak current is too high, then some inductance can be added to control it. In the extreme case, pulse circuits like these sometimes use a lumped transmission line for the storage element to lower the peak current and extend the discharge profile into a fixed length pulse. |
| ricko_uk:
Thank you David and Mariush! :) :) |
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