This is the sort of thing that used to be used in professional flash guns f= or camera use. My memories are of my father servicing Metz flash guns, which could cycle 1= 500uF to 500V in about 5 seconds flat after a flash, somewhere in the range= of 7-10 seconds for a cold start. They used a ringing choke inverter as these are essentially short circuit p= roof, they are current limited by the inductance of the transformer until t= he voltage reaches its upper limit. If there is a short on the output then = the unit oscillates at low frequency determined by the magnetic field colla= pse time of the shorted inductor. In the latter days of my apprenticeship one of my colleagues got involved i= n designing a capacitor discharge ignition system for motor vehicles as a h= obby project. This used a push-pull self-oscillating converter, essentially= for the same reason, the output is inherently short circuit proof. In the = process of this he did a series of temperature tests to ensure it would wor= k straight off in the snows of winter, but we found the biggest problem was= the curie point of the ferrite toroid at the high temperature end. It sounds to me (from the dimensions) like you are doing this for a down ho= le project - in which case the temperature will get you with inductors. See= ing you are starting from around 200V, and wanting to go to around 12x that= , I would try a totem pole FET drive across the 200V supply and feed a Cock= croft-Walton style voltage multiplier. This would mean no inductors and hen= ce save high temperature problems. Oh, and pot the whole thing - highly recommended potting compound is Stycas= t 2850 Blue and select the right catalyst for HV resistance. >=20 > Good day to all. >=20 > I've been asked to design a DC-DC converter and this one is outside my > current experience. Ideally, I'd like to farm this project off to someon= e else. > Barring that, design assistance would be greatly appreciated. >=20 > Here are the specs that I've been given: >=20 >=20 > Input voltage range - 180 Vdc to 220 Vdc >=20 > Output voltage range - from 2000 to 2400VDC (regulated by varying input > voltage from 180 to 220VDC). >=20 > Power rating of the converter should be suitable to charge high voltage > capacitor bank with total capacitance of 250uF in less than 10 seconds. >=20 > Capacitor bank have to be fully charged after not more than 15 seconds. >=20 > Temperature rating is from -20 to +125 Deg C. >=20 > Dimensions of the converter module: have to be made in form of a cylinder > with maximum diameter of 48.5mm and length not more than 670mm. >=20 > Protection: input over-voltage protection; output protection from capacit= or > bank discharge transient voltage/current. >=20 >=20 > I don't have ANY idea how to either design or > specify the transformer (or inductor) so that it > won't have voltage-breakdown issues. >=20 > Anyone want to take this on? Please contact me > privately and we can discuss compensation. >=20 > Many thanks! >=20 > dwayne >=20 > -- > Dwayne Reid > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > 780-489-3199 voice 780-487-6397 fax 888-489-3199 Toll Free > www.trinity-electronics.com > Custom Electronics Design and Manufacturing >=20 >=20 > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .