High negative voltage (-100 to -500V) switching with minimal current

[Saulius]

Hello

I am a final year bachelor in material science and i am quite a novice in electronics, but I have this project on my hands: for magnetron sputtering, on substrate we need to generate 10+ kHz switching 100-500v negative bias voltage ( we have wave generator and high voltage dc power supply, and we need middle part between these too), with minimal current, using only discrete components (i live in a small country and it would take a lot of time to obtain some intricate parts, and time is of essence here).

Thank You

PS, sorry for broken grammar

[qwaarjet]

There are many MOSFETs capable of handling that voltage and frequency. However you will need a proper gate driver. For low frequency I use optical drivers but at this frequency I would look at a transformer based system like this.
http://www.st.com/web/en/resource/technical/document/application_note/CD00003897.pdf

[VK5RC]

Sorry to take things back in time but have you thought about a valve (thermionic)?

[fcb]

I would probably use a small ferrite cored transformer.

Drive it (transformer) with a square wave (probably drive it with an H-bridge made from junk-box transistors or MOSFET's), vary the DC supply to the H-bridge (say 10-50V) to get your 100-500V. Don't use a gapped core - you are using the transformer as a transformer, not a flyback transformer.

Obviously use a fast rectifier diode to give you negative only pulses, probably load the secondary with a suitable resistor (this will reduce the ringing).

[3roomlab]

photoflash style flyback -ve autotransformer?