1200V amplifier

[Nightvision]

People,

I want to build a sor of amplifier which can make 0 to 1200V output out of 0 to 5V input (may also be inverted).

It has to be a lineair control. It also has to be in SMD. Many transistors or FETs can't go further than Vce and Vbe of 200/300V, so I have to make something which can handle the 1200V.

Anyone has an idea?! Thanks!

Martijn

[jackinnj]

good luck finding SMD resistors for KV operations. KV transformers are also special beasts -- once you go over 600V the wire and between-layer insulation becomes quite specialized and expensive. I don't know what the situation is on that side of the Atlantic, over here HV transformers are relatively easy to obtain from military surplus outlets and ham radio flea-markets.

in fact, one of the easiest ways of implementing this design is to regulate the primary side of a transformer, picking up the error signal from the secondary side -- think of it as a linear supply using switching power control loop principles. instead of controlling the duty cycle of a switch, control the amplitude of a primary side amplifier -- you can opto-couple the feedback control just as in a SMPS.

[phase_accurate]

What power and bandwidth are you looking at ? Is it for driving a large ESL, a small piezo actuator, ..... ?

Regards

Charles

[janneman]

Originally posted by jackinnj
good luck finding SMD resistors for KV operations. KV transformers are also special beasts -- once you go over 600V the wire and between-layer insulation becomes quite specialized and expensive. I don't know what the situation is on that side of the Atlantic, over here HV transformers are relatively easy to obtain from military surplus outlets and ham radio flea-markets.

in fact, one of the easiest ways of implementing this design is to regulate the primary side of a transformer, picking up the error signal from the secondary side -- think of it as a linear supply using switching power control loop principles. instead of controlling the duty cycle of a switch, control the amplitude of a primary side amplifier -- you can opto-couple the feedback control just as in a SMPS.

An easy way would be using a standard audio power amp and have it drive a step-up transformer that can handle the voltage levels. That gives you galvanic isolation, low price (an LM3886 would be great for this) and level control.

Jan Didden

[Hanzwillem]

Also, check out Apex microtech
http://eportal.apexmicrotech.com/mainsite/index.asp

They have some piezo drivers and stuff. Also some usefull articles on precautions using high voltage opamps.

succes.

[janneman]

Just thought of something: this 1200V is that peak-to-peak or RMS or what? if it is p-p and balanced you can use a tube power amp and take the output from the primary of the output xformer.

Jan Didden

[jackinnj]

Originally posted by janneman
Just thought of something: this 1200V is that peak-to-peak or RMS or what? if it is p-p and balanced you can use a tube power amp and take the output from the primary of the output xformer.

Jan Didden

that's what we used "in my youth" when doing Electron Spin Resonance experiments -- seems like a shame to have used a McIntosh amplifier, but what the heck, the U.S. Navy was paying for it.

[EC8010]

Originally posted by jackinnj
that's what we used "in my youth" when doing Electron Spin Resonance experiments -- seems like a shame to have used a McIntosh amplifier, but what the heck, the U.S. Navy was paying for it.

Surely the amplifier found other uses when it was "off-duty"?

[SY]

Originally posted by jackinnj


that's what we used "in my youth" when doing Electron Spin Resonance experiments -- seems like a shame to have used a McIntosh amplifier, but what the heck, the U.S. Navy was paying for it.

My dissertation work involved the use of B&K 4003s to measure infrared spectra. For some reason or other, those mikes never seemd to be around unless I was physically in the lab.

Why was the Navy doing ESR?

[pinkmouse]

Originally posted by SY
Why was the Navy doing ESR?

Re-run of the Philadelphia Experiment?