high voltage rail splitter ideas

[Smokey]

Anyone have any experience with high voltage rail splitters for creating a virtual common point?  I'm talking about 150V (split to +/-75V), which in the grand scheme of things isn't that high, but it is higher than any single dedicated rail splitter IC can handle (that I am aware of at least). 
I probably need around 100mA referenced to that virtual midpoint. 

This site has some good info relating to low voltage audio stuff for some background.
http://tangentsoft.net/elec/vgrounds.html

It looks like an active solution using a pair of transistors and biasing components is the way to go as long as I can get the heat out (which I shouldn't have a problem with with existing forced air cooling and heatsink).

Thoughts, suggestions, rants welcome.

[dannyf]

ut it is higher than any single dedicated rail splitter IC can handle

There is nothing special about those "rail splitters". If the load draws very little current, a resistive divider will work. If not, use a high voltage opamp - many audio power opamps can handle high voltage and I am sure you can find ones that fit your needs.

[TerminalJack505]

A unity gain, unipolar version of the circuit they're discussing in this thread would work as a high voltage rail splitter.  The op amp's +/- 15V supply would have to be centered around your virtual ground.  Then, to set the virtual ground output you'd just set the input at the halfway point.

For more information regarding that circuit, you might look at the LT app note (that someone in that thread pointed out) where that circuit appears.

[Smokey]

Cool circuit.  Ill give that a shot in the spice land and see if I can make that work. 
It looks like ill have to use a resistor divider to set the midpoint for the opamp reference and the +/-15 supply for the opamp but the rest of the current can come from the regulated output transistors.

[TerminalJack505]

For fun, I had a play around in the simulator with a couple of implementations of a 150V rail splitter.

I don't know how well they'd actually work but I thought I'd share them in case they might give you some ideas.

[dannyf]

The zener is not really needed. For an open-loop buffer like that, transistors like SAP15P/N would be excellent.

If you want a closed-loop solution, an opamp would work as well.

Or to make it simpler, a high-powered audio amp can function as a rail splitter too.