KD7TOG wrote:

OK, here's a challenge to you guys ... I have been trying to ID a IC /
inductor combination to generate 150 to 200 VDC ... in the nano-microamp
range. I need to supply a bias voltage to an electrostatic microphone
element.

Any ideas ??

Wish list:

Very low current ... 2ma ;-)
Runs from 5 to 9 volt DC source
Minimal components

Most of the specs I find for HV units ( backlight supplies ) are too much
current. Most of the inductor type DC-DC converters seem geared towards low
voltage high current apps.

Will watch the discussion for tips and ideas ... all welcome.
Nothing is likely to be very efficient at this low power level. I
think I would look into a step up transformer design, perhaps using
something like a MT4143:
http://www.tamuracorp.com/pdf/MET-01.pdf
driven by a two transistor half bridge at ultrasonic frequency. With
a 14 to 1 step up, it could produce 200 volts peak across the whole
secondary, with only 7 volts peak across half its primary. If the
secondary was connected to a voltage doubler, you could drive it with
half that. The transformer is rated for 10 mw, but at 20 kHz, I think
it could do a bit more than that or run fairly efficiently at much
less.

--
John Popelish