At 02:25 PM 8/16/01 -0400, you wrote:
>I have done something like this by setting up a constant current source to
>feed an R + Zener. This keeps the wattage to a reasonable value as the volts
>go up.
>
>The total parts amount to 2 low power zeners, a few Rs and a small (but
>relatively high voltage) transistor.

This is nice. I did something similar with a TLV431, high voltage mosfet and
NPN transistor (and a resistor) for the curent source, and a TL431 and two
resistors for a high performance zener. It works on a 200VDC bus to derive
voltages on either side of the bus for monitoring and drive circuits.

Best regards,
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