Hello Mike and Vasile,

>Use a comparator instead of an op-amp. op-amps do not make good
>comparators in many cases.

    what I don't like about the comparators is the open-collector outputs.
As I'm implementing an auxiliary power supply with resistor-zener
regulation, I have to stay low current.

> cmos       : CD4093

    Very good sugestion! I'll this today.

> ttl        : 7413 or equivalents

    Vmm, only 5V I suppose. I need 10V minimum.

> comparators: LM393, LM111

    Open collector.

> discrete   : two transistors

    I've thought of using a pair of TO-92 MOSFETs (BSS100/BSS110) to
implement a driver that could help to sink/source current to the high power
MOSFETs gates.

    I've learned today that Fairchild makes some optocouplers (MOC5007/8/9)
with schmitt trigger outputs that could have VCC as high as 16V. I would
like to try these ones, but they're open collector too...

    Thank you very much,

    Brusque
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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Researcher and Developer               Blumenau  -  SC  -  Brazil
Say NO to HTML mail                          www.citronics.com.br
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