Re: Digital potmeter with on/off switch?

"Joerg" <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> schreef in bericht
news:HdR0g.66292$H71.13208@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hello Folks,

Is there any device that can not only perform digital potmeter action
with up/down rubber buttons but also replace the power switch? Ideally
suitable up to 20V, automotive or so. However, that 20V could possibly
be done via some regulator.

I am looking into replacing a switch/potmeter combo. It is 1M but lower
values are ok. Main thing is that the whole setup does not consume more
than a few uA in the switched off state.

I know that all this can be accomplished with a uC but this is meant for
a quick demo.

Well, all the digital potmeters I've seen had a i2c or SPI or up/dn
control inputs, not suitable for direct pushbutton connections. I'm
afraid you will need a small uC anyway. Maxim has plenty of choice
for digital pots.

I suppose you could make a FF from two cmos nand gates, and power
the uC/pot circuit from one of the outputs, to get that 'few uA when off'.
The 'up' button would always set the FF. The uC can reset the FF,
once the 'down' button has steered the wiper all the way down, and
putting everything to sleep.

--
Thanks, Frank.
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