From: Denny Esterline <desterline@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Fri, 24 Sep 2021 15:10:34 -0700
Subject: Re: [EE] Generating a +/-10V signal
Thread-Topic: [EE] Generating a +/-10V signal
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Suggest you use the magic incantation "offset and scale schematic" while
summoning the great and powerful google.
</attempted humor>

Lots of good results, but one of the first was a TI app note titled:
Designing Gain and Offset in Thirty Seconds
https://www.ti.com/lit/an/sloa097/sloa097.pdf

Lots of ways to do this, but essentially, you'll need two opamps. Set the
software controlled output to call 50% a "zero", the first opamp scales
that down by 1/2 VCC and the second is a gain stage to get you to +/-10v.

-Denny




On Fri, Sep 24, 2021 at 2:15 PM Neil <picdude3@narwani.org> wrote:

> It's just for the input control signal.
> So yes, I can take the output from the microcontroller (I can do a DAC
> or PWM w/RC filter to get an analog output from 0V - 5-ishV).
> But then if I amplify this with an op-amp, can I offset with an same
> op-amp?  I'm a bit unclear on what op-amp configuration I need for
> offsetting by -10V.
>
> FWIW, It seems that the driver has a +10V and -10 output, so I can use
> that to power the op-amp.
>
>
>
>
> On 9/24/2021 4:50 PM, Alan Pearce wrote:
> > On Fri, 24 Sep 2021 16:17:42 -0400
> > Neil <picdude3@narwani.org> wrote:
> >
> >> What's a simple way to get +/-10V from a microcontroller?  This
> >> +/-10V signal will go into a motor driver, so it does not need to be
> >> precise. And it may even be a +/-5V signal, but the concept will stay
> >> the same.
> >>
> >> Cheers,
> >> -Neil.
> >>
> > Is this just for biasing or to supply power?
> >
> > If just to bias something then a voltage multiplier off a PWM output
> > would work.
> >
> > If it needs to generate a voltage that will supply enough power to run
> > a motor then you may be able to use a PWM output to supply boost
> > convertor circuitry, but frankly I would go searching the various
> > manufacturers for boost converter chips. LT/AD certainly have suitable
> > devices, and I think TI do as well from the NS line of devices.
> >
> >
>
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