[sdiy] OT: High voltage diff amp

[John Luciani]

On 5/25/06, John Luciani <jluciani at gmail.com> wrote:
> On 5/25/06, Antti Huovilainen <ajhuovil at cc.hut.fi> wrote:
> > Hi
> >
> > I have a signal (few volts) riding on top of high common mode voltage (few
> > hundreds of volts). I need to isolate only the differential signal. Any
> > advice on how I should approach this?
>
> Look on the TI and ADI websites for isolation amplifiers.
>
> The TI ISO124 is around $7-8 and provides 1500V of isolation. You will have to
> add a second isolated power supply to your circuit that will be referenced to
> the signal you are measuring.
>
> Some isolation amplifiers have this power supply built in (they are
> caller tri-port).
> Tri-port devices are usually a lot more expensive then adding your own
> power supply.

One more component you may want to check out is the Vishay IL300.
The IL300 combines an LED and two photodiodes in a single package.
The datasheet has an optically isolated amplifier circuit.

(* jcl *)

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