I agree, those allegro parts are intriguing.   I actually was looking at=20
the ACS711 at some point... low cost, works, etc.

I guess where I'm hung up is that I really don't want to use a different=20
solution where I'm measuring current on-board vs a customer provided=20
shunt.   I might end up there, just because the solutions aren't all=20
that great for the onboard option as-is.

-forrest

On 4/22/2012 9:58 AM, Dwayne Reid wrote:
> At 02:49 AM 4/22/2012, Forrest Christian wrote:
>> I'm currently using an INA196 high side shunt amplifier in a couple of
>> applications.   As I asked/discussed a couple of weeks ago, one of them
>> involves current monitoring the currents through some P-channel FETS,
>> and am looking at moving the sensing from a sense resistor to sensing
>> across the FETS.
> Can I suggest a somewhat different approach?
>
> Allegro makes some fine hall-effect current sensors for probably less
> money than the INA196 op-amp that you are currently using.  The
> larger units are intended for high current operation (200A plus) but
> the tiny units are rated for plus minus 5A full-scale.  And a whole
> whack of current ratings in-between.
>
> For example, the Allegro ACS712ELCTR-05B-T (Digikey # 620-1189-1-ND)
> sells for Can $4.84 in singles but drops down to just over Can $3 in hund=
reds.
>
> The advantage of using a current sensor like this is that the current
> loop is galvanically isolated from the measurement side.  The ACS712
> datasheet says that the current loop is about 1.2 milli-ohms and the
> device is rated at 2.1kV minimum isolation between the loop and the
> sensor.  Frequency response is stated at 80KHz.
>
> There may be reasons why these parts aren't suitable but I think that
> they are worth a look.
>
> dwayne
>
>
> PS - I have another suggestion that I will post after this one.
>
> dwayne
>

--=20
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