Recommendations for power monitoring

[Jim Flanagan]

Hi
I have a work project which requires me to design a small circuit
for monitoring about 6 different voltages/currents. These currents
will be low, about 250mA. Also, I would like to be able to switch 'on'
power for each of these voltage sources. Now, obviously, this is easy
to do with some power fets for power switching, a resistive divider +
A/D converter and an instrumentation amp + A/D for current monitoring.

I would like to, however, simply use some off the shelf power, self
contained, IC. This is simply due to lack of time for the most part. I
haven't been lucky finding anything that combines these features. Does
anyone have any part recommendations for what I am looking for?

Thanks
Jim

 

[David L. Jones]

Hi
I have a work project which requires me to design a small circuit
for monitoring about 6 different voltages/currents. These currents
will be low, about 250mA. Also, I would like to be able to switch 'on'
power for each of these voltage sources. Now, obviously, this is easy
to do with some power fets for power switching, a resistive divider +
A/D converter and an instrumentation amp + A/D for current monitoring.

I would like to, however, simply use some off the shelf power, self
contained, IC. This is simply due to lack of time for the most part. I
haven't been lucky finding anything that combines these features. Does
anyone have any part recommendations for what I am looking for?

Thanks
Jim

I just put together a multi-channel monitoring system using the
MAX4372 high side current sense amp and MAX1229 ADC
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2104/t/al
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3874/t/al
Accuracy and offset isn't too bad, and the ADC has a useful hardware
averaging mode, and bonus on-chip temp sensor. A lower cost pin
compatible 10bit version of the ADC is available too I think.

If the voltage source is a regulator, then you can simply choose one
with a disable input pin.

There are other current sense amps out there, but I chose the MAX4372
because it has a common mode range down to zero volts.

Dave.