Michael Rigby-Jones wrote:
>>   Besides "use the laptop", can anyone suggest a way of 
>> getting rid of this 
>> noise? It's causing major problems with the opamps in the V/I 
>> sense circuit -- 
>> the noise is going from the Vcc supply to the opamp output. 
> 
> Sounds like you have relatively poor supply rejection?  Is one of the inputs referenced to the Vcc rail?

No, I've got a voltage divider halving the battery voltage and feeding it to 
the positive input of an opamp wired as a voltage follower. The current sense 
circuit is a low-side sensor; the top end of the resistor goes to the positive 
input, and the sense amplifier is wired as a 30x non-inverting amplifier.

The noise is appearing on both outputs, but it's worst on the current sense 
output. It's not present at all on the I(sense) opamp's positive input.

> Have you tried using a serial connection to the ICD instead of USB?  You will need to plug a 9v supply into the ICD though.

I'll try that once I can find a spare 9V power supply with the right type of 
connector on it...

Thanks.
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