Hello,
I need to measure a phase-phase motor voltage (U-V) with a F28335 DSP, including a galvanic isolation and bandwith > 50kHz.
As I already used the component, my plan was initially to use the ISO124, but then I remarked that it does not permit to measure a differential voltage (given that Vin is referenced to GND1 ; maybe I could eventually connect the GND1 to my "V" phase, but I don't like this solution) --> can anybody confirm that ISO124 is not well adapted for my application ?
So, I found the AMC1200 that is a fully differential voltage measurement amplifier, but I would have any questions concerning how we shall use it :
- Component supply (cf. datasheet figure 33 page 16) : the component will be supplied with +5V ; which resistor value shall I use (named R1 on fig. 33) ? what are the diode characteristics?
- Component supply : shall I supply the component in +5V/GND or +5V/-5V?
- Differential voltage measure : my motor phase voltage value will be around +/-65V ; is it ok to use a resistor divider to decrease the voltage to +/-250mV ? We need a good precision, so is it ok if we reduce so much the voltage, including the DSP ADC precision too ?
- Connexion to the ADC input : on §8.2.1.2 page 16, it is indicated I can connect the ACM1200 output directly to the DSP ADC input (0-3V), so I dont need to add any op. amp. to apply any offset ? I simply connect "VOUTP" to the ADC input, and "VOUTN" to the DSP GND (DSP GND will be connected itself to GND2 of AMC1200) ?
Then, if you know a component that could be better than AMC1200 for my application, please let me know !
Thank you in advance for any advise you could provide me,
Best regards,
Julien