Current Transformer to 4-20 mA

Naresh Patel2

Other Parts Discussed in Thread: XTR116, XTR115

Hello,

I am trying to convert CT (Current transformer) output AC current to 4-20mA loop powered output. I have to convert CT's output AC current to AC voltage (using a shunt resistor). Does the XTR115 or XTR116 has internal operation to convert this AC voltage to DC and then it converts to 4-20mA DC or do I have to convert AC voltage to DC before I can apply it to XTR chip?

Does TI have any one chip solution to get 4-20mA from applied ac voltage? If not, what TI chip can be used to convert ac to dc voltage (something like RMS to DC converter)?

Thanks.

over 11 years ago

0 Collin Wells over 11 years ago

TI__Guru 63965 points

Hi Naresh,

The XTR115/116 are meant to operate with dc inputs so you would have to condition the CT ac voltage output to a dc input voltage to be able to properly use the XTR115/6. TI does not have an integrated product that takes an ac input and makes a 4-20mA output.

Also TI does not have any RMS to dc converter integrated circuits. The analog circuitry to required to discretely build an RMS to dc conversion is not trivial and you may consider converting the CT ac voltage to digital and then performing the RMS calculations digitally. Then you could control a DAC output to the proper dc level to drive the 4-20mA loop driver circuit. Otherwise some of our competitors offer integrated analog RMS to dc converter circuits that you may consider.