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0-20/4-20 mA to 48VDC (2A) current-to-voltage converter

Charles Carmichael
Prodigy 10 points
Other Parts Discussed in Thread: OPA548

I'm looking for a device that can convert 0-20 or 4-20 mA (doesn't matter) output linearly to a 0-48VDC (2 A max) signal. Does TI have anything like this?

  • 0
    Guru 21975 points

    Charles,

    Here is a basic circuit using the OPA548 op amp. The 0-20mA is converted to 0-1V with a 50 ohm input resistor, then amplified by a G=48. It is simple enough but untested. The load is connected to ground which may help pull it all the way to zero with zero input. Be cautious about power dissipation. If you have a resistive load referenced to ground and the max output current could be 2A at 48V out, then max dissipation of the op amp could be around 32 watts with a 55V supply. You would need a large heat sink to keep temperature of the op amp safe.

    Again, this is just a possible approach without much refinement or testing. Read the OPA548 data sheet for detail on its use.

    Bruce