• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 47 subscribers
  • Views 819 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

differential output ac constant current source

siauhwa ong
Expert 1510 points
Other Parts Discussed in Thread: OPA2364, OPA2314, OPA364

Hi,

I need a differential output AC constant current source of around 100 or 200mA. Freq is around  20 Hz.

Can I build that using a pair of Howland Current pump ?

Thanks

  • 0
    TI__Guru* 93105 points

    Hello Siauhwa,

    Yes, two Improved Howland Current Pumps can be used to generate differential ac currents. The key to making this straightforward and accurate is to drive the two pumps from the same differential output voltage source. Either an operational amplifier having a differential output, or a dual operational amplifier configured as a single-ended input, differential output amplifier.

    I have attached a slide created by one of my colleagues showing how to create the single-ended input, differential output amplifier. An OPA364 (OPA2364 is the dual) is shown in the schematic. Since your application doesn't require speed a lower current amplifier such as the OPA2314 would be a good choice to reduce power.

    Regards, Thomas

    PA- Linear Applications Engineering

    Sing Ended Input to Diff Output.pptx
  • 0 in reply to Thomas Kuehl
    Expert 1510 points

    Hi Thomas,

    I'll try it and I'll let you know ...

    By the way, do you have the TINA simulation/result  for that circuit ?

    Thanks

  • 0 in reply to siauhwa ong
    TI__Guru* 93105 points

    Hi Siauhwa,

    You can try clicking on the TINA symbol shown on the slide. I think the TINA file for the single-ended input, differential output amplifier is embedded - at least it opens directly from TINA when accessed from my original slide.

    However, if that doesn't work I've attached a TINA file for the circuit.

    Regards, Thomas

    PA - Linear Applications Engineering

    RRIOSE~1.TSC