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sinewave constant current source

siauhwa ong
Expert 1510 points

Hi,

I need a sine wave ac constant current source.  I need to synchronize the sinewave to another part, so I create the sine wave using a dac.

Freq is around 800 Hz, fixed. And load resistance is between  1Kohm to 1 Ohm.  The system will be power up with +/- 12V rail. So, current is about 10mA.

Any suggestion on the current source circuit ?

Thank you so much.

  • 0
    TI__Guru* 93105 points

    Hello Siauhwa,

    Actually, there have been a number of E2E posts on the subject of ac current sources over the past few years. The solution that we have provided uses an Improved Howland Current Pump as a voltage-to-current converter. You apply a sine voltage source to the current pump's input and the pump provides the constant current to the load.

    Here is one detailed E2E thread about the subject:

    http://e2e.ti.com/support/amplifiers/etc_amplifiers__other_linear/f/18/p/53816/192847.aspx#192847

    There is a PowerPoint attachment within the discussion string that provides details about the Improved Howland Current Pump and how to derive the component values.

    You can utilize the E2E "Community Search" entry to search for more information on the subject. There have been other discussions on the subject. You can uncheck the "Just this area" box if you want to extend your search to include other E2E support forums.

    Regards, Thomas

     PA - Linear Applications Engineering