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Constant current source (CCS)

Dr Babankumar Bansod
Prodigy 20 points

Hi!

I'm new to this experience.

Can anyone guide me for building constant current source which is used as a source for impedance measurement scheme.  The frequency of this source will be controlled through DDS which will send frequency, phase and amplitude controlled inputs to CCS. CCS will send stimulation signal to load/network. The load impedacne variations are from 6K ohm to 46 M ohms. Phase angle theta also varies. The load variation were measured using commercial impedance analyser for 100KHz- 10MHz. I can provide complete measurements.

I'm in the process to buid application specific automated impedance analyser. Can you guide if any readily available CCS scheme exists that can be used successfully for 100KHz to 30 MHz freq swep. I also intend to simulate such a circuit in Tina simulations.

I shall be grateful for your support.

Thanks and sincere regards,

Dr.Babankumar

  • 0
    Expert 2580 points

    Hi,

    use bing.com to search for 'Howland current source', take this as an starting Point to see what you can get:

    https://www.circuitlab.com/circuit/9x749h/howland-current-source/

    With best regards

    Gerhard

  • 0 in reply to Gerhard Kreuzer
    Prodigy 20 points

    Hi!

    Thanks and highly appreciate your inputs. I'm trying to measure impedance over a freq sweep of 100KhZ / 1 MHz  to 30MHz. Impedance values would vary from  5k-ohms to several M-ohms. Before doing actual implementation, I would intend to understand circuit behavior and fix-up values of IC's  and discrete components to be used. Can you suggest relevant tool? Is Tina s/w ok and can you get me started with some initial model in this direction.

    I would apply sweep of freq to such a CCS throgugh DDS programmable chips. Or else it may be that for initial experimentation I would use function generators as a signal source to CCS.

    Thanks and sincere regards,

  • 0 in reply to Dr Babankumar Bansod
    Expert 2580 points

    Hi,

    you will Need a sine wave (single freq) but you get a square wave from DDS.

    With best regards

    Gerhard