Improved Howland current source design

Discussion in 'The Projects Forum' started by anushaas, Aug 20, 2015.

  1. anushaas

    Thread Starter New Member

    Jul 18, 2011
    3
    0
    Hi,

    I am designing an Improved Howland Current Source of 500uA using AD8041. The bandwidth needed is DC to 2MHz. The load variation expected is 10 Ohms to 10 kiloOhms.The circuit is as shown below:

    IHCS.png

    The circuit when implemented gives a bandwidth of 1MHz.How can this be improved?
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,990
    3,226
    Is that real bandwidth or simulated bandwidth?
    If real, then you may have too much stray capacitance in the circuit.
    How was it constructed?
     
  3. anushaas

    Thread Starter New Member

    Jul 18, 2011
    3
    0
    Its the real bandwidth.I used a NI ELVIS board to implement the circuit.The output probe used was Tektronix TPP0200 voltage prode which has a capacitance less than 12pF. There could be bread board capacitance as well.

    The frequency response obtained is as shown:
    Bodeplot with 6.8pF capacitance.png

    Will I get a better response if I implement the circuit using a general purpose PCB?
     
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