Output Capacitor

Discussion in 'General Electronics Chat' started by imraneesa, Mar 8, 2015.

  1. imraneesa

    Thread Starter Member

    Dec 18, 2014
    188
    4
    Can anybody help me how to calculate the output capacitor required for the attached ic. i.e. AX2003.

    Input Vmin=7.4V
    Vmax=8.4V
    Current required for Diode = 2A.

    I did not find any details about calculating output capacitor.
    No spikes and No ripple currents. becoz diode is very sensitive of spikes and ripple currents.
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,049
    3,244
    What kind of diode is sensitive to spikes and ripple current?

    Which circuit on the data sheet are you using?
     
  3. imraneesa

    Thread Starter Member

    Dec 18, 2014
    188
    4
    I want to use it as constant current for laser diode.


     
  4. imraneesa

    Thread Starter Member

    Dec 18, 2014
    188
    4
    I don't know the difference between those circuits. I just want to build a buck constant current using that ic. They gave formulas for setting current and finding inductor. But they did not give any details about output capacitor which is important to reduce ripple.

     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,999
    745
    If your talking about C1, on page 5, then its 4.7uF.
     
  6. imraneesa

    Thread Starter Member

    Dec 18, 2014
    188
    4
    so for different inductance if we use the same 4.7uf there will be plenty ripple in the output. and I don't want that. I am attaching a schematic of the same ic circuit. I want to know how they have arrived that from datasheet.

     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,999
    745
    just build the circuit on page 5 ,and modify it as needed..
     
  8. imraneesa

    Thread Starter Member

    Dec 18, 2014
    188
    4
    But they gave the details of L and c2 values only upto Iled 1000mA.
    what if I want to use it for 1.8A. what are the formulas for L and C2?
     
Loading...