Connect with us

Demonstrating SEPIC capacitor overvoltage?

Discussion in 'General Electronics Discussion' started by eem2am, Apr 7, 2013.

Scroll to continue with content
  1. eem2am


    Aug 3, 2009

    Please assist in measuring short term overvoltages on my SEPIC capacitor......

    SEPIC capacitor is 22uF, X7R, 1812, 16V

    I have done a SEPIC converter.
    Max output power = 5W.
    Input voltage = 5 to 8.5V
    Output voltage = 5V or 40V (depending on luminaire)
    Switching frequency = 40KHz to 110KHz
    Constant off time control

    The SEPIC coupled inductor is coilcraft MSD1583-473

    When i looked for overvoltages across the sepic capacitor on the Scope (200MHz bandwidth scope) , i merely placed the scope probe across the SEPIC capacitor.

    However, the scope probe ground will have an associated capacitance to the ground, and so i fear that i may have unwittingly filtered any overvoltage spikes away?
    -Must i use a differential probe to look for the overvoltages on the sepic capacitor?
    I am wondering if there will be overvoltages at start up, due to the ringing with the leakage inductance of the coupled SEPIC inductor?
    Also, as the FET switches, i fear that there may be overvoltages on the SEPIC capacitor at these intervals also?

    Do i need the differential probe?, and what bandwidth Diff probe must i purchase?
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day