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UC3854 peak current limit calculation

Knighty
Intellectual 380 points
Other Parts Discussed in Thread: UC3854

Hi All,

Does anyone explain how to calculate peak current limit (PKLIM)of UC3854? refer to datasheet  page 7   "7.5V*2k/10k=1.5V" how 2K and 10K come from?

Thanks

NT

  • 0
    TI__Guru* 85676 points

    The PKLMT comparator for this device is setup with a voltage divider off the reference and attached to the current sense resistor.  Please refer to figure 1 the typical application.  I do see they used a resistor divider of 10K and 1.6K, which does not match the equation on page 7.  In this case the minimum voltage across the current sense resistor that would trip the peak current limit would be (7.5V/10K)*1.6k = 1.2V

  • 0 in reply to Mike O'
    Prodigy 20 points

    Hi Mike,

    Can you help us resolve few issues with UC3854. We are developing 5kW power source using UC3854.

    We referred to U-134 Application note by TI but was not successful. We have ended up the blowing up the units.

    Observations:

    Not able to regulate the output voltage