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UCC28056: VOSNS terminal Open protector

Hiroshi Doi35
Expert 2845 points
Part Number: UCC28056

Hi all,

Does UCC28056 have "VOSNS terminal Open protector"?

In Japan, Some tragic accident happened by the opened resistor in the past.

So major AC power designer required this protector inside IC.

  • 0
    TI__Prodigy 750 points
    The One pin scenario of the UCC28056 is covered by having an OVP2 setting. When the pin is open or closed, the output voltage wants to rise up. The UCC28056 independently tracks the output voltage through the CS-ZCD pin by looking at the drain voltage. Since the drain voltage is the output voltage when the MOSFET is off, Output voltage information is obtained through an independent resistor string.

    This OVP2 protection scheme is better than having a simple open or short case protection found in many controllers. This is because it not only protects the PFC during pin open/short, but also protects the PFC during partial stress of the HV resistor dividers during surges and other fast transient induced failures and guarantees that the PFC output will always be below the OVP2 threshold.

    Hope this helps