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LNK40x and LNK41x FB pin - short circuit current

Posted by: dave-ml on 03/14/2012

Referring to the Linkswitch-PH datasheet, I can see that 220uA is the minimum feedback pin current threshold to put the device into the 'skip cycle' region. The datasheet also states that the feedback pin 'short-circuit' current, Ifb(sc), is between 320uA and 480uA.

I could not find any other information regarding this short-circuit current. Can you please confirm if this current is simply the maximum current the FB pin will sink? Ie, will the linkswitch still continue to operate in the 'skip cycle' region, or can some other behaviour be expected if the feedback current hits Ifb(sc)?

Kind regards,


Submitted by PI-Skywalker on 03/15/2012

The feedback pin short circuit current is the simply the maximum current the FB pin will sink, and the device will be in the skip cycle mode if the FB pin current is higher than 220 uA.

When the FEEDBACK pin current falls below the IFB(AR) threshold in the event of output short-circuits or an overload condition, the controller enters into the auto-restart mode.