shift in output current after potting and zener in V pin

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Using potting compound in LNK PH series, poliurethane ou poliester resin, I see an increasing in output current. for example 2A to 2,3amps. This phenomena in yur opinion is more related with V pin resistors ou Fedback pin resistor ?

 

and, in some designs there is a zener diode in V pin. What is the porpose of this zener?  Aplication note tell about a resistors in this place...

 

Thanks. 

 

The output current variation with potting material is related with the sensitivity of Vpin, not FB pin.

 

There is 15 V ESD clamp to limit the voltage with 4 Meg resistor in series with the Vpin, and a zener diode in Vpin could be used to limit the Vpin voltage lower than 15 V during start up until BP capacitor is charged.