NCP1340B4 questions (QR flyback controller)

[Flyback]

Hi,
***Can you use just one Brownout diode with NCP1340B4 ?...
NCP1340B4 has 2 diodes connected (OR'd) from the AC points of the bridge, to the HV pin...which then does...
1...startup
2...brownout detection
3...Recovery from brownout
4...X2 cap discharge.

We dont care about X2 cap discharge...But want brownout and "Recovery from brownout", and HV startup.

So can we use just one diode here?
the datasheet doesnt make it clear.....it implys that one diode would be ok for brownout detection...but does not make it clear that recovery from brownout, or startup, would be possible with just one diode?

***Why does V(ZCD pin) need to be at least 8V when the secondary is conducting?, ..as said by page 15 of the NCP1340B4 datasheet
Even with high leakage current, there is no chance that even if V(ZCD pin) was only 5V, that the ZCD pin would ring below 80mV (The ZCD comparator threshold).
So why minimum of 8V?

NCP1340B4
https://www.onsemi.com/products/power-management/acdc-power-conversion/offline-controllers/ncp1340

 

[Lightium]

Perhaps this is an On-semi tech support question?

 

[Diver300]

The brownout timer starts each time the voltage drops below the minimum. Page 25 of the datasheet shows it increasing a bit from zero each half-cycle.

If you only use one diode there is more risk that the circuit will see each negative half-cycle as a brown out.

I've seen a laptop power supply fail to works when powered from a "modified sine" inverter that had gaps each half-cycle. I think it was because of this sort of brown-out protection.

 

[Flyback]

Thanks, but the brownout detect has a 40ms delay, so that half cycle outages dont get detected as brownout......the question is about recovery from brownout....where its not clear that that 40ms delay applies.

Also, i have contacted onsemi tech support, but no answer as yet.