FSGM0565 has no mains input UVLO?

[cupoftea]

Hi,
We have a Flyback with FSGM0565 controller
On the front page of the FSGM0565 datasheet it says it has "UVLO"...but further in the datasheet , there is no mention of "mains UVLO"...only "Vcc UVLO".
Would i be right in saying that this chip has no UVLO, and will just start up if ever the primary DC bus goes above 26V?
Sorry to ask, but it seems unbelievable that a chip would omit a UVLO feature?



FSGM0565

https://www.onsemi.com/pdf/datasheet/fsgm0565rb-d.pdf

--- Updated Jul 9, 2023 ---

The TOPswitch isnt much better....it starts up when mains rises above the UVLO level...but it then keeps workign until the mains drops to a level which is 44% below that. This just doesnt make sense.
Do you know why they do this?
You can sense the mains from a diode from the AC side of the bridge, so that you truly sense the mains, and not the rectified and smoothed HV DC Bus.

 

[cupoftea]

If we look at the NCP1239...

https://www.onsemi.com/pdf/datasheet/ncp1239-d.pdf

..It has UVLO with 82VAC on and 78vac off...this is more like it...why cant topswitch and FSGM0565 manage this?... The NCP1239 also as has multiple other options for Von/Voff.....and you can put a series zener in there to refine it............does anybody know when TOPswitch will be obseleted?
...preferably as soon as possible.......their innoswitch is good, but topswitch?.....the problem is that companies hash up some trashy topswitch design, then call you in to put it into production, and dont want any other extra cctry.......and its trash.....but they insist that you use it...........the sooner we loose topswitch the better.

Now the innoswitch...thats different...that looks like being good......and if they let you clamp the FWD pin so you can have lower NP/NS's then the inno is looking on the way to excellent.

Trouble is, few of power integrations customers seem to be moving over to innoswitch.

--- Updated Jul 9, 2023 ---

...i mean, please can anybody tell us the reason for the topswitch UVLO where it turns on at say 100V......then the turn-off voltage is 44v....i mean.........trash the topswitch now......obselete the thing........engineers get forced to put these things into production...and its trash

Why does the topswitch UVLO go down to 44% of turn on voltage?.....makes no sense.

--- Updated Jul 9, 2023 ---

Power supplies overheat and fail when they run at too low Vin. Scrap PSUs all over the place...which probably means scrapped whole products too...because nobody fixes stuff these days.

 

[cupoftea]

On the same lines, TOPswitch-hx uses a feedback current of some 6.5mA...and has a bias current of up to 2.5mA.....All of that 9mA has to come from the opto transistor......and 9mA/CTR has to come from the opto diode.............and you know what optos are like at high temperature and with age....their CTR massively degrades.......(and just see attached for opto CTR graph..and thats a "highest CTR opto").......Now can anyone tell me why TOPswitch-HX is not obselete yet?
...You go into companies and they insist on TOPswitch-HX being used because they hear its great!