TNY280 BP PIN MAX. CAP VALUE

Posted by: hhmunjani on 11/21/2011

I have designed a universal power supply 20-270 VAC/DC by following the application note DI-152.
I have flyback topology with two secondaries. The regulated secondary is 5V/250mA and unregulated
is 12V/250 mA.
I have put 100 uF cap on BP pin on TNY280P.
When the SMPS is loading/unloading (by a sensor turning ON/OFF a Relay of (12V/40mA)it stops working after approx. 10 minutes. It goes in Latch status and only after removing the power it turns On.
Could you please guide me what could be the reason ?
Could it be a cap on BP pin ?

Comments

Please take a look to the TNY III data sheet
http://www.powerint.com/sites/default/files/PDFFiles/di152.pdf

section BYPASS/MULTI-FUNCTION (BP/M) Pin:
for you to select the right capacitor value

To increase the current limit, First I tried 10 uF then I put 100 uF.
It works fine, but when the load is switching i.e. turning On/Off of relay it stops working.

I am sorry I gave you the wrong link

here is the right link http://www.powerint.com/sites/default/files/product-docs/tny274-280.pdf

BP capacitor can be 0.1uF, 1.0uF or 10 uF,
If you want larger current limit you need to select 10 uF.

select bp capacitor 10uF

use 10 uf