Top 264 OV trips depending on the load
Good afternoon,
I'm using a TOP 264KG for a 40W 300- 950 VDC Flyback design. I've added a mosfet in series to the top switch in order to be able to withstand 1kV input voltage.
The top switch is behaving good in all the input voltage range. The problem started when I tried to set the OV at a desired voltage level.
I'm using 9 Mohm divider to the V pin, calculated value OV= 1008V.
At 2% load measured OV=940V
At 100% load measured value OV=1060 - 1080V.
I couldn't find any relation between the OV and the load of the flyback transformer.
A little help would be appreciated.
Thank you in advance,
Nedialko
Comments
At 1kV there may well be leakage on the board upsetting the ability to accurately set the OV, try cleaning ...
Hello,
I'm sorry for the delayed answer.
I don't feel so good sharing the company schematics and pcb on the forum.
Is there an e-mail or phone where i can contact technical support engineer and send him the documents. The only number I could find is :
For India and Southeast Asia
Phone: 2237-2252 (within Bangalore, India)
+91-80-2237-2252 (outside India)
Best regards,
Nedialko
Hi,
Where is your location? I can refer you to our sales office near your area and you may contact them to forward the schematic and layout. Thank you.
Best Regards,
PI-SevenofNine
Hello,
We are located in Sofia, Bulgaria.
Thank you.
Best regards,
Nedialko
Hi Nedialko,
Thank you for the information. I believe your location is part of Europe. I will provide you contact information of Power Integrations Europe Sales Office. See below:
ITALY
Via Milanese 20
20099 Sesto San Giovanni (MI)
Italy
Tel: +39 02 455 08708
Email: eurosales@power.com
Or you can look on this link your region:
https://ac-dc.power.com/sales/
Best Regards,
Pi-Seven of Nine
Hi Nedialko,
Good day! Thank you for using PI product. How do you measure the OV value? Do you measure it by using an oscilloscope (across the +V where the Vpin resistor was tapped and GND)? Or you rely on the reading of your input source? At higher load, maybe there is already some voltage drop on the level of voltage on where the Vpin resistor was sensed or connected. You might be seeing a higher OV setting in your input source but in reality the trigger point was lower because of voltage drop. Kindly check the OV with an oscilloscope. If there is a small discrepancy on the maximum voltage reading, maybe you can try to move the sense point of the Vpin resistor. If possible please provide us the screenshot of your design layout and schematic of for us to check. Thank you.
Best Regards,
PI-SevenofNine