High input volatge power supply based on HF920/HF920A

DC-DC Power Converters
1

I’m currently using HF920/HF920A for my flyback application. However, I’ve encountered an issue where the HF920 supports up to 900V, but my design starting point can reaches up to 830V DC at the input of the flyback. This leaves minimal safety margin until the IC breakdown. I’m seeking a solution to increase the voltage tolerance of my flyback.

My initial idea is to employ an N-channel MOSFET in series with the internal MOSFET of the HF920, effectively dividing the voltage between them. Can you suggest a suitable MOSFET that matches the characteristics of the internal one? Alternatively, I’m open to other solutions as well.

Thank you in advance for your assistance.

Best regards,
Youcef

2

Hello Youcef,

There is an internal 900V FET, the HF920 is meant to work with a universal AC input (85-240VAC). There is also a power limit and temperature limit on the part, make sure you are staying within those limits.

We also have Flyback controllers where you can size the FET yourself, so you do not have to worry about matching the internal FET.

Regards,
Jonathan Hidalgo

3

thank you for your reply
Do you have a similaire flyback Controller that can support more than 900 V?