offline SMPS aux supply

[kubeek]

I am in the process of deisgning a SMPS supply, and to reduce complexity I want to use a transformer to provide the aux power supply.

How much power do I need to provide for half-bridge gate drivers operating at 75-100kHz, i.e. how much power gets lost in the gate resistor and elswhere?

My simulation says that with a 22ohm gate resistor and 12V gate voltage the source provides 500mW.

[luka]

I have no idea, my sg3525 and ir2110 at 50k draw I think in 50-60mA range@ 12v , maybe I have wrote something in my thread... also depends on what fets you will drive, the bigger they are, more you will need

[kubeek]

Cool, I just wanted to make sure the 10W transformer is enough

[luka]

uff 2w would be.with 10w you can drive some other stuff too

[AutoClassA]

Originally Posted by kubeek

I am in the process of deisgning a SMPS supply, and to reduce complexity I want to use a transformer to provide the aux power supply.

How much power do I need to provide for half-bridge gate drivers operating at 75-100kHz, i.e. how much power gets lost in the gate resistor and elswhere?

My simulation says that with a 22ohm gate resistor and 12V gate voltage the source provides 500mW.

3VA Transformer is what you need