Im searching a controller for high voltage buck.
500V:400V input -> 320V output. 300Khz-400Khz freq. 2KW.
i need also output current regulation as current limit...
I thought about LT3840 (with external drivers off course) but i know that i will have some problems with output current measure and current regulation due to the extream voltage.
1. There any other option connecting the current measurement resistor except in series with inductor? mabe somehow with current transformer?
2. Is there any other IC that fit for this app? i thought about lt3741 because of the Average Current Mode but this ic demand 2V at VIN above the output voltage - again, its not possible.
Thanks for the post.
I'm the applications engineer for the LT3741 and I agree it is not a great starting point for your design requirements.
I thought about this and my best advice would be for you to do a web search on "resonant full bridge reference design" or something similar, and if you are fortunate something close to what you need will come up.
If the source return can float with respect to the 320V return, and a non-synchronous converter is acceptable, you could use a LT3825 to make a negative buck converter on the return side. Feedback and Vcc come from a second winding on the inductor. For 2kW, you will need to add a driver stage.