1MHz LLC DC-DC converter

Herewith a small window into some of the slightly higher tech and more interesting things we get asked to do at Preston Consulting Ltd.

A 1MHz 1kW converter, to fit into a small space, without getting too hot, i.e. reasonably efficient (some cooling available), low noise, and reliable.

The only reason 1MHz is possible is the low Vin ( 26 - 35VDC ), the low Vout - 28VDC flat, and the moderate power - 1kW in this case ( and that we have the know how to design very low leakage transformers with good isolation - 4nH here + wiring connects ).

Note: - this is all do-able with good ol' silicon devices.

Haversine currents are an important part of this design.

ZVS for the power fets and output " diodes" is essential to meet targets.

Full ZVS allows the gate drives to perform without getting too hot.

Circuit topology allows only minor overshoot on the output " diodes " also assisted by full ZVS.

At these frequencies, pcb design, parts choice, magnetics & gate drive design are hyper important in getting an efficient result.

Results: -

and further: -

for more of the tricky stuff done well - pwrtrnx.com