I need a number (~20) of fixed voltages in the range of 4-20V. Isolated and non-isolated, for SIC MOSFET gate drivers, 20V for a small D class audio amplifier, 3.3V and 5V for logic and 10V for some auxiliary circuits. The input voltage is in the range of 10.8-15V, maybe 40W in total.
Due to the number of output rails the complexity of the secondary sides does matter. This basically kills all the PWM forward-derived topologies, as they need output inductors. A flyback might be an option, but I am considering a different aapproch: a stiff LLC "pump" propelling several way-too-good toroidal transformers (primary Lm in the millihenry range), connected in parallel. This will allow me to optimize their properties to match the requirements of a given rail and keep the number of windings within the sane range. Lower inter-winding capacitace of unrelated secondaries would be a benefit too. I'll try to make the effective primary inductance match the LLC design requirements, but if it is too high, I plan to compensate with a parallel choke. Something along the lines of the ideal transformer model of an LLC converter, but this time the equivalent circuit is taken literally.
Has anybody seen anything like that before? Does it make sense?
Best regards, Piotr