I might be searching for the jack of all trades with this one, but I'm still curious if it is possible.
I want to measure current (<32 A) in a voltage range of 5 V to 400 V in both AC & DC circuits, which is not a problem.
However, the remaining circuit (Hall-effect sensor SoC, MCU, WiFi, etc.) needs a power supply of 3.3 V and 200 mA max.
I plan on using the same two conductors I measure the current on to supply the device with power.
My question is: Which one is the most efficient way (in terms of energy efficiency - cost does not matter) to step down such a broad voltage range to a voltage of either 3.3 V or 5 V DC? Would it be a jelly bean buck/boost or SEPIC, a flyback converter, an S3R, or something completely different?
For further clarification - the power supply does not need to be isolated.
I'd appreciate your help!