I'm working on an ultra-efficient fixed output half-bridge DC/DC converter. (Where the input is from variable sources of voltage and current like batteries, solar, wind, and also from fixed sources of voltage/current like ac grid)
So I've speced out my mosfets that I need to be able to switch the half bridge effectively and get excellent efficiency numbers and I've decided to use an ESP32 so that I can control other things as well.
And I'm looking at this GaNFET driver for my purposes (I will also be using this to control BLDC motors in this application): https://www.infineon.com/dgdl/Infineon-2EDF7275F-DataSheet-v02_07-EN.pdf?fileId=5546d462636cc8fb0163b08fd9203057
My issue is to try and find the most efficient way to power this. The ESP32 (or whatever simpler design without wifi, etc.) will be in modem sleep so it should use about 20mA at high speed from the data sheet for it. The GPIOs/PWMs will be used as the interupts can be triggered. It needs 5VDC of course.
The driver needs 3.3VDC which I can get from the ESP32, and it also needs the VOut power which is 17-20VDC depending on which GanFET I choose.
My understanding is that there is VERY little amperage on the driver and GanFET gate in this scenario so the draw and loss is negligable.
I will be putting a hot swap controller in at the VIN of the device for the requisite protections.
But my primary issue is I need to be able to have the ESP32 and Driver powered by the source voltage (i.e. not external) and the source voltage will be either 384VDC (+/- variations of state of charge etc.) and the output will be a fixed 380VDC.
So I've considered:
- A Voltage divider that gets me close from the bottom end of the 384VDC (320VDC) to 5VDC + a regulator and then another voltage divider that gets me close to the Gate Driver's 20VDC + a regulator.
- A less efficient buck converter that is self-powered from the source voltage in a single chip. (But I can't find anything that can step down from 440VDC max to 5/20VDC)
What's the best way to get the ESP32 or equivalent powered and power the GaNFET driver also powered off of the (variable) source voltage in this scenario?