Guru
Joined: 08/02/2015
Location: New ZealandPosts: 1162
| Posted: 11:15am 11 May 2020 |
Well I still haven't sent those files off. I want to do some more experimentation and have made a more generic module that has these optional functions (129 x 46mm).
1: Synchronous mosfet driver
2: PV Isolation Switch
3: Buck driver
I want to run the mppt section at 62 to 100 Khz, so a better design is needed.
The pcb has the functionality such that the buck driver may have the optional sections simple cut off with tin-snips. In light of the work Poida is doing, the mosfet PV isolation switch may not be required or replaced by a relay. The synchronous rectifier section similarly maybe chopped off if not required and a schottky rectifier used instead. Rather than send off multiple board designs its easier to do it on one.
The buck driver section is always needed and maybe used standalone, I have changed the design of this section to use a modern fully isolated emulated opto type coupler driver, Si8261BBC-C-IS this version of it has under voltage lockout set at 8 volts and low 2.5//4 amp capability, the chip drives dual ZXG3005E6 10amp drivers positioned directly at the gate of each mosfet. The mosfets used IRFP4668 need quite a high gate current to switch quickly and as I have at least 50 of those tiny ZXG things, about time they were used.
Here is the PCB, will draw up the schematic to check it.
Cheers
Mike