Testing all of the features of the first JellyfishOPP prototype (described in the last three articles) revealed some design mistakes. The biggest one was definitely the issue with the range switch MOSFET drivers but there were also other ones.
JellyfishOPP is an open source, open hardware, programmable power supply and measurement device. The main page containing the description and links to all of the development updates can be found here: https://hyperglitch.com/jellyfish.
Development of the device is funded by NLnet through the NGI0 Entrust fund. Learn more at the NLnet project page.
It took me a couple of days to implement all of the changes and re-check everything.
Here's the breakdown of the changes:
- wrong orientation of the MOSFETS at the input ORing
- added inline resistor to control signals for higher voltage parts
- removed the extra crystal oscillators I put in the first prototype just in case
- Vref+ on the MCU wasn't powered. I also separated VDDA and added a simple RC filter on it
- added voltage level translation to AUX supply digital potentiometer
- removed the leaky protections from the output and added a low leakage TVS diode
- improved loop compensation for the output control circuit
- added required pullups and pulldowns on the ADC
- fixed high side drivers for range switching MOSFETs
- fixed the capacitor at the +/-8V supply
After the changes and checks were done I took an opportunity to improve the prepare_everything.sh script to remove the need for any manual steps. Now it does the full manufacturing preparation for the board, all using the KiKit and KiCAD's CLI interface:
- extract the main PCB to the separate project
- export the PDF of the schematic
- export the BOM in specified format
- export gerber and drill files and zip them
- export the position files in multiple formats
- create the assembly image in pdf and svg formats
- render the 3D model of the board
The production files are in the hw/production/board_main/20250331/ directory. The repository is, as always, available at https://gitlab.com/hyperglitch/jellyfish/.
Since I was quite satisfied with the build quality of the first prototype, I decided to go again with PCBgogo as the fab house for the second prototype. I also went with three boards this time. Boards were ordered last week and I should get them around 25th of April.
