Kach Johnson’s Work Log

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  • Post last modified:April 6, 2024
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  • Post category:Work Logs

9/23/23 – This week we finalized our system architecture shown in the flowchart below:

This upcoming week we will be focusing our efforts on case design and a comprehensive AC-DC conversion simulation in QSpice. Below are the 2 case designs we are looking to prototype this upcoming week.

10/28/2023 – 3D-printed case has been finished. Ran into problems during print. The current model has too long of a print time and needs to be printed over night (not allowed). Plan for next week is to make case for ‘modular’ to print.

11/4/2023 – Looking into LLC Converter evaluation boards and seeing what are best option is. We are still debating on whether to go with the cheaper, half-bridge UCC25640EVM-020 module or the all-in-one and more expensive PFCLLCSREVM034 Board.

Spring 2024

1/27/2024

Project Sketch

To-do list

  • Review and Change Project Spec
  • Design Expo Signup
  • -12V Topology research
  • Have a first draft for 3D printing

Concerns

  • No concerns so far

2/3/2024

To-do list

Last Week

  • Review Change Project Spec – Completed
  • Design Expo Signup – 75% Done, on-hold until layout for project showcase
  • 12V Topology research – Completed
  • 3D Print First Draft – Completed

This Week

  • Merge McMasterCarr CAD models into 3D Print Draft
  • Find Inverting Buck Boost IC and put into a schematic

2/10/2024 – To-do List

  • Merge McMasterCarr CAD models into 3D Print Draft – Not complete, did not have time with Winter Carnival
  • Find Inverting Buck Boost IC and put into a schematic – Found White paper with IC recommendations but have not ported an IC into a schematic

2/16/2024 To Do List

  • Merge McMasterCarr CAD models into 3D Print Draft – Completed
  • Find Inverting Buck Boost IC and put into a schematic – Completed

Next Week

  • -12V Schematic Finalization aka Footprint selection & Calculation double-checking
  • Slides for CDR
  • Revise 3D print & reprint case design + order hardware needed

2/24/2024 To-Do List

  • Find Inverting Buck Boost IC and put into a schematic – Completed
  • Merge McMasterCarr CAD models into 3D Print Draft – Completed
  • -12V Schematic Finalization aka Footprint selection & Calculation double-checking
  • Slides for CDR
  • Revise 3D print & reprint case design + order hardware needed
  • Start routing for -12 V PCB

3/9/2024 To-Do List

  • Was able to revise 3D print, holding off on ordering hardware because we are not using the case
  • Holding off on PCB routing until our group can do a Schematic review with Chris from Plexus
  • Currently working on a schematic review document that should be ready by next week

3/17/2024 Updates

  • This week we have concentrated on making a schematic review document for Plexus to review. We are still continuing to work on it and are finishing it up at the beginning of the next week.
  • For the -12V subsystem, a document has been made that shows the schematic, engineering intent, and where the -12V subsystem resides in the overall system architecture.
  • For next week, we’ll be aiming to wrap up the schematic review document and start on some basic layout for the -12V board.

3/22/2024 Updates

  • We wrapped up the schematic review document which can be seen here. It shows our overall system architecture, schematic design, and engineering intent behind our design.
  • This week I have been starting the -12V board layout. Still pretty early in its progress, just starting to group components.

3/30/2024 Updates

  • This week we went over our schematic review with Chris from Plexus. He gave us some good insight into our schematic design
  • Regarding the PCB design, we ended up going with a 4 layer board to simplify some of the routing issues we were having. This also means redoing a lot of the layout that we were working on. Currently, I have completed the preliminary layout and am on the routing stage.

4/6/2024 Updates

  • This week, the team finished the PFC, LLC, 5VStandby, & -12V PCB Layouts and Chris was able to review our layouts. We got the green light to order the boards and our parts which was accomplished yesterday. Worst case, we are looking at a shipping arrival date of the Monday before Design Expo.
  • The DC-DC PCB Layout still needs work. We plan to merge the -12V PCB with the DC-DC board to reduce PCB fabrication costs. This work is being completed over the weekend to make sure we can order the PCB by this upcoming Monday.
  • Below is the -12V PCB Layout which I completed. It is a 4-layer board that uses an Inverting Buck Boost topology with a synchronous buck converter. The IC is a VQFN footprint and uses the GND plane as a heatsink. The footprint and packages are harder to assemble but should aid us in the effort to meet the future ATX footprint requirements.