WEEK 5 UPDATE – Project Update 3
Week 5 Reflection
This past week consisted primarily of house keeping items. I spent time with cleaning up my schematics so they follow proper technique. I made some modifications to the schematics based on some feedback from the team, such as condensing certain sections and combining things that were used by both the 5 volt and 3.3 volt schematics. In addition to that, I also made some updates to my bill of materials and further updates to the schematic. I have put together a pretty solid initial BOM based largely on the Texas Instruments evaluation board as well as updating all of the footprints on each of my components in my schematics, which was great preparation for board layout design this upcoming week.
To-Do List for Week 6
- OVERALL GOAL: Board layout design, and preparation for board manufacturing.
- Board Layout Design Sub Goal – Create a board layout in KiCAD that meets all necessary requirements per the manufacturers datasheet and fits within sizing constraints (once those are determined), to do so I must:
- Create and/or reference some type of list of requirements based off the manufacturers datasheet.
- Reference the provided recommended typical application board layout for an initial design.
- Alter BOM and part selection if any components were switched to a different footprint size, such as switching from 0805 to 0603.
- Prepare For Board Manufacturing Sub Goal – Ensure everything is prepared for boards to be ordered and manufactured, to do so I must:
- Double check all my work with my team members to ensure that all potential issues or mistakes are caught and addressed before board manufacturing.
- Make any necessary or recommended design changes.
- Return to my team members to double check my board again.
- Repeat process until every team member is satisfied with the state of the board and ready for it to be put into production.
Week 6 Concerns:
My week 6 concerns assign similarly to last weeks. I am concerned about how to properly create multi-layered boards with large planes for things like the main grounding plane. As well as, the second being the ability to fit both buck converter designs into the rough dimensions of a note card, allowing the back of the board to contain our modular cable connectors.
Posted Date: 09/29/2024
WEEK 4 UPDATE – Project Update 2
Week 4 Reflection
Last week’s to-do list was ambitious. I set out to do a lot in a week that I quickly discovered became quite busy. Despite this, I still managed to complete half of my very lengthy to-do list.
I started with altering the original 2.5 volt schematic to step 12 volts down to 5 volts and 3.3 volts via the recommendations set my the Texas Instruments Excel calculator. Utilizing this calculator not only gave me the necessary values for resistor 1 and 2, but also provided me with the values for every component in each schematic. Meanwhile, the calculator also checked that the selected and calculated component values would perform correctly to step down 12 volts to 5 volts and 3.3 volts while also maintaining a 15 amp current output. This proved to be harder than initially expected as I ran into several issues with the selected inductor limiting our potential current output. Through discussions with my team, we discovered that it was calculating this expected outcome with a huge input voltage range, instead of using the already refined input voltage range from our other boards. After altering this voltage input range, our selected inductors would adequately perform under our set parameters. With this change in mind, I quickly incorporated the few component value changes and finished the 5 volt and 3.3 volt schematics.
After completion of the schematics, I moved onto component selection. Through the use of the Texas Instruments calculator, most of the components and their values were already selected for me, but there were still a few components that I had to settle on. The values of the inductors were already selected, but I had to find physical components that could actually provide the theoretical numbers. I chose to selected not only the recommended 800nH inductor from Coilcraft for the 5 volt circuit, which also happened to be used in the evaluation board from Texas Instruments, but I also chose a 600nH inductor from Coilcraft for the 3.3 volt circuit as well. As for the rest of the components, I chose a standard 0805 footprint for board layout design and will alter the components footprint and bill of materials once the board layout has been complete, just in case a few components are switched to a 0603 sizing to save space.
To-Do List for Week 5
- OVERALL GOAL: Finish both 5 volt and 3.3 volt schematics, part selection, board layout design, and preparation for board manufacturing.
- Board Layout Design Sub Goal – Create a board layout in KiCAD that meets all necessary requirements per the manufacturers datasheet and fits within sizing constraints (once those are determined), to do so I must:
- Create and/or reference some type of list of requirements based off the manufacturers datasheet.
- Reference the provided recommended typical application board layout for an initial design.
- Alter BOM and part selection if any components were switched to a different footprint size, such as switching from 0805 to 0603.
- Prepare For Board Manufacturing Sub Goal – Ensure everything is prepared for boards to be ordered and manufactured, to do so I must:
- Double check all my work with my team members to ensure that all potential issues or mistakes are caught and addressed before board manufacturing.
- Make any necessary or recommended design changes.
- Return to my team members to double check my board again.
- Repeat process until every team member is satisfied with the state of the board and ready for it to be put into production.
Week 5 Concerns:
I only have two big concerns for week 5. The first is learning how to properly create multi-layered boards with large planes for things like the main grounding plane. Then the second is being able to fit both buck converter designs into a small area on the back of the board with our modular cable connectors.
Posted Date: 09/22/2024
WEEK 3 UPDATE – Project Update 1
Image Above: Rough sketch of expected final project design as well as general schematic/layout for buck converter.
To-Do List for Week 4
- OVERALL GOAL: Finish both 5 volt and 3.3 volt schematics, part selection, board layout design, and preparation for board manufacturing.
- Schematic Sub Goal – Alter my current schematic to step down from 12 volts to 5 volts instead of the step down to 2.5 volts, to do so I must:
- Alter resistor 1 to set the buck converter IC to convert 12 volts down to 5 volts instead of the initial design that follows the datasheets typical application of 2.5 volts.
- Utilize Texas Instruments provided Excel calculator to assign the typical input voltage of 12 volts and the wanted output of 5 volts and 15 amps.
- Incorporate the calculators recommendations into my initial schematic.
- Part Selection Sub Goal – Select parts that align with my newly updated schematic, to do so I must:
- Start with the typical application parts list and alter parts based on my updated schematics.
- Ensure my part selections are no smaller than the 0603 footprint to allow for hand soldering to be possible without major difficulty.
- Board Layout Design Sub Goal – Create a board layout in KiCAD that meets all necessary requirements per the manufacturers datasheet, to do so I must:
- Create and/or reference some type of list of requirements based off the manufacturers datasheet.
- Reference the provided recommended typical application board layout for an initial design.
- Alter the initial typical application board layout to fit the 0603 or larger footprints and ensure that there is adequate room to hand solder.
- Prepare For Board Manufacturing Sub Goal – Ensure everything is prepared for boards to be ordered and manufactured, to do so I must:
- Double check all my work with my team members to ensure that all potential issues or mistakes are caught and addressed before board manufacturing.
- Make any necessary or recommended design changes.
- Return to my team members to double check my board again.
- Repeat process until every team member is satisfied with the state of the board and ready for it to be put into production.
Posted Date: 09/12/2024
WEEK 2 UPDATE
- Selected the TPS548A28 as the buck converter IC of choice for our application.
- Created the initial buck converter schematic in KiCAD based on Texas Instrument’s datasheet for the TPS548A28.
Posted Date: 09/12/2024
WEEK 1 UPDATE
- Started my first week in OSHE!
- Started reviewing the plans for the buck converter selection
Posted Date: 08/30/2024