Notes from week one of my capstone project.
This semester I’m finally starting my senior design project, and I wanted to start documenting it here as I go — partly for anyone else working through something similar, and partly so future-me remembers why I made the decisions I did.
The project
I’m building a small DC-DC converter board to demonstrate efficient power delivery for a low-voltage embedded system. The rough goals:
- Input: 12V from a standard wall adapter
- Output: regulated 5V and 3.3V rails
- Efficiency target: >90% at typical load
- Compact enough to fit on a single 2-layer PCB
Why this topology
I’m going with a synchronous buck converter rather than a simple linear regulator. The efficiency math makes the reasoning pretty clear. For a linear regulator, efficiency is roughly:
$$\eta \approx \frac{V_{out}}{V_{in}}$$
Stepping 12V down to 3.3V on a linear regulator would mean throwing away most of the input power as heat. A switching converter doesn’t have that problem, since it stores and transfers energy rather than dissipating the difference.
What’s next
Next up is finalizing the inductor and capacitor selection, then moving into simulation before I commit to ordering parts. I’ll post an update once I have a working schematic.
If you’re also working through a senior design project this year, I’d love to hear what you’re building.