USB-C 3.3V Step-Down Converter — PCB / PCBA

Description

USB-C 3.3V Step-Down Converter — PCB / PCBA

Open-source USB-C power-board design by Mauro De Vecchi (maudeve-it), intended to supply a regulated 3.3V rail from a 5V USB-C source.

Main chip

TPS54331: the buck-converter IC identified as U1 in the original KiCad schematic. The project targets up to 3A under suitable source, component and thermal conditions; this is a design target, not a verified continuous-current rating for this listing.

Design functions

• USB-C input with hardware detection of available source current.
• 3.3V step-down output and access to the input 5V supply.
• No USB Power Delivery negotiation controller: this design does not request higher USB-PD voltages.

Typical applications

• 3.3V power for microcontroller and sensor prototypes.
• USB-C-powered embedded electronics and development fixtures.
• Learning buck-converter and USB-C power-interface design.

Actual available power depends on the USB source, cable, load and cooling. The two outputs share the input power budget. These functions require an assembled board; the PCB-only option contains no components.

Choose your build option

PCBA is made to order; shipping transit time is additional. Power adapter, cable, enclosure and load are not included. The supplied image is a bare PCB render, not an assembled-product photograph.

Upstream design note

The author reports an approximately 12-second transient after connection to a USB-C PD source and discusses adding a filtering capacitor. Review the original documentation and confirm the manufacturing revision and startup behavior before connecting sensitive equipment. This listing does not claim that the upstream transient has been corrected.

Source and attribution

• Original design, schematic and startup notes
• MIT license

Copyright (c) 2023 Mauro De Vecchi. Supplied by DIYIPCB; no endorsement by the original designer is implied.

Contact DIYIPCB for revision, assembly and testing requirements.

5% of eligible net sales supports the Open Hardware Fund at no extra charge.

MIT License

Copyright (c) 2023 Mauro De Vecchi

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.