Yes, Senhor Vasquez — it is possible, but you need two resistors and must break the existing direct FB-to-3.3 V connection. Adding only one resistor will not fix it.
For the adjustable TPS62827:
VOUT=0.6 V(1+RBOTTOMRTOP)
A suitable 1% resistor pair is:
- R_TOP = 453 kΩ: output to FB
- R_BOTTOM = 100 kΩ: FB to GND
This produces approximately:
0.6(1+453/100)=3.318 V
That is suitable for a nominal 3.3 V rail.
Required modification
3.3 V output ── 453 kΩ ──┐
├── TPS62827 FB
GND ────────── 100 kΩ ───┘
Procedure:
- Completely disconnect USB and the LiPo.
- Locate the PCB trace directly connecting U6 FB pin 3 to the 3.3 V output.
- Carefully cut that trace and confirm with a multimeter that FB is no longer shorted to the output.
- Solder 453 kΩ between the 3.3 V output and FB.
- Solder 100 kΩ between FB and GND.
- Keep both resistors and wires extremely close to U6; FB is sensitive to switching noise.
- Check for shorts under magnification.
- Initially power the board from a current-limited bench supply or USB current limiter, without the battery.
- Measure the output before allowing the ESP32-S3 and other loads to run. Expect approximately 3.3 V.
Important cautions
- U6 is a tiny 1.5 mm VSON package, so soldering directly to FB pin 3 is difficult.
- If the FB trace cannot be isolated cleanly, replacing the IC with TPS6282533DMQR may be safer.
- Do not power the board until the modification is complete. With FB directly connected to the output, the adjustable part will attempt to regulate near 0.6 V, not 3.3 V.
- Use 1% resistors. Avoid long jumper wires around the SW pin and inductor because those carry noisy switching signals.