Over a year ago I designed a quick breakout board for the TI BQ25570 power management IC but only recently had a chance to work with it.

The BQ25570 has some cool features:

• Harvests energy from things like solar and thermoelectric
  • Has a programmable MPPT
• DC-DC boost charger for Li-ion, supercapacitors, etc...
• Programmable buck output regulator capable of 3.3V
• Claims 93% efficiency

Import Specs:

1. Energy source input: 5.5V MAX

   (starts charging battery with as little as 100mV)

2. Regulated output: 3.5V, 100mA MAX

3. Energy storage device: 4.5V MAX

4. Charging rate: 110mA MAX

The breakout works fairly well:

👉 https://github.com/maholli/EHB

I don't recall why I put the 5V supply on the breakout... I'm sure I had a good reason at the time, but I'd probably leave it off if I spin another rev of the board.

🔬Things to Test

• [x] PoC parallel 3V3 output

  • [x] Have 3V3 power dev board
  • [ ] Careful parallel output
  • [ ] Careful parallel output

• [x] PoC solar charging

• [x] PoC parallel battery charge

  • investigate 50mA charge rate from DC supply
  • [x] Careful parallel DC charging
  • [x] Careful parallel solar charging

• [x] Verify max charge rate

  • ~75mA from DC supply

• [x] Verify max 3V3 current output

📃Things to Change/Add

• [ ] Remove 5V
• [ ] Add 3V3 output header
• [ ] Better silkscreen on screw terminals