This is in the early stages of prototyping a multi-port 1S Li-po charger.

Features include:

• Wide input voltage (approx 5-24V, untested)
• High charge current (up to ~2.5A, untested)
• Discharge circuit (to arbitrary voltage; connector is limiting factor -- mosfet can do ~10A)
• (Upstream) microcontroller only involved in the slow loops ("is it charged yet?", not "is current limit hit?")
• Relatively inexpensive BOM (compared to all-in-one buck-based chargers)
• Relatively easy to solder (only one part smaller than SO-8 and 0603, no exposed pads)

Open questions:

• Do we need extra soft-start circuitry to avoid current spike at beginning of charge?
• Can we heatsink the discharge circuit so this stacks better (DPAK on back ground plane)?
• How small can we get this as a replaceable daughterboard?
• How will we mount it inside a case?
• Can we trust the sum of individual shunts for calculating used power budget?
• How will MCU stay alive while probing (or backing off)
• Is there a much better way to shut off discharge (second nmos is obvious, but expensive)

License: CC-BY 4.0 International

Disclaimer: This not an official Google product.