Can I power Boron from 12v via VUSB/VBUS, charge Lipo, and use USB?

boron
Tags: #<Tag:0x00007fe21ebb55c8>

#1

Good evening friends.

Can I provide 12-14.x volts to the Boron via the VUSB pin and also use and charge a backup Lipo battery using the provided onboard charging and SOC / Fuel Gauge circuitry? There will be periodic inductive loads on the 12v battery, and charging activity too (14+ volts).

Looking at the datasheet for the BQ24195 it seems operating range is 3.9 - 17v, absolute maximums are a bit higher, and looking at the datasheet and the block diagram for the Boron it looks like it shouldn’t let the magic smoke out to power from 12-14.x volts AND use a lipo as a backup (I assume the IC will treat it the same as a regulated 5v USB power source). Approx: 12-14v -> VUSB / VIN on BQ24195 -> 3.3 regulator via SW and lipo via BAT.

  1. What should I consider to protect the hardware (more heat sinks / cooling, voltage limiting components, additional regulator, etc.). How about reliability?

  2. Is it correct to assume I won’t be able to put 12+v on VUSB pin and plug in and use USB (unless there’s no power line and it’s just data).

  3. Are VUSB and VBUS the same pin?

Thanks!


#2

Whilst the tech specs are valid - I would play safe and stick with the BORON’s stated specifications - why not get a simple buck convertor break out and add inline from the 12-14v. something like https://www.adafruit.com/product/1385 - simple easy and does not invalid the BORON warranty, plus it will clean up the supply line to the BORON ultimately making the end product more stable.


#3

Doesn’t directly answer your questions, but maybe these help:

I’m disappointed I can’t do the same on my xenon.


#4

Good to know. Hadn’t gotten to the point of checking Xenon or Argon datasheets. Luckily I plan to use lipo only on Xenons.


#5

My takeaway is that for a prototype I can probably get away with it, but for a more long term installation I should probably plan to include additional conversion / regulation circuitry. Thanks for the link, btw.