Power supply to LiPo plug instead of VBUS

Hardware
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16

There are some differences between the Boron, which has the bq24195 PMIC, and the Argon and Xenon, which do not have a PMIC.

For the Boron, Li+ can be used as a power input.

  • You must never attach a LiPo battery to the JST connector and supply power to Li+ at the same time.

  • It’s best not to supply power by other means like the USB connector or VIN when powering by Li+.

  • If you disable charging in the PMIC, you could use USB for debugging with a normal USB cable.

  • The maximum voltage is 4.2V!

If you have a way to generate power in the range of 3.6V to 4.2V, Li+ is a good choice.

There’s a situation that can occur if you are powering by VIN or VUSB and do not have a LiPo battery attached. If high current use (like connecting to cellular) causes a voltage dip, the PMIC can believe it needs to boost the voltage output using the battery, but it can cause an even bigger dip when a battery is not attached before it realizes it and switches back to VIN only.

Also, in order to get the absolute lowest current use in SLEEP_MODE_DEEP you have to use Li+. Because the voltage is already in an acceptable range, one of the regulators in the bq24195 is turned off, allowing for lower power consumption in sleep.

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