How to power UP board with battery to read 2 USB devices
When my UPboard is powered with a battery in combination with a 5V 6A DC-DC converter, it will only read one USB device when two USB devices (pressure sensors) are plugged in. However, if the UPboard is powered with a 5V 6A AC adapter, it can read both USB devices.
I have tried a circuit with just the DC-DC converter and with the converter's recommended EMC filter, both gave the same issue of only allowing the UP board to read one USB device.
Do you have any idea of what could be different power-wise between the AC adapter and the batter + step down circuit that can also deliver 5V 6A? Or any idea of what to test to troubleshoot this issue? Need to have the UPboard read these two USB devices on battery power so it's not tethered to a wall plug, so if anyone knows what I could try to fix this issue, I'd greatly appreciate it.
Here are the components I am using:
UP board: 1x UP Board 02/32 (2GB RAM and 32GB storage): https://up-shop.org/up-board-series.html
9S 25C 4400mAh LiPo batttery: https://www.thunderpowerrc.com/collections/4400-mah/products/tp4400-9spx25
5V 6A DC-DC converter: https://www.digikey.com/en/products/detail/cui-inc/PDQ30-Q48-S5-D/6165430
Pressure sensors: https://www.sensorprod.com/pdf/tactilus_shoe_insole_high_performance.pdf
UPBoard AC adapter: https://up-shop.org/up-squared-power-supply-5vat6a.html
Best Answer
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@rgehlhar
Is the DC-DC converter 5V output too low to power the second USB device at startup?
Answers
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Yes! That turned out to be the issue. Looks like the UP board only received 4.86-4.96V from the DC-DC converter, and one of the USB devices apparently will not startup without exactly 5V or a bit more. The UP board received about 5.25V from the AC adapter, so I guess there was a voltage difference even though the voltage rating was the same.