Will having both USB and 5V power active cause problems?

Products & Technology RP2040
#1

Hi,

Will connecting the +5V and GND pins on the Seeed XIAO RP2040 to an active external power source cause any problems if the USB C is connected simultaneously?

Thank you.

#2

Hi there, and welcome here…
Did you read the wiki and the power pins if its not spelled out on the rp2040 like on the other xiao’s not sure why . Anyway a diode is needed between 5V external source and the pin as to not harm the xiao.
Check some of the other threads as well on it.
HTH
GL :slight_smile: PJ :v:

from the Xiao Esp32S3 for example:

  • 5V - This is 5v out from the USB port. You can also use this as a voltage input but you must have some sort of diode (schottky, signal, power) between your external power source and this pin with anode to battery, cathode to 5V pin.
  • 3V3 - This is the regulated output from the onboard regulator. You can draw 700mA
  • GND - Power/data/signal ground

I do see a caution on the rp2040 Wiki about having both, so read the manual.
and here in the online schematic I do see a diode between Vin and VBUS so there’s that

RP2040_power
RP2040_power2811×1606 169 KB

1 Like
#3

Hi,
Please don’t do so. As mentioned on its wiki page:

For power supply pins: The built-in DC-DC converter circuit able to change 5V voltage into 3.3V allows to power the device with a 5V supply via VIN-PIN and 5V-PIN.

XIAO RP2040 currently only supports battery power supply and cannot connect to Type-C while a battery is connected, as it may pose a safety risk.

Please use one kind of power supplying method at a time (USB-C, 5V pin, battery connected to VIN pin).

#4

Hi Seeed_Harrison

Is there any way to disconnect the power from the Seeed XIAO RP2040 USB connector when the device is connected to a USB port?

I need to have power from USB, but if USB power is disconnected then I need fail safe power fall back to be from the external power source.

Would I need to have another usb connector with a circuit to select the power source, which then connects to the Seeed XIAO RP2040 usb connector?

Sort of like a pass through like this hdmi pass through?

https://vi.aliexpress.com/item/1005005102753497.html?spm=a2g0o.order_list.order_list_main.11.27631802Z7cTOV&gatewayAdapt=glo2vnm

Thank you.

#5

Yes, a power managing system is needed for your intent. But I think a better solution is to use another XIAO with charging PMIC. Please check the comparison table here: