Nano 33 BLE Sense powered with Vin and USB at the same time

Projects General Guidance
1

Hi everybody,

I want to buy an Arduino Nano 33 BLE Sense.

I would like to know if it's possible to power the Arduino with Vin and USB at the same time.

I found out on previous models that it's possible and the USB will disconnect if a voltage
of >6.6V is detected on Vin.

I found also the following information from Arduino for the Nano 33 BLE Sense:
https://store.arduino.cc/collections/boards/products/arduino-nano-33-ble-sense-with-headers

Vin: This pin can be used to power the board with a DC voltage source.
If the power is fed through this pin,
the USB power source is disconnected.
This pin is an INPUT.
Respect the voltage limits to assure
the proper functionality of the board.

I want to be able to charge the battery through USB.
But how can I do that if the Arduino keeps disconnecting the USB connection when powered with Vin. It's like, it will charge the battery and past 5V a MOSFet will let the battery power the Arduino
and then the USB power will disconnect. So I will always end up at 5V which will be the cut off
on my battery.

If there was such a >6.6 USB disconnection on the Nano 33 BLE Sense,
that would be perfect because my battery will be between 5 and 6.6V

Would appreciate any suggestion.

Thanks.

Cheers.

2

The statement is that the USB power source is disconnected. That does not mean the USB connection is lost. You should not have any problems.

3

What is "the battery"? Some schematics please. Pen and paper works well.

Words often brings more confusion then they explain things. Grab pen and paper and make a drawing showing the powering You think about.

4

Which cannot be directly recharged by the USB power. You would need a boost converter and a charge controller.

5

Vin Pin and USB connector
Vin Pin and USB connector2142×1390 94.2 KB

That's my best attempt at drawing :sweat_smile:

6

I was under the impression I could use the 3.3V pin of the Arduino to charge the battery.
USB 3.0 can provide
0.9a at 5V
and
USB 2.0 can provide
0.5a at 5V

So at 3.3V that would be lower than these values which I kind of like because it's conservative for the battery.

7

That won't work, since the 3.3V output and the USB supply share the common ground reference. The voltage across the battery is the difference.

9

I'm sure I'm missing out something obvious here but then how could you power the Arduino and shields connected to it while it's connected to the USB power supply ? Or it's just impossible and it's done a different way ?

10

For the moment, forget charging the battery, until you better understand electrical circuits.

Either the USB connection OR the Vin connection provide power to the Arduino and any modules or shields via the "5V" pin and associated circuitry.

If voltage is present at Vin, the USB power contribution is cut off via an internal electronic switch.

Both power sources share a common ground.

1 Like
11

True. I should study the basics first.
So I understand because both power sources share a common ground,
the current could not go to the charging wire of the battery
but would leave through the ground, choosing the path of least resistance.

12

This is a basic and common misconception. Current flows through all possible paths, according to Ohm's Law.

1 Like
13

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.