LiPo shim for pico, for tiny2040?

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1

Hi,

This might be a silly question, but I wonder if it’s possible to use the LiPo shim for pico with the tiny2040?

Comparing the schematic, the tiny2040 pin layout and pico pin layout, I’m guessing the answer is “no” since the vsys, gnd and 3v3 pins of the pico and tiny2040 don’t align.

Now, it looks like tiny2040 doesn’t differentiate between vbus and vsys, but could I just solder the shim’s vbus and vsys to the tiny2040’s vsys, and same for the 3v3?

Thanks!

2

Be careful !!! On a standard Pico vbus is +5V and vsys is +3.3V.
The Pico Lipo Shim uses the 5v for charging the battery.
I wouldn’t short / wire vbus and vsys together.

IMHO, electrically, the Lipo Amigo Pro is a better option.
LiPo Amigo - Pimoroni
Wiring the Amigo Device + to the Tiny 3Vpin, and the - to the Tiny Ground should work.

3

Looking at the Tiny schematic, the 5V pin is vbus. It’s tied to the USB 5V pin and feeds the onboard 3.3V regulator. The output of which feeds the 3V pin and RP2040 chip.
Near as I can figure anyway.
tiny2040.sch (shopify.com)

4

Hey thanks for the help!

The Amigo Pro is the first one I looked at, but I find the LiPo shim’s form factor more interesting (with the tiny2040). Also I’d probably have to desolder the Amigo Pro’s USB-C port (or end up with two ports, one on the tiny2040, one on the Amigo…).

If I were to use the Amigo Pro, would I be able to charge it through the tiny2040’s USB-C port, just by connecting the Tiny’s 3V to the Amigo Pro’s Device + as you suggest above? Or would this only power the Tiny but not charge the Amigo Pro('s battery)?

I admit I’m completely lost when it comes to charging circuits, apologies if these are stupid questions!

5

The Amiga Pro uses it’s USB ports 5V input to charge the battery. I’d have to really study the schematic to see if you could feed 5V from Tiny back to it to do the charging.
You can’t charge the battery from the 3.3v, fully charged the battery is 4.2v.

This type of thing can get complicated.