Fool-proof low cost 5V power supply circuit

[Newtopprojects]

Can someone please advise how to design (or find) a Fool-Proof, simple (and low cost) very low power (0.5W) 5V charging circuit to charge a small LiPO battery? The power source is a stable 5V that can be connected in either way. This is for a very low budget application.

Any guidance will be greatly appreciated!

 

[Newtopprojects]

The LiPO battery is 3.7V and 100mA

 

[Nigel Goodwin]

You can buy simple and cheap charging modules based on the TP4056, the charging current is adjustable by changing a resistor value. You can buy them with or without protection circuits.

 

[danadak]

Protection circuts good, no protection circuits bad.

End of safety story.

 

[Externet]

Never seen a fool proof model. Fools are ingenious to destroy anything, but, pick your flavor :

 

[rjenkinsgb]

Adafruit Micro-Lipo Charger for LiPo/LiIon Batt w/MicroUSB Jack (v1)

Oh so handy, this little lipo charger is so small and easy to use that you can keep it on your desk or mount it easily into any project! Simply plug it via any MicroUSB cable into a USB port and a 3.7V/4.2V lithium polymer or lithium-ion rechargeable battery into the JST plug on the other end...

thepihut.com

Those can use a USB input, or have wires soldered to them.

Or really low cost (80 pence each, in a batch):

https://www.amazon.co.uk/Lithium-Battery-Charging-Protection-Functions/dp/B08DQXPNR1/ref=asc_df_B08DQXPNR1?mcid=e2036d51dddb324594fbd53200f98dc1&tag=googshopuk-21&linkCode=df0&hvadid=697292516770&hvpos=&hvnetw=g&hvrand=715409272829950393&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007258&hvtargid=pla-1651932538483&gad_source=1&th=1

Again, there are solder pads for hard wiring as well as the USB connection option.