Electronics > Projects, Designs, and Technical Stuff
Zener for voltage limit
(1/4) > >>
panoss:
I 've made a device with Arduino and Lora RA-01 module.
The transmitter is powered by a Li-Ion battery charged at 3.6V because Lora module cannot tolerate more than 3.6V.

When I give it to the client, he will charge the battery at full voltage, 4.2V.
So, I 'm thinking of putting at the output of the battery a zenner diode of 3.6V.
So that when the battery is over 3.6V the voltage will be limited at 3.6V.
And when the battery voltage drops at 3.6 the zener will tottaly stop conducting, which is extremelly important as it's a battery operated device and I mind power consumption a lot.

On the other hand I could use an LDO regulator, but I don't think I 'll gain anything.

What do you think?
Kleinstein:
Just a Zenerdiode will not work, as there is nothing to limit the current. A full battery could easily damage the zener diode.
Another point is that the corner in a 3.6 zener is not very sharp: it will already conduct a little at some 3 V, and with enough current (e.g. 100 mA) the voltage may be higher than normal.

So the better way is to use a low power LDO. If possible more like a lower voltage (e.g. 3.3 or 3 V) as  with the AVR µC the current consumption would go down about proportional to voltage. So at 3.3 V one would need something like 10% less than at 3.6 V and this could more than compensate for the little extra current needed by a low power LDO.
Cliff Matthews:
How about just using a barrel jack with an integrated switch? This way customer provided equipment is isolated (or regulated on insertion) rather than doing harm to the uC and Lora modules.
tsman:
The Zener diode is a kludge and won't work. Use a protected cell if you don't want to add a low voltage cutout to your design. Buy/make a 3.3V output buck/boost module like this Pololu one.
panoss:
This pololu looks perfect! I suppose this and this are something similar, right?

But because I can't wait till it comes, which LDO regulator would  you suggest?
Don't they all have the same efficiency?
(Arduino consumes at full power I think around 11mA, Lora 120mA)
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod