Low Power Argon Design with TINY85


True… but since the intent of the B-Series in this project is be in an un-powered state 99.x % of the time, what about just powering via Vbus (recommended input voltage range is between 4.35V to 5.5V DC) ?

In that scenario, the ATTiny would switch a Regulator instead of the the EN Pin.

That leaves the door open for many different possibilities in battery chemistry and pack arrangements.

But it still boils down to designing/finding a replacement for the TPL5110 and 5111 with a sleep interval longer than 2 hours…the rest seems fairly easy.


The “Absolute maximum ratings” just tells you that you (probably) don’t have to power VCC, but you should pay attention to the recommended voltages:

This doesn’t begin to explain why powering this pin from a Li+ connection is acceptable since they tend to be in the range of 3.2-4.2V during operation, but as usual the documentation is inconsistent or leaves out useful design information or commentary.


That’s a thought, I could use 3 Energizer L91 in series to give me 4.5V but only 3.5Ah…


Waking in manual mode to increase a counter and go back under every two hours, is unlikely to cost a lot of power. I bet all the 2 hour wake-sleep cycles power consumption over say 3 years combined, would not amount to many ms of establishing a 2G connection and keeping it going. Could be worth a check for the simpler TPL5111 setup.


I tried that…retained memory doesn’t survive a Power Loss (EN Pin).
That would work if ya have an easy way to store the count externally.
You are correct, the power consumed during a quick wake in manual mode is extremely tiny.


The EN pin is the best alternative for getting the lowest power consumption on the Boron at this time.

Instead of using a Tiny85, I use a NL17SZ74 flip-flop and a MCP79410 real-time clock.

With that, powering this circuitry gets the sleep current down to 75 uA. However, that is still higher than it should be, because there’s a weak 100K pull-up on the EN line, and you have to counteract that all of the time when powered down by EN.

Since there is no regulator or PMIC on the B Series SoM at all, you have complete control over the power supply design you can do whatever you want. I have a sample that uses a high side load switch coming off the LiPo battery. Since I don’t need the actual EN line semantics on the B Series SoM it’s driven directly off the NL17SZ74 and there’s no need for the pull-up and N-MOSFET. I haven’t tested this design yet, however.


Generally not recommended, but any experience with increasing a weak pull-up value to 300k or 1M on a reset or enable line?


The problem is that the pull-up is on the Boron itself. They’re so small (0201) they’re such a pain to rework I didn’t even check to see if it’s under the shield in the bottom or not.

As for the design itself, 100K is about as high as you can go reliably.


Thank you so much for your contribution to the thread @rickkas7 :+1:t3:

Do you have any insight into the best way of powering the B-series using Li-SOCl2 batteries rather than LiPo… does it really need to handle 2A currents?

Also, any update on NB-IoT in the UK with Voda?