nano amp battery circuit for powering up micro controller

How big can it be? Barometric pressure and humidity absorption swing materials could obtain those kinds of power levels in, probably, a fist sized box? Not that that's necessarily something you'd want to bother with ("the cure is worse than the disease")... :^)

Tim

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Tim Williams
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If it's not an order of magnitude higher it could make sense to contact them since your quantities will be very high. Such small companies are often strugging for their first major "anchor client" where they can brag about that, just like the typical shopping mall needs a least one very large tenant which gets a sweet deal to say "yes".

For large volume production there is also the option to get the naked chip, bond it and have it live under a blob of tar, like the IC in Chinese alarm clocks.

[...]
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Regards, Joerg 

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Reply to
Joerg

Not sure what kind of prices you guys get at TI but here is one which is listed at $0.27 for low quantities:

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They come in several flavors. The longest wake-up repetition is 2h but that could be stretched with a follow-up CMOS divider.

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Regards, Joerg 

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Reply to
Joerg

On Thursday, August 30, 2018 at 6:05:28 AM UTC-4, Steve Wilson wrote:

ing it on the bench. Q1 would have to have a high beta at nanoamp currents to initiate switching, and leakage currents may hamper the oscillation. The re are also some unexpected interactions when you change component values.

Phil, I saw your reply. Thanks.

I prepared a reply, but your post has disappeared. It just completely evapo rated. So I will post this in the blind.

I added a model statement for the 2N3904 to vary the beta and see how it af fects the circuit. The performance becomes increasingly erratic as the beta is lowered or raised. Try running it at 35 and 350.

My question is does a 2N3904 have a beta this high at such low current?

Here'e the ASC file. Watch the wrap at the end.

Version 4 SHEET 1 1296 680 WIRE 496 -96 416 -96 WIRE 752 -96 496 -96 WIRE 416 -80 416 -96 WIRE 752 -80 752 -96 WIRE 496 -16 496 -96 WIRE 416 16 416 0 WIRE 752 48 752 0 WIRE 800 48 752 48 WIRE 864 48 800 48 WIRE 944 48 864 48 WIRE 752 96 752 48 WIRE 496 144 496 64 WIRE 672 144 496 144 WIRE 688 144 672 144 WIRE 864 144 864 48 WIRE 944 144 944 48 WIRE 496 192 496 144 WIRE 752 224 752 192 WIRE 752 256 752 224 WIRE 496 304 496 256 WIRE 832 304 816 304 WIRE 864 304 864 208 WIRE 864 304 832 304 WIRE 944 304 944 224 WIRE 944 304 864 304 WIRE 944 320 944 304 WIRE 752 384 752 352 WIRE 944 416 944 400 FLAG 752 384 0 FLAG 496 304 0 FLAG 944 416 0 FLAG 416 16 0 FLAG 672 144 Q1B FLAG 800 48 Q1C FLAG 832 304 Q2B FLAG 752 224 Q1E SYMBOL npn 688 96 R0 SYMATTR InstName Q1 SYMATTR Value 2N3904Z SYMBOL pnp 816 352 R180 SYMATTR InstName Q2 SYMATTR Value 2N3906 SYMBOL res 480 -32 R0 SYMATTR InstName R1 SYMATTR Value 1e9 SYMBOL cap 480 192 R0 SYMATTR InstName C1 SYMATTR Value 100pf SYMBOL res 736 -96 R0 SYMATTR InstName R2 SYMATTR Value 4.7e6 SYMBOL res 928 128 R0 SYMATTR InstName R3 SYMATTR Value 1e9 SYMBOL cap 848 144 R0 SYMATTR InstName C2 SYMATTR Value 0.1uf SYMBOL res 928 304 R0 SYMATTR InstName R4 SYMATTR Value 1e9 SYMBOL voltage 416 -96 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 3v TEXT 512 -192 Left 2 !.tran 0 50 0 1m TEXT 512 -224 Left 2 ;'2 seconds Oscillator original TEXT 280 464 Left 2 ;See

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TEXT 376 512 Left 2 !.model 2N3904Z NPN(Bf=35 BR=4 CJC=4E-12 CJE=8E

-12 IKF=0.4 IS=1E-14 ITF=1 RB=20\n+RC=0.1 RE=0.1 TF=350E-12 T R=250E-9 VAF=100 Vceo=40 VTF=2 XTB=1.5 XTF=3)

Reply to
Steve Wilson

nning it on the bench. Q1 would have to have a high beta at nanoamp current s to initiate switching, and leakage currents may hamper the oscillation. T here are also some unexpected interactions when you change component values .

affects the circuit. The performance becomes increasingly erratic as the be ta is lowered or raised. Try running it at 35 and 350.

Scrap the high beta case. The maximum timestep needs to be reduced to 10u, then it runs fine. But I doubt many transistors exist with such high beta a t these currents.

Reply to
Steve Wilson

typo. 100u

Reply to
Steve Wilson

If I estimate a CR2032 at 250mAh (10.4mAday or 28uAyr) then for ten years average current needs to be below 2.8uA so the present 0.2uA should be fine?

How does the system know "once a day" unless there is a continuously running oscillator? If that is the RC relaxation oscillator you are considering there will be a huge lot to lot variation - does the application care whether it runs once per 18 hours or once per 36 hours or do you have some external means of determining time from a network?

piglet

Reply to
Piglet

You might find something interesting in the GreenPAK devices. These are tiny configurable or programmable devices with low power - they can do things like wakeup and timing.

I haven't used them myself, but they look fun.

Reply to
David Brown

Well, for HC04 dataseet says 100nA. Measurement on few pieces shows

0.1nA or less (it is within measurement error). May be I was just lucky, but it seems that chips improved somewhat from time when datasheet was written. And "typical" here may be quite conservative.
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                              Waldek Hebisch
Reply to
antispam

hout

or those IC's

Leakage current is a strong function of temperature. The datasheet value i ncludes both process variation (I bet they don't even test this parameter s o making it wide means they don't need to) and temperature range. Crank up the temps and your 0.1 nA will turn into 10's of nA I bet.

Rick C.

Reply to
gnuarm.deletethisbit

I measured at temperature close to 25 C (that was "room temperature" on a hot day). Yes, I expect leakage to grow with temperature, but have on oven to test.

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                              Waldek Hebisch
Reply to
antispam

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