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Batteroo testing
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amspire:

--- Quote from: dcac on December 22, 2016, 12:40:22 am ---At least 2 uA quiescent draw are not so bad, I think Jay_Diddy_B's batteriser prototypes was about 20-30uA.

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2 uA is pretty amazing. That is low enough to have no effect on the life of a battery. For the analog circuitry of the regulator, there is a current consumption versus speed trade-off, and so using a very low power analog circuit may mean really bad transient performance.

However, they could be doing another trick. They could switch the converter off totally at low currents, except for a very low powered comparator. When the comparator detects the 200mV drop, the converter circuit wakes up until the voltage is correct again, and then switches off.

It would be a way to get extremely low quiescent current at the expense of the 200mV p-p waveform at low loads. The big negative would be that if a 1A load is suddenly applied, the output voltage could drop down to almost zero before the converter starts up.
razvanme:

--- Quote from: FrankBuss on December 21, 2016, 10:03:44 pm ---Don't know how to measure the switching frequency
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Who wants the two sleeves next? One will be shipped with the construction with the battery holder, for easy measuring. Would be cool if someone with ESD/EMV equipment could take a look at it, or verify the efficiency results with a non-bricked eload, or test the current limiter.

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If nobody wants the sleeves you should sacrifice one for science and find the component values. Also please test with higher currents / oscilloscope attached so we see how it behaves when a load is applied / detached and if the switching frequency and p-p ripple changes. Based on the data so far, it seems like the efficiency has not quite reached it's maximum so higher currents might improve it by a few percent.
You can measure the switching frequency at the inductor, you will have to solder the power in this case. Probe the two sides and see what you get.

Please test the flashlight just so we have more data, even if they said you should not use it in such a device. No need for a movie just a photodector / arduino to track the time.
I have a feeling that we will be ruling out a lot of devices from use.
They might say it's not meant for mp3 players, it's not meant for trains , it's not meant for toy cars, it's not meant for gauged devices, it's not meant for flashlights. And we will be left with the package they came in.
PeterL:

--- Quote from: FrankBuss on December 21, 2016, 10:03:44 pm ---With 100 ohm load:



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Looks like regulator is in sleep mode most of the time, it makes one or two cycle at minimum on-time, overshoots, and goes to sleep. I have seen this behaviour also on convertors from TI and LT. It's not the switching frequency your looking at here, it's an active/sleep rhythm: during the rising edge the converter is active, during the falling edge it's asleep.

Since this is most certainly a boost converter it needs to operate at a duty cycle of (1-Vin/Vout). So if you feed this thing with 1.5V, it basically needs a dutycycle of zero, but these converters use a minimum on-time, which results in a minimum dutycylce if the frequency is fixed.

Things will probably get better once you lower the input voltage, and the converter actually starts boosting.

LabSpokane:
So far, the efficiency is about what I expected, but that sawtooth output is awful. It's hard to believe that isn't going cause issues.

Custom silicon?!  While you were "customizing," Bobby, while the hell didn't you stuff in a bypass FET?
FrankBuss:

--- Quote from: LabSpokane on December 22, 2016, 09:59:28 am ---So far, the efficiency is about what I expected, but that sawtooth output is awful. It's hard to believe that isn't going cause issues.

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It is no problem with the MP3 player, can't hear any distortions or noise. Maybe it has good power supply filtering.
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