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I am building a small LED lamp from a jar(about 100ml), so all components should fit in it. I decided to use a LED drive/Joule Thief, that I found at online Chinese store.
Datasheets (all I can find is in Chinese language): https://pdf1.alldatasheet.com/datasheet-pdf/view/1133536/SHININGIC/YX8122.html
https://datasheetspdf.com/pdf/785935/ETC/YX8122/1
I also found similar question: LEDs driver circuit

The circuit is very simple, but I still failing to make it work. I have a white 5mm LED(3.3V, 20mA), 3v button battery and 47uH inductor, but the LED won't light up. I don't know what I'm doing wrong, if I increase inductor to 1mH the LED is glowing, but not at the full power. I tried to connect red LED (1.8v, 20mA), but it glows even weaker. I don't want to change battery type as it perfectly fits in the jar and I can't use two batteries, for the same reason, they won't fit.

In summary, the goal is to make white led glow as long as possible using 3v button battery. Is it possible to make it by using yx8122 led drive? If no, then what the purpose of this IC?

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  • \$\begingroup\$ The YX8122 can boost the voltage, but it can't do anything about the current. Button cells aren't made to deliver the current it takes to light an LED. \$\endgroup\$
    – JRE
    Commented Jan 16, 2021 at 23:04
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    \$\begingroup\$ @JRE -- Through significant experience with different kinds of Joule Thief circuits, I can tell you that button cells can definitely light a white LED. Shiftas:Try a small low-ESR capacitor on the YX8122 power supply pins, perhaps try 10uH or 100uH. Also try two white LED's in series, or using a 1.5v cell. The boost output voltage might not be high enough over the input voltage, and the straight-through path might be preventing oscillation. My rule of thumb is that a boost circuit should at least double the voltage. \$\endgroup\$
    – MicroservicesOnDDD
    Commented Jun 14, 2021 at 2:55

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A dim LED can be powered from a button battery cell for a short time. I have some cheap solar garden lights that use a 1.2V AAA Ni-MH battery that is charged by a 30mA/2V solar panel all day. Its QX5252 IC is similar to yours but has an English datasheet and it lights a single LED or a colors changing IC brightly all night. My AAA battery is MUCH larger than your button battery and it is charged all day every day.

Some LED novelties use three 1.5V button batteries in series and a resistor to limit the LED current. They light for a few hours.

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