2014-11-6 Solar Recharging Lamp

After this week's meeting, a few of us got to discussing a find I made at

Dollar Tree, namely a small solar-recharging 'desk lamp' which contains:

- 3 white leds

- 200mah Ni-Cd AAA cell

- A small solar panel

- A tiny on-off slide switch

- A small circuit board with an YX805 LED and an inductor

and the 3 parallel-wired LEDs

The YX805 is the same as a 5252 LED Driver and has a data

sheet here:

This IC uses the inductor to boost the 1.5 volt battery to sufficent

voltage to light the leds, and the value of the inductor controls the

current available to the LEDS. The chip also has a cutoff value of

incoming solar panel voltage to switch the LEDs on when the ambient light

drops. The cutoff has hysterisis sufficent to keep the LEDs from

blinking, and it also provides a battery-protecting cut off that prevents

the battery from being too deeply discharged.

For a buck, it's a nice little night-light, there's quite a few parts that

could be useful in other projects.

If you Google YX805 or QX5252, you'll find some images with schematics for

other uses, such as a power failure light that could be useful in dark

hallways or basements.

=^_^= Tigerwolf

George, K9TGR