The Garden Solar Light is a recurring interest of mine. A Joule Thief attempts to extract usable power from an almost dead battery under 0. The somewhat mysterious little Chinese ASIC integrated circuits have been examined by a number of people since I first posted about the subject in A pretty good list of them is HERE. Despite their similarities, one reason for the overabundance choices, besides competition between manufacturers, is to accommodate for different current and voltage applications as well as other improvements, such as over discharge protection.
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The Garden Solar Light is a recurring interest of mine. A Joule Thief attempts to extract usable power from an almost dead battery under 0. The somewhat mysterious little Chinese ASIC integrated circuits have been examined by a number of people since I first posted about the subject in A pretty good list of them is HERE.
Despite their similarities, one reason for the overabundance choices, besides competition between manufacturers, is to accommodate for different current and voltage applications as well as other improvements, such as over discharge protection.
Some of the improvements are patented. It is simple but informative. If the soil is damp, the LED is out. If the soil is dry, the LED is lit. The internal schematic of these Chinese voltage booster chips is elusive. Each pulse causes current to flow into the inductor which creates a magnetic field around the inductor, that is, in essence, stored energy. I configured the basic circuit in Figure 2, below, except for the solar charging portion. For now I am only testing the voltage booster section with an alkaline 1.
This configuration oscillates at kHz. See Fig. The output measured 3. Rectification and stabilization will be needed before the output is usable for anything else. With a 1. Results are very similar as can bee seen in Figure 6, below. The frequency was somewhat higher at kHz and the waveform even less of a square wave than with the YXA. Nonetheless, quite similar and equally usable.
At this point I have not installed the solar cell charger — that will come later. The schematic shown in Figure 7, below, provides 5. With a 33uH inductor it supplies 50ma. These readings match the YXA datasheet in that the smaller inductor value does produce more current kHz but the values differ from the chart.
Conversely, if the capacitor is fully charged prior to applying the load, I measure 5. This test was using a 33uH inductor. The solar charging portion is not part of the initial tests. Without the 5. Using the oscilloscope I measured the 5V ripple at. It worked perfectly for now with the uF capacitor providing a current reserve. What I see it starting at 5. See Figure 8, below. Changing the NANO is on my list. Idle is the low current and LED-on is the high current:.
Idle current consumption is 8. Better, but still a challenge for the ATTiny85 and a transceiver plus sensor. The supply still needs work. I made some changes and have a working circuit again!
I hate the unexplained. See figure 9 below. This circuit correctly runs the ATTiny85 running Blink in the video immediately above. Keep watching this post to expand — it is NOT finished. Other posts may be used will wait for other aspects of my project, such as adding the radio transmitter and sensor.
Until then:. I found your interesting article while searching for info on the YX chip. Good reading. Have the PCB from a garden light on a breadboard and am experimenting with different size inductors to see the effect on battery drain and output voltage. The outhouse light will be built into a small and nondescript plywood box screwed to the outhouse ceiling. Solar panel will be four cells salvaged from the spotlights connected in parallel and stuck down to a piece of perspex with RTV silicone for weatherproofing.
Battery will be a C sized NiMh with mAh capacity which should give a bit of reserve to cope with a succession of dull days. The most interesting part will be seeing how long my solar charged nightlight lasts before some creep steals it.
Like Liked by 1 person. If you were going to build anything from scratch I recommend that instead of the YX chip that you instead used qx chip. It provides significantly more current. Hi, thanks for info on the qx However, batteries are no good in the below freezing temps experienced in many places during winter.
Therefore we need such an ASIC chip that is designed for the lithium titanate battery which is 2. Like Like. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account.
You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Detect And Zero Rightmost One. Skip to content. Voltage Boost via Coil Field Collapse. Share this: Facebook. Like this: Like Loading Bookmark the permalink. Leave a Reply Cancel reply Enter your comment here Fill in your details below or click an icon to log in:.
QX5252 Driver. Datasheet pdf. Equivalent
It seems that many "Joule Thief" circuits depend on a clunky bulky and heavy toroid or "donut" that has to be carefully wound with copper wire. But now there are several very small 4 legged ICs available that do the job using only a simple inductor, single cell battery and a LED. In effect, the 4 legged IC replaces the clunky toroid. I came across these ICs when I disassembled some solar powered yard lights. I looked for a toroid but only found a four legged IC and a part that looked like a resistor but actually was a very physically small inductor coil.
"Joule Thief" Circuits, Crude to Modern...