ITTSB.EU Blog Forum
ITTSB Blog Specific => ITTSB - Small projects by Kiriakos & User reviews => Topic started by: Kiriakos GR on February 04, 2024, 11:56:54 PM
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Few years back I did purchase one LM2596S the supposed be the better version, the one that can do also constant current.
The damn thing blow up right away and I was unable to explore it.
One month ago within an ancient flatbed scanner, I did discover on it PCB one LM2575T ADJ (TO-220), and I did waste my time so to transplant this IC over a PCB designed for DDPAK/TO-263.
Large nice heat sink installed (patent pending), and I thought that now I will get much more juice instead of the poorly cooled version.
No and no, and no gain, at any combination of 10.8 Watt output, the LM2575 get at max of 45 Celsius (because of inadequate cooling), but it does not deliver even a drop of further energy.
My no-name PCB has also one LM358, this has two gates, the one for the Power OK LED this is damaged, and the 100K pot does not help either in any setting while this is working.
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The company that added the LM2575 at their flatbed scanner, it was added for additional DCV stability in case that external DC power block (power supply) this facing very unstable ACV input (old classic transformer with DC rectifiers).
These wise electronic engineers they did not thought to risk the fate of their product by saturating (due overload) this low cost IC.
Instead they use only the smart design of DCV stabilizer by using only a fraction of this 10.8W electrical specification.
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Below are photographs of my freshly revived LM2575 CC / CV. :)
I did connect as power source, one switching PSU 22.5V 0.8A (very common as ADSL router power block).
And here are also electrical conversion examples of how far you can go with 10.8 Watt.
Li-Ion 4.200 V x 5 cells = 21 V / 0.514 A = 10.8W
Li-Ion 4.200 V x 4 cells = 16.8 V / 0.642 A = 10.8W
Li-Ion 4.200 V x 2 cells = 8.4 V / 1.285 A = 10.8W
Li-ion 4.200V x 2.570 A = 10.8W
12V Motorcycle battery 14.500 V x 0.744 A = 10.8W
(13.500 V x 0.800 A = 10.8W)
6V Motorcycle battery 7.250 V x 1.480 A = 10.8W
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LM2575T / 52 kHz / 1A
LM2596 / 150 kHz / 3A
Latest 2023 model = LMR51430 4.5 to 36-V, 3-A, 500-kHz
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Another indoor technological success :)
Basically even 1A of current this is good enough for any battery charger application.
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I did complete 48 hours of circuit testing, by this serving as Ni-CAD charger.
It works and it reliability it is now tested. ;)