Voltlog #45 - Multiple Rail Power Supply Kit Assembly

[@Hasitier]

I have done this kit also about 4 weeks ago. It produces about 16 volts with the step up/step down converter first and than it uses linear regulators to lower it to the 12/5/3.3 Volts. So i have throwen it into a little case and added a lm317 and a voltmeter at the 16 V Point on the pcb. So i got a little power supply with fixed positive and negative voltages and an additional variable voltage from about 1.3 to 15 volts. Great for using it on the go because all works powered from a 5 volt power bank

[@voltlog]

+Michael Bernhardt Nice! Do you remember if your PSU also draws about 150mA in standby ?

[@Hasitier]

+VoltLog good morning from Germany. So i just did a quick measurement before i'll go to work with one of those USB power measurement things. At 5 Volts it draws about 180mA with my additional lm317 and the LED voltmeter. Sounds within the same range as yours does when you substract about 20 mA for the additional circet. The kit says 5 to 24 Volts input and due to the reason it is a step up/step down regulator it sureley will draw half of that in standby at 12V and a quarter of it at 24. A word to those polyfuses or PTC fuses as they are called: It is a 300mA rated one and i think mine has a 400mA one but i did not open my case this morning to look it up. Anyway this does not really matter because the rated value of those polyfuses is the value they stay closed for sure at any condition. In the datasheets of those fuses is another entry telling the current the are surely opened. And this is normally twice the rated stay on value. So it will Open up somewhere in between.

[@Hasitier]

+Michael Bernhardt thinking of the wide input range voltage this might be a kind of compromise to protect the circuit from overload. I did not look up the data sheet of the main regulator but maybe it has no current limiting when getting too hot and those little glued cooling pads cannot push away the heat above a certin limit? If there are any questions just ask. I than could do some measurements on this weekend. I also have some other polyfuses around here For testing

[@voltlog]

+Michael Bernhardt Good morning, I will test the actual poly fuse next week as I am away for the weekend now. I was curious about the standby current but your measurement looks to be similar to what I have so it is normal. You are right about the poly fuses, they are not very precise and would probably go up 600mA but not for long. Quoting specs of 300mA per each rail output is not very realistic, they will get hot quickly so maybe they're limiting that as well through the fuse.

[@javierpallalorden]

Excellent video (nice with the PiP), I really like your soldering skills.

[@voltlog]

+Javier Palla Lorden thanks!

[@adlerweb]

Looks like a good kit if you need somewhat stable voltages and don't own a proper linear lab supply or want to save space. Even if the voltages looked a bit off. The polyfuse looks rather big for 300mA (which would also be far too low to get the specified output currents) so I guess it's really 3A. Since there are usb power supplies with several amps this also seems somewhat reasonable. PC ports are limited to afair 500 and 800mA depending on the used USB version but are also required to implement protective components - as long as your board manufacturer adheres to this specification you shouldn't be able to blow your pc. Air compressor might sound a fast solution but I was told there could be moisture buildup in the lines which may turn into ice due to pressure so it's usually a bad idea to fire directly on electronic components. One note regarding the recording: when showing the smd components the exposure jumped quite a bit - of your camera allows to do so you might want to try fixes exposure.

[@voltlog]

+BitBastelei Thank you for the constructive feedback! I guess I could put that poly fuse to a test by drawing some current from this psu, but as the power supply current draw in standby is already 150mA indeed it doesn't make sense to to have a 300mA fuse.And you are right about motherboards as well, all the modern ones have decent protection. I'm not sure butI think there are filters that you can install on the output of air compressors for use with electronics When doing just a single board DIY, it's acceptable to wait for it to dry naturally but when doing 10-20 pcs.. then you really start to feel the need for an air compressor. Lighting is one thing I need to improve in my videos and I am also experimenting with fixed exposure and hopefully I can improve the quality soon.

[@Wookie.De.v]

What's the best way to debug this if it's not working? When setting 400mA as a limit the voltage drops to 2,4V. Something is damaged on the pcb I think. I rarely destroyed components when soldering

[@Wookie.De.v]

fixed it, i had one smd diode wired the wrong way. Now everything works :)

[@voltlog]

Glad to hear you fixed it, actually that is the first thing I like to check whenever a new kit is not working: that every part was correctly soldered.

[@danz409]

blew up my XL6008 chip. had a diode in the wrong way. turns out they where directional. i honestly didn't pay attentiont to what they was when i put them in. and the markings for polarity wasn't even noticed. normally that wouldn't be an issue. but digikey/mouser dosn't even have that part. and no choice but to order a replacement from china... guess this project is on hold for a month+

[@ФилиппХардкоров]

Hi guys. Help me to understand. Is it possible to use a resistor of 10k instead of a 12k resistor

[@StephenFarthing]

Thanks for a very useful and informative video. I have just ordered the kit from Banggood. It will be a nice addition to my beginners lab.

[@tatu7335]

Nice work!!! Thank you for your explanation!!!

[@voltlog]

thanks!

[@davidprice2861]

A hair dryer will dry things very quickly... Good review.

[@ufohunter3688]

I came across the schematic of this unit while researching for a replacement power supply for a Feeltech FY3224S signal generator. Hope it helps some one. forum.banggood.com/forum-topic-123630.html?page=3 If the link doesn't work, it might have been moved to another page of the forum.

[@voltlog]

thank you for sharing! the link does work