Voltage regulation circuit 12V to 5V in 5A range

[amgen]

I know you already ordered some things, I have used few of these things..... no other regulator needed. The output voltage is pretty stable.

[Ioannis]

Camparing the various chinese power supplies I ended up with Sunny brand, that is represented in Europe by a reputable firm. https://en.sunny-group.com

Opening one of them reveals that the design is in pretty good level.

Please be very carefull with all these cheap SMPS that are sold at low prices. They can have really catastrophic failures (I was almost hurt by this), with very bad "protection" circuits that fail after the big-bang...!

The idea of having a 5V wall adapter may seem good but there is a risk that the user may by mistake connect a 12V adapter at the 5V entry...

Ioannis

[amgen]

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The idea of having a 5V wall adapter may seem good but there is a risk that the user may by mistake connect a 12V adapter at the 5V entry...

Very true. I wouldn't use that for product for resale, only for building and testing some circuits or maybe a simple small product. But I always hardwire power supply in to avoid exactly what you said....... That was interesting what you said about some dangerous failures, those SMPS's 'should' have the input separated from the output with some kind of high frequency transformer for 'galvanic isolation' meaning no actual electrical connection from in to out.

[Ioannis]

Yes, all of these SMPS do have that high frequency transformer and do isolate the secondary. Few have poor isolation.

Many have bad fuses in the line input and they blow after the explosion of low quality capacitor/bridge/MosFet. And had cases of pcb traces that were melted also.

These two images show WellMax LED panel drivers that drop my three phase protection fuse on the wall distribution box! The pcb fuse was the last to blow after burning pcb traces!

Had other similar case of 12V/5A power supplies that were poor made. I do understand that inrush currents are high enough and the fuse should be relatively slow, but they should add a thermistor then to lower that current and have a faster fuse.

Ioannis