Re: Boost converter magic smoke caveat


Brian Flynn GM8BJF
 

I have used these Chinese SMPS boards widely in different projects.  All of the buck types supposedly based on the LM 2596 IC that I have come across used what I took to be a re-marked (not fake) LM2576 chip. This is a cheaper part. The telltale sign is the frequency that they operate at. The real 2596 runs at 150kHz wheras the 2576 runs at 50kHz. Also the markings often wash off with IPA.;-) .It is just a creative way of adding value to the product.  My solution has been to source some LM2596s from a trusted supplier (RS) and just replace the IC. Some simple soldering! While I am at it I usually replace the caps as the ones supplied normally have poor ESR ratings and run hot under a decent load. If the boards are sourced with this in mind it is still cheap for the PCB! I never pay more than 90p for one.
The boost converters using the XL6009 I have found excellent. That (chinese) chip is much more efficient than the NS/TI equivalents as it uses MOS devices as the main switching element with a lower on resistanbce than the aforementioned bipolar parts. That assumes the PCBs are properly soldered, but that is up to "goods inwards" to accertain!

73s
Brian GM8BJF

Join UKMicrowaves@groups.io to automatically receive all group messages.