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I have see this instruction about hacking one ordinary boost/buck converter by adding the current sensing to its FB pin (feedback pin) like this schematic:

enter image description here

and know this system using for current controlling:

enter image description here

so my question is that what would happen if use the output of above current sensor as said at the two or some many LM2596 module based like this ( these Buck converter are so low cost and if could be parallel could give more current and ...) like below picture ?

enter image description here

Update: I thought if I simulated this situation, in some software like EASYEDA (SPICE SIMULATION OPTION ON IT) could it be useful for this question!?

Thanks.

soheil sabz
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    wow, found one that counterfeits the national semiconductor branded LM2596... these haven't been in production for a loooooong time. Counterfeit power semiconductors have a lot of potential to disappoint under load. I'd recommend getting something that comes from a reputable source. – Marcus Müller Jun 11 '20 at 13:51
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    Also, unless your output dampening is excellent, it's usually a bad idea to put unsychnronized SMPS in parallel, unless their datasheet says that's possible. If you need more output current, get a larger inductor, and a switcher IC that can handle more current or one that supports an external MOSFET to handle the current. – Marcus Müller Jun 11 '20 at 13:54
  • I don't get your word, do you say this seller is fake or saying this module don't produced any more , if this why don't produced more? it have has buyers around world and why not produced more! – soheil sabz Jun 11 '20 at 13:56
  • [What to check for when buying an electronic component or module?](https://electronics.stackexchange.com/questions/504044/what-to-check-for-when-buying-an-electronic-component-or-module). – Andy aka Jun 11 '20 at 13:57
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    The seller just sells a generic PCB around the central LM2596 IC. That IC is, today, produced by Texas Instruments, because they bought National Semiconductor a decade ago. The datecode "JM64RP" is easy to google for: A lot of sellers sell it on Aliexpress (because people don't understand the difference between a datecode and a Device Name). Now, it's **very** unlikely that all the cheap LM2596 PCBs sold in 2020 have been manufactured using LM2596 that were produced in the same week of 1996 or 2006. It's more likely that all the ICs marked with exactly that datecode sold today are fake. – Marcus Müller Jun 11 '20 at 14:03
  • The LM2596 is still in production and still carries the marking it used to. You can buy it [directly from TI](https://www.ti.com/product/LM2596#order-quality) (who acquired National), Digikey, etc. – 65Roadster Jun 11 '20 at 14:04
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    @65Roadster not with the National Semiconductor logo, no. And not with that datecode, either. There certainly *was* a legitimate run at NatSemi back in 2006 or 1996 in the 4. week, but as I said, unlikely that 14 or 26 years later, all cheap china LM2596 are based on something produced in that specific week. Way more likely that there's someone still producing NatSemi-branded chips today, and just copying the marking. – Marcus Müller Jun 11 '20 at 14:06
  • It's not like buying a fake Gucci handbag for the woman in your life - yes she'll find out one of these days and probably forgive you but months of being in her good books is probably worth it. Fake electrical chips are a scourge for EEs. – Andy aka Jun 11 '20 at 14:14
  • Guys, my question, has not answered,yet, try for it – soheil sabz Jun 11 '20 at 14:21
  • This model of DCDC converter is **NOT** designed to be used in parallel. Using **linear** regulators in parallel can be done but you have to **know what you're doing** so that they equally **share the load**. With switched converters things are far more complex as converters deliver **current pulses** which means the converters can (and will) disturb each other. Experienced EEs simply **don't do this** and solve the issue by **getting a DCDC converter rated for a higher current**. – Bimpelrekkie Jun 11 '20 at 14:39
  • ...But if you want to try it anyway I wish you good luck (you need it) and if it works now that does not mean it is a **reliable** circuit. Suppose it works only for an hour, a week or a month? If you get a well designed DCDC converter rated for the higher current it might last **years**. – Bimpelrekkie Jun 11 '20 at 14:42
  • @soheilsabz I did, see my second comment from the top. Bimpelrekkie just said the same, too. So, you have your answer: you can't just put your two LM2596 in parallel. The fact that they are fake just makes it worse. – Marcus Müller Jun 11 '20 at 15:16
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    _"so my question is that what would happen if use the output of above current sensor as said at the two or some many LM2596 module based like this"_ - we don't know exactly. Why not just try it? Then you can answer your own question! The IC is a clone of the LM2596, and works the same. As to why the manufacturer doesn't put their own part number on it, I guess it's because they stupidly think people _prefer_ to buy fakes! – Bruce Abbott Jun 11 '20 at 15:23
  • @BruceAbbott Color me *shocked*! Shocked I say! It's as if if you put the datecode on the IC into a search engine, you find hundreds of product pages! That makes no sense! Unless people who don't know what they're dealing with are the target group of these manufacturers! `` – Marcus Müller Jun 11 '20 at 16:45
  • @MarcusMüller I see from TI's website that the marking is the same but they don't show the logo. Did they change it to TI's logo after the acquisition? That can be a real pain, logistically but part of branding. Regardless, I also think an awful lot of these parts are counterfeits. Fine for playing around but some of these DC-DC modules are not well designed or well built! – 65Roadster Jun 12 '20 at 05:04

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