1V to 5V Boost Converter-Module for 1€ (eBay Cheap-Stuff) - Page 1
Forum section: electronics / general

author: SaabFAN
author_rank: Frequent Contributor
timestamp: July 15, 2018, 01:08:41 am
content: Has anyone here bought one of these things, and can tell me how well they work:https://www.ebay.de/itm/1-8V-2-5V-3V-3-3V-3-7V-To-5V-DC-DC-Step-Up-Power-Voltage-Boost-Converter-Board/272677907532?hash=item3f7cdeac4c:g:QLsAAOSwn-tZHrnSI've just received my Active Probe from Transverter Store and because I've got a few LiPo-Batteries in the parts-bin I searched for some boost-modules (went for the MT3608-Module) and stumbles across these things.The logo of the chip seems kind of familiar, but a Google-Search for "2801A Boost Controller" or "SOT223 Boost Controller" came up empty to far.Or is that a chip that's being repurposed for something it can do but wasn't designed to do? I remember a ST-Datasheet for the 78XX-Series that included a application for a switching buck-converter that used a 78XX as the regulator.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: July 15, 2018, 01:17:42 am
content: Ah... "SOT-89 Boost Controller" (looks the same as SOT-223) yields the answer! lolThis Chip (more likely a chip doing the same thing - Mouser wants 0,415€ per piece on a 10.000 qty order) seems to be what the chinese are using:https://www.torexsemi.com/file/xc6372/XC6371-XC6372.pdfI'm curious how these modules will be doing - I've ordered two for testing.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: October 05, 2018, 03:08:28 pm
content: Just got around to test the things.The module is not capable of delivering what's promised by the datasheet.Part of the problem is most likely that there's a inductor soldered on the board marked "220", which I'm guessing stands for 22 * 10^0 µH instead of 220µH.Would explain almost 0,5Vpp (measured with Multimeter - after seeing this, I didn't bother with the scope) slow frequency ripple and the fact that it's barely capable of delivering 40 mA.So at least there's a different inductor required, or, in case the chip itself is fake, a new chip as well.In other words: Not worth even 1$ in the form I received these modules.

author: tsman
author_rank: Frequent Contributor
timestamp: October 05, 2018, 03:39:14 pm
content: Quote from: SaabFAN on October 05, 2018, 03:08:28 pmNot surprised. Most of these ultra cheap power supply modules have wildly inflated specs because of design mistakes and counterfeit components. They usually do work but you have to derate them by 70% or bad things happen. The counterfeit LM2596 modules that sell for less than the 1000 quantity price of a real LM2596 are another example of this. If you try to pull the advertised current then it'll rapidly overheat and die with a input to output hard short.

author: thm_w
author_rank: Super Contributor
timestamp: October 05, 2018, 09:26:23 pm
content: At what input voltage?https://www.aliexpress.com/item/0-9-5V-To-5V-DC-DC-Step-Up-Power-Module-Voltage-Boost-Converter-Board-1/32885246370.htmlThis listing states:Starting Up Voltage:0.8V;output current:7mAInput Voltage:1-1.5V;output voltage 5V;current 40-100mAInput Voltage:1.5-2V;output voltage 5V;current 100-150mAInput Voltage:2-3V;output voltage 5V;current 150-380mAInput Voltage:>3V;output voltage 5V;current 380-480mAI haven't personally used that board, it does seem like bad component selection. Its quite a low frequency converter, maybe 180kHz maximum.Some other info on the chip:https://dzrmo.wordpress.com/2017/01/26/a-tiny-but-good-boost-converter/http://archive.espec.ws/files/ME2108%20Series.pdf(this datasheet is showing 33 and 47uH for an inductor).I use this one a lot:https://www.aliexpress.com/item/MT3608-DC-DC-Step-Up-Power-Apply-Module-Booster-Power-Module-MAX-output-28V-2A/32477478565.htmlSince its running at 1.2MHz the 22uH inductor is actually suitable. But I would not expect to run it near the "2A" rating, most likely capacitors aren't nearly large enough, and inductor current is lower than that. Its also not a fixed output voltage and the size is larger.https://www.olimex.com/Products/Breadboarding/BB-PWR-3608/resources/MT3608.pdf

author: SaabFAN
author_rank: Frequent Contributor
timestamp: October 05, 2018, 09:35:05 pm
content: I'm quite pleased with the performance of the MT3608. I'm using it in my active probe (separated from the actual probe by a 10mH inductor and 4 47µF Caps, as well as yet another ferrite). So far I haven't been able to notice any noise from the PSU of the probe coming out of the probeThe input-voltage of the tiny module was about 4V delivered by a 5C capable 1 Ah LiPo-Accumulator. And with that it was barely capable of powering an arduino Nano.The ripple was pretty small though. Just 38mVpp at a current draw of maybe 40mA.But my Arduino Leonardo with its current draw of 78mA was too much for the little module. Voltage immediately collapsed to VIN - Vf of the Diode.