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ITTSB Blog Specific => ITTSB - Small projects by Kiriakos & User reviews => Topic started by: Kiriakos GR on December 14, 2018, 08:32:40 PM

Title: Tips and Tricks for the latest LM2596 Adjustable CC/CV With current monitor LED
Post by: Kiriakos GR on December 14, 2018, 08:32:40 PM
New generation of  LM2596 Adjustable CC/CV With current monitor LED, this is truly an improvement to the right direction.

I did got one an tested it as battery charger for my NI-Cd pack this requiring 21V to be charged.
Specific LM2596 Adjustable CC/CV, it does serve well my application by this be adjusted at CC of 600mA  and current monitor LED I adjust this at 100mA.

First in row LED this is monitor of current activity, theoretical minimum this is 5% of max adjusted value up to max setting. 
In reality somewhere at below 90mA this LED turn-off.

One product design issue which I faced was current adjusting by following the instruction of using a digital multimeter as short of the output (10A input). 
Shunt resistance lower than 0.05 Ohm this activates short circuit protection !!!   :P
I was had to use my analogue multimeter which this has higher shunt resistance than my modern digital ones at 2.5A & 7.5A range.

First tip that you may use, this is to connect  0.100 Ohm resistance in series with your digital multimeter shunt (10A input).

Second tip DO NOT use 400mA range for such settings, Fuse is five times more expensive that this LM2596.

Third tip, use a blocking diode in the output, when input voltage this is disrupted, there is 23mA load caused by output LED indicators ( Energy supplied by the charged battery).   

In my project I am planning to add and a small digital volt meter ( is on the way) and a small project box.
When I will come down in to a finalized plan, I will also post pictures from this upcoming project. 
Specific module price this is as low as 1.30 Euro at eBay, which is somewhat reasonable.
I did select carefully specific PCB revision, because there is pads for soldering external LED for use in a project box.  ;)       
Title: Re: Tips and Tricks for the latest LM2596 Adjustable CC/CV With current monitor LED
Post by: Kiriakos GR on July 07, 2019, 10:48:00 AM
Originally I was feeling very optimistic about this product design, but I were disappointed when tried to use it in my project.

By trying to find correct polarity for adding external LED, the relative IC ( LM358 )were damaged and demonstrated leakage, the consequences was several.

a) Red LED this indicating current flow, this become constantly on.
b) Blue LED this indicating power up with out current this was unable to power on again.

c) Adjustable current and voltage settings they looked working despite IC leakage and LED misbehavior symptoms.
But up to that point I was unaware that short circuit protection because of IC leakage this was not functioning either.

By a simple short circuit test and at controlled environment (PSU current active limiter at 1A), this time LM2596 is the one which demonstrate permanent leakage and damage.

Lesson learned from this new experience, this is of me to never trust again such a minimalistic build regarding number of electronic components circuits.
In theory LM2596 and LM358 they can both be replaced and the circuit will become functional again.
The new problem is that this PCB it is populated in such a way that soldering and parts exchange it is a huge challenge and the next problem this is the cost of getting such components from China.

Generally speaking  I am now going to use in my project this ZK-J5X 5A, which turned to be a much more trust-able product design.
 DC-DC back converter getting smarter, here is the NEW ZK-J5X 5A ( Mini Review ) (  :)