They look very different
On the one I ordered the PWM input is clearly marked. On the other one I cannot see a PWM input, unless G is the common ground and CE is the PWM input.
Does anyone know anything about the circuit they sent me in error?
The best solution is to contact your vendor and explain the problem and ask for an exchange and that they pay shipping as it was there mistook. I cannot tell as I cannot read the chip labels, but the possibility exists they sent you what you ordered in a different configuration.
Does this discussion help:
Just a different layout and chip package.
CE seems to be the PWM input. See the PT4115 datasheet.
If you connect 12volt or so to Vin/GND then you should measure about 5volt on the unconnected PWM pin.
Ignore the input voltage range on that image.
Chips like that have usually a Vin range of 8-30volt and LEDs in series is much better.
Use 12volt for 3 LED strings and 24volt for 6-7 LED strings.
Leo..
Hello, yes I think they did that, and I found at last an explanation of the delivered component:
And it seems that CE is PWN in. CE = Chip Enable.
Yes, thanks.
So the diagram should show LEDs in series? I’ve only just started looking at this stuff and I thought LEDs in series was the best, not in parallel as shown in the diagram.
It looks like the one they sent me (LD06AJSA) has a max input voltage of 6V, while the one I ordered has a max of 24V (LD24AJTA).
I doubt that that is a voltage number.
I have used hundreds of PT4115 Led drivers and the like (AL8861 etc.).
Led driver chips like that usually have a voltage rating of 30-40volt.
I would try connecting 30volt from a current limiting lab supply to the board (no LED attached) and see what bang you got for your buck.
Leo..
Well, it is a big coincidence if it is not. I’ve already got my bang, because I imagined they’d send me at least a compatible model, but the 6V LD06AJSA) got hot and died at 12V. Really bright LED, then darkness.
Did that. No reply. Gave a 1 star review on Amazon.it. They refused to publish it because the fact that I was sent an incompatible product was not relevant.
I just noticed the difference between the two boards.
The one on the left is a switching (buck) converter, the one on the right is linear (no inductor).
The one on the right will get hot with increasing differential voltage, the one on the left will stay cool.
Leo..
That is what I tried to do after amazon refused my 1 star rating.
Since when does a website publish bad ratings.
The point is that those two boards use a completely different technology.
This is false advertising.
You should get your money back, or get the boards with the inductor.
Leo..
Well, Amazon does publish 1 star reviews of things. I’ve resubmitted the review being more explicit about the fact that it is advertised as working up to 24 volts but blows up at 12V. I’m not holding my breath.
Arrrfg! Ooops! Embarassing 
I’d ordered both types and forgotten I’d done so. All my own mistake. The more powerful ones will arrive in a couple of weeks. Urgh.