Some VERY interesting LED modules

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I did … I do

I have already commented

MichaelG.

It's Your fault ! all of you ! Quriosity got the better of me and I ordered 4 that have just arrived. I did not need my swiss army knife to open the box - it parted with little effort. The numbers on the internal label do not match the pictures posted earlier in the thread and the board is different, having what I can best call test points between each LED chip and other places. The input track runs round the board to the diode block - numbered DBLS207G G7EY and 2pads alternating input, 2 pads + and -. The ESD Numbered P07EM 7C2PJ is connected across the + and- tracks. There are 3 arrays of 14 LEDs. There are no clever optics only the polished plated plastic front. An interesting number on the board 94v-0. Noel.

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A fundamentally important correction, if I may noel !!

The very clever optics are in each ‘cell’ of piece that you prised off.

I can’t do it today, but I will take some photos anon.

MichaelG.

94V-0 is the UL Underwriters Laboratories) flammabiliy rattng for the circuit board

Michael, thank you, yes, I had somehow expected some sort of lens array, indeed the plated reflector is clever, and thankyou Robert. I have a friend who is always on about his super duper torch and one of these units seemed a good starting point for a torch that would leave him in the dark. Powered by a 7Ah 12v rechargeable cell. For a heat sink, having read the plessey document, one thought was a turbo compressor wheel (not the tubine wheel.) with heat transfer film rather than paste. Also an open plan so the heat sink/ lamp unit would be in the open, whilst the battery would be in a case, not unlike the old hand lantern. Noel.

Note:

Aside from the ones behind the Bar … ‘Optics’ comes in three versions

Refractive, Reflective, and any mixture of the two.

MichaelG.

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Just seen your follow-up, Noel

If you want to ‘see it in action’ without blinding yourself … [with the unit un-powered] just look down into one of the cells and see the image of the LED; then lift the front plate by about 1mm and observe the change.

Clever is getting beam-forming without excessive size, weight and cost

MichaelG.

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Here’s a rough, hand-held grab shot:

Edited By Michael Gilligan on 18/01/2023 13:44:04

My 25 degree one has many more facets.

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Yes it would

… I was intending to do the comparison shots anon, but just grabbed a quick picture of a 60° one to support my comments to Noel

MichaelG..

I bought a boost regulator like this one thinking it looked suitable to power one of the Plessey LED modules.

They seem to be sold by a number of ebay sellers. With 12 volts input I set the output to 44 volts with no load. It did take a large current at switch on (About 3 amps.) I then connected a 65 ohm resistor to the output to simulate the LED module. (It would draw about 680 mA) The regulator was trying to draw more then 5 amps which is the maximum current limit my bench power supply can be set to.
i then tried to supply it from a car battery. It then drew so much current that the solder on the input connections then melted.
Although it should have been running within it's advertised specifications it had destroyed the power mosfet in the regulator. I would not advise anyone to buy one of these regulators to power the Plessey LED modules.

Les.

I bought two of the same modules for the LEDs and had a different problem!

The DC:DC boost works fine and I could adjust the output voltage no problem, what did not work though was the constant current control. At no setting of the trimmer pot could I get a constant current, in fact the pot acted as a sort of switch with very little control at lowish current (using a 100 Ohm load) and at part travel the output jumped (and latched) to having no current limiting.

I did power the Leds at 600mA using an ali clad 8 Ohm series resistor but I then had three components that needed heat sinking so abandoned the idea.

I tried tracing the circuit to see why the CC did not works but the 'PCB tracks' are too well concealed under the resist coating that I gave up.

I contacted the ebay seller explaining the fault and he sent a nice apologetic reply and a full refund also saying not to bother returning them. They work as straight DC:DC step up converters so I'm sure I will find another use for them.

Ian P

p.s. You mention 3A at switch on (without load) is that just the momentary inrush?

Just a thought but I see other buck converters of this power come with an obvious finned heatsink. This one looks to have only a thin metal back with four mounting holes. I wonder if it's inexpensive because the user has to provide his own heatsink? Even so I would expect the chip to detect thermal runaway, but maybe not!

Dave

Looks like the current setting is a foldback current limit not a constant current setting. Not unusual for descriptions and specifications of this sort of module from the far east to be wrong.

Robert G8RPI

Comment for SOD, Thermally the design is quite good. It is built on aluminium circuit board. (The sort you see used on LED modules.) It failed in a very few seconds without ever producing any output under load. Even with no load it took quite a large current for a second or two then dropped down to a reasonable value.

Robert, I have not traced out the schematic so I don't know if it is foldback current limiting, It uses a TL494 controller IC so I should be able to work out if it is fold back current regulation. I think it is just a bad design taking such a high startup current even with no load on the output.

Les.

Hello,

As well as the 350 mA LUX Drive modules we used before (see my previous post above) we have also used the Lux Drive 700 module to drive these at 700mA. These modules also have a dimming input.

Just posting about this out of interest really. I might have a couple spare if I can find them. I will post on here if I have.

Edited By Dogboy on 26/01/2023 10:44:29

I await the arrival of a 400W boost converter with CV and CC . It has the switching devices on heatsinks. 12v in and will set to 44V out at 650Ma I hope. What Vout is on the luxdrive units at 700Ma? Noel.

Information on the full range of Luxdrive modules, from the manufacturer: **LINK**

https://leddynamics.com/led-drivers

MichaelG.

On the LUXdrive units (they look nice!) I couldn't see a Vout on the site Michael linked to (may have missed something?) but the LUXdrive A011-D-V-700 is available in the UK from Digi-Key for £20.50 and they give a maximum Vout of 48V - so they should be fine for this application.

On other (cheaper) solutions I, like Noel, ordered a 400W booster (£8.49):

Reading Les' account I went very carefully! With 10V input and no load I adjusted the output to 12.5V - the module drew ~10mA. Connecting an 81 ohm load (shown) the voltage remained stable and it drew 220mA at the input . Cranking the current pot right down the voltage across the load dropped to 11.5V, so I guess it's working as expected and I'm hopeful that it will be OK to drive the LED array..

A slightly odd thing is that the +ve output appears on the leftmost heatsink in the photo. Something to be aware of if going down this road.

Robin.

Edited By Robin Graham on 26/01/2023 21:40:12

Edited By Robin Graham on 26/01/2023 21:42:35

Edited By Robin Graham on 26/01/2023 21:43:21

Edited By Robin Graham on 26/01/2023 21:57:24

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Links within Links will get you here: **LINK**

http://www.leddynamics.com/wp-content/uploads/2018/12/A011_FlexBlock_v2.0.pdf

What you seek is declared on the second page thereof.

MichaelG.

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Incidentally: The Buck Puck unit is very well-regarded by American users on the microbehunter forum

… ideal for powering LED adaptations of classic microscopes.

Edited By Michael Gilligan on 26/01/2023 22:04:34

Ah, I did indeed miss something - an all too frequent happening these days. My intention was to give a source for compatible leddynamics drivers in the UK if anyone was interested.

I'm possibly alone in fretting about heatsinks, but in the spirit of publishing ones findings whatever I bought some round jobs from eBay:

Perhaps overkill as it runs at about 65 degrees at the centre of the array (without the dreaded thermal paste) but it'll do for my needs.

Now I've got the arrays up and running (It's been journey into new territory for me! ) my mind turns back to Michael's original post - the point of these things is that they give a directed beam without ancillary optics. Which they do!

Robin.

Edited By Robin Graham on 29/01/2023 00:23:41