Ericsson PMD 4118O WP - Low voltage 3A driver for SSC P7?

[Winx]

Sorry, but I've drank little too much and it's 3 a.m. at the moment in Finland ... Well anyway...

My dad showed me some Elfa's light brochure and I found info of Ericsson PMD 4118O WP dc/dc converter:

https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/06960405.pdf


Is it possible to use this with 3 NiMH's and get regulated 3A current? I don't understand electronics, so this could be a little stupid question. This driver seems to be very affordable. Net price is about 8-10 euros.

Thanks for any info.

 

[snarfer]

It is not current controlled. Therefore the answer is no.

 

[gillestugan]

The input voltage needs to be 1.1V higher than output according to the data.
Problem with voltage regulated driver is that when the LED operates at a roughly constant voltage, Vf falls as the temperature rises and the current increases. An increase in the current causes Tj to rise still further and Vf to fall further. The current continues increasing until a balance is reached (which may well be beyond the point of destruction of the led). Conversely, at low temperatures Vf rises and the current falls.

You can be relatively safe if you measure the actual VF of the led. Then lower the input vollage to what the VF would be when the led is very hot. Say 50 degrees higher. The Vf fall about 0,003V / degree celsius, so you would have to lower the voltage witch 0,15V to be safe.
That 0,15V may give you 25% lower If At normal temperature, and still lower if you use it outdoors in the cold air.

Also: The efficency of "your" cirquit is only 75%, so you could use a 7135 based driver and get the same numbers. (you need more than 3 nimh though)