Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Long lasting offline power supply, 100W, IP67 rated

Status
Not open for further replies.

treez

Advanced Member level 5
Joined
Sep 22, 2008
Messages
7,602
Helped
561
Reputation
1,125
Reaction score
538
Trophy points
1,393
Location
cambridge
Activity points
76,160
Hello, We have designed a LED luminaire with excellent cooling, so it will last for 20 years or more. We need a power supply (smps) for it which will also last 20 years, (in use 8 hours a day, 7 days a week, 52 weeks of each year).

The PSU needs to have a 60V output, as the luminaire takes in 60VDC and gives constant dimmable current to the leds.

Do you know where we can buy such a PSU (90-265VAC)?...nobody seems to do this kind of thing?...why?
 

Dan Mills

Advanced Member level 2
Joined
Nov 10, 2013
Messages
510
Helped
237
Reputation
474
Reaction score
229
Trophy points
43
Activity points
4,558
Would 48V do you?

20 years at what failure rate? 50% is much cheaper then 0.5% with this sort of thing.
Look at the telecom market, folks like Emerson, GE and Eltek, maybe TDK, but it will not be at all cheap.

For 20 years you are looking for something over built so that it runs at a very low temperature rise, so it will be bigger then you expect as well as being more expensive.

There is actually something to be said for big low frequency iron, a overkill bridge rectifier and a cap....

Regards, Dan.
 
  • Like
Reactions: treez

    treez

    points: 2
    Helpful Answer Positive Rating

treez

Advanced Member level 5
Joined
Sep 22, 2008
Messages
7,602
Helped
561
Reputation
1,125
Reaction score
538
Trophy points
1,393
Location
cambridge
Activity points
76,160
Thanks, I suppose also you would say "no" to electrolytic capacitors in a long lasting smps?....use those expensive film ones instead?...size isn't an issue too much.

The LED string is up to 44V, so 48v, with the wiring drop is going to not give enough headroom for the buck converter led driver unfortunately.
 

Dan Mills

Advanced Member level 2
Joined
Nov 10, 2013
Messages
510
Helped
237
Reputation
474
Reaction score
229
Trophy points
43
Activity points
4,558
Nothing wrong with elcos in that kind of application, just got to respect the lifetime curves. A 10K hour 105 or 125 degree part run at 30 degrees C or so, with seriously derated ripple current will go a long, long time before it hits 50% of its initial value.

Granted this is probably not the place for your beloved flyback topology given what they do to the input cap, some kind of resonant half bridge thing seems more likely to make 20 years.

BTW most of those 48V supplies will turn up to 53.5V or there about (battery charging a 48V nominal lead acid battery bank).

Regards, Dan.
 
  • Like
Reactions: treez

    treez

    points: 2
    Helpful Answer Positive Rating

treez

Advanced Member level 5
Joined
Sep 22, 2008
Messages
7,602
Helped
561
Reputation
1,125
Reaction score
538
Trophy points
1,393
Location
cambridge
Activity points
76,160
So you are saying use electrolytics and just use lots of them so they each have very little ripple current?
This rumour that electrolytics are useless after 2 years of non-use (not getting voltage on them) persists aswell. We don't like the sound of it.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top