Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics 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.

LED slim tube LED driver replacement

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
hello
I have blow up slim LED tube with 2 strips ,each strip have 72 LED chip diode
what would be easiest LED driver replacement i can build myself?
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
21,097
Helped
4,533
Reputation
9,078
Reaction score
4,628
Trophy points
1,393
Activity points
139,228
Hi,

Most important: you need to know the requirements: 2 stripes 72 LED is no useful information. In electronics we need voltage, current....
in your case:
* What´s your energy source (USB power, car battery, mains - which voltage, frequency, anything else)
* what´s the LED strip specification: voltage, current
* how are your LED strips connected? in series or parallel
* do you want to dim them?

Then do an internet search "DIY LED driver"

Klaus
 

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
Hi ...that i know requirement for this strips then i don't ask,,but i dont know and there is no any data we can found on internet.
This is slim flat 2 strips tube ,replacement for standard fluorescent light 120cm length.
it is powered by mains 220AC ,driver is broken-burned because of cheap china electronic ...whatever
I am asking because maybe some of member have experience in fixing or rebuilding such a driver..diy with standard electronic parts.
There are some images of diy LED drivers but i am not sure that are tested...so i will aprecciate answer from someone experienced in this field?
Did i ask properly this time?
--- Updated ---

On the image above is image how strip looks i draw it myself...so is this 24V DC?
As admin say there are images ...but is that smart to build ,here is one of them
 

Attachments

  • LEDstrip72.png
    LEDstrip72.png
    23.1 KB · Views: 37
  • LEDdriver24V.png
    LEDdriver24V.png
    62.3 KB · Views: 36
Last edited:
T

treez

Guest
Well , i simulated what you show with the free download LTspice simulator. i attached the simulation here so you can simulate it and see for yourself.
I assumed the 72 leds were in series. (are they?) I then put the two strips in parallel.

You show a 560R resistor and so this is a low power product....only about one or 2 watts

The LED driver you show is a "capacitive dropper".

There was no fuse?

If you check the diodes with a meter and they are ok you can re-use them.
If the resistor and capacitor is blown then you can buy new ones.
Buy from eg Farnell or an electronics store.
You must buy a resistor of the correct power and voltage rating

Please be very careful with the mains electricity as this as you know can kill you. The driver you show is not isolated, so its dangerous.

By the way as you can see i didnt bother putting in the 100uf capacitor in there....all that cap does is reduce the 100hz flicker , but most peopel cant see this anyway...and those caps often fail.....has it failed?

Can you show photograph, so we can see whats failed?

By the way, what voltage rating is the 100uf capacitor?......when you tell us this, we can make a good guess as to how many of the leds are in series.

Do you have a digital mulitmeter?...if so, then you may be able to check if each led is OK..use the diode tester...hopefully its voltage will rise high enough to light a LED. you can also use the meter to tell how the leds are connected....eg how many in series?....you may have to carefully scrape away the solder resist to do this.
 

Attachments

  • Capacitive dropper_offline LED driver.pdf
    152.7 KB · Views: 7
  • Capacitive dropper_offline LED driver.zip
    807 bytes · Views: 7
Last edited by a moderator:

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
First .thanks for reply
@treez
I am not a kid ,i fixed many electronics radios,TV but never such a things like LED lights
you asking about how diodes are connected i already show you on a given image from (+) goes one diode then i guess is resistor in serie then another diode ,all that in parallel with DC power,i cannot show you burned led driver because i throw it and is completelly black i simply cannot recognize what is what but 4 diode in bridge 100uF7250V cap is with hole etc...and all in sMD, all diodes in strips light i checked with multimeter.
I dont use LTspice because i found it awkward than CM.
 

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
@ZASto that is good idea...how is connected...it is on the image in above post!
This is my simulation
--- Updated ---

If the resistor is 1k then current is 16 mA...but is almost impossible to tell what kind of led diodes are used in strip i can guess 3.4V
 

Attachments

  • LED_resistor.png
    LED_resistor.png
    6.6 KB · Views: 29

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
21,097
Helped
4,533
Reputation
9,078
Reaction score
4,628
Trophy points
1,393
Activity points
139,228
Hi,

If the above schematic is like your LED, then it is very inefficient.
Only about 8V across the LEDs and 16V wasted across the resistor.

Klaus
 
T

treez

Guest
you asking about how diodes are connected i already show you on a given image from (+) goes one diode then i guess is resistor in serie then another diode ,all that in parallel with DC power
thanks, but we need to know if the 72 diodes on the strip are connected in series with each other, or in some series/parallel pattern.
And there are two 72v strips, so how are they both connected to the power rail.?

Then it shoudl be just a case of replacing the parts in the capacitive dropper, but i wonder if your 560R resistor is correct as using that makes it very low power.......but maybe thats it, maybe it is low power.
 

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
@KLAUS
If the above schematic is like your LED, then it is very inefficient.
Only about 8V across the LEDs and 16V wasted across the resistor.
Well maybe ..you must know i don't build this strips .they are fabricated probably in China...

@treez
section of 2 led diode and resistor are in parallel with DC power rail ,so there is 36 sections in one strip
inside plastic tube there are 2 such a strip, and you probably see somewhere such a LED slim light called batten.
--- Updated ---

Just to clarify here is image of similar strips they called modules,it is from China factory but mine are different maybe from India
who knows but for a orientation...it stated 12 cascades,36V ..hmm
well i will build this simple driver and try nothing else ,this 560 ohm should be 1W resistor.
In my case tube is stated as 72W.
 

Attachments

  • SMD_modules.png
    SMD_modules.png
    592.2 KB · Views: 27
Last edited:

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
21,097
Helped
4,533
Reputation
9,078
Reaction score
4,628
Trophy points
1,393
Activity points
139,228
Well maybe ..you must know i don't build this strips .they are fabricated probably in China...
Hi,

I don't complain about you.
I just wanted to inform you that with these stripes twice the enegy is used to heat the stripes than to generate light.
You have to decide yourself whether it makes sense to keep them alive.
I guess nowadays standard Led stripes may give 4 times more light with same power input.

Klaus
 
T

treez

Guest
In my case tube is stated as 72W.
...yes, i reckon the "72W" is the equivalent incandescant lamp power.........the actual real power consumed by your product i believe is much less.

so from what you say......i believe that your 72 leds are in a series parallel arrangement of 12 in series, 6 in parallel....would you agree?
...and then i guess that the two strips are in parallel with each other. But it would be good if you could confirm this.

It looks like a simple capacitive dropper power supply......and these usually only go up to a few watts at most.

Is that really all?....there isnt other circuitry that you have not shown us?

So anyway, i am still not sure what is the overall led circuit....you have the strips there, i would recomend drawing it out in LTspice and running it...and showing it here aswell if you wish.....the 1.5k resistor does seem a bit too high a value.
 
Last edited by a moderator:

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
I agree too many unknown things and different options
of course this 2 strips are in paralel each of them have 72 led diodes
each 2 diode are with resitor,checked with meter 2 light so 2 are in paralell how i already explain
.Well i will find transformer and checked it with power supply
 
T

treez

Guest
OK, there is some question over whether you have 72 parallel strings of 2_LEDS_in_series (each string with a dropping resistor of 1.5k) ?, or whether you have 12 parallel strings of 12_leds_in_series?
Or something else?
What voltage is/was the electrolytic cap? (if its not too fired for you to see).

I am surprised there was no fuse? Or was there?
 

zlatkoMM

Full Member level 5
Joined
Apr 4, 2008
Messages
296
Helped
13
Reputation
26
Reaction score
7
Trophy points
1,298
Location
Croatia
Activity points
2,884
2 LEDS are in serie with resistor which i don't know what value it .is printed on pcb
so 36 pairs in paralel to DC power supply.I hope that is clear now?
Cap is 10uF/350V
There is no fuse.
 

Attachments

  • LEDstrip_tester.png
    LEDstrip_tester.png
    12.1 KB · Views: 26
T

treez

Guest
in your post #3 you show a 100uF,250V cap.
I wasnt sure where is the 10uF,350V cap?

Your single LEDs might actually be LED cobbs, ie, they may be really be many LEDs in series?
You can use your test jig to see what the actual led voltage is....just being careful you dont overcurrent the leds.
 

LaTeX Commands Quick-Menu:

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top