Mains operated outdoor LED lighting

[pashok84]

Hi,

I need a circuit diagram, for LED outdoor lighting, which operates from Mains power.

My plan here is to control all the LED lighting modules ( 6 - 10 modules) using single switch.

Each lighting modules should contains the following

1. convert circuit 230vAC to 12v/5v DC
2. array 18 LEDS / Array of 6 leds *3 parallel rows

Can any one provide cheap and safe circuit for the LED light modules.

Thanks and Regards,
Ashok

 

[thebadtall]

hello,180 leds x 20ma each at 3.2v is 3.6A
so in my opinion you can make use two simple smps of 2A each, and feed a variable voltage regulator lm317 to drop voltage to 3.2v and supply the leds
this will cost no more than $10 .
But you can use any power supply, to supply the regulator ( printer psu, laptop psu etc)
However extra care should be taken driving the led without resistors,as you can easily destroy them with a small overvoltage

 

[pranam77]

Use ready made LED strips made of 3528 or 5050 SMD leds. All are built with 3 led's in series with a resistor connected to 12 volts. Next use a simple SMPS power supply available at dirt cheap prices. What else you expect more? If you are specific about 2 array 18 LEDS / Array of 6 leds *3 parallel rows, could you explain me the reason to use particular configuration?

 

[pashok84]

Hi pranam77,

Thanks for your reply. i don't have any specific configuration for led placement. Is SMD LED gives same brightness? is it available in local shops in Chennai.

Is there any circuit diagram with normal LEDs.

Is it advisable to share SMPS from my computer for this work?

Please validate the design i have in my mind, which is good and safe one.



Thanks and Regards,
Ashok Kumar P

 

[pranam77]

SMD LED's are available in a host of packages and power ratings which are widely used in architectural lightings. Can you clarify your question about what is your application where the said lighting is used, and why 18 LED array with what distance you are planning to install 18 leds apart? Power LED's will naturally require a constant current source which are popularely called as drivers and not just a mere power supply. But in case you prefer to use LED strips, these come with 3 LED's in one segment which are connected to 12 volts through a smd resistor. Thus these strips can be diretcly powered with 12 volts SMPS power supplies. Various power rated strips with 3528 LED, 5050 LED, available with 30 and 60 led populated in a meter are available at local shops all over India. Just have a look and choose which suits you better.
Cheers

 

[thebadtall]

you should prefer 1 regulator for all leds so that you save money.
how much do the led strip cost there?

 

[tpetar]

LM317 voltage regulator can give maximum 1,5A in best conditions, LM338T TO220 or LM338K TO3 will be better choice with 5A.

 

[pashok84]

pranam77, thebadtall and tpetar: thanks for your kind information.

pranam77: I want to install outdoor lightings in my home and garden. 18 leds per module is rough number, don't have any calculation. Just thought 18 leds in module will give good amount of light.

thebadtall: I have not enquired about the price so far.

 

[tpetar]

Each lighting modules should contains the following

convert circuit 230vAC to 12v/5v DC
array 18 LEDS / Array of 6 leds *3 parallel rows

I need some additional info, sorry for that.

What leds do you have and on what voltage and what current they need, or better give model number or datasheet of manufacturer.

If white leds, they are often around 3,7V-3,8V that means only 3 in serie not 6 @12V, and you need 6 arrays not 3.


Do you want transformeless design like this examples or with transformer :

 

[pashok84]

Tpetar:
I have not brought anything so far. I am planing to use white LEDs. Yes i am looking for transformer less circuit, but my worry is it safe to use for this circuit.

 

[tpetar]

See thise designs for transformeless PSU :



On input of circuit you should use varistor with fuse. On output 12V zener to asure output voltage 12V or 5V.

 

[vedagarbhamsandeep]

Tpetar:
I have not brought anything so far. I am planing to use white LEDs. Yes i am looking for transformer less circuit, but my worry is it safe to use for this circuit.

For Example:

20 LED's (1W each with 350mA and 3V) in series means the voltage required is 20x3 = 60V with current 350mA.
You will require a AC-DC Driver (220V to 60V converter, 350mA constant output).

The input of Driver will be given to 220V AC mains while output fed to the LED circuit. Make sure the positive / negative terminals on the LED side.

The above system will give approx 110x20 = 2200 Lumens or equivalent to 20 x 2.5 CFL = 50W CFL Approx.

 

[tpetar]

For Example:

20 LED's (1W each with 350mA and 3V) in series means the voltage required is 20x3 = 60V with current 350mA.
You will require a AC-DC Driver (220V to 60V converter, 350mA constant output).

The input of Driver will be given to 220V AC mains while output fed to the LED circuit. Make sure the positive / negative terminals on the LED side.

The above system will give approx 110x20 = 2200 Lumens or equivalent to 20 x 2.5 CFL = 50W CFL Approx.

Yes just to see how to get 350mA at 60V, its around 21W. :-?

1W leds are big bite for transformeless design.

;-)

 

[jeffrey samuel]

For Example:

20 LED's (1W each with 350mA and 3V) in series means the voltage required is 20x3 = 60V with current 350mA.
You will require a AC-DC Driver (220V to 60V converter, 350mA constant output).

The input of Driver will be given to 220V AC mains while output fed to the LED circuit. Make sure the positive / negative terminals on the LED side.

The above system will give approx 110x20 = 2200 Lumens or equivalent to 20 x 2.5 CFL = 50W CFL Approx.

the plan is to light them and not to fry them i presume

 

[vedagarbhamsandeep]

Why do you think its going to fry ? Assumed ideal current for a 1W LED is 350mA as in example.

We have been installing such LED lights (AC and solar) for more than 4 years now and not 1 have failed or returned to our factory ! we use Osram or CREE LED's and you may check on their datasheets for the current ratings. Hopefully you would be convinced.

 

[jeffrey samuel]

the serial connection of led implies the first led will experience 60 odd volt
hope your led manages to with stand it

 

[vedagarbhamsandeep]

no ways. you can check with a voltmeter, each LED will have a drop of 3 - 3.5V only depending on the make of LED. It is a diode afterall !

 

[jeffrey samuel]

no ways. you can check with a voltmeter, each LED will have a drop of 3 - 3.5V only depending on the make of LED. It is a diode afterall !

you fail to note my point there is no supply voltage without some glitches unless you ensure that the glitches are very minimum for such voltages and if current increases a little the power dissipated rises in a destructive format

do ensure that

also you may try to reduce the no of led's connected in series thereby the voltage current product will be lesser and may serve to protect the led

 

[tpetar]

We have been installing such LED lights (AC and solar) for more than 4 years now and not 1 have failed or returned to our factory ! we use Osram or CREE LED's and you may check on their datasheets for the current ratings. Hopefully you would be convinced.

Can you give us yours transformeless psu circuit which can give several 350mA at 60V?

 

[vedagarbhamsandeep]

you fail to note my point there is no supply voltage without some glitches unless you ensure that the glitches are very minimum for such voltages and if current increases a little the power dissipated rises in a destructive format

do ensure that

also you may try to reduce the no of led's connected in series thereby the voltage current product will be lesser and may serve to protect the led

I agree that in AC voltage which comes from Mains, the voltage could vastly vary (say 170 - 280V) but as we are converting this AC to DC through the driver for constant 60V or so, it is not going to vary big though you may expect a maximum drift of 5% which in no way will harm the LED's.


Its not wise to have 20LED's in parallel with a 3V, (350mA x 20) driver though. But we could have an option of driving 2 rows parallely connected (Each row: 10LED's in series). This way we can have a 30V, 700mA driver but does it matter at all to an extent except that if 1 row fails, the other is still UP !

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Can you give us yours transformeless psu circuit which can give several 350mA at 60V?

Its our company's IP .. cant leak it out, sorry for that but I suppose you could get basic circuits on the forum or net.