How to choose a LED power supply suitable for LEDs

The main problem in installing LEDs is the use of a suitable LED power supply. The primary element to consider is the fact that LEDs are elements that have a non-linear current-voltage characteristic. This means that even small differences in the value of the supply voltage to the diode will cause significant variations in the current value flowing through that element.

The consequence of a poorly chosen power supply can be the destruction of LEDs or permanent damage to the power supply. So, how do you select a power supply suitable for LEDs?

As a model for our calculations, we use the most potent SMD5050 diode on our market. The 5050 diode module consists of three smaller diodes (single chips), each with a current consumption of 0.72W.

The LED strip can be divided into sections of at least 5 cm. Each 5 cm module consists of three individual glowing chips, i.e.:

One meter SMD5050 LED strip consists of 20 modules. 

Each module has a power of (0.24Wx3) = 0.72W

1 meter LED strip is equal to 14.4W (i.e. 0.72W x 20 units) 

If we buy a strip of SMD5050 LEDs in 5-meter rolls, the total power consumption of LEDs is 72W (14.4W/m x 5 meters = 72W).

As a rule, you should buy a power supply that has at least 10-20% more power than the power consumed by the diodes. Therefore, one should buy a 12-volt pulse current power supply with at least 80-90 W or, of course, more (the bigger, the better, but with common sense, i.e., 90 W is enough).

Selection of the suitable power supplies model

Selection of the suitable power supplies model for the LED Lighting project

We use a switching power supply with a minimum efficiency of 85% to supply LEDs without a dimming function. As a result, our power supply does not consume unnecessary electricity, which has a positive effect on electricity bills. LED Power Supplies LED Control Systems.

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How to choose the power supply amper for our LED strips?

We use the formula

P = I x U

P – power [watts],

I – current [amperes],

U – voltage [volts].

We are interested in the current needed to power the entire five meters of LED strips, so we need to convert it and get:

I = P / U

so

6A = 72W / 12V

So, to properly operate a 5-meter strip of SMD 5050 LEDs, we need power supplies with a constant current of 12 V and at least six amps.

If you already know what current will flow in the circuit and the distance between the power supply and the LED strips, you need to choose appropriately thick wires so that they are not destroyed.