Introduction to LED Lighting Products Power Supply

LED POLARIZATION

To obtain light from an LED, it is sufficient to let a direct electric current of the correct intensity flow through its junction, i.e., high enough to produce light, but below the maximum allowable value to avoid damaging the LED.

Manufacturers provide the correct voltage or current specifications to power (Polarize) the LED diode, i.e., the voltage to be applied between the anode and cathode to achieve a specific current value.

This current value must be regulated stably because it changes the brightness of the LED, while the designer's goal is to keep the chosen operating region constant, for example, at 3.4V voltage and 350mA current.

The polarization of LEDs must be in Direct Current (positive anode towards the cathode).

Parallel connection is only used when the supply voltage is very low and close to the LED threshold voltage.

The simplest method to polarize an LED is to power it in continuous mode at a voltage and current higher than the component should work at, and then a resistor is placed in series with the LED, whose value is calculated based on the desired current, according to the formula:

R = (Vcc - Vf) / If

where
R = Resistance
Vcc = supply voltage
Vf = voltage drop across the diode

This approach is also valid for groups of LEDs; in this case, the most common configuration is series, trying to match the sum of voltage drops across the LEDs as