Contents
What is PFC in LED driver?
PFC, which is the Power Factor Correction opening, means to regulate the power ratio. The electricity we use in our homes, offices is an alternative current at 50Hz frequency in 220V voltage. Thus, the difference between current and voltage phase occurs.
What is PF in LED lighting?
The power factor (PF) gives an indication of the phase shift between the mains voltage and the current drawn by the load connected to that mains voltage.
How does a high PF converter reduce flicker?
The output current of the high PF converter can be approximated by a sine 2 function, which is a cosine waveform with double frequency and the average LED current as mean value. The voltage buffer element is now C2, and it is used to reduce the voltage ripple across the LED string.
How to minimize light flicker in LED lighting applications?
RT7302GS is a constant current Flyback LED driver using primary side regulation and constant ON time topology to obtain high power factor. The converter switches in boundary conduction mode. The below picture shows a reference design for a 20W T8 application. Max light flicker is defined at 30%. Figure 7.
LED light output is directly related to the current through the LED, and by nature LED light output reacts instantly on changing LED current conditions. Stable LED driving current is therefore the main criteria to achieve flicker free operation in LED lamps. 2. Relation between Flicker, LED Current and LED Voltage Ripple
Why does my LED light flicker when offline?
In most offline LED drivers, the circuit parameters control the output (LED) voltage ripple, and the LED current ripple is a result of the output voltage ripple. Therefore it is important to know the relation between the voltage ripple across the LED string and the current ripple through the LED.