## Flyback Diode Voltage and Current Analysis

Flyback Converter diode is acting like a switch linking the transformer secondary and the load. When the primary switch is ON, the primary will store energy. This time the diode will be reversed biased. Meaning, the load side will be cut off from the transformer. On the other hand, when the primary switch is off, the stored energy will be

## Transformer Design and Selection QR Flyback

Several factors to consider in order to perfectly arrived a good Quasi Resonant Flyback transformer design. It needs to consider the input voltage and the allowed level of the switch drain to source (or collector to emitter) voltage of the switch to define the level of the reflected voltage (Vref). It is also required to know the level of the

## How to Derive QR Flyback Secondary Current

The key to deriving the current levels of every switching converter knows the type of waveforms. For flyback converter, the primary and secondary current waveforms are in triangular shape. Another important aspect is to know the operation of a QR flyback. The complete operation of a QR flyback is here. The current wave shape is could be summarized as: The

## Quasi Resonant Flyback Primary Current Derivation

In order to derive the primary current of a Quasi resonant flyback, it is important to know the waveform of the current. Quasi resonant flyback primary current is rectangular in shape. It will rise linearly when the flyback switch is ON while drop immediately to zero once the switch is turned OFF. Below figure do more the explanations. Quasi Resonant

## Quasi Resonant Flyback Transformer Saturation Analysis

One of the very important aspect to look at in dealing with quasi resonant flyback transformer is the saturation. A quasi-resonant flyback transformer is not actually a transformer that we usually know. A transformer will transfer energy from the primary to the secondary at real time. However, the flyback converter will store energy on the primary and then transfer that energy to the secondary somehow. This action makes a flyback transformer prone to saturation if not properly been designed.

## Quasi Resonant Flyback Duty Cycle Derivation

Quasi Resonant flyback duty cycle will reach maximum when it operates in the transition mode or boundary region. However, as long as the operation will stay at the discontinues mode (DCM), that is the desired region of operation, the Quasi resonant flyback duty cycle will be variable.

## Quasi Resonant Flyback Step by Step Design Guide

If you want to make a quasi resonant flyback but do not know where to start, therefore this Quasi Resonant Flyback Step by Step Design Guide is perfect for you. Follow below steps.