Contents
How to calculate flyback Converter?
The flyback voltage VOR is equal to VO (the secondary Vout plus the VF for the secondary diode D6) multiplied by the transformer winding ratio Np:Ns. Setting the flyback voltage VOR determines the winding ratio Np：Ns and the Duty ratio. The basic equation and an example are given below.
What is the maximum duty ratio for the stable operation of flyback Converter?
The efficiency is estimated to be relatively low (about 80%), as this is a common value for low-power flyback converters….Step 1: Design Inputs.
| Design Input | Value |
|---|---|
| Operation mode | DCM |
| Ripple factor (KFR) | 1 |
| Maximum duty cycle (DMAX) | 0.5 |
| Switching frequency (fSW) | 160kHz |
How to determine the value of a flyback capacitor?
Uout + Vd = Ls * Ip/Tp where Ls = the inductance of the flyback transformer secondary winding and Vd is the voltage drop in the diode which prevents the output capacitor to discharge back to the transformer. You can use this to determine the needed Ls. If Ls is given, this is the other needed equation to solve both Tp and Ip.
How to design a flyback converter [ comprehensive tutorial ]?
Below we see the fundamental schematic design of a flyback converter. The main sections in this design are the transformer, the switching power mosfet Q1 on the primary side, the bridge rectifier at the secondary side D1, a filter capacitor for smoothing the output from D1, and a PWM controller stage which may be an IC controlled circuit.
How is the dI / dt of a flyback converter determined?
Thus when the current stops in the primary (in FIG 2 this is approx. 1.4A), a current is produced in the secondary of 3×1.4A = 4.2A. It is interesting to note that the value of di/dt is determined ONLY by the inductance value and the voltage across the inductor.
What happens when the MOSFET is switched off in a flyback converter?
When the MOSFET switches off, the voltage on both the primary and secondary windings increase in an effort to maintain the current flow. The winding that conducts first is the one in which the current flows and in the circuit in FIG 1, diode D1 conducts causing the energy to flow into the output capacitors C2, C6, C7.