Determining Peak Secondary Current
**
Mathematical Method
of determining Peak Secondary Current in Flyback
Converters**
This text
describes how to determine the peak secondary
current in a flyback converter working on the
boundary between continuous and discontinuous mode.
For a more intuitive method, please see
Flyback
Converter Design
Energy
in the inductor can be represented by:
and
Also
(where Ls is the secondary winding inductance)
Therefore
Therefore
Where T is the period of the switching waveform
So
is
equal to (1 – Duty Cycle) (i.e. the discharge time
of the secondary winding)
So
and
So
Now, from
i.e. the change in secondary current
So
So to find the peak secondary inductor current, we
take the average output current, multiply by 2 and
divide by (1-DC)
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