FLY BACK CONVERTER

摘要

A fly back converter has a converter (Tr) with a primary winding (LP) and at least one secondary winding (LS), a switch (S) driven by a driving circuit and that connects the primary winding to an input direct voltage (UE), a rectifier (D1) connected downstream of the secondary winding and a load capacitor (C1) to generate an output direct voltage (UA), as well as a current sensor (F1) for detecting the current flowing through the primary winding. The duty factor of the driving signal of the driven switch (S) depends on the one hand from the deviation (UV) of the output direct voltage from its set value and on the other hand from the output signal of the current sensor. A maximum value for the set value of the primary current is fixed and the output direct voltage is regulated up to said maximum value. The clock frequency (f) of the driving signal of the driven switch (S) may be varied in direct proportion to the output direct voltage (UA).