| 摘要 |
<p>An electrical power supply device (10), for example for LED light sources, includes a transformer (T) operating in flyback mode, with a primary winding (P) having coupled thereto a main switch (Qp) switchable on and off to connect and disconnect said primary winding (P) of the transformer from a supply source (V) and a secondary winding (S) having coupled therewith a main branch (D MAIN , C MAIN ) for feeding a load (L) and at least one auxiliary branch (D AUX , Q AUX ) to provide an auxiliary power supply (Aux supply).
The or each auxiliary branch (D AUX , Q AUX ) includes a switching regulator (Q AUX ) with hysteresis with a respective auxiliary switch (Q AUX ) sensitive to the voltage on said secondary winding (S) and the voltage of said auxiliary power supply (Aux supply). Said auxiliary switch (Q AUX ) is configured for closing to draw current from said main branch (D MAIN , C MAIN ) towards said auxiliary power supply (Aux supply) in the presence of a negative transition of the voltage on said secondary winding (S) and for opening when the voltage on said auxiliary power supply (Aux supply) reaches a given upper level (V REF ).</p> |
