| 摘要 |
A power supply circuit (20) for light sources (S), for example lighting LED systems, includes a ground line (22) and a current feed line (24) towards light source (S). The circuit includes an output inductor (L) interposed in current feed line (24), as well as an electronic switch (30) interposed in the same feed line (24). Switch (30) is switchable between an on condition, wherein it ensures continuity of said current feed line (24), and an off condition, wherein current feed line (24) is interrupted. The circuit further comprises a rectifier set (D1, R1, C1) coupled to output inductor (L) in order to rectify the voltage across the inductor. The voltage produced by rectifier set (D1, R1, C1) allows to maintain switch (30) in said on condition. Preferably, the voltage across capacitor (C1) is applied to the control electrode (302, G) of switch (30) via a coupling resistor (R2) and a limiting zener diode (Z1) |
