| 摘要 |
<p>A circuit arrangement for driving LEDs, such as high-flux lighting LEDs includes:-a transformer (18) with a secondary winding (18b) for driving said LEDs and a primary winding,-a half-bridge arrangement (16) fed with an input voltage (IV) and coupled to the transformer (18),-a resonant circuit (Cl, C2, LuI; Cl, C2, LDl) between the half-bridge arrangement (16) and the primary winding of the transformer (18), the resonant circuit having a given resonance frequency (fr), and-a controller (20) configured for switching (22a, 22b) the half-bridge arrangement (16) with a switching frequency variable between a first value (fl) and a second value (f2). The second value (f2) is closer than the first value (fl) to the resonance frequency (fr) of the resonant circuit (Cl, C2, LuI; Cl, C2, LDl) created between the half-bridge arrangement (16) and the primary winding of the transformer (18). This produces a boosting effect of the voltage fed towards the LEDs via the transformer (18). The LEDs-are preferably included in the form of series of LEDs connected to the secondary winding (18b) of the transformer (18) via a rectifier placed outside the housing of the power-supply.</p> |
