| 摘要 |
A circuit arrangement for operating at least one low-power lighting unit with a phase-cut operating voltage from a power supply is disclosed, which circuit arrangement comprises a serial setup of an input device (6), a two-port power shaping circuit (7, 7′, 7″) and a lamp driver unit (8, 8′, 8″). The power shaping circuit (7, 7′, 7″) comprises at least a bleeder (13) and a damping circuit (14). While the bleeder circuit (13) provides an alternative current path to set a global current, drawn during operation from the power supply to a predefined minimum load current, the damping circuit (14) serves to attenuate high frequency oscillations in said operating voltage. To enhance dimmer compatibility and simultaneously provide a cost-efficient circuit setup, a first and a second feedback circuit (18, 25) is provided, allowing to control the bleeder circuit (13) and the lamp driver unit (8, 8′, 8″) according to a two-point control. |
