| 摘要 |
A power supply device for light sources (1), such as halogen lamps, can be supplied from mains (M) via a phase-cut dimmer (28), selectively switchable between a conductive state and a non-conductive state, so as to permit or interrupt feeding of the device from mains. The device includes a power stage (10) to feed at least one light source (L), a drive stage (22, 24) for the power stage (10), and a supply stage (26) for the drive stage (22, 24). Sensor means (30, 34) are provided to detect when said dimmer (28) is non-conductive and when said dimmer (28) is conductive again. The drive stage (22, 24) is coupled to the sensor means (30, 34) to disable driving of power stage (20) when the sensor means (30, 34) indicate that dimmer (28) is non-conductive, and to enable driving of power stage (20) when the sensor means (30, 34) indicate that said dimmer (28) is conductive again, thereby ensuring the feeding of the supply stage and avoiding flickering and flashing of the light source. Preferably, the drive stage (22, 24) comprises a microcontroller which, when the dimmer is non-conductive, switches to a low consumption stand-by state. In these conditions the dimmer (28) is connected to a dummy load (32) adapted to return it to its normal conductive state. |
