| 摘要 |
There is provided a power supply for an electrical device, an electrical device including such a power supply and a method for supplying power to an electrical device. The power supply comprises a transformer having primary and secondary windings. The primary winding is connectable to a AC voltage supply and circuitry on the secondary side is arranged to provide a DC output voltage for the electrical device. The power supply also comprises a switch between the primary winding of the transformer and the AC supply, a rectifier for rectifying the AC voltage, and a current limiter. The switch is arranged to switch on at some point as the rectified AC voltage increases, once it has reached a non-zero value, thereby providing a current flow through the primary winding and hence through the secondary winding. The current limiter is arranged to limit the amount of current flowing through the primary winding. The switch is arranged to switch off before the rectified AC voltage starts to increase again. |
