| 摘要 |
The invention relates to an appliance and a power supply therefor, having a stand-by mode and an active mode. The appliance comprises a work circuit (4), a primary circuit (23) which is connectable to a power source (25), a secondary circuit (24) which comprises a control circuit (32) for controlling a first switch (26) means acting on the work circuit (4) for selectively alternating between the active and the stand-by mode, and an adapting means (20) between the primary circuit (23) and the secondary circuit (24) for adapting in the stand-by mode the power from the primary circuit (23) to the secondary circuit (24) to requirements of the first switch means (26). According to the invention the primary circuit (23) comprises: voltage and/or current limiting means (27) to lower power from the primary circuit (23) to the secondary circuit (24) in correspondence with requirements of the control circuit (32), and a second switch means (28) acting on the limiting means (27) to disable the limiting means (27) in response to a signal from the control circuit (32) which indicates a change to the active mode and to enable the limiting means (27) in response to a signal from the control circuit (32) which indicates a reverse change. Power losses are considerably less and the configuration can be kept very simple while reliability is ensured nevertheless. |
