| 摘要 |
The invention relates to a switched-mode power supply comprising (a) a transformer (T1) which is provided with primary and secondary windings (N, N1, N2) and through which power is transferred from the primary to the secondary, the transformer (T1) comprising at least two secondary windings (N1, N2) for forming at least two separate outputs for the power supply; (b) a first switch (SW1) provided in the primary circuit for chopping a primary current flowing through the primary winding (N) of the transformer; and (c) an adjustment circuit (13) controlling said first switch (SW1) and adjusting output voltage of the power supply by pulse width modulation by varying the ratio between the durations of the ON and OFF periods of the switch (SW1). In order that desired output voltages could be generated with a very high accuracy without significant power losses, an autotransformer (T2) known per se is connected after at least one of the secondary windings (N3).
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