| 摘要 |
A switched mode power supply comprises a switched mode converter (12) and a controller for controlling the switched mode converter, wherein the switched mode converter is provided for converting an input voltage (Vin) to an output voltage (Vout) and includes, on a primary side, a primary winding (X1) and a controllable switch based circuitry (31) connecting the input voltage over the primary winding; and, on a secondary side, a secondary winding (X2) coupled to the primary winding, and a capacitive element (C) connected over the secondary winding, wherein the output voltage is obtained as the voltage over the capacitive element. The primary winding comprises a first winding portion (nP1) and at least one further winding portion (np2); and the switch based circuitry comprises controllable switches (Q11, Q41, Q12, Q42, Q21, Q31) capable of switching between a first operation state wherein the input voltage is connected only over the first winding portion and at least a second operation state wherein the input voltage is connected over the first and the at least one further winding portions, thereby enabling switching between two different transformer ratios (n1, n2). The controller is (i) configured to monitor the output voltage of the switched mode converter and (ii) operatively connected to the controllable switches to control the controllable switches to switch between the first and the at least second operation states in response to the monitored output voltage. |
