| 摘要 |
A converter for converting an input voltage (Ui) into an output voltage (U0). The converter has several modes of operation. The converter can, for example, operate in an up-conversion mode, a down-conversion mode, or a window conversion mode. The converter has at least one switch (S1-S4) for controlling the converter so as to obtain a desired value of the output voltage (U0) in the up-conversion mode and in the down-conversion mode. This is achieved by changing the duty cycle of a binary signal (BS) which controls the switch (S1-S4). The converter further includes means (DMNS) for detecting the duty cycle of the binary signal (BS). This duty cycle is compared with a reference duty cycle (RFDCCL). The result of this comparison is used for deciding whether or not to change over from the up-conversion mode (or the down-conversion mode) to the window conversion mode. In the window conversion mode each switch (S1-S4) in the converter is permanently closed or open. In the window conversion mode the output voltage (U0) is roughly equal to the input voltage (Ui). The converter remains in the window conversion mode as long as the output voltage (U0) is within a given voltage window (range). However, if the output voltage (U0) has become too low, the converter changes over from the window conversion mode to the up-conversion mode. In a similar way, the converter changes over from the window conversion mode to the down-conversion mode when the output voltage (U0) has become too high.
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