| 摘要 |
The invention concerns a circuit arrangement for protecting a pulse-controlled semiconductor switch (5) from overloading. Overload protection is achieved using an effective current limiting network working as a two-step controller. For this purpose, an actual value transmitter (6, 17, 18), which represents the effective current, and a comparator (16), which determines the difference between a preset target value and the acquired actual value, are provided. The semiconductor switch (5) is driven by the comparator (16) via switching logic (10, 11), in the case of a positive or negative control difference, using a release signal 1 or a blocking signal 0 respectively, so that in the first case it can continue to be controlled by pulse control, and in the second case it is blocked. The duration of the blocking signal is dimensioned by a time former (14, 15) so that the semiconductor switch (5), acting as a servo component, holds the effective current under the maximum permitted value. This guarantees that the semiconductor switch (5) can always work in the SOAR area. <IMAGE>
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