| 摘要 |
A semiconductor switch includes a device for measuring the depletion-layer temperature of a semiconductor rectifier (V) which conducts load current. This device consists of a network (N) which electrically simulates the thermal behavior of the semiconductor rectifier (V), a converter element (W) provided between semiconductor rectifier (V) and the network (N) for producing a current (iv) which is proportional to the power dissipation in the semiconductor rectifier (V), and a comparator (A) which is controlled by the output of the network (N) and acts on the semiconductor rectifier (V). The semiconductor rectifier has a simple construction, is secured against short circuits and overloads and at the same time is also capable of easily controlling capacitive loads. This is achieved so that, on the one hand, the converter element (W) is configured as an ohmic resistor (Rw) and is connected together with a first switch element (S1) and a capacitor (C1) of the network (N) in parallel to the semiconductor rectifier (V). On the other hand, two voltage source (Uoff, Uon) are provided which are controlled via further switches (S0 and S2) by the comparator (A) which acts on the semiconductor rectifier (V).
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