Semiconductor control switch e.g. for electric load such as motor vehicle DC fan-motor speed control

摘要

The arrangement includes a semiconductor switch controlled by a control logic. The control logic (20) is connected with a temperature sensor (16) mounted at the semiconductor switch (1), which provides a temperature signal (S1). The clock frequency (F) of the control logic (20) is switchable between two clock frequencies (F1, F2) in dependence to the temperature signal. The load is preferably a cooling fan motor (12), and the clock frequencies lie in the upper and/or in the lower end of the human hearing range, e.g. the frequency F1 equals 20 kHz and the frequency F2 equals 20 Hz.