| 摘要 |
A fan regulation circuit configuration includes an input receiving an input voltage (proportional to fan current and forms a first comparison voltage), a low-pass filter (filters input voltage and a filter output voltage is tapped off as second comparison voltage), a first comparison device for commutation identification (outputs signal indicating a commutation if value of one of the comparison voltages multiplied by first factor is greater than the other comparison voltage), and a regulator (outputs a control voltage dependent upon identified commutation pulses). The circuit has self-adjusting sensitivity adaptation and a second comparison device outputting a signal if the value of one of the comparison voltages multiplied by a second factor is greater than the other comparison voltage, the second factor being less than the first factor. A control device decreases the first and second factors in the event of an output signal of the second comparison device being received to reduce the sensitivity of the commutation identification.
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