Patent ID: 9083268
Filing Date: 2015-07-14
Classification: F04D,H02P,Y02B

Abstract:
1. A controlling circuit for a fan, comprising: first to third comparators each comprising an inverting input terminal, a non-inverting input terminal, an output terminal, a power terminal coupled to a first power source, and a ground terminal connected to ground; and a thermistor; wherein the inverting input terminal of the first comparator is coupled to a second power source, the output terminal of the first comparator is connected to the non-inverting input terminal of the first comparator through a first resistor, and is also coupled to the inverting input terminal of the second comparator through a second resistor and the thermistor in that order; the non-inverting input terminal of the second comparator is coupled to the second power source, and the output terminal of the second comparator is connected to the inverting input terminal of the second comparator through a first capacitor, the output terminal of the second comparator is coupled to the non-inverting input terminal of the first comparator through a third resistor, the output terminal of the second comparator is coupled to the output terminal of the third comparator through fourth and fifth resistors in that order; the inverting input terminal of the third comparator is coupled to a third power source, the non-inverting input terminal of the third comparator is coupled to a node between the fourth and fifth resistors, the output terminal of the third comparator is coupled to the fan.