Patent ID: 8421476

Claim:
A fan failure detector for detecting whether a fan is locked comprising: a drive IC, the drive IC outputting a pulse signal; a coil electrically connected to the drive IC and being driven by the drive IC; and an inspection circuit electrically connected to the drive IC and the coil, wherein the inspection circuit comprises: an RC serial charge/discharge circuit serially connected between the drive IC and circuit ground and defining a first node, a diode connected at one end to the first node and at an opposite end to a second node, a second capacitor connected between the second node and circuit ground, a voltage divider connected between the second node and circuit ground and further defining a third node; and a transistor having an output terminal with the third node connected as a control input of the transistor and, wherein when the fan operates normally, the output terminal outputs a low voltage signal, and when the fan locks, the second capacitor discharges through the voltage divider and enables the transistor to switch into an off state, thereafter the drive IC outputs the pulse signal to enable the diode into conduction and charge the second capacitor, and owing to the design of the voltage divider, the off state of the transistor is maintained such that, the output terminal outputs a high voltage signal to avoid a wrong judgment that a fan still operates normally.