Patent ID: 7385369

Claim:
An AC fan motor driving circuit having capability of monitoring rotation rate and status of the AC fan motor driving circuit comprising: a driving circuit module used to drive an AC fan and at least comprising a driving IC that has two controlling outputs alternately outputting a trigger signal; and a rotation status detecting output, wherein the rotation status detecting output is unconnected when the AC fan motor is in a lock condition and connects to ground when the AC fan motor operates normally; a rotation rate detecting module comprising a transistor connected to one of the two controlling outputs of the driving IC; and a photo coupler having an input connected to the transistor; and at least one output outputting a rotation rate signal for computing the rotation rate of the AC fan motor; and a rotation status detecting module comprising a photo coupler having an input connected to the rotation status detecting output of the driving IC; and at least one output outputting a rotation status signal to determine whether the AC fan motor operates normally.