Patent ID: 7633254

Claim:
A single phase motor driving device for controlling the rotation of a single phase motor according to at least a control signal, comprising: a control apparatus for detecting the rotation or stopped rotation of the single phase motor to generate a detection signal and at least the control signal; and a detection apparatus coupled to the control apparatus for generating a first comparison signal and a second comparison signal according to the detection signal, comparing the first comparison signal with the second comparison signal to generate a comparison result, and outputting a rotation signal or a stopped rotation signal according the comparison result, wherein the detection apparatus comprises; a voltage source; an inverter having an input terminal and an output terminal, wherein the input terminal coupled to the control apparatus receives the detection signal and generates an opposite signal; a first transistor having three terminals, the first transistor having a first terminal coupled to the voltage source, a second terminal coupled to the output terminal of the inverter to receive the opposite signal; a second transistor having three terminals, the second transistor having a first terminal coupled to the control apparatus to receive the detection signal, and a third terminal coupled to a ground; a capacitor having two terminals, the capacitor having a first terminal coupled to the third terminal of the first transistor, and a second terminal coupled to the second terminal of the second transistor, to generate the first comparison signal based on a first current on the first terminal and the second comparison signal based on a second current on the second terminal; and a comparator having a positive input terminal and a negative input terminal, wherein the positive input terminal coupled to the first terminal of the capacitor, and the negative input terminal coupled to the second terminal of the capacitor, to compare the first comparison signal with the second comparison signal for generating the comparison result, and further generating the rotation signal or stopped rotation signal based on the comparison result; wherein the control apparatus generates at least the control signal according to the rotation signal and the stopped rotation signal.