Abstract: A method for confirming correctness of a signal includes: providing a current to flow through a time-dependent impedance circuit, wherein the time-dependent impedance circuit provides at least two resistances at two different time points, the current flowing through the time-dependent impedance circuit to generate a first voltage at a first time point, and the current flowing through the time-dependent impedance circuit to generate a second voltage at a second time point, the first voltage and the second voltage being different from each other. When a predetermined relationship exists between the first voltage and the second voltage, it is confirmed that a signal provided from a node coupled to the time-dependent impedance circuit is correct.

Abstract: A back electromotive force (EMF) detector for a motor is disclosed. The back EMF detector includes an upper switch, a lower switch, a current sensing resistor and a first to third resistance providers. The upper and lower switches are controlled by a first and a second control signal respectively. The current sensing resistor coupled between the lower switch and a reference ground voltage. A first terminal of the first resistance provider coupled to the upper switch, and a back EMF detection result is generated at a second terminal of the first resistance provider. The second resistance provider coupled between the reference ground voltage and the first resistance provider. The third resistance provider is coupled between the coupled terminal of the first and second resistance provider and the lower switch. Wherein, the first to the third resistance providers are determined by at least one characteristic parameter of the motor.

Abstract: A back electromotive force (EMF) detector for a motor is disclosed. The back EMF detector includes an upper switch, a lower switch, a current sensing resistor and a first to third resistance providers. The upper and lower switches are controlled by a first and a second control signal respectively. The current sensing resistor coupled between the lower switch and a reference ground voltage. A first terminal of the first resistance provider coupled to the upper switch, and a back EMF detection result is generated at a second terminal of the first resistance provider. The second resistance provider coupled between the reference ground voltage and the first resistance provider. The third resistance provider is coupled between the coupled terminal of the first and second resistance provider and the lower switch. Wherein, the first to the third resistance providers are determined by at least one characteristic parameter of the motor.