Abstract: A gamma voltage generator including an operation amplifier, a first reference impedance unit, a second reference impedance unit, a first variable impedance unit, a second variable impedance unit, and a select unit is provided. The operation amplifier generates an amplified output voltage. The first reference impedance unit receives a first gamma voltage, and the second reference impedance unit receives a second gamma voltage. The first variable impedance unit provides a first variable impedance, and the second variable impedance unit receives the first gamma voltage and provides a second variable impedance. The select unit selects the amplified output voltage or the first gamma voltage according to a control signal to generate an interpolated gamma output voltage.

Abstract: A gamma voltage generator including an operation amplifier, a first reference impedance unit, a second reference impedance unit, a first variable impedance unit, a second variable impedance unit, and a select unit is provided. The operation amplifier generates an amplified output voltage. The first reference impedance unit receives a first gamma voltage, and the second reference impedance unit receives a second gamma voltage. The first variable impedance unit provides a first variable impedance, and the second variable impedance unit receives the first gamma voltage and provides a second variable impedance. The select unit selects the amplified output voltage or the first gamma voltage according to a control signal to generate an interpolated gamma output voltage.

Abstract: A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60° is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30°, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30°??? and 30°+?? are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Abstract: A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60° is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30°, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30°??? and 30°+?? are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Abstract: A method for measuring the electromotive force of motors is provided. The method enables the motor to rotate in single phase mode, and thereby measures the electromotive force constant of the motor. According to the principles and the method, motors do not have to work in close-loop. Neither encoders for detecting angle displacement or angle velocity are needed for motors, nor the motor impedance or current have to obtain in advance. Compared with the prior art, the disclosed method is more efficiency and economic.

Abstract: A method for measuring the electromotive force of motors is provided. The method enables the motor to rotate in single phase mode, and thereby measures the electromotive force constant of the motor. According to the principles and the method, motors do not have to work in close-loop. Neither encoders for detecting angle displacement or angle velocity are needed for motors, nor the motor impedance or current have to obtain in advance. Compared with the prior art, the disclosed method is more efficiency and economic.