Abstract: A unity-gain buffer circuit structure, used to receive an input voltage and output an output voltage, includes a first operational amplifier and a second operational amplifier. The first operational amplifier includes a first positive input, a first output and a first negative input. The second operational amplifier, coupled electrically with the first operational amplifier, includes a second positive input, a second output and a second negative input. The second positive input is used to receive the output voltage. The second output, coupled with first negative input, is used to output a second output voltage. The second negative input, coupled with the second output, is used to receive the second output voltage. After the first negative input receives the second output voltage, an offset voltage between the output voltage outputted from the first operational amplifier and the input voltage received by the first operational amplifier is close to 0.

Abstract: A unity-gain buffer circuit structure, used to receive an input voltage and output an output voltage, includes a first operational amplifier and a second operational amplifier. The first operational amplifier includes a first positive input, a first output and a first negative input. The second operational amplifier, coupled electrically with the first operational amplifier, includes a second positive input, a second output and a second negative input. The second positive input is used to receive the output voltage. The second output, coupled with first negative input, is used to output a second output voltage. The second negative input, coupled with the second output, is used to receive the second output voltage. After the first negative input receives the second output voltage, an offset voltage between the output voltage outputted from the first operational amplifier and the input voltage received by the first operational amplifier is close to 0.

Abstract: A semiconductor structure for electromagnetic induction sensing and a method for manufacturing the same are provided: forming the Hall sensor in a first semiconductor fabrication; forming the passivation layer above the Hall sensor to cover the Hall sensor according to the first semiconductor fabrication; and forming the current-carrying layer above the passivation layer in a second semiconductor fabrication to form the semiconductor structure for electromagnetic induction sensing. The current-carrying layer carries the current to be sensed; and the Hall sensor senses the magnetic field generated. The Hall sensor generates a voltage or a current signal proportional to the strength of the current to be sensed.

Abstract: A method for controlling a direct current (DC) brushless motor, and a control circuit thereof are provided. The DC brushless motor is sensorless. In response to a digital output signal that is applied to drive the direct current brushless motor, detection of a back electromotive force (BEMF) is ceased in a predetermined time interval, so as to avoid detecting erroneous BEMF and keep normal operation of the direct current brushless motor.

Abstract: The connection system of the present invention includes a human-machine interface device and a host device. The human-machine interface device includes a signal generating module and a control module. The host device includes an operation module, an identification module and a system module. After the signal generating module generates an original working signal, the original working signal is sent to the operation module to generate a transforming signal via control module, and then the operation module sends the transforming signal back to the control module such that the control module generates a final working signal meeting an identification condition. Finally, the control module sends the final working signal to the identification module for identification such that the system module executes a predetermined work.

Abstract: A starting apparatus for a direct current (DC) brushless motor and a method thereof are provided. The DC brushless motor comprises a plurality of windings presenting a joint connection via a common connection. The starting apparatus provides current to two of the three windings and rotates the DC brushless motor to obtain a Back Electro-Motive Force (BEMF) from the floating winding. Then, the starting apparatus provides a current to another two windings to operate the motor according to the variation of BEMF induced by the swing of the motor when it rotates to a static equilibrium point.

Abstract: A method for controlling a direct current (DC) brushless motor, and a control circuit thereof are provided. The DC brushless motor is sensorless. In response to a digital output signal that is applied to drive the direct current brushless motor, detection of a back electromotive force (BEMF) is ceased in a predetermined time interval, so as to avoid detecting erroneous BEMF and keep normal operation of the direct current brushless motor.

Abstract: The present invention discloses a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof. The brushless dc motor driver circuit of the present invention comprises a Time-Voltage Digital/Analog Converter. The Time-Voltage Digital/Analog Converter further comprises: at least one magnetic field detecting circuit, at least one counter, and a signal processor. The Time-Voltage Digital/Analog Converter is connected to a driver circuit of a brushless dc motor and detects the periodically varying magnetic field of the brushless dc motor. Based on the rising time and the falling time of the preceding magnetic field variation, the Time-Voltage Digital/Analog Converter calculates the elapsed time from the current phase-change point and generates a linearly rising signal and a linearly falling signal. Then, those two sets of analog signals are used to drive the brushless dc motor. Thereby, the vibration or shock noise of the brushless dc motor is reduced.

Abstract: The present invention discloses a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof. The brushless dc motor driver circuit of the present invention comprises a Time-Voltage Digital/Analog Converter. The Time-Voltage Digital/Analog Converter further comprises: at least one magnetic field detecting circuit, at least one counter, and a signal processor. The Time-Voltage Digital/Analog Converter is connected to a driver circuit of a brushless dc motor and detects the periodically varying magnetic field of the brushless dc motor. Based on the rising time and the falling time of the preceding magnetic field variation, the Time-Voltage Digital/Analog Converter calculates the elapsed time from the current phase-change point and generates a linearly rising signal and a linearly falling signal. Then, those two sets of analog signals are used to drive the brushless dc motor. Thereby, the vibration or shock noise of the brushless dc motor is reduced.

Abstract: A waveform shaping circuit includes an input terminal, an output terminal, and a plurality of cascaded circuit stages. Each of the cascaded circuit stages includes a delay circuit having an output and an input, a current source, and a switch circuit, connected electrically to the output of the delay circuit and controlled by the delay circuit, for connecting electrically the current source to the output terminal. The input of the delay circuit of a first one of the circuit stages is connected electrically to the input terminal. The input of the delay circuit of remaining ones of the circuit stages is connected electrically to the output of the delay circuit of an immediately preceding one of the circuit stages. The delay circuits have equal delay times. The total delay time provided by the delay circuits of the circuit stages is equal to or is a multiple of half a bit time of the fundamental data rate.