Abstract: The present invention relates to electric bicycle speed control device and method. According to the present invention, a torque of a motor for driving a wheel is controlled so that a speed of a pedal driven by a user follows a speed of the wheel, and a torque of the pedal is also controlled by applying an assist level according to the torque of the motor. Therefore, even in an electric bicycle with a chain, it is possible to feel a feeling of the pedal like a bicycle with a chain, and it is possible to adjust the force applied to the pedal according to the assist level.

Abstract: The present disclosure relates to a boosting mode of an electric bicycle, and has the effect of enabling safe operation of the electric bicycle while providing a necessary acceleration force by preventing a sudden acceleration not intended by a user by double determining the user's intention when rapid acceleration is required, such as when starting or overtaking an electric bicycle.

Abstract: The present invention relates to a system for driving a chainless electric bicycle comprising: a driving wheel; a pedal; a motor mechanically connected to the driving wheel; a generator mechanically connected to the pedal; and a battery, wherein provided is a system comprising: a generator location sensor for measuring the value of a rotation location of the generator; a motor location sensor for measuring the value of a rotation location of the motor; and a controller configured to calculate a difference value of the value of the rotation location of the motor minus the value of the rotation location of the generator multiplied by a gear ratio, and to control at least one of the generator and the motor on the basis of the difference value.

Abstract: The present invention relates to electric bicycle speed control device and method. According to the present invention, a torque of a motor for driving a wheel is controlled so that a speed of a pedal driven by a user follows a speed of the wheel, and a torque of the pedal is also controlled by applying an assist level according to the torque of the motor. Therefore, even in an electric bicycle with a chain, it is possible to feel a feeling of the pedal like a bicycle with a chain, and it is possible to adjust the force applied to the pedal according to the assist level.

Abstract: A method of operating a pre-amplifier of a hard disk drive is provided. The method includes generating a comparison signal corresponding to a result of comparing a reference signal with a difference between differential signals corresponding to write data, and controlling transmission of the differential signals to a write head in response to the comparison signal.

Abstract: A method of operating a pre-amplifier of a hard disk drive is provided. The method includes generating a comparison signal corresponding to a result of comparing a reference signal with a difference between differential signals corresponding to write data, and controlling transmission of the differential signals to a write head in response to the comparison signal.

Abstract: A recording current optimization method to optimize a recording current according to a change of a driving voltage applied to a pre-amplifier that generates the recording current supplied to a head, a recording medium storing a program that executes the method, and an apparatus that employs the method. The method of optimizing the recording current provided to the recording head of the hard disk drive includes detecting a driving voltage of the pre-amplifier, determining a voltage difference between the detected driving voltage and a reference driving voltage of the pre-amplifier, and optimizing the recording current according to the determined voltage difference. The recording current is adaptively optimized according to the change of the pre-amplifier driving power to provide the recording current to the head such that adjacent track erasure (ATE) and weak write (WW) are prevented from occurring due to the change of the driving power.

Abstract: A recording current optimization method to optimize a recording current according to a change of a driving voltage applied to a pre-amplifier that generates the recording current supplied to a head, a recording medium storing a program that executes the method, and an apparatus that employs the method. The method of optimizing the recording current provided to the recording head of the hard disk drive includes detecting a driving voltage of the pre-amplifier, determining a voltage difference between the detected driving voltage and a reference driving voltage of the pre-amplifier, and optimizing the recording current according to the determined voltage difference. The recording current is adaptively optimized according to the change of the pre-amplifier driving power to provide the recording current to the head such that adjacent track erasure (ATE) and weak write (WW) are prevented from occurring due to the change of the driving power.

Abstract: A method of making and updating an optimal unlatch profile for a hard disk drive (HDD) to adjust an input current to a voice coil motor (VCM) by making an optimal unlatch profile for the characteristics of a HDD, downloading the optimal unlatch profile to a flash ROM (FROM), and updating the optimal unlatch profile is provided. The method includes making an optimal unlatch profile for the characteristics of the HDD, and updating the unlatch profile by downloading the optimal unlatch profile to the FROM and thereby update the FROM.