Aimtron Technology Corp.

Feng-Rurng Juang

Chi-Yang Chen

Jung-Dar Ho

Guang-Nan Tzeng

A switching amplifier includes a level shifting circuit for adjusting a voltage level of an original input signal to generate a first input signal and a second input signal. The first input signal is identical to the original input signal except for referring to a first reference level. The second input signal is identical to the original input signal except for referring to a second reference level. In response to the first input signal and an oscillating signal, a first control circuit generates a first width-limited PWM signal for controlling a first half-bridge switching circuit. In response to the second input signal and the oscillating signal, a second control circuit generates a second width-limited PWM signal for controlling a second half-bridge switching circuit.

Low-distortion tri-state switching amplifier

A motor control circuit includes a detector circuit, a comparator circuit, a sifter circuit, and a driver circuit. The detector circuit is coupled to a plurality of coils of a motor for generating a detection signal. The detection signal is in association with a terminal voltage of a selected-to-be-floated coil of the plurality of coils. Based on comparison between the detection signal and a reference voltage, the comparator circuit generates a comparison signal. The sifter circuit receives in sequence a first-time crossing and a second-time crossing from the comparison signal, and generates an indication signal in response to the second-time crossing. The driver circuit controls a commutation of the motor in response to the indication signal.

Sensorless motor control circuit without employing any mask process

A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to drive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

Brushless motor drive device

A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to dive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

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Hsinchu, Taiwan

Feng-Rurng Juang