Abstract: The present invention provides a motor drive apparatus which improves a trade-off relation between a stable position detection and noise at its driving. A sensorless drive operation circuit calculates by operation a zero cross point (point p) of a voltage of a position detection phase at the next interval, using time information measured based on an output signal from a comparison circuit at the previous interval and the present interval. After the point p has been calculated, points a and b are detected by interrupting a predetermined time drive current.

Abstract: The present invention provides a motor drive apparatus which improves a trade-off relation between a stable position detection and noise at its driving. A sensorless drive operation circuit calculates by operation a zero cross point (point p) of a voltage of a position detection phase at the next interval, using time information measured based on an output signal from a comparison circuit at the previous interval and the present interval. After the point p has been calculated, points a and b are detected by interrupting a predetermined time drive current.

Abstract: A stationary position detection circuit and a motor drive circuit capable of more properly detecting the rotor position are disclosed. The stationary position detection circuit supplies an alternating current to each phase load of the motor. The time during which the current flows in a first direction and the time during which the current flows in a second direction opposite to the first direction are converted into electrical signals and amplified. In accordance with the value of the electrical signals, the position of the motor rotor in stationary mode is determined. The use of the alternating current, unlike the kickback voltage, makes it possible to improve the detection accuracy by amplifying the electrical signals with an increased number of alternations. An increased number of alternations can amplify the electrical signals without increasing the value of the alternating current, and therefore, unlike in the case of the kickback voltage, the alternating current of a large value is not required.

Abstract: A stationary position detection circuit and a motor drive circuit capable of more properly detecting the rotor position are disclosed. The stationary position detection circuit supplies an alternating current to each phase load of the motor. The time during which the current flows in a first direction and the time during which the current flows in a second direction opposite to the first direction are converted into electrical signals and amplified. In accordance with the value of the electrical signals, the position of the motor rotor in stationary mode is determined. The use of the alternating current, unlike the kickback voltage, makes it possible to improve the detection accuracy by amplifying the electrical signals with an increased number of alternations. An increased number of alternations can amplify the electrical signals without increasing the value of the alternating current, and therefore, unlike in the case of the kickback voltage, the alternating current of a large value is not required.

Abstract: A stationary position detection circuit and a motor drive circuit capable of more properly detecting the rotor position are disclosed. The stationary position detection circuit supplies an alternating current to each phase load of the motor. The time during which the current flows in a first direction and the time during which the current flows in a second direction opposite to the first direction are converted into electrical signals and amplified. In accordance with the value of the electrical signals, the position of the motor rotor in stationary mode is determined. The use of the alternating current, unlike the kickback voltage, makes it possible to improve the detection accuracy by amplifying the electrical signals with an increased number of alternations. An increased number of alternations can amplify the electrical signals without increasing the value of the alternating current, and therefore, unlike in the case of the kickback voltage, the alternating current of a large value is not required.

Abstract: A motor driving circuit includes an induced voltage detecting circuit for detecting induced voltages in a motor; a rotation speed/phase detecting circuit and an output matrix circuit for generating a plurality of control signals in response to the detection result of the voltage detecting circuit; a current control circuit for generating current control command values in response to the control signals; and a current detecting circuit for detecting output currents that are driving the motor, and for controlling output transistors in response to its detection result and the current control command values. The motor driving circuit can sharply reduce the driving noise of the motor with improving the efficiency of the motor drive by shaping the output currents in a sinusoidal waveform.

Abstract: A motor driving circuit includes an induced voltage detecting circuit for detecting induced voltages in a motor; a rotation speed/phase detecting circuit and an output matrix circuit for generating a plurality of control signals in response to the detection result of the voltage detecting circuit; a current control circuit for generating current control command values in response to the control signals; and a current detecting circuit for detecting output currents that are driving the motor, and for controlling output transistors in response to its detection result and the current control command values. The motor driving circuit can sharply reduce the driving noise of the motor with improving the efficiency of the motor drive by shaping the output currents in a sinusoidal waveform.

Abstract: There is disclosed an apparatus for reducing motor driving noise, comprising: a selecting circuit for selecting and outputting a current increasing or reducing signal based on a commutation control signal; and a signal synthesizing circuit for synthesizing the current increasing or reducing signal selected by the selecting circuit with a current application control signal supplied to the power supply side switching element of at least a pair of switching elements.

Abstract: A PWM duty ratio control signal having pulses set to a frequency higher than an audio frequency range and set to a fixed duty ratio is produced in a PWM duty ratio control signal producing unit. In a PWM control unit, when a rotational frequency of a motor is lower than a prescribed rotational frequency, a time period ratio of a charging operation to a discharging operation for the motor is determined according to the fixed duty ratio of the PWM duty ratio control signal. The rotational frequency of the motor lower than the prescribed rotational frequency denotes that a driving operation of the motor is just started. A driving unit drives the motor to alternately perform the charging operation and the discharging operation of the motor with the time period ratio.

Abstract: There is disclosed an apparatus for reducing motor driving noise, comprising: a selecting circuit for selecting and outputting a current increasing or reducing signal based on a commutation control signal; and a signal synthesizing circuit for synthesizing the current increasing or reducing signal selected by the selecting circuit with a current application control signal supplied to the power supply side switching element of at least a pair of switching elements.

Abstract: In a lateral bipolar transistor, a control wiring layer is laid down under an emitter electrode wiring layer, and a voltage according to a reverse bias voltage applied to the collector diffusion layer is applied to the control wiring layer, thereby preventing the occurrence of a leakage current from the emitter diffusion and further the flow of the leakage current to the device isolation region, even under a situation that a certain reverse bias voltage is applied to the collector of the transistor.

Abstract: In a lateral bipolar transistor, a control wiring layer is laid down under an emitter electrode wiring layer, and a voltage according to a reverse bias voltage applied to the collector diffusion layer is applied to the control wiring layer, thereby preventing the occurrence of a leakage current from the emitter diffusion and further the flow of the leakage current to the device isolation region, even under a situation that a certain reverse bias voltage is applied to the collector of the transistor.