Abstract: A disk drive apparatus reproduces an information signal from a disk and/or records an information signal on the disk. FET power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings so as to rotate the disk. A voltage detecting part compares terminal voltages of the three-phase windings and produces a detected pulse signal in response to a comparison result. An activation operation block controls active periods of the FET power transistors in response to the detected pulse signal. A commanding part produces a command signal in response to an output pulse signal of the voltage detecting part. A switching operation block produces a switching pulse signal in response to a comparison result of a current-detection signal with the command signal, and causes at least an FET power transistor of the power supplying part to perform high-frequency switching in response to the switching pulse signal.

Abstract: FET power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings. A voltage detecting part compares terminal voltages of the three-phase windings and produces a detected pulse signal in response to a comparison result. A state shifting part and an activation control part control active periods of the FET power transistors in response to the detected pulse signal. A commanding part produces a command signal in response to an output pulse signal of the voltage detecting means. A switching operation block produces a switching pulse signal in response to a comparison result of a current-detection signal with the command signal, and causes at least an FET power transistor of the power supplying part to perform high-frequency switching in response to the switching pulse signal.

Abstract: First power transistors of first power amplifying parts and second power transistors of second power amplifying parts form current paths from a DC power source to three-phase windings. A first distribution control block activates the first power amplifying parts with first three-phase signals, each having an active electrical angle larger than 120 degrees. A second distribution control block activates the second power amplifying parts with second three-phase signals, each having an active electrical angle larger than 120 degrees. A switching operation block has a current detecting part and a switching control part. The current detecting part obtains a current detected signal corresponding to a composed supply current of negative or positive parts of the three-phase drive currents to the three-phase windings.

Abstract: In the present invention, a Q-phase motor, which electronically switches current paths to plural-phase windings, comprises waveform shaping signal producing device for producing Q-phase waveform shaping signals having a conduction width larger than an electric angle of 360/Q degrees and superimposed signal producing device for superimposing signals to the waveform shaping signals. The superimposed signal producing device comprises superimposed timing producing device for producing superimposed timing signals which are output in a period shorter than a conduction period of the waveform shaping signals in a conduction period of the waveform shaping signals, synchronous rectifying control device for controlling the timing for synchronous rectification, and superimposed signal composing device for composing the signals output from the synchronous rectifying control device with the superimposed timing signals.

Abstract: First FET power transistors of first power amplifying parts and second FET power transistors of second power amplifying parts form current paths from a DC power source to three-phase windings. Three-phase first amplified current signals varying smoothly in rising and falling slopes are supplied to conduction control terminal sides of the first power amplifying parts. Three-phase second amplified current signals varying smoothly in rising and falling slopes are supplied to conduction control terminal sides of the second power amplifying parts. A switching control part performs simultaneous on-off switching of the conduction control terminal sides of the first power amplifying parts, thereby causing first FET power transistors of the first power amplifying parts to perform high-frequency on-off switching. As a result, three-phase drive currents to the windings vary smoothly, thereby reducing motor vibration.

Abstract: A turbocharger of the present invention is provided with a thermo-reducing means between the turbine housing and the bearing housing in order to reduce the heat transferred from the turbine housing to the bearing housing. The thermo-reducing means comprises a thermo-isolating means such as an annular member made of a low heat conductive material. Also, the annular member contacts with the wall of the turbine housing which has a high thermal resistance, so that the heat transferred from the turbine housing to the connecting portion is reduced. The thermo-reducing means also comprises a sensible heat reducing means which is composed of a layer made of a low conductive material, on the inner surface of the wall of the turbine housing, preventing the heat transferred from the exhaust gas to the wall, and a layer made of a high emissive material, on the outer surface of the wall of the turbine housing radiating out the heat effectively.