Abstract: A control circuit generates a driving signal indicating an actuator torque. A first operation unit generates position, speed, and acceleration signals, based upon a detection signal indicating the actuator mover state. A second operation unit generates a first difference signal indicating the difference between a target signal and the position signal. A third operation unit generates a second difference signal indicating the difference between signals based on the first difference signal and the speed signal. A fourth operation unit generates a position control signal such that the second difference signal becomes zero. A fifth operation unit generates a third difference signal indicating the difference between signals based on a driving signal and the acceleration signal. A sixth operation unit generates a driving signal by summing a signal based on the position control signal and a disturbance estimation signal based on the third difference signal.

Abstract: A motor drive circuit includes an H-bridge circuit, voltage difference detection circuit, calibration circuit, back electromotive voltage detection circuit, control circuit, and calibration value acquisition circuit. The H-bridge circuit is connected to a DC motor. The voltage difference detection circuit outputs terminal voltage according to voltage difference occurring between both terminals of the DC motor. The calibration circuit outputs calibration voltage according to the resistance component. The back electromotive voltage detection circuit outputs voltage according to the difference between the terminal voltage and the calibration voltage, as detection voltage indicating back electromotive voltage. The control circuit drives the H-bridge circuit by pulse width modulation.

Abstract: A control circuit generates a driving signal indicating an actuator torque. A first operation unit generates position, speed, and acceleration signals, based upon a detection signal indicating the actuator mover state. A second operation unit generates a first difference signal indicating the difference between a target signal and the position signal. A third operation unit generates a second difference signal indicating the difference between signals based on the first difference signal and the speed signal. A fourth operation unit generates a position control signal such that the second difference signal becomes zero. A fifth operation unit generates a third difference signal indicating the difference between signals based on a driving signal and the acceleration signal. A sixth operation unit generates a driving signal by summing a signal based on the position control signal and a disturbance estimation signal based on the third difference signal.

Abstract: First and second A/D converters perform analog/digital conversion of first and second signals of a Hall signal so as to generate third and fourth signals as digital signals. A differential conversion circuit generates a fifth signal as a single-ended signal that corresponds to the difference between the third and fourth signals. An offset correction circuit corrects offset of the fifth signal so as to generate a sixth signal. An amplitude control circuit stabilizes the amplitude of the sixth signal to a predetermined target value, and generates its absolute value, thus generating a seventh signal. A control signal generating unit generates a control signal upon the seventh signal. A driver circuit drives a motor according to the control signal.

Abstract: A test signal generating circuit generates an AC test signal. A driving unit supplies, to a motor, a driving voltage on which the test signal has been superimposed. A current detection circuit generates a detection signal that corresponds to an actual current that flows through a coil of the motor. A filter extracts, from the detection signal, a frequency component that corresponds to the test signal. A coil constant calculation circuit calculates the resistance value and the inductance value of the motor based upon the amplitude of the detection signal output from the filter, the amplitude of the test signal, and the phase difference between these signals.

Abstract: A first calculation unit subtracts third digital data which indicates the minimum value of the duty ratio from first digital data which indicates the duty ratio of the PWM driving operation. A slope calculation unit generates slope data which is dependent on the temperature based upon second digital data which indicates the temperature. A second calculation unit multiplies the slope data by the output data of the first calculation unit. A third calculation unit sums the output data of the second calculation unit and the third digital data. A selector receives the output data of the third calculation unit and the third digital data, selects one data that corresponds to the sign of the output data of the first calculation unit, and outputs the data thus selected as a duty ratio control signal.

Abstract: First and second A/D converters perform analog/digital conversion of first and second signals of a Hall signal so as to generate third and fourth signals as digital signals. A differential conversion circuit generates a fifth signal as a single-ended signal that corresponds to the difference between the third and fourth signals. An offset correction circuit corrects offset of the fifth signal so as to generate a sixth signal. An amplitude control circuit stabilizes the amplitude of the sixth signal to a predetermined target value, and generates its absolute value, thus generating a seventh signal. A control signal generating unit generates a control signal based upon the seventh signal. A driver circuit drives a motor according to the control signal.

Abstract: A motor drive circuit includes an H-bridge circuit, voltage difference detection circuit, calibration circuit, back electromotive voltage detection circuit, control circuit, and calibration value acquisition circuit. The H-bridge circuit is connected to a DC motor. The voltage difference detection circuit outputs terminal voltage according to voltage difference occurring between both terminals of the DC motor. The calibration circuit outputs calibration voltage according to the resistance component. The back electromotive voltage detection circuit outputs voltage according to the difference between the terminal voltage and the calibration voltage, as detection voltage indicating back electromotive voltage. The control circuit drives the H-bridge circuit by pulse width modulation.

Abstract: An optical disc device includes a recording section which records recording information in an optical disk, a reproducing section to reproduce the information recorded in the optical disk, a storage section which stores information Po?n to Po+n or Pb?n to Pb+n of a preceding or succeeding position Po±n or Pb±n while a recording start position Po or a recording interrupt position Pb is defined as a reference, the information being reproduced by the reproducing section, when recording of the recording information is started or recording is restarted after the recording has been interrupted, and processing section which comparing reproduction information obtained by reproducing the information Po?n to Po+n or Pb?n to Pb+n again, cache information stored in the storage section, and the recording information, and then, determining whether or not recording has been normally performed on the optical disk when recording of the recording information terminates or is interrupted.

Abstract: A light receiving device generates photocurrent that corresponds to the quantity of incident light. A capacitor is arranged with one terminal set to a fixed electric potential, and is charged using the photocurrent. A comparator compares the voltage that occurs between both terminals of the capacitor with a predetermined threshold voltage, and generates a judgment signal that corresponds to the comparison result. An initialization switch initializes the voltage that occurs both terminals of the capacitor. A judgment unit acquires, as data which indicates the quantity of light, the level of the judgment signal at a timing after the passage of a predetermined judgment period of time from the commencement of charging of the capacitor using the photocurrent.

Abstract: An optical disc device includes a recording section which records recording information in an optical disk, a reproducing section to reproduce the information recorded in the optical disk, a storage section which stores information Po?n to Po+n or Pb?n to Pb+n of a preceding or succeeding position Po±n or Pb±n while a recording start position Po or a recording interrupt position Pb is defined as a reference, the information being reproduced by the reproducing section, when recording of the recording information is started or recording is restarted after the recording has been interrupted, and processing section which comparing reproduction information obtained by reproducing the information Po?n to Po+n or Pb?n to Pb+n again, cache information stored in the storage section, and the recording information, and then, determining whether or not recording has been normally performed on the optical disk when recording of the recording information terminates or is interrupted.

Abstract: An optical disc apparatus comprises a driving unit which drives an optical pickup head (PUH) for irradiating laser light onto an optical disc in such a manner that laser light is irradiated onto a plurality of positions on the optical disc, a photodetector unit which outputs a photo sense signal on the basis of the reflected light from the optical disc onto which laser light is irradiated from the PUH, a signal generating unit which generates tracking error signals of a plurality of different methods on the basis of the photo sense signal, and a tracking error signal selecting unit which selects a tracking error signal of any one of the methods on the basis of the state of the tracking error signals of the plurality of methods generated in a plurality of different positions on the disc.

Abstract: An optical disk device includes a format determination unit which determines a format causing an intersymbol interference ratio of not less than a preset value, as a format for power calibration performed on an optical disk, when an intersymbol interference ratio of data to be recorded on the optical disk is lower than a preset value, a power calibration unit which executes power calibration on the optical disk using the format determined by the format determination unit, an optimal power determination unit which determines optimal power for a laser beam used to record the data, based on a result of the power calibration by the power calibration unit, and a recording unit which records the data on the optical disk using a laser beam corresponding to the optimal power determined by the optimal power determination unit.

Abstract: An optical disk has a reflecting layer and a transparent substrate formed on the reflecting layer. The type of the optical disk changes depending on the physical characteristics of the reflecting layer and the thickness of the transparent substrate. When discriminating such a disk, an objective lens which focuses an optical beam on the disk is moved toward the disk. Along with this movement, a detection signal that detects an optical beam reflected by the disk generates a detection signal. First, a peak accompanying mirror surface reflection of the surface of the disk appears, and then a peak accompanying reflection of the reflecting layer appears. The type of the disk which concerns the transparent substrate of the optical disk is discriminated from the time interval between the two peaks. The characteristics and reflection level of the RF component of detection signal generated by the detector change in accordance with the count of reflecting layers and the reflectance of the reflecting layer(s).