Abstract: Provided is an LED driving apparatus capable of improving a power factor through a non-insulation type simplified circuit structure, including: a light emitting unit having at least one LED; a rectifier rectifying an alternate current (AC) voltage applied from external power; a power supply unit supplying driving power to the light emitting unit, and having an inductor connected to an output terminal of the light emitting unit; and a switch controller.

Abstract: Provided is an LED driving apparatus capable of improving a power factor through a non-insulation type simplified circuit structure, including: a light emitting unit having at least one LED; a rectifier rectifying an alternate current (AC) voltage applied from external power; a power supply unit supplying driving power to the light emitting unit, and having an inductor connected to an output terminal of the light emitting unit; and a switch controller.

Abstract: Disclosed are an illumination apparatus for adjusting a color temperature and brightness, which can determine duties of pulse width modulation (PWM) control pulses for driving two light sources having different color temperatures, and an illumination system including the same. The illumination apparatus includes first and second light source units emitting light of different color temperatures, first and second pulse width modulation (PWM) driving units respectively driving the first and second light source units by a PWM control method, and a duty control unit controlling respective duties of PWM control pulses of the first and second PWM driving units according to a color-temperature set value and a brightness set value input from the outside. The duty control unit controls the duties such that the color-temperature set value is reflected in the respective duties of the PWM control pulses of the first and second PWM driving units in a complementary relation.

Abstract: Disclosed are an illumination apparatus for adjusting a color temperature and brightness, which can determine duties of pulse width modulation (PWM) control pulses for driving two light sources having different color temperatures, and an illumination system including the same. The illumination apparatus includes first and second light source units emitting light of different color temperatures, first and second pulse width modulation (PWM) driving units respectively driving the first and second light source units by a PWM control method, and a duty control unit controlling respective duties of PWM control pulses of the first and second PWM driving units according to a color-temperature set value and a brightness set value input from the outside. The duty control unit controls the duties such that the color-temperature set value is reflected in the respective duties of the PWM control pulses of the first and second PWM driving units in a complementary relation.

Abstract: Optical disk recording device includes a beam projection section for projecting a light beam onto a write-once optical disk, and a photodetector having two light receiving surfaces divided in a radial direction of the optical disk for detecting reflected light from the optical disk, and wobble-signal reproduction circuitry for reproducing a wobble signal on the basis of reflected light detection signals output from the two light receiving surfaces of the photodetector. The wobble-signal reproduction circuitry includes peak-holding circuits for, when the optical disk device is in a reproduction mode, detecting and holding respective upper envelopes of the two light detection signals from the photodetector. The wobble-signal reproduction circuitry also includes holding circuits for, when the optical disk device is in a recording mode, detecting respective lower envelopes of the two light detection signals from the photodetector.

Abstract: An error signal detection circuit in a servo control device comprises a reference signal generation circuit for selectively generating reference signals of different periods, each having a slope which changes from a reference value at a substantially constant gradient, an error detection timing generation circuit for generating timing of detection of an error signal of an object of control, an error signal detection circuit for generating an error signal by detecting the value of a reference signal generated by the reference signal generation circuit at a timing provided by the error detection timing generation circuit, and a slope varying circuit for varying the slope of the reference signal in accordance with the period of the reference signal.

Abstract: A magnetic recording and reproducing device such as an R-DAT performs fast search for detecting a desired reproducing position during fast feeding or rewinding of recorded tape. The magnetic recording and reproducing device comprises a rotary head incorporating a rotary drum for recording and reproducing an input signal by tracing a magnetic tape, a rotary drum drive circuit for driving the rotary drum for rotation, a tape reel drive circuit for driving a tape reel for running a magnetic tape and a relative speed detection circuit for detecting relative speed between the magnetic tape and the rotary head. The rotary drum is driven in such a manner that, upon receiving a fast search order, the relative speed substantially becomes a predetermined speed without increasing the tape speed.

Abstract: A rotation control device for a rotary head in a rotary head type magnetic recording and reproducing device such as an R-DAT cmprises a rotary head including an FG (frequency generator) for producing a signal at a period determined by equally dividing one rotation of a drum and a PG (phase generator) for detecting a rotation reference position of the drum, a circuit for generating a PG reference signal as a reference signal for a PG detection signal provided by the PG, a circuit for generating an FG reference signal as a reference signal for an FG detection signal provided by the FG, and a control circuit for controlling rotation phase of the drum to a predetermined state by controlling rotation of the drum in accordance with a phase error between the PG detection signal and the PG reference signal and a phase error between the FG detection signal and the FG reference signal.

Abstract: A PWM circuit for generating a PWM wave which is pulse-width modulated in response to binary information and is used for a signal such as a motor driving signal in an R-DAT (rotary head type digital audio tape recorder) comprises a circuit for dividing binary information such as a motor speed error signal provided for generating a PWM wave into plural bit groups and generates PWM waves corresponding to numerical values of these plural bit groups, and a circuit for weighting the generated PWM waves in an analog manner at a ratio corresponding to orders of the respective bit groups and adding the weighted PWM waves. Since binary information is divided into plural bit groups, the bit number of each bit group is small so that the period of PWM wave can be shortened without reducing the quantization bit number of the binary information or shortening reference clock period whereby accuracy of an error signal can be improved when the invention is applied to, e.g., a motor drive device.