Abstract: A power supply device is configured with input terminal (11) connectable to AC power supply (1) whose power supply frequency fluctuates, rectifier (12) that rectifies an AC voltage applied to power input terminal (11), frequency detector (13) that measures frequency of rectifier (12), current limiter (14) that regulates current output from rectifier (12), charge accumulation unit (15) that accumulates charge output from current limiter (14), current detector (16) that measures current output from charge accumulation unit (15), load connection terminal (17) connectable to load (20) that is operated by current output from current detector (16), and controller (18) that controls a regulated value of current limiter (14) and capacitance of charge accumulation unit (15) in accordance with fluctuation of the frequency measured by frequency detector (13) in such a manner that the current output from charge accumulation unit (15) becomes larger than current consumed by load (20) at a predetermined time.

Abstract: A power supply device is configured with input terminal (11) connectable to AC power supply (1) whose power supply frequency fluctuates, rectifier (12) that rectifies an AC voltage applied to power input terminal (11), frequency detector (13) that measures frequency of rectifier (12), current limiter (14) that regulates current output from rectifier (12), charge accumulation unit (15) that accumulates charge output from current limiter (14), current detector (16) that measures current output from charge accumulation unit (15), load connection terminal (17) connectable to load (20) that is operated by current output from current detector (16), and controller (18) that controls a regulated value of current limiter (14) and capacitance of charge accumulation unit (15) in accordance with fluctuation of the frequency measured by frequency detector (13) in such a manner that the current output from charge accumulation unit (15) becomes larger than current consumed by load (20) at a predetermined time.

Abstract: An optical disc recording and reproducing apparatus is provided. The apparatus detects the level of a focus error signal output from an optical pickup and a peak of the focus error signal occurred before the focus is obtained while an objective lens of the optical pickup moves in the focusing direction, discriminates a type of the loaded optical disc based on a first reference level or a second reference level, and actuates a focus servo before the objective lens moving in the focusing direction reaches a focalized position. Thus, a read only disc or a recordable disc can be rapidly reproduced.

Abstract: An optical disc recording and reproducing apparatus realizes stable tracking control for correcting the displacement of an objective lens caused by gravity depending on the positional attitude of the apparatus.

Abstract: In a CLV control of a spindle motor, a clock extracting unit (5) extracts a clock component from the reproduction data, and a CLV control unit (6) controls the spindle motor (8) in accordance with the extracted clock component to rotate the optical disk in a CLV mode, while a rotational velocity detecting unit (14, 15) detects a frequency or period value corresponding to a rotational velocity of the spindle motor (8) and a CAV control unit (16) controls the spindle motor (8) in accordance with the rotational velocity of the spindle motor detected by the rotational velocity detecting unit to thereby rotate the optical disk in a CAV mode.

Abstract: In the case where a CPS unit (9) detects a period of clock components of reproduction data to be within a given range, the spindle motor (8) is driven in the CLV mode in stable and the mean value or the low-frequency components of the drive signal data (Smd) during a given time period is stored in the memory unit (11), and in the meanwhile, when the clock components of the reproduction data can not be extracted, the spindle motor is driven in accordance with the mean value or low-frequency components stored in the memory unit. In the case where the reproduction data per se including the clock signal components for use in the CLV control is not obtained due to cracks and stains on the optical disk or due to external shock or vibrations applied from the outside, the stable rotation of the optical disk can be maintained for reproducing the data without causing undesirable burst rotation of the optical disk.