Abstract:
Provided are a delay locked loop (DLL) and a method for generating a divided clock therein. In the DLL, a width of a reference frequency for phase comparison can be changed depending on a magnitude of an operating frequency. In the DLL, a clock buffer receives a clock equal to an external clock and generates an internal clock. An enable clock generator generates a 1-period enable clock or a 2-period enable clock using a command signal generated for performing a predefined operation. The command signal is generated according to an address command signal inputted from an exterior. A clock divider divides the internal clock to generate a divided clock. The divided clock is controlled by the 1-period enable clock or the 2-period enable clock, such that the divided clock is made to be a 1-period based dividing clock or a 2-period based dividing clock.
Abstract:
Disclosed is an optical pickup apparatus. Particularly, a photo detector for use in the optical pickup apparatus detects a beam reflected from the disc, and includes a substrate for transmitting three beams (one main beam and two sub beams) reflected from the optical disc; a liquid crystal for refracting the two sub beams, that are transmitted through the substrate, at different refractive indexes according to the wavelength of a laser beam outputted from the laser diode; an electrode material for supplying power to the liquid crystal; a switch for adjusting the magnitude of an applied voltage to the electrode material; and a photodiode on which the main beam and the refracted sub beams while transmitting the substrate and the liquid crystal are projected, and transformed into electric signals. The photo detector enables to change the light-receiving magnification by installing the substrate and the crystal layer(s) in front of the photodiode, and adjusting the magnitude of an applied voltage to the liquid crystal. By refracting the beams refracted from the disc at a proper refractive index, the ±1st-order beams can be projected onto the same position, irrespective of the wavelengths. As such, the optical pickup apparatus of the present invention is capable of recording and/or reproducing information onto and/or from discs having diverse specifications.
Abstract:
A delay detecting apparatus detects delay amounts of delay elements in a semiconductor device by using a test mode. The semiconductor device comprises a delay signal detecting unit for detecting delays of delay elements in the semiconductor device by using a signal that is synchronized with an external clock, and a delay signal outputting unit for outputting a delayed signal from the delay signal detecting unit to a data pad by using the signal that is synchronized with the external clock.
Abstract:
The present invention relates to a self-refresh apparatus and method. In the self-refresh method according to the present invention, when a partial array self-refresh operation is performed on a bank, internal address is counted in a predetermined cycle corresponding to a refresh rate regardless of PASR types. The bank is selectively activated depending on the PASR types. As a result, errors of the refresh rate which result from a half of bank or quarter of bank self refresh operation can be prevented.
Abstract:
A plasma display panel (PDP) is capable of directly and effectively removing impurities from a discharging space for enhancing the purity of a discharging gas. The PDP has a getter layer formed of at least a portion of a barrier rib. The getter layer is independently formed at an upper portion of each barrier rib with respect to each discharging cell or maybe formed to cross each other at every other cell with respect to the discharging cells formed in a direction in which the barrier ribs extend. The getter material particles are dispersed in an insulation material so that the getter layer has an electrical insulation characteristic.
Abstract:
The present invention relates to a continuous process for the preparation of [3S-(3&agr;, 4a&bgr;, 8a&bgr;)]-N-tert-butyl-decahydro-3-isoquinolinecarboxamide, an intermediate useful in the synthesis of compounds for the treatment of viral diseases, from the reduction of N-tert-butyl-1,2,3,4-tetrahydro-3(S)-isoquinolinecarboxamide with a noble metal catalyst supported on inorganic oxide carrier in a fixed bed reaction system, with a high optical yield.
Abstract:
Disclosed is a process for the production of optically pure (S)-beta-hydroxy-gamma-butyrolactone through the hydrogenation of substituted carboxylic acid derivatives. A solution containing 1 to 50% by weight of a substituted carboxylic acid derivative is fed at a WHSV of 0.1 to 10 h−1, to a fixed bed reactor which is filled with a catalyst and maintained at a reaction temperature of 50 to 550° C. under a halogen partial pressure of 15 to 5,500 psig. The catalyst is composed of a noble metal as a catalytically effective ingredient which is impregnated in an inorganic oxide as a support. The molar ratio of the hydrogen to the substituted carboxylic acid derivative is maintained at a molar ratio of 1:1 to 10:1. The process can produce optically pure (S)-beta-hydroxy-gamma-butyrolactone with higher purities at higher yields than can conventional techniques. In addition to being relatively simple and environmentally friendly, the process is so economically favorable as to apply to industrial production.
Abstract:
A data bus line control circuit prevents a problem of a data access operation on a global data bus (GDB) line although two blocks are simultaneously selected. The data bus line control circuit includes: a global data bus line which is arranged between memory units adjacent to each other as two pairs, and transmits a data from a local data bus line positioned between adjacent sub blocks; and transmission means which is connected between the local data bus line and the global data bus line, and transmits bit line signals of two sub blocks to one pair of global data bus lines different from each other through the local data bus line, when the two sub blocks are simultaneously selected by a block isolation selection signal. As a result, a circuit arrangement and a layout design become simplified, and two operations of 8K refresh and 4K refresh are possible in one chip, therefore, two kinds of effects can be achieved by one chip.
Abstract:
A repair circuit of a semiconductor memory device utilizes a plurality of current blocking circuits, each provided with a programmable anti-fuse, to reduce current consumption in DRAM devices, particularly during a normal operation mode. The repair circuit includes a first operation switch having an output for outputting a supply voltage in accordance with a CAS-before-RAS signal; a first fuse selector, including a first plurality of fuses connected to the output of the first operation switch, to output a sub-block select signal in accordance with the output voltage of the first operation switch and a spare column enable signal; a second operation switch having an output for outputting the supply voltage in accordance with the sub-block select signal output from the first fuse selector and an address transition detection signal for performing a pre-charge function during a normal operation mode of a DRAM device; and a second fuse selector, including a second plurality of fuses connected to the output of the second operation switch, to generate a repair column select signal in accordance with the sub-block select signal output from the first fuse selector. The current blocking circuit generate a repair value signal for controlling the operation of one or the other operation switch based on a programming status of the anti-fuse.
Abstract:
There is disclosed an AC PDP comprising two plates. These two plates are opposite to each other with a plurality of parallel electrodes on one plate being across a plurality of parallel electrodes on the other. The space therebetween, sealed by a side wall, is filled with a discharge gas. A fluorescent layer is formed on the side of one of the plates in the sealed space. Opposite to the fluorescent layer, a dielectric multilayer structure is laminated on the electrodes and covered with an overcoat layer, wherein its sub-layers are of lower fluidity as they are nearer to the overcoat layer. This is accomplished by arranging the sub-layers in such a way that they may be higher in softening temperature as they are nearer to the overcoat layer. Since the sub-layers are made of glass materials, this softening temperature gradient is determined by the content of PbO and/or B.sub.2 O.sub.3 in each of the sub-layers, ranging from approximately 20-50% by weight and approximately 0.5-12.5% by weight, respectively, based on the total weight of each layer. This multilayer structure effectively prevents cracks from occurring in the overcoat layer upon sintering. Therefore, the problems of the electrode damage and the discharge gas pollution, both attributable to the cracks, can be effectively solved, and a high quality and endurable AC PDP can be provided.