Patent application number | Description | Published |
20080238502 | Delay cell and phase locked loop using the same - A phase locked loop that generates an internal clock by controlling a delay time of a delay cell according to conditions of PVT, thereby improving a jitter characteristic of the internal clock. The delay cell includes a first current controller for controlling first and second currents in response to a control voltage, and a second current controller for controlling the first and second currents in response to frequency range selection signals. The phase locked loop includes a phase comparator for comparing a reference clock with a feedback clock, a control voltage generator for generating a control voltage corresponding to an output of the phase comparator, and a voltage controlled oscillator for generating an internal clock having a frequency in response to the control voltage and one or more frequency range control signals, wherein the feedback clock is generated using the internal clock. | 10-02-2008 |
20090058481 | Semiconductor memory device and method for driving the same - A semiconductor memory device has a duty cycle correction circuit capable of outputting a duty cycle corrected clock and its inverted clock having substantially exactly 180° phase difference therebetween. The semiconductor memory device includes a duty cycle corrector configured to receive a first clock and a second clock to generate a first output clock and a second output clock whose duty cycle ratios are corrected in response to correction signals, and a clock edge detector configured to generate the correction signals corresponding to an interval between a reference transition timing of the first output clock and a reference transition timing of the second output clock. | 03-05-2009 |
20090058482 | Duty detection circuit - Semiconductor memory device with duty correction circuit includes a clock edge detector configured to generate first and second detection pulses in response to a transition timing of a common clock signal in an initial measurement operation; a duty detector configured to compare the first and second detection pulses to output comparison result signals; and a code counter configured to control the duty detector based on the comparison signals outputted from the duty detector in the initial measurement operation. | 03-05-2009 |
20090086881 | Counter with overflow prevention capability - A counter with overflow prevention capability includes a counting unit configured to count an output code in response to an input signal and an overflow preventing unit configured to control the counting unit to stop counting the output code when a current value of the output code is a maximum value but a previous value thereof is not the maximum value. | 04-02-2009 |
20090115459 | Semiconductor device and operation method thereof - A semiconductor device includes a pulse signal generating unit for generating a plurality of pulse signals each of which has a different pulse width from each other, a signal multiplexing unit for outputting one of the plurality of the pulse signals as an enable signal in response to an operating frequency of the semiconductor device, and a duty ratio detecting unit for detecting a duty ratio of external clock signals in response to the enable signal. | 05-07-2009 |
20090115467 | Semiconductor device and operation method thereof - A semiconductor memory device can optimize the layout area and current consumption based on multi-phase clock signals which are generated by dividing a source clock signal using a reset signal without a delay locked loop and a phase locked loop in order to have various phase information of low frequencies and different activation timings with a constant phase difference. | 05-07-2009 |
20090116598 | Semiconductor memory device having data clock training circuit - A data clock frequency divider circuit includes a training decoder and a frequency divider. The training decoder outputs a clock alignment training signal, which is indicative of the start of a clock alignment training, in response to a command and an address of a mode register set. The frequency divider, which is reset in response to an output of the training decoder, receives an internal data clock to divide a frequency of the internal data clock in half. The data clock frequency divider circuit secures a sufficient operating margin so that a data clock and a system clock are aligned within a pre-set clock training operation time by resetting the data clock to correspond to a timing in which the clock training operation starts, thereby providing a clock training for a high-speed system. | 05-07-2009 |
20090160510 | BIAS VOLTAGE GENERATION CIRCUIT AND CLOCK SYNCHRONIZING CIRCUIT - Bias voltage generator circuit and clock synchronizing circuit includes a bias unit configured to control a current in response to a bandwidth control signal, an amplification unit configured to differentially amplify an input signal in response to the current controlled by the bias unit and an output unit configured to receive an output signal of the amplification unit to output the bias voltage. | 06-25-2009 |
20090160560 | Phase locked loop and method for controlling the same - Phase locked loop and method for controlling the same includes a phase/frequency detector configured to detect a phase difference between an input clock and a feedback clock to generate an up signal or a down signal depending on the detected phase difference, a charge pump configured to variably control a bandwidth according to a bandwidth control signal input thereinto, the charge pump operating in response to the up signal or the down signal and a voltage controlled oscillator configured to change a frequency according to an output of the charge pump. | 06-25-2009 |
20090167386 | Charge pumping circuit, clock synchronization circuit having the charge pumping circuit, and method for operating the clock synchronization circuit - A charge pumping circuit includes a first charge pump configured to perform a charge pumping operation on an output terminal in response to a first pumping control signal, an auxiliary charge pumping controller configured to generate a second pumping control signal activated during a predetermined section of an activation period of the first pumping control signal and a second charge pump configured to perform a charge pumping operation on the output terminal in response to the second pumping control signal. | 07-02-2009 |
20090167441 | Injection locking clock generator and clock synchronization circuit using the same - An injection locking clock generator can vary the free running frequency of an injection locking oscillator to broaden an operating frequency range of an oscillation signal injected to itself, thereby performing an injection locking with respect to all frequencies of an operating frequency range. The clock generator includes a main oscillator configured to generate oscillation signals of a frequency corresponding to a control voltage, and an injection locking oscillator configured to generate division signals synchronized with the oscillation signals by dividing the oscillation signals, wherein a free running frequency of the injection locking oscillator is set according to the frequency of the oscillation signals. | 07-02-2009 |
20090168552 | Semiconductor memory device and method for operating the same - A semiconductor memory device includes an edge detector configured to receive two pairs of complementary clocks to detect edges of the clocks, a comparator configured to compare output signals of the edge detector to detect whether clocks of the same pair have a phase difference of 180 degrees and detect whether clocks of different pairs have a phase difference of 90 degrees, a control signal generator configured to generate a control signal for controlling phases of the clocks according to an output signal of the comparator, and a phase corrector configured to correct phases of the clocks in response to the control signal. | 07-02-2009 |
20090273381 | DELAYED LOCKED LOOP CIRCUIT - A delay locked loop circuit for compensating for a phase skew of a memory device includes a first delay locking unit configured to delay an external clock of the memory device by a first amount of delay to output a first internal clock, a second locking unit configured to delay the external clock by a second amount of delay to output a second internal clock, the second amount of delay being greater than the first amount of delay, and a selecting unit configured to select one of the first internal clock and the second internal clock as an internal clock of the memory device. | 11-05-2009 |
20090273493 | Parallel-to-serial converter - A parallel-to-serial converter includes a data input unit configured to receive a plurality of parallel data by using a plurality of clock signals having different phases, and a parallel-to-serial conversion unit configured to sequentially select and output an output signal of the data input unit by using a plurality of clock signals having a predetermined phase difference from the plurality of clock signals used in the data input unit. | 11-05-2009 |
20090279378 | SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device including a clock input for receiving a source clock and supplying a generated clock to a plurality of clock transmission lines; a plurality of clock amplifiers, each amplifying a respective generated clock loaded on one of the plurality of clock transmission lines in response to a column enable signal; and a data input/output for inputting/outputting a plurality of data in response to the amplified clocks output by the plurality of clock amplifiers. | 11-12-2009 |
20110204943 | DELAY CELL AND PHASE LOCKED LOOP USING THE SAME - A phase locked loop that generates an internal clock by controlling a delay time of a delay cell according to conditions of PVT, thereby improving a jitter characteristic of the internal clock. The delay cell includes a first current controller for controlling first and second currents in response to a control voltage, and a second current controller for controlling the first and second currents in response to frequency range selection signals. The phase locked loop includes a phase comparator for comparing a reference clock with a feedback clock, a control voltage generator for generating a control voltage corresponding to an output of the phase comparator, and a voltage controlled oscillator for generating an internal clock having a frequency in response to the control voltage and one or more frequency range control signals, wherein the feedback clock is generated using the internal clock. | 08-25-2011 |
20110273937 | SEMICONDUCTOR MEMORY DEVICE AND METHOD FOR OPERATING THE SAME - A semiconductor memory device includes an edge detector configured to receive two pairs of complementary clocks to detect edges of the clocks, a comparator configured to compare output signals of the edge detector to detect whether clocks of the same pair have a phase difference of 180 degrees and detect whether clocks of different pairs have a phase difference of 90 degrees, a control signal generator configured to generate a control signal for controlling phases of the clocks according to an output signal of the comparator, and a phase corrector configured to correct phases of the clocks in response to the control signal. | 11-10-2011 |