Abstract:
PURPOSE: A phase locked loop(PLL) circuit and locking control method therefor is provided to generate an output having an accurate frequency together with reducing a locking time independent of manufacturing process and temperature effects. CONSTITUTION: A PLL circuit includes a phase frequency detector(31) for detecting a phase difference by comparing a phase of feedback signal with that of a reference signal, an electron pump(32) for pumping electrons in response to the output signals from the phase frequency detector(31), a loop filter(15) for filtering the output signals from the electron pump(32), a voltage control oscillator(VCO)(34) for varying the frequency of the feedback signals in response to the output signals from the loop filter(15), a register(35) for storing the digital signals, a digital-to-analog(DA) converter(36), a lock detector(37) for determining by receiving the output signals from the phase frequency detector(31) whether or not the feedback signals are locked with the reference signals and an analog-to-digital(AD) converter(38). The DA converter(36) controls the voltage level of the output signals from the loop filter(15) by converting the digital signals stored in the register(35). The AD converter(38) supplies the digital signals by converting the output signals from the loop filter(15) into the digital signals, which is activated when the lock detector(37) outputs a signal representing a status of locking.
Abstract:
A frequency multiplier using a delay locked loop is provided to acquire an output clock signal having frequencies of M times of an input clock signal by connecting a small number of frequency multipliers in series. A frequency multiplier using a delay locked loop includes a delay locked loop circuit(110), and a frequency calculation unit(150). The delay locked loop circuit(110) outputs N delay clock signals which delay an input clock signal by a predetermined time unit. The N is an integer. The frequency calculation unit(150) receives the N delay clock signals, and outputs frequency output clock signals of M times of a frequency of the input clock signal. The frequency calculation unit(150) includes first to N/2th logical multiply units and a logical sum unit. The first to N/2th logical multiply units output first to N/2th logical multiply signals obtained by logical-multiplying signals into which ith to i+1th delay clock signals are inverted. The logical sum unit outputs the output clock signals of the frequency of M times of the input clock signal.
Abstract:
히스테리시스 회로를 구비한 비교기가 개시되어 있다. 비교기는 차동증폭 회로, 및 히스테리시스 회로를 구비한다. 차동증폭 회로는 입력신호들 사이의 차이에 대응하는 차신호를 증폭하여 제 1 신호를 발생시킨다. 히스테리시스 회로는 제 1 신호에 응답하여, 제 1 천이 스레숄드 전압과 제 1 천이 스레숄드 전압보다 낮은 제 2 천이 스레숄드 전압을 설정하고, 차신호가 상승할 때는 제 1 천이 스레숄드 전압에서 천이되고 차신호가 하강할 때는 제 2 천이 스레숄드 전압에서 천이되는 제 2 신호를 발생시킨다. 따라서, 비교기는 차동증폭회로의 출력단에 히스테리시스 회로를 구비함으로써, 입력신호의 동작 가능한 주파수를 감소시키지 않으면서 노이즈 면역성을 증가시킬 수 있다.
Abstract:
본 발명은 카운터에 관한 것으로서, 더 구체적으로는 데이터의 변화로 인한 전류 소모를 줄일 수 있는 래치 회로를 갖는 카운터에 관한 것으로서, N 비트 카운터 의 래치 회로는 하위 비트 정보에 대응되는 제 1 선택 신호에 응답하여 하위 비트 정보와 접지 전압 레벨의 정보중 하나를 선택하기 위한 제 1 선택 회로와; 제 2 선택 신호에 응답하여 상기 제 1 선택 회로의 출력과 상위 비트 정보 중 하나를 선택하기 위한 제 2 선택 회로와; 전단으로 선택된 데이터를 인가받고, 클럭 신호에 응답하여 상기 데이터를 래치하기 위한 래치 회로를 포함한다.
Abstract:
PURPOSE: A frequency synthesizer is provided to control gate number by decreasing bit number of a counter. CONSTITUTION: The frequency synthesizer comprises: a divider(10) for dividing input frequency; a scaler(90) receiving the output of a phase synchronous loop(100) to integrate pulse number; and a m-bit counter(110) for counting the output of the scaler, wherein the scaler receives the output of a voltage control oscillating circuit to transmit the first signal to the counter and the second signal to outdoor and contains a circuit outputting divided signals in synchronous with the output of the voltage control oscillating circuit and a selection circuit for selecting one of the output of the voltage control oscillating circuit and the divided signal.