Abstract: A spread spectrum clock generator is disclosed. The spread spectrum clock generator (SSCG) bases on the structure of the phase-lock loop. The SSCG uses the voltage control oscillator with multi-phase output function for outputting clock signals of different phases. The clock signals of different phases are selectively fed back to the phase frequency detector. In this way, the frequency of the output signal is changed, which achieves spreading spectrum.

Abstract: A duty cycle correction circuit comprises a tuned circuit, a delay circuit and a phase-locked loop; wherein the tuned circuit receives an input clock, generates a periodic pulse according to the input clock, tunes the periodic pulse depending on a reference voltage, and outputs an output clock; a delay circuit receives the output clock, and generates a complementary signal; a phase lock loop receives the complementary signal, measures the periods of time of the high level state and the low level state of the complementary signal, generates the reference voltage and feeds back to the tuned circuit. By using the technique of the present invention, it is able to track the delay time between the input clock and the output clock, and the drift of the output clock is reduced.

Abstract: An inverter with adjustable threshold and irrelative to voltage, temperature, and process is disclosed. The inverter includes an input end for receiving an input signal; an output end for outputting an inverted signal of the input signal; a first PMOS whose gate is coupled to the input end, drain is coupled to the output end, and the source is coupled to a power supply; a first NMOS whose gate is coupled to the input end, drain is coupled to the output end, and source is coupled to a ground end, and an adjustable current source coupled to the output end for providing current with adjustable size to the output end for adjusting threshold of the inverter.

Abstract: A duty cycle correction circuit comprises a tuned circuit, a delay circuit and a phase-locked loop; wherein the tuned circuit receives an input clock, generates a periodic pulse according to the input clock, tunes the periodic pulse depending on a reference voltage, and outputs an output clock; a delay circuit receives the output clock, and generates a complementary signal; a phase lock loop receives the complementary signal, measures the periods of time of the high level state and the low level state of the complementary signal, generates the reference voltage and feeds back to the tuned circuit. By using the technique of the present invention, it is able to track the delay time between the input clock and the output clock, and the drift of the output clock is reduced.

Abstract: The method and circuit provide an effective implementation to handle the data transferring problem between multiple clock domains. A shift circuit shifts the incoming data stream and a sampling module sequentially samples and outputs each signal in the first group signals and the second group signals by the N sampling pulses with a sequence.