Southeast University

Zhiyi Ye

Longxing Shi

Hong Li

Jianhui Wu

Meng Zhang

Chao Chen

Zixuan Wang

Wei Zhao

Jie Sun

Dahai Hu

Danhong Gu

Junhui Gu

A high-speed fully differential clock duty cycle calibration circuit applied to calibrating the clock duty cycle in a high-speed system. The circuit detects the duty cycle with a continuous time integrator, and directly adjusts the duty cycle on a clock transmission link so as to increase the working speed. Being of a fully differential circuit structure, the circuit can calibrate the duty cycle under a designated process within a higher and wider frequency range, and has relatively good constraining force for process mismatch and common mode noise. The circuit comprises adjustment level ADJand ADJ, a first buffer level BUF, a second buffer level BUFand a duty cycle detection level DCD.

High-speed fully-differential clock duty cycle calibration circuit

A return-type current-reuse mixer having a transconductance/amplification stage, a mixing stage, and a high-pass and a low-pass filter network. The transconductance/amplification stage has a current-reuse CMOS topology wherein an input frequency signal is converted into a frequency current, low-frequency components are removed from the frequency current by the high-pass filter network, the frequency current is fed into the mixing stage, modulation occurs in the mixing stage, and then an intermediate-frequency signal is generated and output. Once high-frequency components are removed from the intermediate-frequency signal by the low-pass filter network, the intermediate-frequency signal is sent again for input into the transconductance/amplification stage, then amplified in the transconductance/amplification stage and output. The mixer transconductance/amplification stage employs a current-reuse technique. The input frequency and the output intermediate-frequency signal share a common transconductance/amplification stage. The mixer reduces power consumption, simplifies the circuit topology, and provides high conversion gain.

Return-type current-reuse mixer

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Jiangsu, China

Zhiyi Ye