Common Mode Level Reset Circuit for Differential Signals

Abstract

The invention discloses a common-mode level reset circuit for differential signals. The common-mode level reset circuit comprises a source follow circuit, a voltage-current conversion circuit, a current output circuit and a common-mode reset circuit, wherein the source follow circuit, the voltage-current conversion circuit, the current output circuit and the common-mode reset circuit are sequentially connected. The common-mode level reset circuit can achieve level resetting of output common-mode points, meet the requirement of the next stage input common-mode points, and maintain high differential linearity. The source follow device circuit of a PMOS tube enables the VTH of the input common-mode points to be increased, and the input common-mode points are connected with an NMOS of a following form to form the voltage-current conversion circuit, the input voltage linearity is converted into the current signals, the current signals are transmitted to the current output circuit through image currents, the common-mode level of the current output circuit is reset through the common-mode reset circuit, and finally the common-mode level of the output level VOUT and the VREF are identical. The common-mode level reset circuit achieves resetting of the differential signal common-mode level, maintains the differential linearity of the signals to the maximum degree, and is suitable for the differential signals with the medium amplitude.

Description

technical field [0001] The invention relates to a common-mode level reset circuit for differential signals, and is especially aimed at the level conversion between module circuits in integrated circuits. Background technique [0002] Integrated circuits have developed rapidly in recent years, and the process and integration level have been rapidly improved. The types and quantities of integrated circuits are increasing, and the functions are becoming more and more powerful. Among them, the types and functions of analog circuits are always on the rise. Differential signals are commonly used in small signal processing and transmission modes in analog integrated circuits, and their anti-interference properties can be used to effectively reduce interference. [0003] In integrated circuits, differential MOS pair tubes are a common way to process differential signals. When NMOS and PMOS are used as differential pair tubes, the optimal common-mode voltage may be different. In addi...

AI Technical Summary

Problems solved by technology

There are many kinds of common-mode transfer circuits, and the level transfer can be realized through diodes or MOS devices connected in the form of diodes combined with resistors, but its driving ability sometimes cannot meet the needs of the lower level, and the level transfer takes VT as the basic unit, and cannot Flexible Adjustment to Any Common-Mode Bias Voltage

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