Title：System for acquiring human body motion information and method thereof

Country：China

Patent No.：202110316024.8

Legal Status：Under review

Inventor：Wei Song, Xuecheng Wang,Milin Zhang,Xiao yan Ma,Xin Lin, Yu Pan

Assignee：Tsinghua University

Address：Tsinghua University,Haidian District Beijing 100084, China

Filing Date：2021-03-24

Issue Date：

The invention discloses a current source for improving linearity of a current-steering DAC (Digital-to-Analog Converter) and the DAC. The current source comprises two groups of current source tubes (Mn1, Mn3, Mn2 and Mn4) with positive and negative resistor parallel structures, two common-gate tubes (Mcas) and two groups of differential switch tubes (Msw), the two groups of current source tubes are formed by cross coupling and parallel connection of positive resistance parts (Mn1 and Mn4) and negative resistance parts (Mn2 and Mn3); the drain electrodes of the positive resistance part and the negative resistance part are respectively connected with the source electrodes of the two common-gate tubes; and the drain electrodes of the two common-gate tubes are respectively connected to the source electrodes of the two groups of differential switch tubes. According to the invention, the output impedance of the DAC current source is greatly improved, the influence of a nonlinear problem caused by non-ideal output impedance is reduced, and the nonlinear distortion problem caused by limited output impedance can be greatly improved; the voltage space can be saved, an additional amplifier circuit is not needed, the complexity of the whole circuit is reduced, and power consumption is saved.

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