Title：A Low Dropout Linear Regulator with Digital Circuit Compensation Capacitance
Country：China
Patent No.：201611105561.3
Legal Status：Authorized
Inventor：Ziqiang Wang, Yuxing Zhou, Chun Zhang, Zhihua Wang, Fule Li
Assignee：Tsinghua University
Address：Tsinghua University,Haidian District Beijing 100086, China
Filing Date：2016-12-05
Issue Date：2017-12-19
Abstract：
A low dropout regulator is of a closed-loop negative feedback structure, the stability of a loop can be guaranteed by adopting a miller compensation method, however, when a load changes, miller capacitance equivalent to the grid electrode of an adjustment resistor changes accordingly, a dominant pole of the loop changes accordingly, and therefore the stability of the loop is difficult to guarantee. The invention provides a low dropout regulator adopting a digital circuit for compensating for capacitance. The low dropout regulator is characterized in that in a low dropout regulator circuit using miller compensation, a voltage detecting circuit is utilized for detecting the output voltage of an error amplifier, the detected voltage is input into a digital-analog converter to be converted into a digital signal, the digital signal is input into the digital logic control circuit which judges the working state of the adjustment resistor, the capacitance needing to be compensated for at the moment is obtained according to prestored information, a control signal is output, on-off of a capacitor array is adjusted, the total capacitance of the grid electrode of the adjustment resistor is kept unchanged, and then the dominant pole of the loop is stabilized.
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