Equivalent Saturated MOSFET Circuit with Wide Input Range

Takahide SATO  Shigetaka TAKAGI  Nobuo FUJII  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E88-A   No.2   pp.431-437
Publication Date: 2005/02/01
Online ISSN: 
DOI: 10.1093/ietfec/e88-a.2.431
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
Category: 
Keyword: 
MOSFET,  saturation region,  equivalent MOSFET circuit,  

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Summary: 
An equivalent MOSFET circuit with a wide input range is proposed. The proposed circuit is suitable for a realization of a wide input range under a low power supply voltage. The circuit consists of a MOSFET array and level shift circuits. The sum of drain currents of the MOSFET array is used as an equivalent drain current. The equivalent drain current is represented by K(VGS-VT)2 even when its drain-to-source voltage is quite small and some MOSFETs in the array are in the non-saturation region or the cut-off region. The input range of the proposed circuit realized by k-MOSFET array is k times as wide as that of a single MOSFET. It is confirmed through HSPICE simulations that the proposed circuit is effective in applications with a wide dynamic range.