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.

A building block for widening an input range under low power-supply voltages is proposed and the block is used in a popular linearization technique for voltage-to-current converters. The block employs two MOSFETs each of which actively works when and only when the other is in cutoff region. Accurate level shift circuits for the control of the MOSFETs enable such exclusive operation. Simulation results show that the complementary MOSFETs perform as an equivalent MOSFET without any cutoff region. It is also confirmed that the novel linear voltage-to-current converter is effective for not only a wide input range but also low-power consumption.