Look-up table circuits and field programmable gate array

A look-up table circuit comprising:

• a variable resistance circuit comprising a plurality of variable resistance devices and selecting a variable resistance device from the plurality of variable resistance devices based on an input signal, a first terminal of the variable resistance circuit being connected to a power supply voltage;
• a reference circuit having a resistance value between the largest resistance value and the smallest resistance value of the variable resistance circuit, a first terminal of the reference circuit being connected to the power supply voltage;
• a first p-channel MOSFET comprising a source connected to a second terminal of the variable resistance circuit, and comprising a gate and a drain connected to each other;
• a second p-channel MOSFET comprising a source connected to a second terminal of the reference circuit and comprising a gate connected to the gate of the first p-channel MOSFET;
• a first current supply circuit to supply a current to the variable resistance circuit through the drain of the first p-channel MOSFET;
• a second current supply circuit to supply a current to the reference circuit through a drain of the second p-channel MOSFET;
• and
• a comparator to compare voltages at a first input terminal and a second input terminal, the first input terminal connected to the drain of the first p-channel MOSFET and the second input terminal connected to the drain of the second p-channel MOSFET.