Patent ID: 8373437

Claim:
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 ground 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 ground voltage; a first n-channel MOSFET comprising a source connected to a second terminal of the variable resistance circuit, and comprising a gate and a drain connected each other; a second n-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 n-channel MOSFET; a first current supply circuit to supply a current to the variable resistance circuit through the drain of the first n-channel MOSFET; a second current supply circuit to supply a current to the reference circuit through a drain of the second n-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 n-channel MOSFET and the second input terminal connected to the drain of the second n-channel MOSFET.