Patent ID: 6100741
Filing Date: 2000-08-08
Classification: G06G

Abstract:
A semiconductor integrated circuit comprising insulated gate type transistors which operate in a subthreshold region where a gate-source voltage is lower than a threshold and where a drain current is expressed by an exponential function of the gate-source voltage,wherein a gate-drain connection point of a first insulated gate type transistor whose gate and drain are shorted and whose source is connected to a lower-voltage-side power-supply potential or a higher-voltage-side power-supply potential is connected to a source of a second insulated gate type transistor whose gate and drain are shorted, and first input signal current means is connected to a gate-drain connection point of the second insulated gate type transistor,wherein a gate-drain connection point of a third insulated gate type transistor whose gate and drain are shorted and whose source is connected to the lower-voltage-side power-supply potential or the higher-voltage-side power-supply potential is connected to a source of a fourth insulated gate type transistor whose gate and drain are shorted, and second input signal current means is connected to a gate-drain connection point of the fourth insulated gate type transistor,wherein the gate-drain connection points of said second and fourth insulated gate type transistors are connected to first and second capacitor means, respectively, outputs of said first and second capacitor means are connected to each other and to a gate of a fifth insulated gate type transistor to form a floating point, and a source of the fifth insulated gate type transistor is connected to the lower-voltage-side power-supply potential or the higher-voltage-side power-supply potential, andwherein a drain current of said fifth insulated gate type transistor is an operation output.