Abstract: A temperature compensatory constant current generator comprises a temperature inversely proportional constant current generator for supplying a temperature inversely proportional current, a temperature proportional constant current generator for supplying a temperature proportional current, a temperature inversely proportional current supplier for outputting the temperature inversely proportional current from the temperature inversely proportional constant current generator, a temperature proportional current supplier for outputting the temperature proportional current from the temperature proportional constant current generator and a square root generator for providing a current proportional to multiplied square roots of the temperature inversely proportional current and the temperature proportional current.

Abstract: An adaptive biasing circuit is combined to a fully differential cascode operational amplifier ("OP AMP") to eliminate the effect of a slew rate, thereby increasing the operation speed of the OP AMP while maintaining a high DC voltage gain. A common mode feedback circuit with a large input common mode voltage range is also connected to the OP AMP, thereby maximizing a linear output voltage swing range. The common mode feedback circuit comprises a nMOS input stage differential amplifier and a pMOS input stage differential amplifier which are connected in parallel, and a push-pull CMOS amplifier for converting current outputs from the nMOS and the pMOS input stage differential amplifiers to an output voltage signal. The adaptive bias circuit comprises an operational transconductance amplifier, two current subtractor circuits and four output transistors.