ABSTRACT
The bias and current reference circuits should be designed to feature a good stability over the integrated circuit (IC) process, and supply voltage and temperature variations. A review of different techniques used to achieve this goal is then necessary. Current mirrors find applications in analog ICs as biasing elements, which can set transistor bias levels such that the circuit characteristics are less affected by power supply and temperature variations. In order to obtain a high resistance, current mirrors can be designed using cascode transistor structures. However, an adequate transistor biasing is required to achieve a high output swing, which is desired for the low-voltage operation. The use of an adequate bias circuit may then be required to maintain the cascode connected transistors in the saturation region regardless of changes in the current and voltage levels due to nonideal effects. The band gap reference is designed to provide a voltage that is independent of supply voltage and temperature variations.
