A Novel Technique for Improvement of Power Supply Rejection Ratio in Amplifer Circuits

Most of the time, power supplies fail to provide a constant voltage supply and some external voltage signal may override on the power supply giving unwanted fluctuation at the output node. This paper discusses 3 techniques to improve the power supply rejection ratio (PSRR) in amplifier circuits. (1) Cascoding technique - cascoding increases the gain from input node to output node giving high PSRR values at low frequency. (2) Feedback technique - a negative feedback in circuits generally improves PSRR since it ensures that output follows the input signal and any other external disturbance is rejected. (3) Designing an additional circuit which could nullify the effect of the voltage gain from the power supply to the output node.