A novel switched capacitor frequency tuning technique for continuous-time Gm-C filters

摘要

A novel approach for the automatic frequency tuningof Continuous Time Filters is presented. This approach is basedon a switched capacitor circuit and only needs three capacitors,some switches and a replica transconductor to adjust the polefrequency of the filter. Despite the simplicity of the scheme, theaccuracy of the proposed system is under 1% of frequency error.To evaluate the idea a version of the circuit has been designed ina 0.5 µm CMOS technology with a 3.3 V power supply andsimulation results are provided.