High order discrete time charge rotating passive infinite impulse response filter

摘要

A novel and useful high-order discrete-time charge rotating (CR) infinite impulse response (IIR) low-pass filter is presented. The filter utilizes capacitors and a gm-cell, rather than operational amplifiers, and is thus compatible with digital nanoscale technology. A 7th-order charge-sampling and 6th-order voltage-sampling discrete time filter is disclosed. The order of the filter is easily extendable to higher orders. The charge rotating filter is process-scalable with Moore's law and amenable to digital nanoscale CMOS technology. Bandwidth of this filter is precise and robust to PVT variation. The filter exhibits very low power consumption per filter pole, low input-referred noise, wide tuning range, excellent linearity and low area per minimum bandwidth and filter pole.

主权项

1. A discrete time analog filter, comprising:
an input node for receiving an input signal; a plurality of history capacitors (CH); a sampling capacitor (CS) coupled to said plurality of history capacitors and operative to cyclically share charge with said plurality of history capacitors; wherein during each multi-phase cycle of said filter, each history capacitor is individually connected to said sampling capacitor such that only a single history capacitor is connected to said sampling capacitor during each phase; and wherein an output node generates a filtered output signal once each cycle.