Patent ID: 8872580
Filing Date: 2014-10-28
Classification: H03H

Abstract:
1. A reconfigurable high-order integrated circuit filter, comprising: a plurality of current followers (CFs) arranged in cascade, the cascade having: a plurality of resistor-capacitor (RC) integrators, the at least one intermediate stage current follower and the final stage current follower having a corresponding one of the RC integrators connected to its corresponding input, the first inverting output of the at least one intermediate stage current follower and the final stage current follower being connected to the corresponding RC integrator at its corresponding input; a plurality of external feedback current division networks (CDNs), the at least one intermediate stage current follower and the final stage current follower each having a corresponding one of the CDNs disposed in a feedback loop between the first non-inverting output of the respective one of the at least one intermediate stage current follower and the final stage current follower and the input of the first stage current follower; a summing current follower having an input and an output, the output of the summing current follower being the output of the filter; and a plurality of external feed forward current division networks (CDNs), the first stage current follower having a corresponding one of the feed forward CDNs connected in a feed forward loop from its non-inverting output to the input of the summing current follower, each of the succeeding current followers having a corresponding one of the feed forward CDNs disposed in a feed forward loop from its second non-inverting output to the input of the summing current follower; wherein each of the feedback CDNs has an input accepting a β whereby the filter has a transfer function characterized by the relation: in which β gm is the transfer function numerator coefficient parameter configurable by adjusting the control signals to the feed forward CDNs and β ft is the transfer function denominator coefficient parameter configurable by adjusting the control signals to the feedback CDNs, where i m (s) represents a Laplace transform of an output of the filter in the s-domain, and i s (s) represents a Laplace transform of an input of the filter in the s-domain.