Patent ID: 6433626
Filing Date: 2002-08-13
Classification: G05F

Abstract:
A current-mode filter with a transfer function having complex zeros, comprising:a voltage differentiator having first and second transistors with respective first and second inputs and outputs and being coupled in a follower configuration, third and fourth transistors on second branches are coupled to the first and second transistors respectively and are substantially matched thereto; a floating capacitor coupled between the first and second outputs of the voltage differentiator, the floating capacitor forming a finite zero in the transfer function of the filter; and two current mirrors isolated from the floating capacitor, each current mirror coupled to drive each collector the voltage differentiator transistors and also coupled to the associated second branch transistors, the two current mirrors subtract a non-linear signal from the associated second branched transistors to substantially cancel any signal non-linearities introduced by the follower configuration.