Transconductor and filter circuit using the same

Abstract

A filter circuit capable of suppressing an increase of circuit area, enabling easy circuit design, realizing a reduction of power consumption by a common control voltage operation, and able to stably control the cut-off frequency, that is, a filter circuit including a Gm-C circuit comprising a plurality of transconductors and load capacitors driven by the transconductors, where control signals (bias voltages) to be supplied to the transconductors are controlled by bias circuits in accordance with output voltages output from the transconductors and a reference voltage input from the outside so that output common-mode potentials of the transconductors become identical, the common-mode input potentials are controlled so that gm values become desired values in the transconductors, and W/L ratios of MOS transistors of a differential pair are set to be predetermined values.

Dependencies are inferred from the claim text.