Transconductor and filter circuit
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTakashi Morie, Shiro Dosho
Life of this patent
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Abstract
A transconductor which has a transconductance gm and which receives an input voltage Vin and outputs in response to the input voltage Vin an output current Iout of gm×Vin, wherein: the transconductor includes a plurality of sub-transconductors which are connected in parallel to one another; and at least one control signal is input to the plurality of sub-transconductors, and the plurality of sub-transconductors are controlled by the at least one control signal such that at least one of the plurality of sub-transconductors has a negative transconductance, whereby the transconductance gm of the transconductor can be varied.
Claims5
A filter circuit, comprising:
- a plurality of transconductors, each of the plurality of transconductors outputting an output current which is proportional to an input voltage, each of the plurality of transconductors having an input terminal to which the input voltage is input and an output terminal from which the output current is output;
- a plurality of capacitors;
- a plurality of first switching sections;
- and
- a plurality of second switching sections, wherein each of the plurality of capacitors is connected to an output terminal of at least one of the plurality of transconductors,
- each of the plurality of first switching sections is connected to an input terminal of one of the plurality of transconductors,
- each of the plurality of second switching sections is connected to an output terminal of one of the plurality of transconductors, and
- a transconductor to be selected among the plurality of transconductors can be controlled by one of a plurality of first control signals which is input to each of the plurality of transconductors and a second control signal which is input to each of the plurality of first and second switching sections.
Dependencies are inferred from the claim text.