Tunable filter
AssigneeHuawei Technologies Co., Ltd.
InventorGiuseppe Gramegna
Life of this patent
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Abstract
A tunable filter is provided. The tunable filter includes: a filter input; a filter output; at least one feedback loop coupled between the filter output and the filter input, where the at least one feedback loop includes at least one tunable feedback capacitance which is configured to tune a cut-off frequency of the tunable filter; and an active element, coupled between the filter input and the filter output and configured to drive the at least one tunable feedback capacitance, the active element having a transfer function with a primary pole and at least one secondary pole, where the active element includes a first stabilization element that is coupled to a first internal node of the active element.
Claims22
A closed loop analogue circuit comprising:
- an input terminal;
- an output terminal;
- at least one feedback loop coupled between the output and the input terminals, wherein the at least one feedback loop comprises at least one tunable feedback capacitance;
- an operational amplifier coupled between the input and the output terminals,
- wherein the operational amplifier comprises a first internal node, a first transistor and a first stabilization element,
- wherein the first internal node is coupled to the first stabilization element,
- wherein the first stabilization element comprises at least one capacitance,
- wherein the operational amplifier has a transfer function with a primary pole and at least one secondary pole, and
- wherein the first stabilization element is configured to move the location of the primary pole;
- a control terminal of the first transistor coupled to the input;
- and
- a second terminal of the first transistor coupled to the first internal node of the operational amplifier.
A tunable filter comprising:
- a filter input terminal;
- a filter output terminal;
- at least one feedback loop coupled between the filter output terminal and the filter input terminal, wherein the at least one feedback loop comprises at least one tunable feedback capacitance;
- an operational amplifier coupled between the filter input terminal and the filter output terminal,
- wherein the operational amplifier comprises a first internal node, a first transistor and a first stabilization element,
- wherein the first internal node is coupled to the first stabilization element,
- wherein the first stabilization element comprises at least one capacitance,
- wherein the operational amplifier has a transfer function with a primary pole and at least one secondary pole, and
- wherein the first stabilization element is configured to move the location of the primary pole;
- a control terminal of the first transistor coupled to the input;
- and
- a second terminal of the first transistor coupled to the first internal node of the operational amplifier.
Dependencies are inferred from the claim text.