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US 6,618,579 B1Granted
Tunable filter with bypass
AssigneeThe Chase Manhattan Bank
InventorsMalcolm H. Smith, Valerie J. Risk, Mark K. Lesher
Life of this patent
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Abstract
An electrical circuit which includes a filter bypass mode. The circuit includes an amplifier including an inverting terminal, a noninverting terminal and an output terminal, at least one first capacitor coupled to the inverting terminal of the amplifier through at least one first switch, and, at least one second capacitor coupled to the noninverting terminal of the amplifier through at least one second switch. The electrical circuit provides filtering when the first and second switches are in a first state, and when the first and second switches are in a second state, the electrical circuit provides substantially no filtering.
Claims27
An integrated circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch;
- and
- at least one second capacitor coupled between the inverting terminal of the amplifier and the noninverting terminal of the amplifier through at least one second switch, wherein when the second switch is in a first state, the integrated circuit provides filtering, and when the second switch is in a second state, the integrated circuit provides no filtering,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
2 more elements
An integrated circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- and,
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering,
- wherein in the first state the circuit acts as a low pass filter.
2 more elements
An integrated circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch;
- and
- a first resistor coupled between the noninverting terminal of the amplifier and an input terminal of the integrated circuit,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
2 more elements
An integrated circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch;
- a first resistor coupled between the inverting terminal of the amplifier and the noninverting terminal of the amplifier;
- and,
- a second resistor coupled between the inverting terminal of the amplifier and ground,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
3 more elements
An integrated circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and at least two output terminals;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and one of the at least two output terminals of the amplifier through at least one first switch;
- at least one second capacitor coupled between the inverting terminal of the amplifier and the other of the at least two output terminals of the amplifier through at least one second switch;
- and,
- at least one third capacitor coupled between the inverting terminal and the noninverting terminal of the amplifier through at least one third switch,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
3 more elements
A tunable filter circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- and,
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch,
- a first resistor coupled between the noninverting terminal of the amplifier and an input terminal of the filter,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
2 more elements
A tunable filter circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch;
- and,
- at least one second capacitor coupled between the inverting terminal of the amplifier and the noninverting terminal of the amplifier through at least one second switch, wherein when the second switch is in a first state, the filter circuit provides filtering, and when the second switch is in a second state, the filter circuit provides no filtering,
- wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
2 more elements
A tunable filter circuit comprising:
- an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and the output terminal of the amplifier through at least one first switch;
- and,
- at least one third capacitor coupled between the inverting terminal and the noninverting terminal of the amplifier through at least one third switch,
- wherein when the first switch is in a first state, the filter circuit provides filtering, and when the first switch is in a second state, the filter circuit provides no filtering.
2 more elements
A method of bypassing a filter circuit comprising the steps of:
- providing at least one switched filtering element in a filtering circuit;
- and,
- switching the filtering element out of the filter circuit in order to bypass the filter circuit.
A wireless communications device comprising:
- one of the group consisting of a transmitter and a receiver;
- and,
- a tunable filter circuit, coupled to the transmitter or receiver, comprising an amplifier including an inverting terminal, a noninverting terminal and an output terminal;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and ground through at least one first switch;
- and at least one second capacitor coupled between the inverting terminal of the amplifier and the noninverting terminal of the amplifier through at least one second switch, wherein when the second switch is in a first state, the integrated circuit provides filtering, and when the second switch is in a second state, the integrated circuit provides no filtering, wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering.
2 more elements
A wireless communications device comprising:
- one of the group consisting of a transmitter and a receiver;
- and,
- a tunable filter circuit, coupled to the transmitter or receiver, comprising an amplifier including an inverting terminal, a noninverting terminal and at least two output terminals;
- at least one first capacitor coupled between the noninverting terminal of the amplifier and one of the at least two output terminals of the amplifier through at least one first switch;
- and, at least one second capacitor coupled between the inverting terminal of the amplifier and the other of the at least two output terminals of the amplifier through at least one second switch, wherein when the first switch is in a first state, the integrated circuit provides filtering, and when the first switch is in a second state, the integrated circuit provides no filtering, further comprising,
- at least one third capacitor coupled between the inverting terminal and the noninverting terminal of the amplifier through at least one third switch.
3 more elements
Dependencies are inferred from the claim text.