Back to results
US 8,138,828 B2Granted
Active mute scheme for an amplifier
AssigneeTexas Instruments Incorporated
InventorsAllan N. Nielsen, Kim N. Madsen
Life of this patent
Estimating the term…
Abstract
Conventional muting circuitry for amplifiers (which usually uses clamps) generally has about 20-30 dB of attenuation. Here, an integrated circuit or IC is provided that includes an amplifier, switch networks, and a controller. The controller provides control signals to the switch network to provide mute functionality by actively muting the amplifier. In particular, feedback is provided through at least one of the switch networks to drive the output of the amplifier to null or ground so as to provide 70-80 dB (or more) of attenuation.
Claims20
An apparatus comprising;
- a first pin;
- a second pin;
- a third pin;
- an amplifier having a first input terminal, a second input terminal, and an output terminal, wherein the output terminal of the amplifier is coupled to the third pin;
- a first switch network that is coupled between the first pin and the first input terminal of the amplifier and that is coupled between the second pin and the second input terminal of the amplifier;
- a second switch network that is coupled to the first input terminal of the amplifier, the second input terminal of the amplifier, and the output terminal of the amplifier;
- and
- a controller that is coupled to provide a first control signal to the first switch network and that is coupled to provide a second control signal to the second switch network, wherein the first control signal activates each switch in the first switch network during an amplify mode and a transition mode, and wherein the second control signal activates each switch in the second switch network during a mute mode and the transition mode, and wherein feedback through the amplifier during the mute mode actively mutes the amplifier.
5 more elements
An apparatus comprising:
- a first pin;
- a second pin;
- a third pin;
- an amplifier having a first input terminal, a second input terminal, and an output terminal, wherein the output terminal of the amplifier is coupled to the third pin;
- a first switch network having:
- a first switch that is coupled between the first pin and the first input terminal of the amplifier;
- and
- a second switch that is coupled between the second pin and the second input terminal of the amplifier;
- a second switch network having:
- a third switch that is coupled to the output terminal of the amplifier;
- a fourth switch that is coupled between the second input terminal of the amplifier and ground;
- a first resistor that is coupled between the first switch and the first input terminal of the amplifier;
- a fifth switch that is coupled to the first input terminal of the amplifier;
- and
- a second resistor that is coupled between the third switch and ground;
- and
- a controller that is coupled to provide a first control signal to the first and second switches and that is coupled to provide a second control signal to the third, fourth, and fifth switches, wherein the first control signal activates each of the first and second switches switch in the first switch network during an amplify mode and a transition mode, and wherein the second control signal activates each of the third, fourth, and fifth switches in the second switch network during a mute mode and the transition mode, and wherein feedback through the amplifier during the mute mode actively mutes the amplifier.
14 more elements
A method comprising:
- activating a plurality of switches in a first switch network with a first control signal during an active mode so as to amplify a signal from a signal source with an amplifier,
- wherein the first switch network is coupled between a first pin and a first input terminal of the amplifier, the amplifier further including a second input terminal and an output terminal, wherein the output terminal of the amplifier is coupled to a third pin, wherein the first switch network is also coupled between a second pin and the second input terminal of the amplifier;
- activating a plurality of switches in a second switch network with a second control signal during a transition mode to retain closed loop operation of the amplifier,
- wherein said second switch network is coupled to the first input terminal of the amplifier, the second input terminal of the amplifier, and the output terminal of the amplifier;
- and
- deactivating the plurality of switches in the first switch network with the first control signal during a mute mode so that feedback through the amplifier actively mutes the amplifier, wherein the mute mode follows the transition mode,
- wherein the first control signal activates each switch in the first switch network during an amplify mode and a transition mode, and wherein the second control signal activates each switch in the second switch network during the mute mode and the transition mode.
4 more elements
Dependencies are inferred from the claim text.