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US 7,023,983 B2Granted
Versatile circuit for interfacing with audio headsets
AssigneeQUALCOMM Incorporated
InventorJay Steven King
Life of this patent
Estimating the term…
Abstract
A signal conditioning circuit is described which can facilitate dual mode use of a connector circuit, e.g., audio mode or data mode. In other words, a headset or alternatively, a data interface may be coupled to the connector circuit and signal conditioning circuit, depending on the mode of the device. In accordance with this disclosure, the signal conditioning circuit operates in audio mode without the need for conventional blocking capacitors in the speaker channels. Moreover, in some embodiments, the signal conditioning circuit also provides backwards compatibility with conventional connector circuits that include such blocking capacitors.
Claims27
A circuit comprising:
- a first multiplexer to select a bias for a microphone when the microphone is electrically coupled to the circuit;
- a channel to provide a signal to a speaker, the signal including an alternating current (AC) component and direct current (DC) component, the DC component being approximately equal to a common mode voltage;
- and
- a return path for the microphone and the speaker, the return path including a second multiplexer to select the common mode voltage when the microphone and speaker are coupled to the circuit and to select a ground voltage when the microphone and speaker are not coupled to the circuit.
1 more element
A circuit comprising:
- a first multiplexer programmed to select a bias for a microphone based on whether a blocking capacitor is used wit a speaker;
- a channel to provide a signal to the speaker, the signal including an alternating current (AC) component and a direct current (DC) component that is approximately equal to a common mode voltage;
- and
- a return pat for the microphone and the speaker, the return path including a second multiplexer to select the common mode voltage when the blocking capacitor is not used in the channel and to select a ground voltage when the blocking capacitor is used in the channel, wherein the selected bias defines a voltage sufficient to properly bias the microphone when the blocking capacitor is used and the selected bias defines the voltage sufficient to properly bias the microphone plus the common mode voltage when the blocking capacitor is not used.
1 more element
A device comprising:
- a connector circuit to receive a microphone and one or more speakers, or a data interface;
- and
- a signal conditioning circuit comprising a first multiplexer to select a bias for the microphone when the microphone is coupled to the connector circuit, a channel to provide a signal to the speaker, the signal including an alternating current (AC) component and a direct current (DC) component, the DC component of the signal being approximately equal to a common mode voltage, and a return path for the microphone and the spear, the return path including a second multiplexer to select the common mode voltage when the microphone and speaker are coupled to the connector circuit and to select a ground voltage when the microphone and speaker are not coupled to the connector circuit.
A system comprising:
- a headset including a speaker and a microphone;
- a data interface;
- and
- a device including:
- a connector circuit to receive either the headset or the data interface, and
- a signal conditioning circuit comprising a first multiplexer to select a bias for a microphone when the headset is connected to the connector circuit, a channel to provide a signal to the speaker when the headset is connected to the connector circuit, the signal including an alternating current (AC) component and a direct current (DC) component, the DC component of the signal being approximately equal to a common mode voltage, and a return path, the return pat including a second multiplexer to select the common mode voltage when the headset is connected to the connector circuit and to select a ground voltage when the data interface is connected to the connector circuit, wherein the first multiplexer is programmable to select the bias from one of a plurality of biases based on whether or not the connector circuit includes a blocking capacitor for the channel.
3 more elements
A method comprising:
- identifying between a data mode and an audio mode in a device;
- selecting a ground voltage for a return path when the data mode is identified;
- selecting a common mode voltage for the return path when the audio mode is identified;
- and
- selecting a bias for a microphone when the audio mode is identified, the bias having a voltage value sufficient to bias the microphone plus the common mode voltage.
2 more elements
A circuit comprising:
- a microphone electrically coupled to an input amplifier through an input channel;
- a first speaker electrically coupled to a first output amplifier through a first output channel;
- a second speaker electrically coupled to a second output amplifier through a second output channel;
- a first multiplexer to select a bias for the microphone;
- and
- a second multiplexer to select a reference voltage for a return path of the microphone and first and second speakers.
3 more elements
A circuit comprising:
- a channel to provide a signal to a speaker, the signal including an alternating current (AC) component and a direct current (DC) component that is approximately equal to a common mode voltage;
- and
- a return path for the speaker, the return path including a multiplexer to select the common mode voltage when a blocking capacitor is used in the channel and to select a ground voltage when the blocking capacitor is not used in the channel, wherein the multiplexer selects the ground voltage when a data interface is coupled to the circuit and the speaker is not coupled to the circuit.
Dependencies are inferred from the claim text.