Communications circuits for electronic devices and accessories
First Claim
Patent Images
1. An electronic device that supports communications with electronic equipment, comprising:
- an audio connector having four contacts including left channel and right channel audio contacts;
a first hybrid circuit having a common port coupled to the left channel audio contact and having a differential amplifier that receives a shared bias voltage;
a left channel audio output that transmits left channel analog audio signals through the first hybrid circuit;
a left channel microphone input that receives left channel microphone signals from the first hybrid circuit;
a second hybrid circuit having a common port coupled to the right channel audio contact and having a differential amplifier that receives the shared bias voltage;
a right channel audio output that transmits right channel analog audio signals through the second hybrid circuit;
a right channel microphone input that receives right channel microphone signals from the second hybrid circuit; and
a shared circuit that generates the shared bias voltage for the first and second hybrid circuits.
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Abstract
Hybrid circuits for electronic devices and accessories for electronic devices are provided. One or more pairs of hybrid circuits may convey audio signals, noise cancellation audio signals, microphone signals, control signals, and other signals between an electronic device and an accessory. The hybrid circuits may include a voltage controlled current source, a differential amplifier, separate signal and ground pins, multiple ground lines, an amplifier on a ground noise sense input line that can sense ground noise that may result from parasitic resistance, and other circuitry.
138 Citations
18 Claims
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1. An electronic device that supports communications with electronic equipment, comprising:
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an audio connector having four contacts including left channel and right channel audio contacts; a first hybrid circuit having a common port coupled to the left channel audio contact and having a differential amplifier that receives a shared bias voltage; a left channel audio output that transmits left channel analog audio signals through the first hybrid circuit; a left channel microphone input that receives left channel microphone signals from the first hybrid circuit; a second hybrid circuit having a common port coupled to the right channel audio contact and having a differential amplifier that receives the shared bias voltage; a right channel audio output that transmits right channel analog audio signals through the second hybrid circuit; a right channel microphone input that receives right channel microphone signals from the second hybrid circuit; and a shared circuit that generates the shared bias voltage for the first and second hybrid circuits. - View Dependent Claims (2, 3, 4, 5)
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6. An accessory comprising:
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an audio connector having a left channel audio contact, a right channel audio contact, a power contact, and a ground contact; at least one hybrid circuit having a common node coupled to one of the audio contacts in the audio connector; a wired path having a length between the audio connector and the hybrid circuit, wherein the length of the wired path between the audio connector and the hybrid circuit includes separate power ground and signal ground lines and wherein the power ground line and the signal ground line are both coupled to the ground contact in the audio connector; a summing resistor coupled between the common node and the signal ground line; and circuitry coupled to the power ground line. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. An electronic device that supports communications with electronic equipment, comprising:
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an audio connector having a left channel audio contact, a right channel audio contact, a power contact, and a ground contact; a first hybrid circuit having a common port coupled to the left channel audio contact; a second hybrid circuit having a common port coupled to the right channel audio contact; ground noise sensing circuitry including an amplifier that is coupled to the ground contact in the audio connector; and audio codec circuitry having a left channel audio output coupled to the first hybrid circuit, a right channel audio output coupled to the second hybrid circuit, and a ground noise input coupled to the ground noise sensing circuitry. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification