Apple Inc.

Cara S Yang

David C Breece, Iii

Nathan Alan Johanningsmeier

Kavitha Srinivasan

Roderick Brian Hogan

Joseph C Curcio

Nathan A Johanningsmeir

Circuits, methods, and apparatus for grounding contacts in an audio jack. One example may provide a driver, such as a charge pump, driving a first transistor or switch coupled between a first contact in an audio jack and ground, and a second transistor or switch coupled between a second contact in the audio jack and ground. The first transistor or switch and second transistor or switch may be p-channel transistors or n-channel transistors depletion or enhancement-mode transistors, floating-gate transistors, MEMs, relays, or other switching devices. The first and second transistors or switches may be on and conducting when power is removed from the driver.

Grounding circuit for alternate audio plug designs

Circuits, methods, and apparatus for grounding contacts in an audio jack. One example may provide a driver, such as a charge pump, driving a first depletion mode transistor coupled between a first contact in an audio jack and ground, and a second depletion mode transistor coupled between a second contact in the audio jack and ground. The first depletion mode transistor and second depletion mode transistor may be p-channel transistors or n-channel transistors.

An audio source device has an audio connector to which an external load can be connected. An audio signal is amplified and then driven through the connector, wherein the amplification process uses feedback from the return pin of the connector. The return pin is directly connected to a ground break resistor circuit. The ground break resistor circuit is connected between the return pin of the audio connector and circuit ground. A determination is made as to whether the connected external load has a low impedance or a high impedance. When a low impedance load is detected, such as a headset, the ground break resistor circuit is essentially short-circuited. When a high impedance load is detected, the ground break resistor circuit is maintained and its value is set in accordance with the detected load. Other embodiments are also described.

Increasing ground noise rejection in audio systems

An electronic audio system that determines matching and non-matching speakers is disclosed. The electronic audio system includes a first speaker; a second speaker; and a comparator circuit. The comparator circuit is coupled to the first speaker and the second speaker to receive an input signal from both the first and second speaker. The comparator circuit is configured to determine if the first speaker and the second speaker are matching speakers or non-matching speakers, in which, the first and second speakers are matching speakers if they are common vendor speakers. Other embodiments are also described and claimed.

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Mountain View, CA, United States of America

Cara S Yang