GROUNDING CIRCUIT FOR ALTERNATE AUDIO PLUG DESIGNS

摘要

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.

主权项

1. An electronic device comprising:
an audio jack comprising a first contact and a second contact; audio circuitry comprising a microphone circuit; multiplexing circuitry to couple the microphone circuitry to the first contact or to the second contact; a first switch coupled between the first contact and ground; and a second switch coupled between the second contact and ground; wherein the first switch and the second switch are off when the electronic device is powered on and the audio circuit is active, and the first switch and the second switch are on when the electronic device is powered off.