Patent ID: 7899946

Claim:
An analog/digital switching circuit for connecting a primary device to a peripheral device, the primary device comprising a primary USB connector, a power/audio manager and at least one primary listening device, and the peripheral device comprising a peripheral USB connector and at least one peripheral listening device comprising: first and second data signal lines connected to the power/audio manager, for transmitting respective first and second data signals; first and second audio signal lines for transmitting respective first and second audio signals generated by the power/audio manager to the at least one primary listening device or the at least one peripheral listening device; first and second primary USB signal lines connected to the primary USB connector, for transmitting respective first and second USB signals; first and second peripheral USB signal lines connected to the peripheral USB connector and to the respective first and second primary USB signal lines; a USB detection line connected to the power/audio manager, to the primary USB connector and to the peripheral USB connector, for detecting a USB charger attached to the primary USB connector or to the peripheral USB connector; a first switch for multiplexing the first USB signal to the first data signal or the first audio signal; a second switch for multiplexing the second USB signal to the second data signal or the second audio signal; and configuration detection circuitry for detecting, based on states of said first and second switches, each of the following configurations: (c1) primary device not connected to peripheral device, audio not to be output to a primary listening device, USB charger not connected to primary device; (c2) primary device not connected to peripheral device, audio is to be output to a primary listening device, USB charger not connected to primary device; (c3) primary device not connected to peripheral device, audio not to be output to a primary listening device, USB charger is connected to primary device; (c4) primary device not connected to peripheral device, audio is to be output to a primary listening device, USB charger is connected to primary device; (c5) primary device is connected to peripheral device, audio not to be output to a peripheral listening device, USB charger not connected to peripheral device; (c6) primary device is connected to peripheral device, audio is to be output to a peripheral listening device, USB charger not connected to peripheral device; (c7) primary device is connected to peripheral device, audio not to be output to a peripheral listening device, USB charger is connected to peripheral device; and (c8) primary device is connected to peripheral device, audio is to be output to a peripheral listening device, USB charger is connected to peripheral device.