MULTIPLEXING CIRCUIT, INTERFACE CIRCUIT SYSTEM AND MOBILE TERMINAL

Embodiments of this application relate to the field of electronic and communications technologies, and provide a multiplexing circuit, an interface circuit system, and a mobile terminal, to resolve a problem that a charging current significantly decreases when a headset is used during charging of the mobile terminal, compared with a case in which the mobile terminal is charged independently. In a multiplexing circuit, a first switch circuit transmits a right-channel audio signal on a right-channel transmission end to a first external transmission end; a second switch circuit transmits a left-channel audio signal on a left-channel transmission end to a second external transmission end; when a second on voltage is received, but a first on voltage is not received, an isolation circuit transmits the second on voltage to a third switch circuit; and when the first on voltage and the second on voltage are received, the isolation circuit pulls down the third switch circuit, and isolates a ground end from a second on voltage end; and the third switch circuit controls connection between the first external transmission end and a first internal transmission end, and controls connection between the second external transmission end and a second internal transmission end.