Charging system

A charging system, comprising a charging adapter and a mobile terminal, wherein,

• the charging adapter comprises:
• a second USB interface, having P second power wires, Q second ground wires and N second data wires, wherein P is greater than or equal to 2, Q is greater than or equal to 2, and N is greater than or equal to 1;
• and
• an adjusting circuit, having a power terminal, a power signal output terminal and a ground signal output terminal, the power terminal being coupled to an external mains supply, the power signal output terminal being coupled to each of the P second power wires, the ground signal output terminal being coupled to each of the Q second ground wires, and the adjusting circuit being configured to perform a rectifying and a filtering on the mains supply to obtain an original power signal, to perform a voltage adjustment on the original power signal and to output a power signal after the voltage adjustment via the power signal output terminal,
• the mobile terminal comprises:
• a first USB interface, having P first power wires, Q first ground wires and N first data wires, the P first power wires of the first USB interface being insertion-connected with the P second power wires of the second USB interface correspondingly, the Q first ground wires of the first USB interface being insertion-connected with the Q second ground wires of the second USB interface correspondingly, and the N first data wires of the first USB interface being insertion-connected with the N second data wires of the second USB interface correspondingly,
• the mobile terminal further comprises:
• a first controller, having a sample terminal and a first data terminal, the first data terminal being coupled to one or more first data wires of the first USB interface, and the first controller being configured to receive a voltage value of a cell output by a cell connector via the sample terminal and to send the voltage value of the cell via the first data terminal;
• and
• a switch circuit, having a cell terminal, a charging terminal, a first controlled terminal and a second controlled terminal, the cell terminal being coupled to an anode of the cell, the charging terminal being coupled to the first power wires of the first USB interface, the first controlled terminal being coupled to a first control terminal of the first controller, the second controlled terminal being coupled to a second control terminal of the first controller, and the switch circuit being configured to couple the charging terminal with the cell terminal when receiving via the first controlled terminal a coupling instruction sent by the first controller, such that the charging adapter charges the cell;
• and to switch off a coupling between the charging terminal and the cell terminal when receiving via the second controlled terminal a first switch-off instruction sent by the first controller, such that the charging adapter stops charging the cell,
• the switch circuit comprises a second capacitor, a third capacitor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first Schottky diode, a second Schottky diode, a third Schottky diode, a NPN triode and a switch module;
• a first terminal of the second resistor, a second terminal of the switch module, a first terminal of the second capacitor and a second terminal of the second resistor are configured as the cell terminal, the charging terminal, the first controlled terminal and the second controlled terminal of the switch circuit respectively, a first terminal and a second terminal of the third resistor are coupled to the second terminal of the second resistor and a base electrode of the NPN triode respectively, an anode and a cathode of the third Schottky diode are coupled to an emitter electrode of the NPN triode and ground respectively, an anode and a cathode of the first Schottky diode are coupled to the first terminal of the second resistor and a second terminal of the second capacitor respectively, an anode and a second cathode of the second Schottky diode are coupled to the second terminal of the second capacitor and a first terminal of the fourth resistor respectively, a first terminal and a second terminal of the third capacitor are coupled to the cathode of the first Schottky diode and ground respectively, a first terminal and a second terminal of the fifth resistor are coupled to a second terminal of the fourth resistor and ground respectively, a collector electrode of the NPN triode is coupled to the second terminal of the fourth resistor, and a first terminal and a controlled terminal of the switch module are coupled to the first terminal of the second resistor and the second terminal of the fourth resistor respectively.