An N-channel metal oxide semiconductor, NMOS, switch driving circuit, applicable to a power supply device equipped with a first interface ( N 1) and a second interface ( N 2), the NMOS switch driving circuit comprising: a power-supply unit configured to output a first voltage; a switch unit electrically coupled between the power-supply unit and a load and configured to establish or disconnect an electrical coupling between the power-supply unit and the load, wherein the switch unit comprises at least one NMOS switch; a driving unit; a control unit electrically coupled to the driving unit and configured to output a driving signal to the driving unit; a power conversion unit, wherein the power conversion unit comprises a port coupled to the power-supply unit and another port electrically coupled to the switch unit via the driving unit, and the power conversion unit is configured to convert the first voltage into a constant driving voltage and output the constant driving voltage to the driving unit, and the driving unit is configured to output the constant driving voltage to the switch unit according to the driving signal to drive the switch unit to be switched on, to establish the electrical coupling between the power-supply unit and the load; a current detection unit electrically coupled between the power-supply unit and the load, and configured to detect an output current of the power-supply unit; wherein the control unit is electrically coupled to the current detection unit to collect a current signal detected by the current detection unit, characterised by the control unit being further configured to stop outputting a conversion signal for controlling the power conversion unit to work when the current signal collected by the control unit is greater than a preset threshold. a power-supply unit configured to output a first voltage; a switch unit electrically coupled between the power-supply unit and a load and configured to establish or disconnect an electrical coupling between the power-supply unit and the load, wherein the switch unit comprises at least one NMOS switch; a driving unit; a control unit electrically coupled to the driving unit and configured to output a driving signal to the driving unit; a power conversion unit, wherein the power conversion unit comprises a port coupled to the power-supply unit and another port electrically coupled to the switch unit via the driving unit, and the power conversion unit is configured to convert the first voltage into a constant driving voltage and output the constant driving voltage to the driving unit, and the driving unit is configured to output the constant driving voltage to the switch unit according to the driving signal to drive the switch unit to be switched on, to establish the electrical coupling between the power-supply unit and the load; a current detection unit electrically coupled between the power-supply unit and the load, and configured to detect an output current of the power-supply unit; wherein the control unit is electrically coupled to the current detection unit to collect a current signal detected by the current detection unit, characterised by the control unit being further configured to stop outputting a conversion signal for controlling the power conversion unit to work when the current signal collected by the control unit is greater than a preset threshold.