CHARGING SIGNAL DETECTION CIRCUIT AND CHARGING SIGNAL DETECTION METHOD

A charging signal detection circuit and a charging signal detection method. The charging signal detection circuit comprises a power supply (101), a constant-current source circuit (120), a voltage division circuit (130), a change-over switch (102), a microcontrol unit (103), and a vehicle ground wire (104); a positive electrode of the power supply (101) is connected to an input end of the constant-current source circuit (120) and an input end of the voltage division circuit (130), and an output end of the constant-current source circuit (120) is connected to a first change-over port of the change-over switch (102); an output end of the voltage division circuit (130) is connected to a second change-over port of the change-over switch (102), a fixed port of the change-over switch (102) is connected to a first end of the microcontrol unit (103), and a second end of the microcontrol unit (103) is connected to the vehicle ground wire (104); when an electric vehicle is charged, the fixed port of the change-over swi